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2017-08-03mm: take memory hotplug lock within numa_zonelist_order_handler()Heiko Carstens1-0/+2
Andre Wild reported the following warning: WARNING: CPU: 2 PID: 1205 at kernel/cpu.c:240 lockdep_assert_cpus_held+0x4c/0x60 Modules linked in: CPU: 2 PID: 1205 Comm: bash Not tainted 4.13.0-rc2-00022-gfd2b2c57ec20 #10 Hardware name: IBM 2964 N96 702 (z/VM 6.4.0) task: 00000000701d8100 task.stack: 0000000073594000 Krnl PSW : 0704f00180000000 0000000000145e24 (lockdep_assert_cpus_held+0x4c/0x60) ... Call Trace: lockdep_assert_cpus_held+0x42/0x60) stop_machine_cpuslocked+0x62/0xf0 build_all_zonelists+0x92/0x150 numa_zonelist_order_handler+0x102/0x150 proc_sys_call_handler.isra.12+0xda/0x118 proc_sys_write+0x34/0x48 __vfs_write+0x3c/0x178 vfs_write+0xbc/0x1a0 SyS_write+0x66/0xc0 system_call+0xc4/0x2b0 locks held by bash/1205: #0: (sb_writers#4){.+.+.+}, at: vfs_write+0xa6/0x1a0 #1: (zl_order_mutex){+.+...}, at: numa_zonelist_order_handler+0x44/0x150 #2: (zonelists_mutex){+.+...}, at: numa_zonelist_order_handler+0xf4/0x150 Last Breaking-Event-Address: lockdep_assert_cpus_held+0x48/0x60 This can be easily triggered with e.g. echo n > /proc/sys/vm/numa_zonelist_order In commit 3f906ba23689a ("mm/memory-hotplug: switch locking to a percpu rwsem") memory hotplug locking was changed to fix a potential deadlock. This also switched the stop_machine() invocation within build_all_zonelists() to stop_machine_cpuslocked() which now expects that online cpus are locked when being called. This assumption is not true if build_all_zonelists() is being called from numa_zonelist_order_handler(). In order to fix this simply add a mem_hotplug_begin()/mem_hotplug_done() pair to numa_zonelist_order_handler(). Link: http://lkml.kernel.org/r/20170726111738.38768-1-heiko.carstens@de.ibm.com Fixes: 3f906ba23689a ("mm/memory-hotplug: switch locking to a percpu rwsem") Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Reported-by: Andre Wild <wild@linux.vnet.ibm.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-08-03mm/page_io.c: fix oops during block io poll in swapin pathTetsuo Handa1-0/+7
When a thread is OOM-killed during swap_readpage() operation, an oops occurs because end_swap_bio_read() is calling wake_up_process() based on an assumption that the thread which called swap_readpage() is still alive. Out of memory: Kill process 525 (polkitd) score 0 or sacrifice child Killed process 525 (polkitd) total-vm:528128kB, anon-rss:0kB, file-rss:4kB, shmem-rss:0kB oom_reaper: reaped process 525 (polkitd), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC Modules linked in: nf_conntrack_netbios_ns nf_conntrack_broadcast ip6t_rpfilter ipt_REJECT nf_reject_ipv4 ip6t_REJECT nf_reject_ipv6 xt_conntrack ip_set nfnetlink ebtable_nat ebtable_broute bridge stp llc ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 ip6table_mangle ip6table_raw iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle iptable_raw ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter coretemp ppdev pcspkr vmw_balloon sg shpchp vmw_vmci parport_pc parport i2c_piix4 ip_tables xfs libcrc32c sd_mod sr_mod cdrom ata_generic pata_acpi vmwgfx ahci libahci drm_kms_helper ata_piix syscopyarea sysfillrect sysimgblt fb_sys_fops mptspi scsi_transport_spi ttm e1000 mptscsih drm mptbase i2c_core libata serio_raw CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.13.0-rc2-next-20170725 #129 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 07/31/2013 task: ffffffffb7c16500 task.stack: ffffffffb7c00000 RIP: 0010:__lock_acquire+0x151/0x12f0 Call Trace: <IRQ> lock_acquire+0x59/0x80 _raw_spin_lock_irqsave+0x3b/0x4f try_to_wake_up+0x3b/0x410 wake_up_process+0x10/0x20 end_swap_bio_read+0x6f/0xf0 bio_endio+0x92/0xb0 blk_update_request+0x88/0x270 scsi_end_request+0x32/0x1c0 scsi_io_completion+0x209/0x680 scsi_finish_command+0xd4/0x120 scsi_softirq_done+0x120/0x140 __blk_mq_complete_request_remote+0xe/0x10 flush_smp_call_function_queue+0x51/0x120 generic_smp_call_function_single_interrupt+0xe/0x20 smp_trace_call_function_single_interrupt+0x22/0x30 smp_call_function_single_interrupt+0x9/0x10 call_function_single_interrupt+0xa7/0xb0 </IRQ> RIP: 0010:native_safe_halt+0x6/0x10 default_idle+0xe/0x20 arch_cpu_idle+0xa/0x10 default_idle_call+0x1e/0x30 do_idle+0x187/0x200 cpu_startup_entry+0x6e/0x70 rest_init+0xd0/0xe0 start_kernel+0x456/0x477 x86_64_start_reservations+0x24/0x26 x86_64_start_kernel+0xf7/0x11a secondary_startup_64+0xa5/0xa5 Code: c3 49 81 3f 20 9e 0b b8 41 bc 00 00 00 00 44 0f 45 e2 83 fe 01 0f 87 62 ff ff ff 89 f0 49 8b 44 c7 08 48 85 c0 0f 84 52 ff ff ff <f0> ff 80 98 01 00 00 8b 3d 5a 49 c4 01 45 8b b3 18 0c 00 00 85 RIP: __lock_acquire+0x151/0x12f0 RSP: ffffa01f39e03c50 ---[ end trace 6c441db499169b1e ]--- Kernel panic - not syncing: Fatal exception in interrupt Kernel Offset: 0x36000000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) ---[ end Kernel panic - not syncing: Fatal exception in interrupt Fix it by holding a reference to the thread. [akpm@linux-foundation.org: add comment] Fixes: 23955622ff8d231b ("swap: add block io poll in swapin path") Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by: Shaohua Li <shli@fb.com> Cc: Tim Chen <tim.c.chen@intel.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Jens Axboe <axboe@fb.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-08-03zram: do not free pool->size_classMinchan Kim1-1/+0
Mike reported kernel goes oops with ltp:zram03 testcase. zram: Added device: zram0 zram0: detected capacity change from 0 to 107374182400 BUG: unable to handle kernel paging request at 0000306d61727a77 IP: zs_map_object+0xb9/0x260 PGD 0 P4D 0 Oops: 0000 [#1] SMP Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: zram(E) xfs(E) libcrc32c(E) btrfs(E) xor(E) raid6_pq(E) loop(E) ebtable_filter(E) ebtables(E) ip6table_filter(E) ip6_tables(E) iptable_filter(E) ip_tables(E) x_tables(E) af_packet(E) br_netfilter(E) bridge(E) stp(E) llc(E) iscsi_ibft(E) iscsi_boot_sysfs(E) nls_iso8859_1(E) nls_cp437(E) vfat(E) fat(E) intel_powerclamp(E) coretemp(E) cdc_ether(E) kvm_intel(E) usbnet(E) mii(E) kvm(E) irqbypass(E) crct10dif_pclmul(E) crc32_pclmul(E) crc32c_intel(E) iTCO_wdt(E) ghash_clmulni_intel(E) bnx2(E) iTCO_vendor_support(E) pcbc(E) ioatdma(E) ipmi_ssif(E) aesni_intel(E) i5500_temp(E) i2c_i801(E) aes_x86_64(E) lpc_ich(E) shpchp(E) mfd_core(E) crypto_simd(E) i7core_edac(E) dca(E) glue_helper(E) cryptd(E) ipmi_si(E) button(E) acpi_cpufreq(E) ipmi_devintf(E) pcspkr(E) ipmi_msghandler(E) nfsd(E) auth_rpcgss(E) nfs_acl(E) lockd(E) grace(E) sunrpc(E) ext4(E) crc16(E) mbcache(E) jbd2(E) sd_mod(E) ata_generic(E) i2c_algo_bit(E) ata_piix(E) drm_kms_helper(E) ahci(E) syscopyarea(E) sysfillrect(E) libahci(E) sysimgblt(E) fb_sys_fops(E) uhci_hcd(E) ehci_pci(E) ttm(E) ehci_hcd(E) libata(E) drm(E) megaraid_sas(E) usbcore(E) sg(E) dm_multipath(E) dm_mod(E) scsi_dh_rdac(E) scsi_dh_emc(E) scsi_dh_alua(E) scsi_mod(E) efivarfs(E) autofs4(E) [last unloaded: zram] CPU: 6 PID: 12356 Comm: swapon Tainted: G E 4.13.0.g87b2c3f-default #194 Hardware name: IBM System x3550 M3 -[7944K3G]-/69Y5698 , BIOS -[D6E150AUS-1.10]- 12/15/2010 task: ffff880158d2c4c0 task.stack: ffffc90001680000 RIP: 0010:zs_map_object+0xb9/0x260 Call Trace: zram_bvec_rw.isra.26+0xe8/0x780 [zram] zram_rw_page+0x6e/0xa0 [zram] bdev_read_page+0x81/0xb0 do_mpage_readpage+0x51a/0x710 mpage_readpages+0x122/0x1a0 blkdev_readpages+0x1d/0x20 __do_page_cache_readahead+0x1b2/0x270 ondemand_readahead+0x180/0x2c0 page_cache_sync_readahead+0x31/0x50 generic_file_read_iter+0x7e7/0xaf0 blkdev_read_iter+0x37/0x40 __vfs_read+0xce/0x140 vfs_read+0x9e/0x150 SyS_read+0x46/0xa0 entry_SYSCALL_64_fastpath+0x1a/0xa5 Code: 81 e6 00 c0 3f 00 81 fe 00 00 16 00 0f 85 9f 01 00 00 0f b7 13 65 ff 05 5e 07 dc 7e 66 c1 ea 02 81 e2 ff 01 00 00 49 8b 54 d4 08 <8b> 4a 48 41 0f af ce 81 e1 ff 0f 00 00 41 89 c9 48 c7 c3 a0 70 RIP: zs_map_object+0xb9/0x260 RSP: ffffc90001683988 CR2: 0000306d61727a77 He bisected the problem is [1]. After commit cf8e0fedf078 ("mm/zsmalloc: simplify zs_max_alloc_size handling"), zram doesn't use double pointer for pool->size_class any more in zs_create_pool so counter function zs_destroy_pool don't need to free it, either. Otherwise, it does kfree wrong address and then, kernel goes Oops. Link: http://lkml.kernel.org/r/20170725062650.GA12134@bbox Fixes: cf8e0fedf078 ("mm/zsmalloc: simplify zs_max_alloc_size handling") Signed-off-by: Minchan Kim <minchan@kernel.org> Reported-by: Mike Galbraith <efault@gmx.de> Tested-by: Mike Galbraith <efault@gmx.de> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-08-03kasan: avoid -Wmaybe-uninitialized warningArnd Bergmann1-0/+1
