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2011-08-14mm: fix wrong vmap address calculations with odd NR_CPUS valuesClemens Ladisch1-3/+4
Commit db64fe02258f ("mm: rewrite vmap layer") introduced code that does address calculations under the assumption that VMAP_BLOCK_SIZE is a power of two. However, this might not be true if CONFIG_NR_CPUS is not set to a power of two. Wrong vmap_block index/offset values could lead to memory corruption. However, this has never been observed in practice (or never been diagnosed correctly); what caught this was the BUG_ON in vb_alloc() that checks for inconsistent vmap_block indices. To fix this, ensure that VMAP_BLOCK_SIZE always is a power of two. BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=31572 Reported-by: Pavel Kysilka <goldenfish@linuxsoft.cz> Reported-by: Matias A. Fonzo <selk@dragora.org> Signed-off-by: Clemens Ladisch <clemens@ladisch.de> Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> Cc: Nick Piggin <npiggin@suse.de> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Krzysztof Helt <krzysztof.h1@poczta.fm> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: 2.6.28+ <stable@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-08-10Revert "memcg: get rid of percpu_charge_mutex lock"Michal Hocko1-2/+10
This reverts commit 8521fc50d433507a7cdc96bec280f9e5888a54cc. The patch incorrectly assumes that using atomic FLUSHING_CACHED_CHARGE bit operations is sufficient but that is not true. Johannes Weiner has reported a crash during parallel memory cgroup removal: BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 IP: [<ffffffff81083b70>] css_is_ancestor+0x20/0x70 Oops: 0000 [#1] PREEMPT SMP Pid: 19677, comm: rmdir Tainted: G W 3.0.0-mm1-00188-gf38d32b #35 ECS MCP61M-M3/MCP61M-M3 RIP: 0010:[<ffffffff81083b70>] css_is_ancestor+0x20/0x70 RSP: 0018:ffff880077b09c88 EFLAGS: 00010202 Process rmdir (pid: 19677, threadinfo ffff880077b08000, task ffff8800781bb310) Call Trace: [<ffffffff810feba3>] mem_cgroup_same_or_subtree+0x33/0x40 [<ffffffff810feccf>] drain_all_stock+0x11f/0x170 [<ffffffff81103211>] mem_cgroup_force_empty+0x231/0x6d0 [<ffffffff811036c4>] mem_cgroup_pre_destroy+0x14/0x20 [<ffffffff81080559>] cgroup_rmdir+0xb9/0x500 [<ffffffff81114d26>] vfs_rmdir+0x86/0xe0 [<ffffffff81114e7b>] do_rmdir+0xfb/0x110 [<ffffffff81114ea6>] sys_rmdir+0x16/0x20 [<ffffffff8154d76b>] system_call_fastpath+0x16/0x1b We are crashing because we try to dereference cached memcg when we are checking whether we should wait for draining on the cache. The cache is already cleaned up, though. There is also a theoretical chance that the cached memcg gets freed between we test for the FLUSHING_CACHED_CHARGE and dereference it in mem_cgroup_same_or_subtree: CPU0 CPU1 CPU2 mem=stock->cached stock->cached=NULL clear_bit test_and_set_bit test_bit() ... <preempted> mem_cgroup_destroy use after free The percpu_charge_mutex protected from this race because sync draining is exclusive. It is safer to revert now and come up with a more parallel implementation later. Signed-off-by: Michal Hocko <mhocko@suse.cz> Reported-by: Johannes Weiner <jweiner@redhat.com> Acked-by: Johannes Weiner <jweiner@redhat.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-08-09slub: Fix partial count comparison confusionChristoph Lameter1-1/+1
deactivate_slab() has the comparison if more than the minimum number of partial pages are in the partial list wrong. An effect of this may be that empty pages are not freed from deactivate_slab(). The result could be an OOM due to growth of the partial slabs per node. Frees mostly occur from __slab_free which is okay so this would only affect use cases where a lot of switching around of per cpu slabs occur. Switching per cpu slabs occurs with high frequency if debugging options are enabled. Reported-and-tested-by: Xiaotian Feng <xtfeng@gmail.com> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-08-09slub: fix check_bytes() for slub debuggingAkinobu Mita1-1/+1
The check_bytes() function is used by slub debugging. It returns a pointer to the first unmatching byte for a character in the given memory area. If the character for matching byte is greater than 0x80, check_bytes() doesn't work. Becuase 64-bit pattern is generated as below. value64 = value | value << 8 | value << 16 | value << 24; value64 = value64 | value64 << 32; The integer promotions are performed and sign-extended as the type of value is u8. The upper 32 bits of value64 is 0xffffffff in the first line, and the second line has no effect. This fixes the 64-bit pattern generation. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Matt Mackall <mpm@selenic.com> Reviewed-by: Marcin Slusarz <marcin.slusarz@gmail.com> Acked-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-08-09slub: Fix full list corruption if debugging is onChristoph Lameter1-2/+4
When a slab is freed by __slab_free() and the slab can only contain a single object ever then it was full (and therefore not on the partial lists but on the full list in the debug case) before we reached slab_empty. This caused the following full list corruption when SLUB debugging was enabled: [ 5913.233035] ------------[ cut here ]------------ [ 5913.233097] WARNING: at lib/list_debug.c:53 __list_del_entry+0x8d/0x98() [ 5913.233101] Hardware name: Adamo 13 [ 5913.233105] list_del corruption. prev->next should be ffffea000434fd20, but was ffffea0004199520 [ 5913.233108] Modules linked in: nfs fscache fuse ebtable_nat ebtables ppdev parport_pc lp parport ipt_MASQUERADE iptable_nat nf_nat nfsd lockd nfs_acl auth_rpcgss xt_CHECKSUM sunrpc iptable_mangle bridge stp llc cpufreq_ondemand acpi_cpufreq freq_table mperf ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 ip6table_filter ip6_tables rfcomm bnep arc4 iwlagn snd_hda_codec_hdmi snd_hda_codec_idt snd_hda_intel btusb mac80211 snd_hda_codec bluetooth snd_hwdep snd_seq snd_seq_device snd_pcm usb_debug dell_wmi sparse_keymap cdc_ether usbnet cdc_acm uvcvideo cdc_wdm mii cfg80211 snd_timer dell_laptop videodev dcdbas snd microcode v4l2_compat_ioctl32 soundcore joydev tg3 pcspkr snd_page_alloc iTCO_wdt i2c_i801 rfkill iTCO_vendor_support wmi virtio_net kvm_intel kvm ipv6 xts gf128mul dm_crypt i915 drm_kms_helper drm i2c_algo_bit i2c_core video [last unloaded: scsi_wait_scan] [ 5913.233213] Pid: 0, comm: swapper Not tainted 3.0.0+ #127 [ 5913.233213] Call Trace: [ 5913.233213] <IRQ> [<ffffffff8105df18>] warn_slowpath_common+0x83/0x9b [ 5913.233213] [<ffffffff8105dfd3>] warn_slowpath_fmt+0x46/0x48 [ 5913.233213] [<ffffffff8127e7c1>] __list_del_entry+0x8d/0x98 [ 5913.233213] [<ffffffff8127e7da>] list_del+0xe/0x2d [ 5913.233213] [<ffffffff814e0430>] __slab_free+0x1db/0x235 [ 5913.233213] [<ffffffff811706ab>] ? bvec_free_bs+0x35/0x37 [ 5913.233213] [<ffffffff811706ab>] ? bvec_free_bs+0x35/0x37 [ 5913.233213] [<ffffffff811706ab>] ? bvec_free_bs+0x35/0x37 [ 5913.233213] [<ffffffff81133085>] kmem_cache_free+0x88/0x102 [ 5913.233213] [<ffffffff811706ab>] bvec_free_bs+0x35/0x37 [ 5913.233213] [<ffffffff811706e1>] bio_free+0x34/0x64 [ 5913.233213] [<ffffffff813dc390>] dm_bio_destructor+0x12/0x14 [ 5913.233213] [<ffffffff8116fef6>] bio_put+0x2b/0x2d [ 5913.233213] [<ffffffff813dccab>] clone_endio+0x9e/0xb4 [ 5913.233213] [<ffffffff8116f7dd>] bio_endio+0x2d/0x2f [ 5913.233213] [<ffffffffa00148da>] crypt_dec_pending+0x5c/0x8b [dm_crypt] [ 5913.233213] [<ffffffffa00150a9>] crypt_endio+0x78/0x81 [dm_crypt] [ Full discussion here: https://lkml.org/lkml/2011/8/4/375 ] Make sure that we remove such a slab also from the full lists. Reported-and-tested-by: Dave Jones <davej@redhat.com> Reported-and-tested-by: Xiaotian Feng <xtfeng@gmail.com> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-08-05Merge branch 'core-urgent-for-linus' of ↵Linus Torvalds1-21/+71
