Subject: + move-mmu-notifier-call-from-change_protection-to-change_pmd_range.patch added to -mm tree To: riel@xxxxxxxxxx,aarcange@xxxxxxxxxx,chegu_vinod@xxxxxx,gang.xing@xxxxxx,peterz@xxxxxxxxxxxxx,rientjes@xxxxxxxxxx From: akpm@xxxxxxxxxxxxxxxxxxxx Date: Wed, 19 Feb 2014 11:27:48 -0800 The patch titled Subject: mm: move mmu notifier call from change_protection to change_pmd_range has been added to the -mm tree. Its filename is move-mmu-notifier-call-from-change_protection-to-change_pmd_range.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/move-mmu-notifier-call-from-change_protection-to-change_pmd_range.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/move-mmu-notifier-call-from-change_protection-to-change_pmd_range.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Rik van Riel <riel@xxxxxxxxxx> Subject: mm: move mmu notifier call from change_protection to change_pmd_range The NUMA scanning code can end up iterating over many gigabytes of unpopulated memory, especially in the case of a freshly started KVM guest with lots of memory. This results in the mmu notifier code being called even when there are no mapped pages in a virtual address range. The amount of time wasted can be enough to trigger soft lockup warnings with very large KVM guests. This patch moves the mmu notifier call to the pmd level, which represents 1GB areas of memory on x86-64. Furthermore, the mmu notifier code is only called from the address in the PMD where present mappings are first encountered. The hugetlbfs code is left alone for now; hugetlb mappings are not relocatable, and as such are left alone by the NUMA code, and should never trigger this problem to begin with. Signed-off-by: Rik van Riel <riel@xxxxxxxxxx> Acked-by: David Rientjes <rientjes@xxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx> Reported-by: Xing Gang <gang.xing@xxxxxx> Tested-by: Chegu Vinod <chegu_vinod@xxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/hugetlb.c | 2 ++ mm/mprotect.c | 15 ++++++++++++--- 2 files changed, 14 insertions(+), 3 deletions(-) diff -puN mm/hugetlb.c~move-mmu-notifier-call-from-change_protection-to-change_pmd_range mm/hugetlb.c --- a/mm/hugetlb.c~move-mmu-notifier-call-from-change_protection-to-change_pmd_range +++ a/mm/hugetlb.c @@ -3185,6 +3185,7 @@ unsigned long hugetlb_change_protection( BUG_ON(address >= end); flush_cache_range(vma, address, end); + mmu_notifier_invalidate_range_start(mm, start, end); mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex); for (; address < end; address += huge_page_size(h)) { spinlock_t *ptl; @@ -3214,6 +3215,7 @@ unsigned long hugetlb_change_protection( */ flush_tlb_range(vma, start, end); mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex); + mmu_notifier_invalidate_range_end(mm, start, end); return pages << h->order; } diff -puN mm/mprotect.c~move-mmu-notifier-call-from-change_protection-to-change_pmd_range mm/mprotect.c --- a/mm/mprotect.c~move-mmu-notifier-call-from-change_protection-to-change_pmd_range +++ a/mm/mprotect.c @@ -109,9 +109,11 @@ static inline unsigned long change_pmd_r pgprot_t newprot, int dirty_accountable, int prot_numa) { pmd_t *pmd; + struct mm_struct *mm = vma->vm_mm; unsigned long next; unsigned long pages = 0; unsigned long nr_huge_updates = 0; + unsigned long mni_start = 0; pmd = pmd_offset(pud, addr); do { @@ -120,6 +122,13 @@ static inline unsigned long change_pmd_r next = pmd_addr_end(addr, end); if (!pmd_trans_huge(*pmd) && pmd_none_or_clear_bad(pmd)) continue; + + /* invoke the mmu notifier if the pmd is populated */ + if (!mni_start) { + mni_start = addr; + mmu_notifier_invalidate_range_start(mm, mni_start, end); + } + if (pmd_trans_huge(*pmd)) { if (next - addr != HPAGE_PMD_SIZE) split_huge_page_pmd(vma, addr, pmd); @@ -143,6 +152,9 @@ static inline unsigned long change_pmd_r pages += this_pages; } while (pmd++, addr = next, addr != end); + if (mni_start) + mmu_notifier_invalidate_range_end(mm, mni_start, end); + if (nr_huge_updates) count_vm_numa_events(NUMA_HUGE_PTE_UPDATES, nr_huge_updates); return pages; @@ -202,15 +214,12 @@ unsigned long change_protection(struct v unsigned long end, pgprot_t newprot, int dirty_accountable, int prot_numa) { - struct mm_struct *mm = vma->vm_mm; unsigned long pages; - mmu_notifier_invalidate_range_start(mm, start, end); if (is_vm_hugetlb_page(vma)) pages = hugetlb_change_protection(vma, start, end, newprot); else pages = change_protection_range(vma, start, end, newprot, dirty_accountable, prot_numa); - mmu_notifier_invalidate_range_end(mm, start, end); return pages; } _ Patches currently in -mm which might be from riel@xxxxxxxxxx are origin.patch mm-hwpoison-release-page-on-pagehwpoison-in-__do_fault.patch mm-close-pagetail-race.patch mm-page_alloc-make-first_page-visible-before-pagetail.patch mm-include-vm_mixedmap-flag-in-the-vm_special-list-to-avoid-munlocking.patch mm-vmscan-respect-numa-policy-mask-when-shrinking-slab-on-direct-reclaim.patch mm-vmscan-move-call-to-shrink_slab-to-shrink_zones.patch mm-vmscan-remove-shrink_control-arg-from-do_try_to_free_pages.patch mm-compaction-ignore-pageblock-skip-when-manually-invoking-compaction.patch mm-vmstat-fix-up-zone-state-accounting.patch fs-cachefiles-use-add_to_page_cache_lru.patch lib-radix-tree-radix_tree_delete_item.patch mm-shmem-save-one-radix-tree-lookup-when-truncating-swapped-pages.patch mm-filemap-move-radix-tree-hole-searching-here.patch mm-fs-prepare-for-non-page-entries-in-page-cache-radix-trees.patch mm-fs-store-shadow-entries-in-page-cache.patch mm-thrash-detection-based-file-cache-sizing.patch lib-radix_tree-tree-node-interface.patch mm-keep-page-cache-radix-tree-nodes-in-check.patch mm-keep-page-cache-radix-tree-nodes-in-check-fix.patch mm-keep-page-cache-radix-tree-nodes-in-check-fix-fix.patch mm-compaction-avoid-isolating-pinned-pages.patch mm-compactionc-mark-function-as-static.patch mm-memoryc-mark-functions-as-static.patch mm-mmapc-mark-function-as-static.patch include-linux-mmh-remove-ifdef-condition.patch pagewalk-update-page-table-walker-core.patch pagewalk-add-walk_page_vma.patch smaps-redefine-callback-functions-for-page-table-walker.patch clear_refs-redefine-callback-functions-for-page-table-walker.patch pagemap-redefine-callback-functions-for-page-table-walker.patch numa_maps-redefine-callback-functions-for-page-table-walker.patch memcg-redefine-callback-functions-for-page-table-walker.patch madvise-redefine-callback-functions-for-page-table-walker.patch arch-powerpc-mm-subpage-protc-use-walk_page_vma-instead-of-walk_page_range.patch pagewalk-remove-argument-hmask-from-hugetlb_entry.patch mempolicy-apply-page-table-walker-on-queue_pages_range.patch mm-rename-__do_fault-do_fault.patch mm-do_fault-extract-to-call-vm_ops-do_fault-to-separate-function.patch mm-introduce-do_read_fault.patch mm-introduce-do_cow_fault.patch mm-introduce-do_shared_fault-and-drop-do_fault.patch mm-consolidate-code-to-call-vm_ops-page_mkwrite.patch mm-consolidate-code-to-call-vm_ops-page_mkwrite-fix.patch mm-consolidate-code-to-setup-pte.patch schednuma-add-cond_resched-to-task_numa_work.patch mmnuma-reorganize-change_pmd_range.patch mmnuma-reorganize-change_pmd_range-fix.patch move-mmu-notifier-call-from-change_protection-to-change_pmd_range.patch fs-proc-meminfo-meminfo_proc_show-fix-typo-in-comment.patch linux-next.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html