gcc-7 produces this warning: mm/kasan/report.c: In function 'kasan_report': mm/kasan/report.c:351:3: error: 'info.first_bad_addr' may be used uninitialized in this function [-Werror=maybe-uninitialized] print_shadow_for_address(info->first_bad_addr); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ mm/kasan/report.c:360:27: note: 'info.first_bad_addr' was declared here The code seems fine as we only print info.first_bad_addr when there is a shadow, and we always initialize it in that case, but this is relatively hard for gcc to figure out after the latest rework. Adding an intialization to the most likely value together with the other struct members shuts up that warning. Fixes: b235b9808664 ("kasan: unify report headers") Link: https://patchwork.kernel.org/patch/9641417/ Link: http://lkml.kernel.org/r/20170725152739.4176967-1-arnd@arndb.de Signed-off-by: Arnd Bergmann <arnd@arndb.de> Suggested-by: Alexander Potapenko <glider@google.com> Suggested-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-08-03userfaultfd: non-cooperative: notify about unmap of destination during mremapMike Rapoport1-2/+5
When mremap is called with MREMAP_FIXED it unmaps memory at the destination address without notifying userfaultfd monitor. If the destination were registered with userfaultfd, the monitor has no way to distinguish between the old and new ranges and to properly relate the page faults that would occur in the destination region. Fixes: 897ab3e0c49e ("userfaultfd: non-cooperative: add event for memory unmaps") Link: http://lkml.kernel.org/r/1500276876-3350-1-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Acked-by: Pavel Emelyanov <xemul@virtuozzo.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-08-03mm, mprotect: flush TLB if potentially racing with a parallel reclaim ↵Mel Gorman6-1/+44
leaving stale TLB entries Nadav Amit identified a theoritical race between page reclaim and mprotect due to TLB flushes being batched outside of the PTL being held. He described the race as follows: CPU0 CPU1 ---- ---- user accesses memory using RW PTE [PTE now cached in TLB] try_to_unmap_one() ==> ptep_get_and_clear() ==> set_tlb_ubc_flush_pending() mprotect(addr, PROT_READ) ==> change_pte_range() ==> [ PTE non-present - no flush ] user writes using cached RW PTE ... try_to_unmap_flush() The same type of race exists for reads when protecting for PROT_NONE and also exists for operations that can leave an old TLB entry behind such as munmap, mremap and madvise. For some operations like mprotect, it's not necessarily a data integrity issue but it is a correctness issue as there is a window where an mprotect that limits access still allows access. For munmap, it's potentially a data integrity issue although the race is massive as an munmap, mmap and return to userspace must all complete between the window when reclaim drops the PTL and flushes the TLB. However, it's theoritically possible so handle this issue by flushing the mm if reclaim is potentially currently batching TLB flushes. Other instances where a flush is required for a present pte should be ok as either the page lock is held preventing parallel reclaim or a page reference count is elevated preventing a parallel free leading to corruption. In the case of page_mkclean there isn't an obvious path that userspace could take advantage of without using the operations that are guarded by this patch. Other users such as gup as a race with reclaim looks just at PTEs. huge page variants should be ok as they don't race with reclaim. mincore only looks at PTEs. userfault also should be ok as if a parallel reclaim takes place, it will either fault the page back in or read some of the data before the flush occurs triggering a fault. Note that a variant of this patch was acked by Andy Lutomirski but this was for the x86 parts on top of his PCID work which didn't make the 4.13 merge window as expected. His ack is dropped from this version and there will be a follow-on patch on top of PCID that will include his ack. [akpm@linux-foundation.org: tweak comments] [akpm@linux-foundation.org: fix spello] Link: http://lkml.kernel.org/r/20170717155523.emckq2esjro6hf3z@suse.de Reported-by: Nadav Amit <nadav.amit@gmail.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: <stable@vger.kernel.org> [v4.4+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-08-03mm/hugetlb.c: __get_user_pages ignores certain follow_hugetlb_page errorsDaniel Jordan1-6/+3
Commit 9a291a7c9428 ("mm/hugetlb: report -EHWPOISON not -EFAULT when FOLL_HWPOISON is specified") causes __get_user_pages to ignore certain errors from follow_hugetlb_page. After such error, __get_user_pages subsequently calls faultin_page on the same VMA and start address that follow_hugetlb_page failed on instead of returning the error immediately as it should. In follow_hugetlb_page, when hugetlb_fault returns a value covered under VM_FAULT_ERROR, follow_hugetlb_page returns it without setting nr_pages to 0 as __get_user_pages expects in this case, which causes the following to happen in __get_user_pages: the "while (nr_pages)" check succeeds, we skip the "if (!vma..." check because we got a VMA the last time around, we find no page with follow_page_mask, and we call faultin_page, which calls hugetlb_fault for the second time. This issue also slightly changes how __get_user_pages works. Before, it only returned error if it had made no progress (i = 0). But now, follow_hugetlb_page can clobber "i" with an error code since its new return path doesn't check for progress. So if "i" is nonzero before a failing call to follow_hugetlb_page, that indication of progress is lost and __get_user_pages can return error even if some pages were successfully pinned. To fix this, change follow_hugetlb_page so that it updates nr_pages, allowing __get_user_pages to fail immediately and restoring the "error only if no progress" behavior to __get_user_pages. Tested that __get_user_pages returns when expected on error from hugetlb_fault in follow_hugetlb_page. Fixes: 9a291a7c9428 ("mm/hugetlb: report -EHWPOISON not -EFAULT when FOLL_HWPOISON is specified") Link: http://lkml.kernel.org/r/1500406795-58462-1-git-send-email-daniel.m.jordan@oracle.com Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com> Acked-by: Punit Agrawal <punit.agrawal@arm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com> Cc: James Morse <james.morse@arm.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: zhong jiang <zhongjiang@huawei.com> Cc: <stable@vger.kernel.org> [4.12.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-15Merge branch 'work.mount' of ↵Linus Torvalds1-0/+24
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull ->s_options removal from Al Viro: "Preparations for fsmount/fsopen stuff (coming next cycle). Everything gets moved to explicit ->show_options(), killing ->s_options off + some cosmetic bits around fs/namespace.c and friends. Basically, the stuff needed to work with fsmount series with minimum of conflicts with other work. It's not strictly required for this merge window, but it would reduce the PITA during the coming cycle, so it would be nice to have those bits and pieces out of the way" * 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: isofs: Fix isofs_show_options() VFS: Kill off s_options and helpers orangefs: Implement show_options 9p: Implement show_options isofs: Implement show_options afs: Implement show_options affs: Implement show_options befs: Implement show_options spufs: Implement show_options bpf: Implement show_options ramfs: Implement show_options pstore: Implement show_options omfs: Implement show_options hugetlbfs: Implement show_options VFS: Don't use save/replace_mount_options if not using generic_show_options VFS: Provide empty name qstr VFS: Make get_filesystem() return the affected filesystem VFS: Clean up whitespace in fs/namespace.c and fs/super.c Provide a function to create a NUL-terminated string from unterminated data
2017-07-15mm: fix overflow check in expand_upwards()Helge Deller1-1/+1