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: slab, lockdep: Annotate the locks before using them lockdep: Clear whole lockdep_map on initialization slab, lockdep: Annotate slab -> rcu -> debug_object -> slab lockdep: Fix up warning lockdep: Fix trace_hardirqs_on_caller() futex: Fix regression with read only mappings
2011-08-04slab, lockdep: Annotate the locks before using themPeter Zijlstra1-3/+3
Fernando found we hit the regular OFF_SLAB 'recursion' before we annotate the locks, cure this. The relevant portion of the stack-trace: > [ 0.000000] [<c085e24f>] rt_spin_lock+0x50/0x56 > [ 0.000000] [<c04fb406>] __cache_free+0x43/0xc3 > [ 0.000000] [<c04fb23f>] kmem_cache_free+0x6c/0xdc > [ 0.000000] [<c04fb2fe>] slab_destroy+0x4f/0x53 > [ 0.000000] [<c04fb396>] free_block+0x94/0xc1 > [ 0.000000] [<c04fc551>] do_tune_cpucache+0x10b/0x2bb > [ 0.000000] [<c04fc8dc>] enable_cpucache+0x7b/0xa7 > [ 0.000000] [<c0bd9d3c>] kmem_cache_init_late+0x1f/0x61 > [ 0.000000] [<c0bba687>] start_kernel+0x24c/0x363 > [ 0.000000] [<c0bba0ba>] i386_start_kernel+0xa9/0xaf Reported-by: Fernando Lopez-Lezcano <nando@ccrma.Stanford.EDU> Acked-by: Pekka Enberg <penberg@kernel.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1311888176.2617.379.camel@laptop Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-08-04slab, lockdep: Annotate slab -> rcu -> debug_object -> slabPeter Zijlstra1-18/+68
Lockdep thinks there's lock recursion through: kmem_cache_free() cache_flusharray() spin_lock(&l3->list_lock) <----------------. free_block() | slab_destroy() | call_rcu() | debug_object_activate() | debug_object_init() | __debug_object_init() | kmem_cache_alloc() | cache_alloc_refill() | spin_lock(&l3->list_lock) --' Now debug objects doesn't use SLAB_DESTROY_BY_RCU and hence there is no actual possibility of recursing. Luckily debug objects marks it slab with SLAB_DEBUG_OBJECTS so we can identify the thing. Mark all SLAB_DEBUG_OBJECTS (all one!) slab caches with a special lockdep key so that lockdep sees its a different cachep. Also add a WARN on trying to create a SLAB_DESTROY_BY_RCU | SLAB_DEBUG_OBJECTS cache, to avoid possible future trouble. Reported-and-tested-by: Sebastian Siewior <sebastian@breakpoint.cc> [ fixes to the initial patch ] Reported-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Pekka Enberg <penberg@kernel.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1311341165.27400.58.camel@twins Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-08-04Merge branch 'apei-release' of ↵Linus Torvalds1-0/+92
git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6 * 'apei-release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6: ACPI, APEI, EINJ Param support is disabled by default APEI GHES: 32-bit buildfix ACPI: APEI build fix ACPI, APEI, GHES: Add hardware memory error recovery support HWPoison: add memory_failure_queue() ACPI, APEI, GHES, Error records content based throttle ACPI, APEI, GHES, printk support for recoverable error via NMI lib, Make gen_pool memory allocator lockless lib, Add lock-less NULL terminated single list Add Kconfig option ARCH_HAVE_NMI_SAFE_CMPXCHG ACPI, APEI, Add WHEA _OSC support ACPI, APEI, Add APEI bit support in generic _OSC call ACPI, APEI, GHES, Support disable GHES at boot time ACPI, APEI, GHES, Prevent GHES to be built as module ACPI, APEI, Use apei_exec_run_optional in APEI EINJ and ERST ACPI, APEI, Add apei_exec_run_optional ACPI, APEI, GHES, Do not ratelimit fatal error printk before panic ACPI, APEI, ERST, Fix erst-dbg long record reading issue ACPI, APEI, ERST, Prevent erst_dbg from loading if ERST is disabled
2011-08-04mm: clarify the radix_tree exceptional casesHugh Dickins3-26/+53
Make the radix_tree exceptional cases, mostly in filemap.c, clearer. It's hard to devise a suitable snappy name that illuminates the use by shmem/tmpfs for swap, while keeping filemap/pagecache/radix_tree generality. And akpm points out that /* radix_tree_deref_retry(page) */ comments look like calls that have been commented out for unknown reason. Skirt the naming difficulty by rearranging these blocks to handle the transient radix_tree_deref_retry(page) case first; then just explain the remaining shmem/tmpfs swap case in a comment. Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-08-04tmpfs radix_tree: locate_item to speed up swapoffHugh Dickins1-37/+1
We have already acknowledged that swapoff of a tmpfs file is slower than it was before conversion to the generic radix_tree: a little slower there will be acceptable, if the hotter paths are faster. But it was a shock to find swapoff of a 500MB file 20 times slower on my laptop, taking 10 minutes; and at that rate it significantly slows down my testing. Now, most of that turned out to be overhead from PROVE_LOCKING and PROVE_RCU: without those it was only 4 times slower than before; and more realistic tests on other machines don't fare as badly. I've tried a number of things to improve it, including tagging the swap entries, then doing lookup by tag: I'd expected that to halve the time, but in practice it's erratic, and often counter-productive. The only change I've so far found to make a consistent improvement, is to short-circuit the way we go back and forth, gang lookup packing entries into the array supplied, then shmem scanning that array for the target entry. Scanning in place doubles the speed, so it's now only twice as slow as before (or three times slower when the PROVEs are on). So, add radix_tree_locate_item() as an expedient, once-off, single-caller hack to do the lookup directly in place. #ifdef it on CONFIG_SHMEM and CONFIG_SWAP, as much to document its limited applicability as save space in other configurations. And, sadly, #include sched.h for cond_resched(). Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-08-04mm: a few small updates for radix-swapHugh Dickins3-22/+17
