kernel/linux.git/arch/powerpc/mm/pgtable_64.c, branch linux-4.4.y

powerpc/booke64: Move mb() to __set_pte_at() with kernel-addr test

2015-08-08T04:00:01+00:00

map_kernel() doesn't catch all places that create kernel PTEs. In particular, vmalloc() calls set_pte_at() directly. This causes a crash when booting a non-SMP kernel on e6500. Move the sync to __set_pte(), to be executed only for kernel addresses. Signed-off-by: Scott Wood

mm: clarify that the function operates on hugepage pte

2015-06-25T00:49:44+00:00

We have confusing functions to clear pmd, pmd_clear_* and pmd_clear. Add _huge_ to pmdp_clear functions so that we are clear that they operate on hugepage pte. We don't bother about other functions like pmdp_set_wrprotect, pmdp_clear_flush_young, because they operate on PTE bits and hence indicate they are operating on hugepage ptes Signed-off-by: Aneesh Kumar K.V Acked-by: Kirill A. Shutemov Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman Cc: Andrea Arcangeli Cc: Martin Schwidefsky Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

powerpc/mm: use generic version of pmdp_clear_flush()

2015-06-25T00:49:44+00:00

Also move the pmd_trans_huge check to generic code. Signed-off-by: Aneesh Kumar K.V Acked-by: Kirill A. Shutemov Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman Cc: Andrea Arcangeli Cc: Martin Schwidefsky Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/thp: split out pmd collapse flush into separate functions

2015-06-25T00:49:44+00:00

Architectures like ppc64 [1] need to do special things while clearing pmd before a collapse. For them this operation is largely different from a normal hugepage pte clear. Hence add a separate function to clear pmd before collapse. After this patch pmdp_* functions operate only on hugepage pte, and not on regular pmd_t values pointing to page table. [1] ppc64 needs to invalidate all the normal page pte mappings we already have inserted in the hardware hash page table. But before doing that we need to make sure there are no parallel hash page table insert going on. So we need to do a kick_all_cpus_sync() before flushing the older hash table entries. By moving this to a separate function we capture these details and mention how it is different from a hugepage pte clear. This patch is a cleanup and only does code movement for clarity. There should not be any change in functionality. Signed-off-by: Aneesh Kumar K.V Acked-by: Kirill A. Shutemov Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman Cc: Andrea Arcangeli Cc: Martin Schwidefsky Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

powerpc/thp: Serialize pmd clear against a linux page table walk.

2015-05-12T01:03:29+00:00

Serialize against find_linux_pte_or_hugepte() which does lock-less lookup in page tables with local interrupts disabled. For huge pages it casts pmd_t to pte_t. Since the format of pte_t is different from pmd_t we want to prevent transit from pmd pointing to page table to pmd pointing to huge page (and back) while interrupts are disabled. We clear pmd to possibly replace it with page table pointer in different code paths. So make sure we wait for the parallel find_linux_pte_or_hugepage() to finish. Without this patch, a find_linux_pte_or_hugepte() running in parallel to __split_huge_zero_page_pmd() or do_huge_pmd_wp_page_fallback() or zap_huge_pmd() can run into the above issue. With __split_huge_zero_page_pmd() and do_huge_pmd_wp_page_fallback() we clear the hugepage pte before inserting the pmd entry with a regular pgtable address. Such a clear need to wait for the parallel find_linux_pte_or_hugepte() to finish. With zap_huge_pmd(), we can run into issues, with a hugepage pte getting zapped due to a MADV_DONTNEED while other cpu fault it in as small pages. Reported-by: Kirill A. Shutemov Signed-off-by: Aneesh Kumar K.V Reviewed-by: Kirill A. Shutemov Signed-off-by: Michael Ellerman

powerpc: Replace mem_init_done with slab_is_available()