Jörn Engel noticed that the expand_upwards() function might not return -ENOMEM in case the requested address is (unsigned long)-PAGE_SIZE and if the architecture didn't defined TASK_SIZE as multiple of PAGE_SIZE. Affected architectures are arm, frv, m68k, blackfin, h8300 and xtensa which all define TASK_SIZE as 0xffffffff, but since none of those have an upwards-growing stack we currently have no actual issue. Nevertheless let's fix this just in case any of the architectures with an upward-growing stack (currently parisc, metag and partly ia64) define TASK_SIZE similar. Link: http://lkml.kernel.org/r/20170702192452.GA11868@p100.box Fixes: bd726c90b6b8 ("Allow stack to grow up to address space limit") Signed-off-by: Helge Deller <deller@gmx.de> Reported-by: Jörn Engel <joern@purestorage.com> Cc: Hugh Dickins <hughd@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-13writeback: rework wb_[dec|inc]_stat family of functionsNikolay Borisov1-5/+5
Currently the writeback statistics code uses a percpu counters to hold various statistics. Furthermore we have 2 families of functions - those which disable local irq and those which doesn't and whose names begin with double underscore. However, they both end up calling __add_wb_stats which in turn calls percpu_counter_add_batch which is already irq-safe. Exploiting this fact allows to eliminated the __wb_* functions since they don't add any further protection than we already have. Furthermore, refactor the wb_* function to call __add_wb_stat directly without the irq-disabling dance. This will likely result in better runtime of code which deals with modifying the stat counters. While at it also document why percpu_counter_add_batch is in fact preempt and irq-safe since at least 3 people got confused. Link: http://lkml.kernel.org/r/1498029937-27293-1-git-send-email-nborisov@suse.com Signed-off-by: Nikolay Borisov <nborisov@suse.com> Acked-by: Tejun Heo <tj@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Josef Bacik <jbacik@fb.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jeff Layton <jlayton@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-13mm, migration: do not trigger OOM killer when migrating memoryMichal Hocko1-1/+2
Page migration (for memory hotplug, soft_offline_page or mbind) needs to allocate a new memory. This can trigger an oom killer if the target memory is depleated. Although quite unlikely, still possible, especially for the memory hotplug (offlining of memoery). Up to now we didn't really have reasonable means to back off. __GFP_NORETRY can fail just too easily and __GFP_THISNODE sticks to a single node and that is not suitable for all callers. But now that we have __GFP_RETRY_MAYFAIL we should use it. It is preferable to fail the migration than disrupt the system by killing some processes. Link: http://lkml.kernel.org/r/20170623085345.11304-7-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Alex Belits <alex.belits@cavium.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: David Daney <david.daney@cavium.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@suse.de> Cc: NeilBrown <neilb@suse.com> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-13mm: kvmalloc support __GFP_RETRY_MAYFAIL for all sizesMichal Hocko1-10/+4
Now that __GFP_RETRY_MAYFAIL has a reasonable semantic regardless of the request size we can drop the hackish implementation for !costly orders. __GFP_RETRY_MAYFAIL retries as long as the reclaim makes a forward progress and backs of when we are out of memory for the requested size. Therefore we do not need to enforce__GFP_NORETRY for !costly orders just to silent the oom killer anymore. Link: http://lkml.kernel.org/r/20170623085345.11304-5-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Alex Belits <alex.belits@cavium.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: David Daney <david.daney@cavium.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@suse.de> Cc: NeilBrown <neilb@suse.com> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-13mm, tree wide: replace __GFP_REPEAT by __GFP_RETRY_MAYFAIL with more useful ↵Michal Hocko7-16/+24
semantic __GFP_REPEAT was designed to allow retry-but-eventually-fail semantic to the page allocator. This has been true but only for allocations requests larger than PAGE_ALLOC_COSTLY_ORDER. It has been always ignored for smaller sizes. This is a bit unfortunate because there is no way to express the same semantic for those requests and they are considered too important to fail so they might end up looping in the page allocator for ever, similarly to GFP_NOFAIL requests. Now that the whole tree has been cleaned up and accidental or misled usage of __GFP_REPEAT flag has been removed for !costly requests we can give the original flag a better name and more importantly a more useful semantic. Let's rename it to __GFP_RETRY_MAYFAIL which tells the user that the allocator would try really hard but there is no promise of a success. This will work independent of the order and overrides the default allocator behavior. Page allocator users have several levels of guarantee vs. cost options (take GFP_KERNEL as an example) - GFP_KERNEL & ~__GFP_RECLAIM - optimistic allocation without _any_ attempt to free memory at all. The most light weight mode which even doesn't kick the background reclaim. Should be used carefully because it might deplete the memory and the next user might hit the more aggressive reclaim - GFP_KERNEL & ~__GFP_DIRECT_RECLAIM (or GFP_NOWAIT)- optimistic allocation without any attempt to free memory from the current context but can wake kswapd to reclaim memory if the zone is below the low watermark. Can be used from either atomic contexts or when the request is a performance optimization and there is another fallback for a slow path. - (GFP_KERNEL|__GFP_HIGH) & ~__GFP_DIRECT_RECLAIM (aka GFP_ATOMIC) - non sleeping allocation with an expensive fallback so it can access some portion of memory reserves. Usually used from interrupt/bh context with an expensive slow path fallback. - GFP_KERNEL - both background and direct reclaim are allowed and the _default_ page allocator behavior is used. That means that !costly allocation requests are basically nofail but there is no guarantee of that behavior so failures have to be checked properly by callers (e.g. OOM killer victim is allowed to fail currently). - GFP_KERNEL | __GFP_NORETRY - overrides the default allocator behavior and all allocation requests fail early rather than cause disruptive reclaim (one round of reclaim in this implementation). The OOM killer is not invoked. - GFP_KERNEL | __GFP_RETRY_MAYFAIL - overrides the default allocator behavior and all allocation requests try really hard. The request will fail if the reclaim cannot make any progress. The OOM killer won't be triggered. - GFP_KERNEL | __GFP_NOFAIL - overrides the default allocator behavior and all allocation requests will loop endlessly until they succeed. This might be really dangerous especially for larger orders. Existing users of __GFP_REPEAT are changed to __GFP_RETRY_MAYFAIL because they already had their semantic. No new users are added. __alloc_pages_slowpath is changed to bail out for __GFP_RETRY_MAYFAIL if there is no progress and we have already passed the OOM point. This means that all the reclaim opportunities have been exhausted except the most disruptive one (the OOM killer) and a user defined fallback behavior is more sensible than keep retrying in the page allocator. [akpm@linux-foundation.org: fix arch/sparc/kernel/mdesc.c] [mhocko@suse.com: semantic fix] Link: http://lkml.kernel.org/r/20170626123847.GM11534@dhcp22.suse.cz [mhocko@kernel.org: address other thing spotted by Vlastimil] Link: http://lkml.kernel.org/r/20170626124233.GN11534@dhcp22.suse.cz Link: http://lkml.kernel.org/r/20170623085345.11304-3-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Alex Belits <alex.belits@cavium.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Christoph Hellwig <hch@infradead.org> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: David Daney <david.daney@cavium.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@suse.de> Cc: NeilBrown <neilb@suse.com> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-13mm/memory.c: mark create_huge_pmd() inline to prevent build failureGeert Uytterhoeven1-1/+1
With gcc 4.1.2: mm/memory.o: In function `create_huge_pmd': memory.c:(.text+0x93e): undefined reference to `do_huge_pmd_anonymous_page' Interestingly, create_huge_pmd() is emitted in the assembler output, but never called. Converting transparent_hugepage_enabled() from a macro to a static inline function reduced the ability of the compiler to remove unused code. Fix this by marking create_huge_pmd() inline. Fixes: 16981d763501c0e0 ("mm: improve readability of transparent_hugepage_enabled()") Link: http://lkml.kernel.org/r/1499842660-10665-1-git-send-email-geert@linux-m68k.org Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11kasan: make get_wild_bug_type() staticColin Ian King1-1/+1