Remove PageSwapBacked (!page_is_file_cache) cases from add_to_page_cache_locked() and add_to_page_cache_lru(): those pages now go through shmem_add_to_page_cache(). Remove a comment on maximum tmpfs size from fsstack_copy_inode_size(), and add a comment on swap entries to invalidate_mapping_pages(). And mincore_page() uses find_get_page() on what might be shmem or a tmpfs file: allow for a radix_tree_exceptional_entry(), and proceed to find_get_page() on swapper_space if so (oh, swapper_space needs #ifdef). Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-08-04tmpfs: use kmemdup for short symlinksHugh Dickins1-13/+18
But we've not yet removed the old swp_entry_t i_direct[16] from shmem_inode_info. That's because it was still being shared with the inline symlink. Remove it now (saving 64 or 128 bytes from shmem inode size), and use kmemdup() for short symlinks, say, those up to 128 bytes. I wonder why mpol_free_shared_policy() is done in shmem_destroy_inode() rather than shmem_evict_inode(), where we usually do such freeing? I guess it doesn't matter, and I'm not into NUMA mpol testing right now. Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Rik van Riel <riel@redhat.com> Reviewed-by: Pekka Enberg <penberg@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-08-04tmpfs: convert shmem_writepage and enable swapHugh Dickins1-51/+37
Convert shmem_writepage() to use shmem_delete_from_page_cache() to use shmem_radix_tree_replace() to substitute swap entry for page pointer atomically in the radix tree. As with shmem_add_to_page_cache(), it's not entirely satisfactory to be copying such code from delete_from_swap_cache, but again judged easier to sell than making its other callers go through the extras. Remove the toy implementation's shmem_put_swap() and shmem_get_swap(), now unreferenced, and the hack to disable swap: it's now good to go. The way things have worked out, info->lock no longer helps to guard the shmem_swaplist: we increment swapped under shmem_swaplist_mutex only. That global mutex exclusion between shmem_writepage() and shmem_unuse() is not pretty, and we ought to find another way; but it's been forced on us by recent race discoveries, not a consequence of this patchset. And what has become of the WARN_ON_ONCE(1) free_swap_and_cache() if a swap entry was found already present? That's no longer possible, the (unknown) one inserting this page into filecache would hit the swap entry occupying that slot. Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-08-04tmpfs: convert mem_cgroup shmem to radix-swapHugh Dickins2-129/+20
Remove mem_cgroup_shmem_charge_fallback(): it was only required when we had to move swappage to filecache with GFP_NOWAIT. Remove the GFP_NOWAIT special case from mem_cgroup_cache_charge(), by moving its call out from shmem_add_to_page_cache() to two of thats three callers. But leave it doing mem_cgroup_uncharge_cache_page() on error: although asymmetrical, it's easier for all 3 callers to handle. These two changes would also be appropriate if anyone were to start using shmem_read_mapping_page_gfp() with GFP_NOWAIT. Remove mem_cgroup_get_shmem_target(): mc_handle_file_pte() can test radix_tree_exceptional_entry() to get what it needs for itself. Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-08-04tmpfs: convert shmem_getpage_gfp to radix-swapHugh Dickins1-147/+112
Convert shmem_getpage_gfp(), the engine-room of shmem, to expect page or swap entry returned from radix tree by find_lock_page(). Whereas the repetitive old method proceeded mainly under info->lock, dropping and repeating whenever one of the conditions needed was not met, now we can proceed without it, leaving shmem_add_to_page_cache() to check for a race. This way there is no need to preallocate a page, no need for an early radix_tree_preload(), no need for mem_cgroup_shmem_charge_fallback(). Move the error unwinding down to the bottom instead of repeating it throughout. ENOSPC handling is a little different from before: there is no longer any race between find_lock_page() and finding swap, but we can arrive at ENOSPC before calling shmem_recalc_inode(), which might occasionally discover freed space. Be stricter to check i_size before returning. info->lock is used for little but alloced, swapped, i_blocks updates. Move i_blocks updates out from under the max_blocks check, so even an unlimited size=0 mount can show accurate du. Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-08-04tmpfs: convert shmem_unuse_inode to radix-swapHugh Dickins1-26/+107
Convert shmem_unuse_inode() to use a lockless gang lookup of the radix tree, searching for matching swap. This is somewhat slower than the old method: because of repeated radix tree descents, because of copying entries up, but probably most because the old method noted and skipped once a vector page was cleared of swap. Perhaps we can devise a use of radix tree tagging to achieve that later. shmem_add_to_page_cache() uses shmem_radix_tree_replace() to compensate for the lockless lookup by checking that the expected entry is in place, under lock. It is not very satisfactory to be copying this much from add_to_page_cache_locked(), but I think easier to sell than insisting that every caller of add_to_page_cache*() go through the extras. Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-08-04tmpfs: convert shmem_truncate_range to radix-swapHugh Dickins1-46/+146
Disable the toy swapping implementation in shmem_writepage() - it's hard to support two schemes at once - and convert shmem_truncate_range() to a lockless gang lookup of swap entries along with pages, freeing both. Since the second loop tightens its noose until all entries of either kind have been squeezed out (and we shall make sure that there's not an instant when neither is visible), there is no longer a need for yet another pass below. shmem_radix_tree_replace() compensates for the lockless lookup by checking that the expected entry is in place, under lock, before replacing it. Here it just deletes, but will be used in later patches to substitute swap entry for page or page for swap entry. Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-08-04tmpfs: copy truncate_inode_pages_rangeHugh Dickins1-20/+79
Bring truncate.c's code for truncate_inode_pages_range() inline into shmem_truncate_range(), replacing its first call (there's a followup call below, but leave that one, it will disappear next). Don't play with it yet, apart from leaving out the cleancache flush, and (importantly) the nrpages == 0 skip, and moving shmem_setattr()'s partial page preparation into its partial page handling. Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-08-04tmpfs: miscellaneous trivial cleanupsHugh Dickins1-109/+107
