The patch titled Subject: mm: numa: avoid unnecessary TLB flushes when setting NUMA hinting entries has been added to the -mm tree. Its filename is mm-numa-avoid-unnecessary-tlb-flushes-when-setting-numa-hinting-entries.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-numa-avoid-unnecessary-tlb-flushes-when-setting-numa-hinting-entries.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-numa-avoid-unnecessary-tlb-flushes-when-setting-numa-hinting-entries.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: Mel Gorman <mgorman@xxxxxxx> Subject: mm: numa: avoid unnecessary TLB flushes when setting NUMA hinting entries If a PTE or PMD is already marked NUMA when scanning to mark entries for NUMA hinting then it is not necessary to update the entry and incur a TLB flush penalty. Avoid the avoidhead where possible. Signed-off-by: Mel Gorman <mgorman@xxxxxxx> Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Cc: Dave Jones <davej@xxxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Kirill Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Paul Mackerras <paulus@xxxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxx> Cc: Sasha Levin <sasha.levin@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/huge_memory.c | 14 ++++++++------ mm/mprotect.c | 4 ++++ 2 files changed, 12 insertions(+), 6 deletions(-) diff -puN mm/huge_memory.c~mm-numa-avoid-unnecessary-tlb-flushes-when-setting-numa-hinting-entries mm/huge_memory.c --- a/mm/huge_memory.c~mm-numa-avoid-unnecessary-tlb-flushes-when-setting-numa-hinting-entries +++ a/mm/huge_memory.c @@ -1519,12 +1519,14 @@ int change_huge_pmd(struct vm_area_struc return 0; } - ret = 1; - entry = pmdp_get_and_clear_notify(mm, addr, pmd); - entry = pmd_modify(entry, newprot); - ret = HPAGE_PMD_NR; - set_pmd_at(mm, addr, pmd, entry); - BUG_ON(pmd_write(entry)); + if (!prot_numa || !pmd_protnone(*pmd)) { + ret = 1; + entry = pmdp_get_and_clear_notify(mm, addr, pmd); + entry = pmd_modify(entry, newprot); + ret = HPAGE_PMD_NR; + set_pmd_at(mm, addr, pmd, entry); + BUG_ON(pmd_write(entry)); + } spin_unlock(ptl); } diff -puN mm/mprotect.c~mm-numa-avoid-unnecessary-tlb-flushes-when-setting-numa-hinting-entries mm/mprotect.c --- a/mm/mprotect.c~mm-numa-avoid-unnecessary-tlb-flushes-when-setting-numa-hinting-entries +++ a/mm/mprotect.c @@ -86,6 +86,10 @@ static unsigned long change_pte_range(st page = vm_normal_page(vma, addr, oldpte); if (!page || PageKsm(page)) continue; + + /* Avoid TLB flush if possible */ + if (pte_protnone(oldpte)) + continue; } ptent = ptep_modify_prot_start(mm, addr, pte); _ Patches currently in -mm which might be from mgorman@xxxxxxx are mm-debug-pagealloc-prepare-boottime-configurable-on-off.patch mm-vmscan-prevent-kswapd-livelock-due-to-pfmemalloc-throttled-process-being-killed.patch mm-page_alloc-place-zone_id-check-before-vm_bug_on_page-check.patch mm-vmscan-wake-up-all-pfmemalloc-throttled-processes-at-once.patch mm-numa-do-not-dereference-pmd-outside-of-the-lock-during-numa-hinting-fault.patch mm-add-p-protnone-helpers-for-use-by-numa-balancing.patch mm-convert-p_numa-users-to-p_protnone_numa.patch ppc64-add-paranoid-warnings-for-unexpected-dsisr_protfault.patch mm-convert-p_mknonnuma-and-remaining-page-table-manipulations.patch mm-remove-remaining-references-to-numa-hinting-bits-and-helpers.patch mm-numa-do-not-trap-faults-on-the-huge-zero-page.patch x86-mm-restore-original-pte_special-check.patch mm-numa-add-paranoid-check-around-pte_protnone_numa.patch mm-numa-avoid-unnecessary-tlb-flushes-when-setting-numa-hinting-entries.patch do_shared_fault-check-that-mmap_sem-is-held.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