The helper function get_wild_bug_type() does not need to be in global scope, so make it static. Cleans up sparse warning: "symbol 'get_wild_bug_type' was not declared. Should it be static?" Link: http://lkml.kernel.org/r/20170622090049.10658-1-colin.king@canonical.com Signed-off-by: Colin Ian King <colin.king@canonical.com> Acked-by: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm/kasan/kasan.c: rename XXX_is_zero to XXX_is_nonzeroJoonsoo Kim1-7/+7
They return positive value, that is, true, if non-zero value is found. Rename them to reduce confusion. Link: http://lkml.kernel.org/r/20170516012350.GA16015@js1304-desktop Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm/kasan: add support for memory hotplugAndrey Ryabinin2-6/+35
KASAN doesn't happen work with memory hotplug because hotplugged memory doesn't have any shadow memory. So any access to hotplugged memory would cause a crash on shadow check. Use memory hotplug notifier to allocate and map shadow memory when the hotplugged memory is going online and free shadow after the memory offlined. Link: http://lkml.kernel.org/r/20170601162338.23540-4-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Alexander Potapenko <glider@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Ingo Molnar <mingo@redhat.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm/kasan: get rid of speculative shadow checksAndrey Ryabinin1-82/+16
For some unaligned memory accesses we have to check additional byte of the shadow memory. Currently we load that byte speculatively to have only single load + branch on the optimistic fast path. However, this approach has some downsides: - It's unaligned access, so this prevents porting KASAN on architectures which doesn't support unaligned accesses. - We have to map additional shadow page to prevent crash if speculative load happens near the end of the mapped memory. This would significantly complicate upcoming memory hotplug support. I wasn't able to notice any performance degradation with this patch. So these speculative loads is just a pain with no gain, let's remove them. Link: http://lkml.kernel.org/r/20170601162338.23540-1-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Acked-by: Dmitry Vyukov <dvyukov@google.com> Cc: Alexander Potapenko <glider@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm/kasan/kasan_init.c: use kasan_zero_pud for p4d tableJoonsoo Kim1-0/+12
There is missing optimization in zero_p4d_populate() that can save some memory when mapping zero shadow. Implement it like as others. Link: http://lkml.kernel.org/r/1494829255-23946-1-git-send-email-iamjoonsoo.kim@lge.com Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm/zsmalloc: simplify zs_max_alloc_size handlingJerome Marchand1-37/+15
Commit 40f9fb8cffc6 ("mm/zsmalloc: support allocating obj with size of ZS_MAX_ALLOC_SIZE") fixes a size calculation error that prevented zsmalloc to allocate an object of the maximal size (ZS_MAX_ALLOC_SIZE). I think however the fix is unneededly complicated. This patch replaces the dynamic calculation of zs_size_classes at init time by a compile time calculation that uses the DIV_ROUND_UP() macro already used in get_size_class_index(). [akpm@linux-foundation.org: use min_t] Link: http://lkml.kernel.org/r/20170630114859.1979-1-jmarchan@redhat.com Signed-off-by: Jerome Marchand <jmarchan@redhat.com> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: Mahendran Ganesh <opensource.ganesh@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm/memory-hotplug: switch locking to a percpu rwsemThomas Gleixner2-75/+16
Andrey reported a potential deadlock with the memory hotplug lock and the cpu hotplug lock. The reason is that memory hotplug takes the memory hotplug lock and then calls stop_machine() which calls get_online_cpus(). That's the reverse lock order to get_online_cpus(); get_online_mems(); in mm/slub_common.c The problem has been there forever. The reason why this was never reported is that the cpu hotplug locking had this homebrewn recursive reader writer semaphore construct which due to the recursion evaded the full lock dep coverage. The memory hotplug code copied that construct verbatim and therefor has similar issues. Three steps to fix this: 1) Convert the memory hotplug locking to a per cpu rwsem so the potential issues get reported proper by lockdep. 2) Lock the online cpus in mem_hotplug_begin() before taking the memory hotplug rwsem and use stop_machine_cpuslocked() in the page_alloc code to avoid recursive locking. 3) The cpu hotpluck locking in #2 causes a recursive locking of the cpu hotplug lock via __offline_pages() -> lru_add_drain_all(). Solve this by invoking lru_add_drain_all_cpuslocked() instead. Link: http://lkml.kernel.org/r/20170704093421.506836322@linutronix.de Reported-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Davidlohr Bueso <dave@stgolabs.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm: swap: provide lru_add_drain_all_cpuslocked()Thomas Gleixner1-3/+8
The rework of the cpu hotplug locking unearthed potential deadlocks with the memory hotplug locking code. The solution for these is to rework the memory hotplug locking code as well and take the cpu hotplug lock before the memory hotplug lock in mem_hotplug_begin(), but this will cause a recursive locking of the cpu hotplug lock when the memory hotplug code calls lru_add_drain_all(). Split out the inner workings of lru_add_drain_all() into lru_add_drain_all_cpuslocked() so this function can be invoked from the memory hotplug code with the cpu hotplug lock held. Link: http://lkml.kernel.org/r/20170704093421.419329357@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reported-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Davidlohr Bueso <dave@stgolabs.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm: use dedicated helper to access rlimit valueKrzysztof Opasiak1-3/+2
Use rlimit() helper instead of manually writing whole chain from current task to rlim_cur. Link: http://lkml.kernel.org/r/20170705172811.8027-1-k.opasiak@samsung.com Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm/list_lru.c: fix list_lru_count_node() to be race freeSahitya Tummala1-8/+6
list_lru_count_node() iterates over all memcgs to get the total number of entries on the node but it can race with memcg_drain_all_list_lrus(), which migrates the entries from a dead cgroup to another. This can return incorrect number of entries from list_lru_count_node(). Fix this by keeping track of entries per node and simply return it in list_lru_count_node(). Link: http://lkml.kernel.org/r/1498707555-30525-1-git-send-email-stummala@codeaurora.org Signed-off-by: Sahitya Tummala <stummala@codeaurora.org> Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Jan Kara <jack@suse.cz> Cc: Alexander Polakov <apolyakov@beget.ru> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm/mmap.c: expand_downwards: don't require the gap if !vm_prevOleg Nesterov1-7/+3
expand_stack(vma) fails if address < stack_guard_gap even if there is no vma->vm_prev. I don't think this makes sense, and we didn't do this before the recent commit 1be7107fbe18 ("mm: larger stack guard gap, between vmas"). We do not need a gap in this case, any address is fine as long as security_mmap_addr() doesn't object. This also simplifies the code, we know that address >= prev->vm_end and thus underflow is not possible. Link: http://lkml.kernel.org/r/20170628175258.GA24881@redhat.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Hugh Dickins <hughd@google.com> Cc: Larry Woodman <lwoodman@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm/mmap.c: do not blow on PROT_NONE MAP_FIXED holes in the stackMichal Hocko1-2/+4
Commit 1be7107fbe18 ("mm: larger stack guard gap, between vmas") has introduced a regression in some rust and Java environments which are trying to implement their own stack guard page. They are punching a new MAP_FIXED mapping inside the existing stack Vma. This will confuse expand_{downwards,upwards} into thinking that the stack expansion would in fact get us too close to an existing non-stack vma which is a correct behavior wrt safety. It is a real regression on the other hand. Let's work around the problem by considering PROT_NONE mapping as a part of the stack. This is a gros hack but overflowing to such a mapping would trap anyway an we only can hope that usespace knows what it is doing and handle it propely. Fixes: 1be7107fbe18 ("mm: larger stack guard gap, between vmas") Link: http://lkml.kernel.org/r/20170705182849.GA18027@dhcp22.suse.cz Signed-off-by: Michal Hocko <mhocko@suse.com> Debugged-by: Vlastimil Babka <vbabka@suse.cz> Cc: Ben Hutchings <ben@decadent.org.uk> Cc: Willy Tarreau <w@1wt.eu> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm/balloon_compaction.c: enqueue zero page to balloon devicezhenwei.pi1-1/+1