While it's at its least, make a number of boring nitpicky cleanups to shmem.c, mostly for consistency of variable naming. Things like "swap" instead of "entry", "pgoff_t index" instead of "unsigned long idx". And since everything else here is prefixed "shmem_", better change init_tmpfs() to shmem_init(). Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-08-04tmpfs: demolish old swap vector supportHugh Dickins1-698/+84
The maximum size of a shmem/tmpfs file has been limited by the maximum size of its triple-indirect swap vector. With 4kB page size, maximum filesize was just over 2TB on a 32-bit kernel, but sadly one eighth of that on a 64-bit kernel. (With 8kB page size, maximum filesize was just over 4TB on a 64-bit kernel, but 16TB on a 32-bit kernel, MAX_LFS_FILESIZE being then more restrictive than swap vector layout.) It's a shame that tmpfs should be more restrictive than ramfs, and this limitation has now been noticed. Add another level to the swap vector? No, it became obscure and hard to maintain, once I complicated it to make use of highmem pages nine years ago: better choose another way. Surely, if 2.4 had had the radix tree pagecache introduced in 2.5, then tmpfs would never have invented its own peculiar radix tree: we would have fitted swap entries into the common radix tree instead, in much the same way as we fit swap entries into page tables. And why should each file have a separate radix tree for its pages and for its swap entries? The swap entries are required precisely where and when the pages are not. We want to put them together in a single radix tree: which can then avoid much of the locking which was needed to prevent them from being exchanged underneath us. This also avoids the waste of memory devoted to swap vectors, first in the shmem_inode itself, then at least two more pages once a file grew beyond 16 data pages (pages accounted by df and du, but not by memcg). Allocated upfront, to avoid allocation when under swapping pressure, but pure waste when CONFIG_SWAP is not set - I have never spattered around the ifdefs to prevent that, preferring this move to sharing the common radix tree instead. There are three downsides to sharing the radix tree. One, that it binds tmpfs more tightly to the rest of mm, either requiring knowledge of swap entries in radix tree there, or duplication of its code here in shmem.c. I believe that the simplications and memory savings (and probable higher performance, not yet measured) justify that. Two, that on HIGHMEM systems with SWAP enabled, it's the lowmem radix nodes that cannot be freed under memory pressure - whereas before it was the less precious highmem swap vector pages that could not be freed. I'm hoping that 64-bit has now been accessible for long enough, that the highmem argument has grown much less persuasive. Three, that swapoff is slower than it used to be on tmpfs files, since it's using a simple generic mechanism not tailored to it: I find this noticeable, and shall want to improve, but maybe nobody else will notice. So... now remove most of the old swap vector code from shmem.c. But, for the moment, keep the simple i_direct vector of 16 pages, with simple accessors shmem_put_swap() and shmem_get_swap(), as a toy implementation to help mark where swap needs to be handled in subsequent patches. Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-08-04mm: let swap use exceptional entriesHugh Dickins2-26/+43
If swap entries are to be stored along with struct page pointers in a radix tree, they need to be distinguished as exceptional entries. Most of the handling of swap entries in radix tree will be contained in shmem.c, but a few functions in filemap.c's common code need to check for their appearance: find_get_page(), find_lock_page(), find_get_pages() and find_get_pages_contig(). So as not to slow their fast paths, tuck those checks inside the existing checks for unlikely radix_tree_deref_slot(); except for find_lock_page(), where it is an added test. And make it a BUG in find_get_pages_tag(), which is not applied to tmpfs files. A part of the reason for eliminating shmem_readpage() earlier, was to minimize the places where common code would need to allow for swap entries. The swp_entry_t known to swapfile.c must be massaged into a slightly different form when stored in the radix tree, just as it gets massaged into a pte_t when stored in page tables. In an i386 kernel this limits its information (type and page offset) to 30 bits: given 32 "types" of swapfile and 4kB pagesize, that's a maximum swapfile size of 128GB. Which is less than the 512GB we previously allowed with X86_PAE (where the swap entry can occupy the entire upper 32 bits of a pte_t), but not a new limitation on 32-bit without PAE; and there's not a new limitation on 64-bit (where swap filesize is already limited to 16TB by a 32-bit page offset). Thirty areas of 128GB is probably still enough swap for a 64GB 32-bit machine. Provide swp_to_radix_entry() and radix_to_swp_entry() conversions, and enforce filesize limit in read_swap_header(), just as for ptes. Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-08-04radix_tree: exceptional entries and indicesHugh Dickins1-2/+2
A patchset to extend tmpfs to MAX_LFS_FILESIZE by abandoning its peculiar swap vector, instead keeping a file's swap entries in the same radix tree as its struct page pointers: thus saving memory, and simplifying its code and locking. This patch: The radix_tree is used by several subsystems for different purposes. A major use is to store the struct page pointers of a file's pagecache for memory management. But what if mm wanted to store something other than page pointers there too? The low bit of a radix_tree entry is already used to denote an indirect pointer, for internal use, and the unlikely radix_tree_deref_retry() case. Define the next bit as denoting an exceptional entry, and supply inline functions radix_tree_exception() to return non-0 in either unlikely case, and radix_tree_exceptional_entry() to return non-0 in the second case. If a subsystem already uses radix_tree with that bit set, no problem: it does not affect internal workings at all, but is defined for the convenience of those storing well-aligned pointers in the radix_tree. The radix_tree_gang_lookups have an implicit assumption that the caller can deduce the offset of each entry returned e.g. by the page->index of a struct page. But that may not be feasible for some kinds of item to be stored there. radix_tree_gang_lookup_slot() allow for an optional indices argument, output array in which to return those offsets. The same could be added to other radix_tree_gang_lookups, but for now keep it to the only one for which we need it. Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-08-04fault-injection: add ability to export fault_attr in arbitrary directoryAkinobu Mita2-15/+12
