The patch titled
Subject: mm: skip over all consecutive none ptes in do_zap_pte_range()
has been added to the -mm mm-unstable branch. Its filename is
mm-skip-over-all-consecutive-none-ptes-in-do_zap_pte_range.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-skip-over-all-consecutive-none-ptes-in-do_zap_pte_range.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
Subject: mm: skip over all consecutive none ptes in do_zap_pte_range()
Date: Wed, 4 Dec 2024 19:09:45 +0800
Skip over all consecutive none ptes in do_zap_pte_range(), which helps
optimize away need_resched() + force_break + incremental pte/addr
increments etc.
Link: https://lkml.kernel.org/r/8ecffbf990afd1c8ccc195a2ec321d55f0923908.1733305182.git.zhengqi.arch@xxxxxxxxxxxxx
Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
Suggested-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Zach O'Keefe <zokeefe@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory.c | 27 ++++++++++++++++++++-------
1 file changed, 20 insertions(+), 7 deletions(-)
--- a/mm/memory.c~mm-skip-over-all-consecutive-none-ptes-in-do_zap_pte_range
+++ a/mm/memory.c
@@ -1665,17 +1665,30 @@ static inline int do_zap_pte_range(struc
{
pte_t ptent = ptep_get(pte);
int max_nr = (end - addr) / PAGE_SIZE;
+ int nr = 0;
- if (pte_none(ptent))
- return 1;
+ /* Skip all consecutive none ptes */
+ if (pte_none(ptent)) {
+ for (nr = 1; nr < max_nr; nr++) {
+ ptent = ptep_get(pte + nr);
+ if (!pte_none(ptent))
+ break;
+ }
+ max_nr -= nr;
+ if (!max_nr)
+ return nr;
+ pte += nr;
+ addr += nr * PAGE_SIZE;
+ }
if (pte_present(ptent))
- return zap_present_ptes(tlb, vma, pte, ptent, max_nr,
- addr, details, rss, force_flush,
- force_break);
+ nr += zap_present_ptes(tlb, vma, pte, ptent, max_nr, addr,
+ details, rss, force_flush, force_break);
+ else
+ nr += zap_nonpresent_ptes(tlb, vma, pte, ptent, max_nr, addr,
+ details, rss);
- return zap_nonpresent_ptes(tlb, vma, pte, ptent, max_nr, addr,
- details, rss);
+ return nr;
}
static unsigned long zap_pte_range(struct mmu_gather *tlb,
_
Patches currently in -mm which might be from zhengqi.arch@xxxxxxxxxxxxx are
mm-pgtable-make-ptep_clear-non-atomic.patch
mm-khugepaged-recheck-pmd-state-in-retract_page_tables.patch
mm-userfaultfd-recheck-dst_pmd-entry-in-move_pages_pte.patch
mm-introduce-zap_nonpresent_ptes.patch
mm-introduce-do_zap_pte_range.patch
mm-skip-over-all-consecutive-none-ptes-in-do_zap_pte_range.patch
mm-zap_install_uffd_wp_if_needed-return-whether-uffd-wp-pte-has-been-re-installed.patch
mm-do_zap_pte_range-return-any_skipped-information-to-the-caller.patch
mm-make-zap_pte_range-handle-full-within-pmd-range.patch
mm-pgtable-reclaim-empty-pte-page-in-madvisemadv_dontneed.patch
x86-mm-free-page-table-pages-by-rcu-instead-of-semi-rcu.patch
x86-select-arch_supports_pt_reclaim-if-x86_64.patch