presently pages in the balloon device have random value, and these pages will be scanned by ksmd on the host. They usually cannot be merged. Enqueue zero pages will resolve this problem. Link: http://lkml.kernel.org/r/1498698637-26389-1-git-send-email-zhenwei.pi@youruncloud.com Signed-off-by: zhenwei.pi <zhenwei.pi@youruncloud.com> Cc: Gioh Kim <gi-oh.kim@profitbricks.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Minchan Kim <minchan@kernel.org> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Cc: Rafael Aquini <aquini@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11cma: fix calculation of aligned offsetDoug Berger1-9/+6
The align_offset parameter is used by bitmap_find_next_zero_area_off() to represent the offset of map's base from the previous alignment boundary; the function ensures that the returned index, plus the align_offset, honors the specified align_mask. The logic introduced by commit b5be83e308f7 ("mm: cma: align to physical address, not CMA region position") has the cma driver calculate the offset to the *next* alignment boundary. In most cases, the base alignment is greater than that specified when making allocations, resulting in a zero offset whether we align up or down. In the example given with the commit, the base alignment (8MB) was half the requested alignment (16MB) so the math also happened to work since the offset is 8MB in both directions. However, when requesting allocations with an alignment greater than twice that of the base, the returned index would not be correctly aligned. Also, the align_order arguments of cma_bitmap_aligned_mask() and cma_bitmap_aligned_offset() should not be negative so the argument type was made unsigned. Fixes: b5be83e308f7 ("mm: cma: align to physical address, not CMA region position") Link: http://lkml.kernel.org/r/20170628170742.2895-1-opendmb@gmail.com Signed-off-by: Angus Clark <angus@angusclark.org> Signed-off-by: Doug Berger <opendmb@gmail.com> Acked-by: Gregory Fong <gregory.0xf0@gmail.com> Cc: Doug Berger <opendmb@gmail.com> Cc: Angus Clark <angus@angusclark.org> Cc: Laura Abbott <labbott@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Lucas Stach <l.stach@pengutronix.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Shiraz Hashim <shashim@codeaurora.org> Cc: Jaewon Kim <jaewon31.kim@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm/memory_hotplug.c: remove unused local zone_type from __remove_zone()John Hubbard1-3/+0
__remove_zone() sets up up zone_type, but never uses it for anything. This does not cause a warning, due to the (necessary) use of -Wno-unused-but-set-variable. However, it's noise, so just delete it. Link: http://lkml.kernel.org/r/20170624043421.24465-2-jhubbard@nvidia.com Signed-off-by: John Hubbard <jhubbard@nvidia.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm/swap_slots.c: don't disable preemption while taking the per-CPU cacheSebastian Andrzej Siewior1-3/+2
get_cpu_var() disables preemption and returns the per-CPU version of the variable. Disabling preemption is useful to ensure atomic access to the variable within the critical section. In this case however, after the per-CPU version of the variable is obtained the ->free_lock is acquired. For that reason it seems the raw accessor could be used. It only seems that ->slots_ret should be retested (because with disabled preemption this variable can not be set to NULL otherwise). This popped up during PREEMPT-RT testing because it tries to take spinlocks in a preempt disabled section. In RT, spinlocks can sleep. Link: http://lkml.kernel.org/r/20170623114755.2ebxdysacvgxzott@linutronix.de Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ying Huang <ying.huang@intel.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm/page_alloc.c: eliminate unsigned confusion in __rmqueue_fallbackRasmus Villemoes1-4/+7
Since current_order starts as MAX_ORDER-1 and is then only decremented, the second half of the loop condition seems superfluous. However, if order is 0, we may decrement current_order past 0, making it UINT_MAX. This is obviously too subtle ([1], [2]). Since we need to add some comment anyway, change the two variables to signed, making the counting-down for loop look more familiar, and apparently also making gcc generate slightly smaller code. [1] https://lkml.org/lkml/2016/6/20/493 [2] https://lkml.org/lkml/2017/6/19/345 [akpm@linux-foundation.org: fix up reject fixupping] Link: http://lkml.kernel.org/r/20170621185529.2265-1-linux@rasmusvillemoes.dk Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Reported-by: Hao Lee <haolee.swjtu@gmail.com> Acked-by: Wei Yang <weiyang@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm: avoid taking zone lock in pagetypeinfo_showmixed()Vinayak Menon2-11/+19
pagetypeinfo_showmixedcount_print is found to take a lot of time to complete and it does this holding the zone lock and disabling interrupts. In some cases it is found to take more than a second (On a 2.4GHz,8Gb RAM,arm64 cpu). Avoid taking the zone lock similar to what is done by read_page_owner, which means possibility of inaccurate results. Link: http://lkml.kernel.org/r/1498045643-12257-1-git-send-email-vinmenon@codeaurora.org Signed-off-by: Vinayak Menon <vinmenon@codeaurora.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: zhongjiang <zhongjiang@huawei.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: David Rientjes <rientjes@google.com> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm, hugetlb, soft_offline: use new_page_nodemask for soft offline migrationMichal Hocko1-9/+1
new_page is yet another duplication of the migration callback which has to handle hugetlb migration specially. We can safely use the generic new_page_nodemask for the same purpose. Please note that gigantic hugetlb pages do not need any special handling because alloc_huge_page_nodemask will make sure to check pages in all per node pools. The reason this was done previously was that alloc_huge_page_node treated NO_NUMA_NODE and a specific node differently and so alloc_huge_page_node(nid) would check on this specific node. Link: http://lkml.kernel.org/r/20170622193034.28972-4-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Reported-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Tested-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11hugetlb: add support for preferred node to alloc_huge_page_nodemaskMichal Hocko1-44/+44
alloc_huge_page_nodemask tries to allocate from any numa node in the allowed node mask starting from lower numa nodes. This might lead to filling up those low NUMA nodes while others are not used. We can reduce this risk by introducing a concept of the preferred node similar to what we have in the regular page allocator. We will start allocating from the preferred nid and then iterate over all allowed nodes in the zonelist order until we try them all. This is mimicing the page allocator logic except it operates on per-node mempools. dequeue_huge_page_vma already does this so distill the zonelist logic into a more generic dequeue_huge_page_nodemask and use it in alloc_huge_page_nodemask. This will allow us to use proper per numa distance fallback also for alloc_huge_page_node which can use alloc_huge_page_nodemask now and we can get rid of alloc_huge_page_node helper which doesn't have any user anymore. Link: http://lkml.kernel.org/r/20170622193034.28972-3-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Tested-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm, hugetlb: unclutter hugetlb allocation layersMichal Hocko1-104/+29