init_fault_attr_dentries() is used to export fault_attr via debugfs. But it can only export it in debugfs root directory. Per Forlin is working on mmc_fail_request which adds support to inject data errors after a completed host transfer in MMC subsystem. The fault_attr for mmc_fail_request should be defined per mmc host and export it in debugfs directory per mmc host like /sys/kernel/debug/mmc0/mmc_fail_request. init_fault_attr_dentries() doesn't help for mmc_fail_request. So this introduces fault_create_debugfs_attr() which is able to create a directory in the arbitrary directory and replace init_fault_attr_dentries(). [akpm@linux-foundation.org: extraneous semicolon, per Randy] Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Tested-by: Per Forlin <per.forlin@linaro.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Matt Mackall <mpm@selenic.com> Cc: Randy Dunlap <rdunlap@xenotime.net> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-08-03Merge branch 'apei' into apei-releaseLen Brown1-0/+92
Some trivial conflicts due to other various merges adding to the end of common lists sooner than this one. arch/ia64/Kconfig arch/powerpc/Kconfig arch/x86/Kconfig lib/Kconfig lib/Makefile Signed-off-by: Len Brown <len.brown@intel.com>
2011-08-03HWPoison: add memory_failure_queue()Huang Ying1-0/+92
memory_failure() is the entry point for HWPoison memory error recovery. It must be called in process context. But commonly hardware memory errors are notified via MCE or NMI, so some delayed execution mechanism must be used. In MCE handler, a work queue + ring buffer mechanism is used. In addition to MCE, now APEI (ACPI Platform Error Interface) GHES (Generic Hardware Error Source) can be used to report memory errors too. To add support to APEI GHES memory recovery, a mechanism similar to that of MCE is implemented. memory_failure_queue() is the new entry point that can be called in IRQ context. The next step is to make MCE handler uses this interface too. Signed-off-by: Huang Ying <ying.huang@intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com>
2011-08-02oom: task->mm == NULL doesn't mean the memory was freedOleg Nesterov1-1/+3
exit_mm() sets ->mm == NULL then it does mmput()->exit_mmap() which frees the memory. However select_bad_process() checks ->mm != NULL before TIF_MEMDIE, so it continues to kill other tasks even if we have the oom-killed task freeing its memory. Change select_bad_process() to check ->mm after TIF_MEMDIE, but skip the tasks which have already passed exit_notify() to ensure a zombie with TIF_MEMDIE set can't block oom-killer. Alternatively we could probably clear TIF_MEMDIE after exit_mmap(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-31Merge branch 'for-linus' of ↵Linus Torvalds1-3/+4
git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6 * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6: slab: use NUMA_NO_NODE slab: remove one NR_CPUS dependency
2011-07-31slab: use NUMA_NO_NODEAndrew Morton1-1/+1
Use the nice enumerated constant. Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-07-30Merge branch 'slub/lockless' of ↵Linus Torvalds1-252/+512
git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6 * 'slub/lockless' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6: (21 commits) slub: When allocating a new slab also prep the first object slub: disable interrupts in cmpxchg_double_slab when falling back to pagelock Avoid duplicate _count variables in page_struct Revert "SLUB: Fix build breakage in linux/mm_types.h" SLUB: Fix build breakage in linux/mm_types.h slub: slabinfo update for cmpxchg handling slub: Not necessary to check for empty slab on load_freelist slub: fast release on full slab slub: Add statistics for the case that the current slab does not match the node slub: Get rid of the another_slab label slub: Avoid disabling interrupts in free slowpath slub: Disable interrupts in free_debug processing slub: Invert locking and avoid slab lock slub: Rework allocator fastpaths slub: Pass kmem_cache struct to lock and freeze slab slub: explicit list_lock taking slub: Add cmpxchg_double_slab() mm: Rearrange struct page slub: Move page->frozen handling near where the page->freelist handling occurs slub: Do not use frozen page flag but a bit in the page counters ...
2011-07-28slab: remove one NR_CPUS dependencyEric Dumazet1-2/+3
Reduce high order allocations in do_tune_cpucache() for some setups. (NR_CPUS=4096 -> we need 64KB) Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Christoph Lameter <cl@linux.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2011-07-27atomic: use <linux/atomic.h>Arun Sharma4-4/+4
This allows us to move duplicated code in <asm/atomic.h> (atomic_inc_not_zero() for now) to <linux/atomic.h> Signed-off-by: Arun Sharma <asharma@fb.com> Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: David Miller <davem@davemloft.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-27fail_page_alloc: simplify debugfs initializationAkinobu Mita1-31/+16
Now cleanup_fault_attr_dentries() recursively removes a directory, So we can simplify the error handling in the initialization code and no need to hold dentry structs for each debugfs file. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-27failslab: simplify debugfs initializationAkinobu Mita1-21/+10
Now cleanup_fault_attr_dentries() recursively removes a directory, So we can simplify the error handling in the initialization code and no need to hold dentry structs for each debugfs file. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Matt Mackall <mpm@selenic.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-27fault-injection: use debugfs_remove_recursiveAkinobu Mita2-2/+2
Use debugfs_remove_recursive() to simplify initialization and deinitialization of fault injection debugfs files. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-27cpusets: randomize node rotor used in cpuset_mem_spread_node()Michal Hocko1-0/+16
[ This patch has already been accepted as commit 0ac0c0d0f837 but later reverted (commit 35926ff5fba8) because it itroduced arch specific __node_random which was defined only for x86 code so it broke other archs. This is a followup without any arch specific code. Other than that there are no functional changes.] Some workloads that create a large number of small files tend to assign too many pages to node 0 (multi-node systems). Part of the reason is that the rotor (in cpuset_mem_spread_node()) used to assign nodes starts at node 0 for newly created tasks. This patch changes the rotor to be initialized to a random node number of the cpuset. [akpm@linux-foundation.org: fix layout] [Lee.Schermerhorn@hp.com: Define stub numa_random() for !NUMA configuration] [mhocko@suse.cz: Make it arch independent] [akpm@linux-foundation.org: fix CONFIG_NUMA=y, MAX_NUMNODES>1 build] Signed-off-by: Jack Steiner <steiner@sgi.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Paul Menage <menage@google.com> Cc: Jack Steiner <steiner@sgi.com> Cc: Robin Holt <holt@sgi.com> Cc: David Rientjes <rientjes@google.com> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: David Rientjes <rientjes@google.com> Cc: Jack Steiner <steiner@sgi.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Paul Menage <menage@google.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Robin Holt <holt@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-27memcg: get rid of percpu_charge_mutex lockMichal Hocko1-10/+2