2015-04-10T10:02:48+00:00

We have a powerpc specific global called mem_init_done which is "set on boot once kmalloc can be called". But that's not *quite* true. We set it at the bottom of mem_init(), and rely on the fact that mm_init() calls kmem_cache_init() immediately after that, and nothing is running in parallel. So replace it with the generic and 100% correct slab_is_available(). Signed-off-by: Michael Ellerman

powerpc: Fix compile errors with STRICT_MM_TYPECHECKS enabled

2015-04-10T10:02:47+00:00

Signed-off-by: Aneesh Kumar K.V [mpe: Fix the 32-bit code also] Signed-off-by: Michael Ellerman

powerpc: drop _PAGE_FILE and pte_file()-related helpers

2015-02-17T01:56:05+00:00

We've replaced remap_file_pages(2) implementation with emulation. Nobody creates non-linear mapping anymore. Signed-off-by: Kirill A. Shutemov Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: convert p[te|md]_numa users to p[te|md]_protnone_numa

2015-02-13T02:54:08+00:00

Convert existing users of pte_numa and friends to the new helper. Note that the kernel is broken after this patch is applied until the other page table modifiers are also altered. This patch layout is to make review easier. Signed-off-by: Mel Gorman Acked-by: Linus Torvalds Acked-by: Aneesh Kumar Acked-by: Benjamin Herrenschmidt Tested-by: Sasha Levin Cc: Dave Jones Cc: Hugh Dickins Cc: Ingo Molnar Cc: Kirill Shutemov Cc: Paul Mackerras Cc: Rik van Riel Cc: Sasha Levin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

powerpc/mm: don't do tlbie for updatepp request with NO HPTE fault

2014-12-05T05:26:15+00:00

upatepp can get called for a nohpte fault when we find from the linux page table that the translation was hashed before. In that case we are sure that there is no existing translation, hence we could avoid doing tlbie. We could possibly race with a parallel fault filling the TLB. But that should be ok because updatepp is only ever relaxing permissions. We also look at linux pte permission bits when filling hash pte permission bits. We also hold the linux pte busy bits while inserting/updating a hashpte entry, hence a paralle update of linux pte is not possible. On the other hand mprotect involves ptep_modify_prot_start which cause a hpte invalidate and not updatepp. Performance number: We use randbox_access_bench written by Anton. Kernel with THP disabled and smaller hash page table size. 86.60% random_access_b [kernel.kallsyms] [k] .native_hpte_updatepp 2.10% random_access_b random_access_bench [.] doit 1.99% random_access_b [kernel.kallsyms] [k] .do_raw_spin_lock 1.85% random_access_b [kernel.kallsyms] [k] .native_hpte_insert 1.26% random_access_b [kernel.kallsyms] [k] .native_flush_hash_range 1.18% random_access_b [kernel.kallsyms] [k] .__delay 0.69% random_access_b [kernel.kallsyms] [k] .native_hpte_remove 0.37% random_access_b [kernel.kallsyms] [k] .clear_user_page 0.34% random_access_b [kernel.kallsyms] [k] .__hash_page_64K 0.32% random_access_b [kernel.kallsyms] [k] fast_exception_return 0.30% random_access_b [kernel.kallsyms] [k] .hash_page_mm With Fix: 27.54% random_access_b random_access_bench [.] doit 22.90% random_access_b [kernel.kallsyms] [k] .native_hpte_insert 5.76% random_access_b [kernel.kallsyms] [k] .native_hpte_remove 5.20% random_access_b [kernel.kallsyms] [k] fast_exception_return 5.12% random_access_b [kernel.kallsyms] [k] .__hash_page_64K 4.80% random_access_b [kernel.kallsyms] [k] .hash_page_mm 3.31% random_access_b [kernel.kallsyms] [k] data_access_common 1.84% random_access_b [kernel.kallsyms] [k] .trace_hardirqs_on_caller Signed-off-by: Aneesh Kumar K.V Signed-off-by: Michael Ellerman