Patch series "mm, hugetlb: allow proper node fallback dequeue". While working on a hugetlb migration issue addressed in a separate patchset[1] I have noticed that the hugetlb allocations from the preallocated pool are quite subotimal. [1] //lkml.kernel.org/r/20170608074553.22152-1-mhocko@kernel.org There is no fallback mechanism implemented and no notion of preferred node. I have tried to work around it but Vlastimil was right to push back for a more robust solution. It seems that such a solution is to reuse zonelist approach we use for the page alloctor. This series has 3 patches. The first one tries to make hugetlb allocation layers more clear. The second one implements the zonelist hugetlb pool allocation and introduces a preferred node semantic which is used by the migration callbacks. The last patch is a clean up. This patch (of 3): Hugetlb allocation path for fresh huge pages is unnecessarily complex and it mixes different interfaces between layers. __alloc_buddy_huge_page is the central place to perform a new allocation. It checks for the hugetlb overcommit and then relies on __hugetlb_alloc_buddy_huge_page to invoke the page allocator. This is all good except that __alloc_buddy_huge_page pushes vma and address down the callchain and so __hugetlb_alloc_buddy_huge_page has to deal with two different allocation modes - one for memory policy and other node specific (or to make it more obscure node non-specific) requests. This just screams for a reorganization. This patch pulls out all the vma specific handling up to __alloc_buddy_huge_page_with_mpol where it belongs. __alloc_buddy_huge_page will get nodemask argument and __hugetlb_alloc_buddy_huge_page will become a trivial wrapper over the page allocator. In short: __alloc_buddy_huge_page_with_mpol - memory policy handling __alloc_buddy_huge_page - overcommit handling and accounting __hugetlb_alloc_buddy_huge_page - page allocator layer Also note that __hugetlb_alloc_buddy_huge_page and its cpuset retry loop is not really needed because the page allocator already handles the cpusets update. Finally __hugetlb_alloc_buddy_huge_page had a special case for node specific allocations (when no policy is applied and there is a node given). This has relied on __GFP_THISNODE to not fallback to a different node. alloc_huge_page_node is the only caller which relies on this behavior so move the __GFP_THISNODE there. Not only does this remove quite some code it also should make those layers easier to follow and clear wrt responsibilities. Link: http://lkml.kernel.org/r/20170622193034.28972-2-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Tested-by: Mike Kravetz <mike.kravetz@oracle.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm/oom_kill.c: add tracepoints for oom reaper-related eventsRoman Gushchin1-0/+7
During the debugging of the problem described in https://lkml.org/lkml/2017/5/17/542 and fixed by Tetsuo Handa in https://lkml.org/lkml/2017/5/19/383 , I've found that the existing debug output is not really useful to understand issues related to the oom reaper. So, I assume, that adding some tracepoints might help with debugging of similar issues. Trace the following events: 1) a process is marked as an oom victim, 2) a process is added to the oom reaper list, 3) the oom reaper starts reaping process's mm, 4) the oom reaper finished reaping, 5) the oom reaper skips reaping. How it works in practice? Below is an example which show how the problem mentioned above can be found: one process is added twice to the oom_reaper list: $ cd /sys/kernel/debug/tracing $ echo "oom:mark_victim" > set_event $ echo "oom:wake_reaper" >> set_event $ echo "oom:skip_task_reaping" >> set_event $ echo "oom:start_task_reaping" >> set_event $ echo "oom:finish_task_reaping" >> set_event $ cat trace_pipe allocate-502 [001] .... 91.836405: mark_victim: pid=502 allocate-502 [001] .N.. 91.837356: wake_reaper: pid=502 allocate-502 [000] .N.. 91.871149: wake_reaper: pid=502 oom_reaper-23 [000] .... 91.871177: start_task_reaping: pid=502 oom_reaper-23 [000] .N.. 91.879511: finish_task_reaping: pid=502 oom_reaper-23 [000] .... 91.879580: skip_task_reaping: pid=502 Link: http://lkml.kernel.org/r/20170530185231.GA13412@castle Signed-off-by: Roman Gushchin <guro@fb.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11userfaultfd: non-cooperative: add madvise() event for MADV_FREE requestMike Rapoport1-20/+22
MADV_FREE is identical to MADV_DONTNEED from the point of view of uffd monitor. The monitor has to stop handling #PF events in the range being freed. We are reusing userfaultfd_remove callback along with the logic required to re-get and re-validate the VMA which may change or disappear because userfaultfd_remove releases mmap_sem. Link: http://lkml.kernel.org/r/1497876311-18615-1-git-send-email-rppt@linux.vnet.ibm.com Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Pavel Emelyanov <xemul@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm/truncate.c: fix THP handling in invalidate_mapping_pages()Jan Kara1-2/+8
The condition checking for THP straddling end of invalidated range is wrong - it checks 'index' against 'end' but 'index' has been already advanced to point to the end of THP and thus the condition can never be true. As a result THP straddling 'end' has been fully invalidated. Given the nature of invalidate_mapping_pages(), this could be only performance issue. In fact, we are lucky the condition is wrong because if it was ever true, we'd leave locked page behind. Fix the condition checking for THP straddling 'end' and also properly unlock the page. Also update the comment before the condition to explain why we decide not to invalidate the page as it was not clear to me and I had to ask Kirill. Link: http://lkml.kernel.org/r/20170619124723.21656-1-jack@suse.cz Signed-off-by: Jan Kara <jack@suse.cz> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm/hugetlb.c: replace memfmt with string_get_sizeMatthew Wilcox1-14/+5
The hugetlb code has its own function to report human-readable sizes. Convert it to use the shared string_get_size() function. This will lead to a minor difference in user visible output (MiB/GiB instead of MB/GB), but some would argue that's desirable anyway. Link: http://lkml.kernel.org/r/20170606190350.GA20010@bombadil.infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Cc: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com> Cc: zhong jiang <zhongjiang@huawei.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm, memcg: fix potential undefined behavior in mem_cgroup_event_ratelimit()Michal Hocko1-1/+1
Alice has reported the following UBSAN splat: UBSAN: Undefined behaviour in mm/memcontrol.c:661:17 signed integer overflow: -2147483644 - 2147483525 cannot be represented in type 'long int' CPU: 1 PID: 11758 Comm: mybibtex2filena Tainted: P O 4.9.25-gentoo #4 Hardware name: XXXXXX, BIOS YYYYYY Call Trace: dump_stack+0x59/0x87 ubsan_epilogue+0xe/0x40 handle_overflow+0xbb/0xf0 __ubsan_handle_sub_overflow+0x12/0x20 memcg_check_events.isra.36+0x223/0x360 mem_cgroup_commit_charge+0x55/0x140 wp_page_copy+0x34e/0xb80 do_wp_page+0x1e6/0x1300 handle_mm_fault+0x88b/0x1990 __do_page_fault+0x2de/0x8a0 do_page_fault+0x1a/0x20 error_code+0x67/0x6c The reason is that we subtract two signed types. Let's fix this by truly mimicing time_after and cast the result of the subtraction. Link: http://lkml.kernel.org/r/20170616150057.GQ30580@dhcp22.suse.cz Signed-off-by: Michal Hocko <mhocko@suse.com> Reported-by: Alice Ferrazzi <alicef@gentoo.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm, hugetlb: schedule when potentially allocating many hugepagesDavid Rientjes1-0/+2
A few hugetlb allocators loop while calling the page allocator and can potentially prevent rescheduling if the page allocator slowpath is not utilized. Conditionally schedule when large numbers of hugepages can be allocated. Anshuman: "Fixes a task which was getting hung while writing like 10000 hugepages (16MB on POWER8) into /proc/sys/vm/nr_hugepages." Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1706091535300.66176@chino.kir.corp.google.com Signed-off-by: David Rientjes <rientjes@google.com> Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com> Tested-by: Anshuman Khandual <khandual@linux.vnet.ibm.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm: unify new_node_page and alloc_migrate_targetMichal Hocko2-26/+3