percpu_charge_mutex protects from multiple simultaneous per-cpu charge caches draining because we might end up having too many work items. At least this was the case until commit 26fe61684449 ("memcg: fix percpu cached charge draining frequency") when we introduced a more targeted draining for async mode. Now that also sync draining is targeted we can safely remove mutex because we will not send more work than the current number of CPUs. FLUSHING_CACHED_CHARGE protects from sending the same work multiple times and stock->nr_pages == 0 protects from pointless sending a work if there is obviously nothing to be done. This is of course racy but we can live with it as the race window is really small (we would have to see FLUSHING_CACHED_CHARGE cleared while nr_pages would be still non-zero). The only remaining place where we can race is synchronous mode when we rely on FLUSHING_CACHED_CHARGE test which might have been set by other drainer on the same group but we should wait in that case as well. Signed-off-by: Michal Hocko <mhocko@suse.cz> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-27memcg: add mem_cgroup_same_or_subtree() helperMichal Hocko1-25/+26
We are checking whether a given two groups are same or at least in the same subtree of a hierarchy at several places. Let's make a helper for it to make code easier to read. Signed-off-by: Michal Hocko <mhocko@suse.cz> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <bsingharora@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-27memcg: unify sync and async per-cpu charge cache drainingMichal Hocko1-14/+34
Currently we have two ways how to drain per-CPU caches for charges. drain_all_stock_sync will synchronously drain all caches while drain_all_stock_async will asynchronously drain only those that refer to a given memory cgroup or its subtree in hierarchy. Targeted async draining has been introduced by 26fe6168 (memcg: fix percpu cached charge draining frequency) to reduce the cpu workers number. sync draining is currently triggered only from mem_cgroup_force_empty which is triggered only by userspace (mem_cgroup_force_empty_write) or when a cgroup is removed (mem_cgroup_pre_destroy). Although these are not usually frequent operations it still makes some sense to do targeted draining as well, especially if the box has many CPUs. This patch unifies both methods to use the single code (drain_all_stock) which relies on the original async implementation and just adds flush_work to wait on all caches that are still under work for the sync mode. We are using FLUSHING_CACHED_CHARGE bit check to prevent from waiting on a work that we haven't triggered. Please note that both sync and async functions are currently protected by percpu_charge_mutex so we cannot race with other drainers. Signed-off-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <bsingharora@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-27memcg: do not try to drain per-cpu caches without pagesMichal Hocko1-6/+7
drain_all_stock_async tries to optimize a work to be done on the work queue by excluding any work for the current CPU because it assumes that the context we are called from already tried to charge from that cache and it's failed so it must be empty already. While the assumption is correct we can optimize it even more by checking the current number of pages in the cache. This will also reduce a work on other CPUs with an empty stock. For the current CPU we can simply call drain_local_stock rather than deferring it to the work queue. [kamezawa.hiroyu@jp.fujitsu.com: use drain_local_stock for current CPU optimization] Signed-off-by: Michal Hocko <mhocko@suse.cz> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-27memcg: add memory.vmscan_statKAMEZAWA Hiroyuki2-11/+200
The commit log of 0ae5e89c60c9 ("memcg: count the soft_limit reclaim in...") says it adds scanning stats to memory.stat file. But it doesn't because we considered we needed to make a concensus for such new APIs. This patch is a trial to add memory.scan_stat. This shows - the number of scanned pages(total, anon, file) - the number of rotated pages(total, anon, file) - the number of freed pages(total, anon, file) - the number of elaplsed time (including sleep/pause time) for both of direct/soft reclaim. The biggest difference with oringinal Ying's one is that this file can be reset by some write, as # echo 0 ...../memory.scan_stat Example of output is here. This is a result after make -j 6 kernel under 300M limit. [kamezawa@bluextal ~]$ cat /cgroup/memory/A/memory.scan_stat [kamezawa@bluextal ~]$ cat /cgroup/memory/A/memory.vmscan_stat scanned_pages_by_limit 9471864 scanned_anon_pages_by_limit 6640629 scanned_file_pages_by_limit 2831235 rotated_pages_by_limit 4243974 rotated_anon_pages_by_limit 3971968 rotated_file_pages_by_limit 272006 freed_pages_by_limit 2318492 freed_anon_pages_by_limit 962052 freed_file_pages_by_limit 1356440 elapsed_ns_by_limit 351386416101 scanned_pages_by_system 0 scanned_anon_pages_by_system 0 scanned_file_pages_by_system 0 rotated_pages_by_system 0 rotated_anon_pages_by_system 0 rotated_file_pages_by_system 0 freed_pages_by_system 0 freed_anon_pages_by_system 0 freed_file_pages_by_system 0 elapsed_ns_by_system 0 scanned_pages_by_limit_under_hierarchy 9471864 scanned_anon_pages_by_limit_under_hierarchy 6640629 scanned_file_pages_by_limit_under_hierarchy 2831235 rotated_pages_by_limit_under_hierarchy 4243974 rotated_anon_pages_by_limit_under_hierarchy 3971968 rotated_file_pages_by_limit_under_hierarchy 272006 freed_pages_by_limit_under_hierarchy 2318492 freed_anon_pages_by_limit_under_hierarchy 962052 freed_file_pages_by_limit_under_hierarchy 1356440 elapsed_ns_by_limit_under_hierarchy 351386416101 scanned_pages_by_system_under_hierarchy 0 scanned_anon_pages_by_system_under_hierarchy 0 scanned_file_pages_by_system_under_hierarchy 0 rotated_pages_by_system_under_hierarchy 0 rotated_anon_pages_by_system_under_hierarchy 0 rotated_file_pages_by_system_under_hierarchy 0 freed_pages_by_system_under_hierarchy 0 freed_anon_pages_by_system_under_hierarchy 0 freed_file_pages_by_system_under_hierarchy 0 elapsed_ns_by_system_under_hierarchy 0 total_xxxx is for hierarchy management. This will be useful for further memcg developments and need to be developped before we do some complicated rework on LRU/softlimit management. This patch adds a new struct memcg_scanrecord into scan_control struct. sc->nr_scanned at el is not designed for exporting information. For example, nr_scanned is reset frequentrly and incremented +2 at scanning mapped pages. To avoid complexity, I added a new param in scan_control which is for exporting scanning score. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Michal Hocko <mhocko@suse.cz> Cc: Ying Han <yinghan@google.com> Cc: Andrew Bresticker <abrestic@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-27memcg: fix behavior of mem_cgroup_resize_limit()Daisuke Nishimura1-1/+1