Commit 394e31d2ceb4 ("mem-hotplug: alloc new page from a nearest neighbor node when mem-offline") has duplicated a large part of alloc_migrate_target with some hotplug specific special casing. To be more precise it tried to enfore the allocation from a different node than the original page. As a result the two function diverged in their shared logic, e.g. the hugetlb allocation strategy. Let's unify the two and express different NUMA requirements by the given nodemask. new_node_page will simply exclude the node it doesn't care about and alloc_migrate_target will use all the available nodes. alloc_migrate_target will then learn to migrate hugetlb pages more sanely and use preallocated pool when possible. Please note that alloc_migrate_target used to call alloc_page resp. alloc_pages_current so the memory policy of the current context which is quite strange when we consider that it is used in the context of alloc_contig_range which just tries to migrate pages which stand in the way. Link: http://lkml.kernel.org/r/20170608074553.22152-4-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Xishi Qiu <qiuxishi@huawei.com> Cc: zhong jiang <zhongjiang@huawei.com> Cc: Joonsoo Kim <js1304@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11hugetlb, memory_hotplug: prefer to use reserved pages for migrationMichal Hocko2-7/+29
new_node_page will try to use the origin's next NUMA node as the migration destination for hugetlb pages. If such a node doesn't have any preallocated pool it falls back to __alloc_buddy_huge_page_no_mpol to allocate a surplus page instead. This is quite subotpimal for any configuration when hugetlb pages are no distributed to all NUMA nodes evenly. Say we have a hotplugable node 4 and spare hugetlb pages are node 0 /sys/devices/system/node/node0/hugepages/hugepages-2048kB/nr_hugepages:10000 /sys/devices/system/node/node1/hugepages/hugepages-2048kB/nr_hugepages:0 /sys/devices/system/node/node2/hugepages/hugepages-2048kB/nr_hugepages:0 /sys/devices/system/node/node3/hugepages/hugepages-2048kB/nr_hugepages:0 /sys/devices/system/node/node4/hugepages/hugepages-2048kB/nr_hugepages:10000 /sys/devices/system/node/node5/hugepages/hugepages-2048kB/nr_hugepages:0 /sys/devices/system/node/node6/hugepages/hugepages-2048kB/nr_hugepages:0 /sys/devices/system/node/node7/hugepages/hugepages-2048kB/nr_hugepages:0 Now we consume the whole pool on node 4 and try to offline this node. All the allocated pages should be moved to node0 which has enough preallocated pages to hold them. With the current implementation offlining very likely fails because hugetlb allocations during runtime are much less reliable. Fix this by reusing the nodemask which excludes migration source and try to find a first node which has a page in the preallocated pool first and fall back to __alloc_buddy_huge_page_no_mpol only when the whole pool is consumed. [akpm@linux-foundation.org: remove bogus arg from alloc_huge_page_nodemask() stub] Link: http://lkml.kernel.org/r/20170608074553.22152-3-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Xishi Qiu <qiuxishi@huawei.com> Cc: zhong jiang <zhongjiang@huawei.com> Cc: Joonsoo Kim <js1304@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm, memory_hotplug: simplify empty node mask handling in new_node_pageMichal Hocko1-9/+10
new_node_page tries to allocate the target page on a different NUMA node than the source page. This makes sense in most cases during the hotplug because we are likely to offline the whole numa node. But there are cases where there are no other nodes to fallback (e.g. when offlining parts of the only existing node) and we have to fallback to allocating from the source node. The current code does that but it can be simplified by checking the nmask and updating it before we even try to allocate rather than special casing it. This patch shouldn't introduce any functional change. Link: http://lkml.kernel.org/r/20170608074553.22152-2-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Xishi Qiu <qiuxishi@huawei.com> Cc: zhong jiang <zhongjiang@huawei.com> Cc: Joonsoo Kim <js1304@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm, memory_hotplug: support movable_node for hotpluggable nodesMichal Hocko1-3/+16
movable_node kernel parameter allows making hotpluggable NUMA nodes to put all the hotplugable memory into movable zone which allows more or less reliable memory hotremove. At least this is the case for the NUMA nodes present during the boot (see find_zone_movable_pfns_for_nodes). This is not the case for the memory hotplug, though. echo online > /sys/devices/system/memory/memoryXYZ/state will default to a kernel zone (usually ZONE_NORMAL) unless the particular memblock is already in the movable zone range which is not the case normally when onlining the memory from the udev rule context for a freshly hotadded NUMA node. The only option currently is to have a special udev rule to echo online_movable to all memblocks belonging to such a node which is rather clumsy. Not to mention this is inconsistent as well because what ended up in the movable zone during the boot will end up in a kernel zone after hotremove & hotadd without special care. It would be nice to reuse memblock_is_hotpluggable but the runtime hotplug doesn't have that information available because the boot and hotplug paths are not shared and it would be really non trivial to make them use the same code path because the runtime hotplug doesn't play with the memblock allocator at all. Teach move_pfn_range that MMOP_ONLINE_KEEP can use the movable zone if movable_node is enabled and the range doesn't overlap with the existing normal zone. This should provide a reasonable default onlining strategy. Strictly speaking the semantic is not identical with the boot time initialization because find_zone_movable_pfns_for_nodes covers only the hotplugable range as described by the BIOS/FW. From my experience this is usually a full node though (except for Node0 which is special and never goes away completely). If this turns out to be a problem in the real life we can tweak the code to store hotplug flag into memblocks but let's keep this simple now. Link: http://lkml.kernel.org/r/20170612111227.GI7476@dhcp22.suse.cz Signed-off-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Reza Arbab <arbab@linux.vnet.ibm.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Yasuaki Ishimatsu <yasu.isimatu@gmail.com> Cc: <qiuxishi@huawei.com> Cc: Kani Toshimitsu <toshi.kani@hpe.com> Cc: <slaoub@gmail.com> Cc: Joonsoo Kim <js1304@gmail.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: David Rientjes <rientjes@google.com> Cc: Daniel Kiper <daniel.kiper@oracle.com> Cc: Igor Mammedov <imammedo@redhat.com> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm/migrate.c: stabilise page count when migrating transparent hugepagesWill Deacon1-13/+2
When migrating a transparent hugepage, migrate_misplaced_transhuge_page guards itself against a concurrent fastgup of the page by checking that the page count is equal to 2 before and after installing the new pmd. If the page count changes, then the pmd is reverted back to the original entry, however there is a small window where the new (possibly writable) pmd is installed and the underlying page could be written by userspace. Restoring the old pmd could therefore result in loss of data. This patch fixes the problem by freezing the page count whilst updating the page tables, which protects against a concurrent fastgup without the need to restore the old pmd in the failure case (since the page count can no longer change under our feet). Link: http://lkml.kernel.org/r/1497349722-6731-4-git-send-email-will.deacon@arm.com Signed-off-by: Will Deacon <will.deacon@arm.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Steve Capper <steve.capper@arm.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm/hugetlb.c: warn the user when issues arise on boot due to hugepagesLiam R. Howlett1-12/+24