Commit 22a668d7c3ef ("memcg: fix behavior under memory.limit equals to memsw.limit") introduced "memsw_is_minimum" flag, which becomes true when mem_limit == memsw_limit. The flag is checked at the beginning of reclaim, and "noswap" is set if the flag is true, because using swap is meaningless in this case. This works well in most cases, but when we try to shrink mem_limit, which is the same as memsw_limit now, we might fail to shrink mem_limit because swap doesn't used. This patch fixes this behavior by: - check MEM_CGROUP_RECLAIM_SHRINK at the begining of reclaim - If it is set, don't set "noswap" flag even if memsw_is_minimum is true. Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <bsingharora@gmail.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Ying Han <yinghan@google.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-27memcg: fix vmscan count in small memcgsKAMEZAWA Hiroyuki1-6/+12
Commit 246e87a93934 ("memcg: fix get_scan_count() for small targets") fixes the memcg/kswapd behavior against small targets and prevent vmscan priority too high. But the implementation is too naive and adds another problem to small memcg. It always force scan to 32 pages of file/anon and doesn't handle swappiness and other rotate_info. It makes vmscan to scan anon LRU regardless of swappiness and make reclaim bad. This patch fixes it by adjusting scanning count with regard to swappiness at el. At a test "cat 1G file under 300M limit." (swappiness=20) before patch scanned_pages_by_limit 360919 scanned_anon_pages_by_limit 180469 scanned_file_pages_by_limit 180450 rotated_pages_by_limit 31 rotated_anon_pages_by_limit 25 rotated_file_pages_by_limit 6 freed_pages_by_limit 180458 freed_anon_pages_by_limit 19 freed_file_pages_by_limit 180439 elapsed_ns_by_limit 429758872 after patch scanned_pages_by_limit 180674 scanned_anon_pages_by_limit 24 scanned_file_pages_by_limit 180650 rotated_pages_by_limit 35 rotated_anon_pages_by_limit 24 rotated_file_pages_by_limit 11 freed_pages_by_limit 180634 freed_anon_pages_by_limit 0 freed_file_pages_by_limit 180634 elapsed_ns_by_limit 367119089 scanned_pages_by_system 0 the numbers of scanning anon are decreased(as expected), and elapsed time reduced. By this patch, small memcgs will work better. (*) Because the amount of file-cache is much bigger than anon, recalaim_stat's rotate-scan counter make scanning files more. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Michal Hocko <mhocko@suse.cz> Cc: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-27memcg: change memcg_oom_mutex to spinlockMichal Hocko1-11/+11
memcg_oom_mutex is used to protect memcg OOM path and eventfd interface for oom_control. None of the critical sections which it protects sleep (eventfd_signal works from atomic context and the rest are simple linked list resp. oom_lock atomic operations). Mutex is also too heavyweight for those code paths because it triggers a lot of scheduling. It also makes makes convoying effects more visible when we have a big number of oom killing because we take the lock mutliple times during mem_cgroup_handle_oom so we have multiple places where many processes can sleep. Signed-off-by: Michal Hocko <mhocko@suse.cz> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-27memcg: make oom_lock 0 and 1 based rather than counterMichal Hocko1-16/+70
Commit 867578cb ("memcg: fix oom kill behavior") introduced a oom_lock counter which is incremented by mem_cgroup_oom_lock when we are about to handle memcg OOM situation. mem_cgroup_handle_oom falls back to a sleep if oom_lock > 1 to prevent from multiple oom kills at the same time. The counter is then decremented by mem_cgroup_oom_unlock called from the same function. This works correctly but it can lead to serious starvations when we have many processes triggering OOM and many CPUs available for them (I have tested with 16 CPUs). Consider a process (call it A) which gets the oom_lock (the first one that got to mem_cgroup_handle_oom and grabbed memcg_oom_mutex) and other processes that are blocked on the mutex. While A releases the mutex and calls mem_cgroup_out_of_memory others will wake up (one after another) and increase the counter and fall into sleep (memcg_oom_waitq). Once A finishes mem_cgroup_out_of_memory it takes the mutex again and decreases oom_lock and wakes other tasks (if releasing memory by somebody else - e.g. killed process - hasn't done it yet). A testcase would look like: Assume malloc XXX is a program allocating XXX Megabytes of memory which touches all allocated pages in a tight loop # swapoff SWAP_DEVICE # cgcreate -g memory:A # cgset -r memory.oom_control=0 A # cgset -r memory.limit_in_bytes= 200M # for i in `seq 100` # do # cgexec -g memory:A malloc 10 & # done The main problem here is that all processes still race for the mutex and there is no guarantee that we will get counter back to 0 for those that got back to mem_cgroup_handle_oom. In the end the whole convoy in/decreases the counter but we do not get to 1 that would enable killing so nothing useful can be done. The time is basically unbounded because it highly depends on scheduling and ordering on mutex (I have seen this taking hours...). This patch replaces the counter by a simple {un}lock semantic. As mem_cgroup_oom_{un}lock works on the a subtree of a hierarchy we have to make sure that nobody else races with us which is guaranteed by the memcg_oom_mutex. We have to be careful while locking subtrees because we can encounter a subtree which is already locked: hierarchy: A / \ B \ /\ \ C D E B - C - D tree might be already locked. While we want to enable locking E subtree because OOM situations cannot influence each other we definitely do not want to allow locking A. Therefore we have to refuse lock if any subtree is already locked and clear up the lock for all nodes that have been set up to the failure point. On the other hand we have to make sure that the rest of the world will recognize that a group is under OOM even though it doesn't have a lock. Therefore we have to introduce under_oom variable which is incremented and decremented for the whole subtree when we enter resp. leave mem_cgroup_handle_oom. under_oom, unlike oom_lock, doesn't need be updated under memcg_oom_mutex because its users only check a single group and they use atomic operations for that. This can be checked easily by the following test case: # cgcreate -g memory:A # cgset -r memory.use_hierarchy=1 A # cgset -r memory.oom_control=1 A # cgset -r memory.limit_in_bytes= 100M # cgset -r memory.memsw.limit_in_bytes= 100M # cgcreate -g memory:A/B # cgset -r memory.oom_control=1 A/B # cgset -r memory.limit_in_bytes=20M # cgset -r memory.memsw.limit_in_bytes=20M # cgexec -g memory:A/B malloc 30 & #->this will be blocked by OOM of group B # cgexec -g memory:A malloc 80 & #->this will be blocked by OOM of group A While B gets oom_lock A will not get it. Both of them go into sleep and wait for an external action. We can make the limit higher for A to enforce waking it up # cgset -r memory.memsw.limit_in_bytes=300M A # cgset -r memory.limit_in_bytes=300M A malloc in A has to wake up even though it doesn't have oom_lock. Finally, the unlock path is very easy because we always unlock only the subtree we have locked previously while we always decrement under_oom. Signed-off-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <bsingharora@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-27memcg: consolidate memory cgroup lru stat functionsKAMEZAWA Hiroyuki2-128/+51
In mm/memcontrol.c, there are many lru stat functions as.. mem_cgroup_zone_nr_lru_pages mem_cgroup_node_nr_file_lru_pages mem_cgroup_nr_file_lru_pages mem_cgroup_node_nr_anon_lru_pages mem_cgroup_nr_anon_lru_pages mem_cgroup_node_nr_unevictable_lru_pages mem_cgroup_nr_unevictable_lru_pages mem_cgroup_node_nr_lru_pages mem_cgroup_nr_lru_pages mem_cgroup_get_local_zonestat Some of them are under #ifdef MAX_NUMNODES >1 and others are not. This seems bad. This patch consolidates all functions into mem_cgroup_zone_nr_lru_pages() mem_cgroup_node_nr_lru_pages() mem_cgroup_nr_lru_pages() For these functions, "which LRU?" information is passed by a mask. example: mem_cgroup_nr_lru_pages(mem, BIT(LRU_ACTIVE_ANON)) And I added some macro as ALL_LRU, ALL_LRU_FILE, ALL_LRU_ANON. example: mem_cgroup_nr_lru_pages(mem, ALL_LRU) BTW, considering layout of NUMA memory placement of counters, this patch seems to be better. Now, when we gather all LRU information, we scan in following orer for_each_lru -> for_each_node -> for_each_zone. This means we'll touch cache lines in different node in turn. After patch, we'll scan for_each_node -> for_each_zone -> for_each_lru(mask) Then, we'll gather information in the same cacheline at once. [akpm@linux-foundation.org: fix warnigns, build error] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-27memcg: export memory cgroup's swappiness with mem_cgroup_swappiness()KAMEZAWA Hiroyuki2-21/+17
Each memory cgroup has a 'swappiness' value which can be accessed by get_swappiness(memcg). The major user is try_to_free_mem_cgroup_pages() and swappiness is passed by argument. It's propagated by scan_control. get_swappiness() is a static function but some planned updates will need to get swappiness from files other than memcontrol.c This patch exports get_swappiness() as mem_cgroup_swappiness(). With this, we can remove the argument of swapiness from try_to_free... and drop swappiness from scan_control. only memcg uses it. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Ying Han <yinghan@google.com> Cc: Shaohua Li <shaohua.li@intel.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-26Merge branch 'for-linus' of ↵Linus Torvalds4-72/+300
git://git.kernel.org/pub/scm/linux/kernel/git/wfg/writeback * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/writeback: (27 commits) mm: properly reflect task dirty limits in dirty_exceeded logic writeback: don't busy retry writeback on new/freeing inodes writeback: scale IO chunk size up to half device bandwidth writeback: trace global_dirty_state writeback: introduce max-pause and pass-good dirty limits writeback: introduce smoothed global dirty limit writeback: consolidate variable names in balance_dirty_pages() writeback: show bdi write bandwidth in debugfs writeback: bdi write bandwidth estimation writeback: account per-bdi accumulated written pages writeback: make writeback_control.nr_to_write straight writeback: skip tmpfs early in balance_dirty_pages_ratelimited_nr() writeback: trace event writeback_queue_io writeback: trace event writeback_single_inode writeback: remove .nonblocking and .encountered_congestion writeback: remove writeback_control.more_io writeback: skip balance_dirty_pages() for in-memory fs writeback: add bdi_dirty_limit() kernel-doc writeback: avoid extra sync work at enqueue time writeback: elevate queue_io() into wb_writeback() ... Fix up trivial conflicts in fs/fs-writeback.c and mm/filemap.c
2011-07-26Merge 'akpm' patch seriesLinus Torvalds19-482/+695
* Merge akpm patch series: (122 commits) drivers/connector/cn_proc.c: remove unused local Documentation/SubmitChecklist: add RCU debug config options reiserfs: use hweight_long() reiserfs: use proper little-endian bitops pnpacpi: register disabled resources drivers/rtc/rtc-tegra.c: properly initialize spinlock drivers/rtc/rtc-twl.c: check return value of twl_rtc_write_u8() in twl_rtc_set_time() drivers/rtc: add support for Qualcomm PMIC8xxx RTC drivers/rtc/rtc-s3c.c: support clock gating drivers/rtc/rtc-mpc5121.c: add support for RTC on MPC5200 init: skip calibration delay if previously done misc/eeprom: add eeprom access driver for digsy_mtc board misc/eeprom: add driver for microwire 93xx46 EEPROMs checkpatch.pl: update $logFunctions checkpatch: make utf-8 test --strict checkpatch.pl: add ability to ignore various messages checkpatch: add a "prefer __aligned" check checkpatch: validate signature styles and To: and Cc: lines checkpatch: add __rcu as a sparse modifier checkpatch: suggest using min_t or max_t ... Did this as a merge because of (trivial) conflicts in - Documentation/feature-removal-schedule.txt - arch/xtensa/include/asm/uaccess.h that were just easier to fix up in the merge than in the patch series.
2011-07-26devres: fix possible use after freeMaxin B John1-1/+1
devres uses the pointer value as key after it's freed, which is safe but triggers spurious use-after-free warnings on some static analysis tools. Rearrange code to avoid such warnings. Signed-off-by: Maxin B. John <maxin.john@gmail.com> Reviewed-by: Rolf Eike Beer <eike-kernel@sf-tec.de> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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