When the user specifies too many hugepages or an invalid default_hugepagesz the communication to the user is implicit in the allocation message. This patch adds a warning when the desired page count is not allocated and prints an error when the default_hugepagesz is invalid on boot. During boot hugepages will allocate until there is a fraction of the hugepage size left. That is, we allocate until either the request is satisfied or memory for the pages is exhausted. When memory for the pages is exhausted, it will most likely lead to the system failing with the OOM manager not finding enough (or anything) to kill (unless you're using really big hugepages in the order of 100s of MB or in the GBs). The user will most likely see the OOM messages much later in the boot sequence than the implicitly stated message. Worse yet, you may even get an OOM for each processor which causes many pages of OOMs on modern systems. Although these messages will be printed earlier than the OOM messages, at least giving the user errors and warnings will highlight the configuration as an issue. I'm trying to point the user in the right direction by providing a more robust statement of what is failing. During the sysctl or echo command, the user can check the results much easier than if the system hangs during boot and the scenario of having nothing to OOM for kernel memory is highly unlikely. Mike said: "Before sending out this patch, I asked Liam off list why he was doing it. Was it something he just thought would be useful? Or, was there some type of user situation/need. He said that he had been called in to assist on several occasions when a system OOMed during boot. In almost all of these situations, the user had grossly misconfigured huge pages. DB users want to pre-allocate just the right amount of huge pages, but sometimes they can be really off. In such situations, the huge page init code just allocates as many huge pages as it can and reports the number allocated. There is no indication that it quit allocating because it ran out of memory. Of course, a user could compare the number in the message to what they requested on the command line to determine if they got all the huge pages they requested. The thought was that it would be useful to at least flag this situation. That way, the user might be able to better relate the huge page allocation failure to the OOM. I'm not sure if the e-mail discussion made it obvious that this is something he has seen on several occasions. I see Michal's point that this will only flag the situation where someone configures huge pages very badly. And, a more extensive look at the situation of misconfiguring huge pages might be in order. But, this has happened on several occasions which led to the creation of this patch" [akpm@linux-foundation.org: reposition memfmt() to avoid forward declaration] Link: http://lkml.kernel.org/r/20170603005413.10380-1-Liam.Howlett@Oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com> Cc: zhongjiang <zhongjiang@huawei.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm/cma.c: warn if the CMA area could not be activatedAnshuman Khandual1-2/+3
While activating a CMA area we check to make sure that all the PFNs in the range are inside the same zone. This is a requirement for alloc_contig_range() to work. Any CMA area failing the check is disabled for good. This happens silently right now making all future cma_alloc() allocations failure inevitable. Here we add an error message stating that the CMA area could not be activated which makes it easier to explain any future cma_alloc() failures on it. While in there, change the bail out goto label from 'err' to 'not_in_zone' which makes more sense. Link: http://lkml.kernel.org/r/20170605023729.26303-1-khandual@linux.vnet.ibm.com Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11vmalloc: show lazy-purged vma info in vmallocinfoYisheng Xie1-1/+9
When ioremap a 67112960 bytes vm_area with the vmallocinfo: [..] 0xec79b000-0xec7fa000 389120 ftl_add_mtd+0x4d0/0x754 pages=94 vmalloc 0xec800000-0xecbe1000 4067328 kbox_proc_mem_write+0x104/0x1c4 phys=8b520000 ioremap we get the result: 0xf1000000-0xf5001000 67112960 devm_ioremap+0x38/0x7c phys=40000000 ioremap For the align for ioremap must be less than '1 << IOREMAP_MAX_ORDER': if (flags & VM_IOREMAP) align = 1ul << clamp_t(int, get_count_order_long(size), PAGE_SHIFT, IOREMAP_MAX_ORDER); So it makes idiot like me a litte puzzled why this was a jump the vm_area from 0xec800000-0xecbe1000 to 0xf1000000-0xf5001000, and leaving 0xed000000-0xf1000000 as a big hole. This patch is to show all of vm_area, including vmas which are freeing but still in the vmap_area_list, to make it more clear about why we will get 0xf1000000-0xf5001000 in the above case. And we will get a vmallocinfo like: [..] 0xec79b000-0xec7fa000 389120 ftl_add_mtd+0x4d0/0x754 pages=94 vmalloc 0xec800000-0xecbe1000 4067328 kbox_proc_mem_write+0x104/0x1c4 phys=8b520000 ioremap [..] 0xece7c000-0xece7e000 8192 unpurged vm_area 0xece7e000-0xece83000 20480 vm_map_ram 0xf0099000-0xf00aa000 69632 vm_map_ram after this patch. Link: http://lkml.kernel.org/r/1496649682-20710-1-git-send-email-xieyisheng1@huawei.com Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com> Cc: Michal Hocko <mhocko@suse.com> Cc: zijun_hu <zijun_hu@htc.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Hanjun Guo <guohanjun@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-11mm/memcontrol: exclude @root from checks in mem_cgroup_lowSean Christopherson1-18/+32
Make @root exclusive in mem_cgroup_low; it is never considered low when looked at directly and is not checked when traversing the tree. In effect, @root is handled identically to how root_mem_cgroup was previously handled by mem_cgroup_low. If @root is not excluded from the checks, a cgroup underneath @root will never be considered low during targeted reclaim of @root, e.g. due to memory.current > memory.high, unless @root is misconfigured to have memory.low > memory.high. Excluding @root enables using memory.low to prioritize memory usage between cgroups within a subtree of the hierarchy that is limited by memory.high or memory.max, e.g. when ROOT owns @root's controls but delegates the @root directory to a USER so that USER can create and administer children of @root. For example, given cgroup A with children B and C: A / \ B C and 1. A/memory.current > A/memory.high 2. A/B/memory.current < A/B/memory.low 3. A/C/memory.current >= A/C/memory.low As 'A' is high, i.e. triggers reclaim from 'A', and 'B' is low, we should reclaim from 'C' until 'A' is no longer high or until we can no longer reclaim from 'C'. If 'A', i.e. @root, isn't excluded by mem_cgroup_low when reclaming from 'A', then 'B' won't be considered low and we will reclaim indiscriminately from both 'B' and 'C'. Here is the test I used to confirm the bug and the patch. 20:00:55@sjchrist-vm ? ~ $ cat ~/.bin/memcg_low_test #!/bin/bash x62mb=$((62<<20)) x66mb=$((66<<20)) x94mb=$((94<<20)) x98mb=$((98<<20)) setup() { set -e if [[ -n $DEBUG ]]; then set -x fi trap teardown EXIT HUP INT TERM if [[ ! -e /mnt/1gb.swap ]]; then sudo fallocate -l 1G /mnt/1gb.swap > /dev/null sudo mkswap /mnt/1gb.swap > /dev/null fi if ! swapon --show=NAME | grep -q "/mnt/1gb.swap"; then sudo swapon /mnt/1gb.swap fi if [[ ! -e /cgroup/cgroup.controllers ]]; then sudo mount -t cgroup2 none /cgroup fi grep -q memory /cgroup/cgroup.controllers sudo sh -c "echo '+memory' > /cgroup/cgroup.subtree_control" sudo mkdir /cgroup/A && sudo chown $USER:$USER /cgroup/A sudo sh -c "echo '+memory' > /cgroup/A/cgroup.subtree_control" sudo sh -c "echo '96m' > /cgroup/A/memory.high" mkdir /cgroup/A/0 mkdir /cgroup/A/1 echo 64m > /cgroup/A/0/memory.low } teardown() { set +e trap - EXIT HUP INT TERM if [[ -z $1 ]]; then printf "\n" printf "%0.s*" {1..35} printf "\nFAILED!\n\n" tail /cgroup/A/**/memory.current printf "%0.s*" {1..35} printf "\n\n" fi ps | grep stress | tr -s ' ' | cut -f 2 -d ' ' | xargs -I % kill % sleep 2 if [[ -e /cgroup/A/0 ]]; then rmdir /cgroup/A/0 fi if [[ -e /cgroup/A/1 ]]; then rmdir /cgroup/A/1 fi if [[ -e /cgroup/A ]]; then sudo rmdir /cgroup/A fi } stress_test() { sudo sh -c "echo $$ > /cgroup/A/$1/cgroup.procs" stress --vm 1 --vm-bytes 64M --vm-keep > /dev/null & sudo sh -c "echo $$ > /cgroup/A/$2/cgroup.procs" stress --vm 1 --vm-bytes 64M --vm-keep > /dev/null & sudo sh -c "echo $$ > /cgroup/cgroup.procs" sleep 1 # A/0 should be consuming more memory than A/1 [[ $(cat /cgroup/A/0/memory.current) -ge $(cat /cgroup/A/1/memory.current) ]] # A/0 should be consuming ~64mb [[ $(cat /cgroup/A/0/memory.current) -ge $x62mb ]] && [[ $(cat /cgroup/A/0/memory.current) -le $x66mb ]] # A should cumulatively be consuming ~96mb [[ $(cat /cgroup/A/memory.current) -ge $x94mb ]] && [[ $(cat /cgroup/A/memory.current) -le $x98mb ]] # Stop the stressors ps | grep stress | tr -s ' ' | cut -f 2 -d ' ' | xargs -I % kill % } teardown 1 setup for ((i=1;i<=$1;i++)); do printf "ITERATION $i of $1 - stress_test 0 1" stress_test 0 1 printf "\x1b[2K\r" printf "ITERATION $i of $1 - stress_test 1 0" stress_test 1 0 printf "\x1b[2K\r" printf "ITERATION $i of $1 - PASSED\n" done teardown 1 echo PASSED! 20:11:26@sjchrist-vm ? ~ $ memcg_low_test 10 Link: http://lkml.kernel.org/r/1496434412-21005-1-git-send-email-sean.j.christopherson@intel.com Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com> Acked-by: Balbir Singh <bsingharora@gmail.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
generated by cgit v1.2.3 (git 2.39.0) at 2024-11-29 11:49:04 +0300