The patch titled
Subject: mm: multi-gen LRU: improve walk_pmd_range()
has been added to the -mm mm-unstable branch. Its filename is
mm-multi-gen-lru-improve-walk_pmd_range.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-multi-gen-lru-improve-walk_pmd_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: "T.J. Alumbaugh" <talumbau@xxxxxxxxxx>
Subject: mm: multi-gen LRU: improve walk_pmd_range()
Date: Wed, 18 Jan 2023 00:18:26 +0000
Improve readability of walk_pmd_range() and walk_pmd_range_locked().
Link: https://lkml.kernel.org/r/20230118001827.1040870-7-talumbau@xxxxxxxxxx
Signed-off-by: T.J. Alumbaugh <talumbau@xxxxxxxxxx>
Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/mm/vmscan.c~mm-multi-gen-lru-improve-walk_pmd_range
+++ a/mm/vmscan.c
@@ -3999,8 +3999,8 @@ restart:
}
#if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG)
-static void walk_pmd_range_locked(pud_t *pud, unsigned long next, struct vm_area_struct *vma,
- struct mm_walk *args, unsigned long *bitmap, unsigned long *start)
+static void walk_pmd_range_locked(pud_t *pud, unsigned long addr, struct vm_area_struct *vma,
+ struct mm_walk *args, unsigned long *bitmap, unsigned long *first)
{
int i;
pmd_t *pmd;
@@ -4013,18 +4013,19 @@ static void walk_pmd_range_locked(pud_t
VM_WARN_ON_ONCE(pud_leaf(*pud));
/* try to batch at most 1+MIN_LRU_BATCH+1 entries */
- if (*start == -1) {
- *start = next;
+ if (*first == -1) {
+ *first = addr;
+ bitmap_zero(bitmap, MIN_LRU_BATCH);
return;
}
- i = next == -1 ? 0 : pmd_index(next) - pmd_index(*start);
+ i = addr == -1 ? 0 : pmd_index(addr) - pmd_index(*first);
if (i && i <= MIN_LRU_BATCH) {
__set_bit(i - 1, bitmap);
return;
}
- pmd = pmd_offset(pud, *start);
+ pmd = pmd_offset(pud, *first);
ptl = pmd_lockptr(args->mm, pmd);
if (!spin_trylock(ptl))
@@ -4035,15 +4036,16 @@ static void walk_pmd_range_locked(pud_t
do {
unsigned long pfn;
struct folio *folio;
- unsigned long addr = i ? (*start & PMD_MASK) + i * PMD_SIZE : *start;
+
+ /* don't round down the first address */
+ addr = i ? (*first & PMD_MASK) + i * PMD_SIZE : *first;
pfn = get_pmd_pfn(pmd[i], vma, addr);
if (pfn == -1)
goto next;
if (!pmd_trans_huge(pmd[i])) {
- if (arch_has_hw_nonleaf_pmd_young() &&
- get_cap(LRU_GEN_NONLEAF_YOUNG))
+ if (arch_has_hw_nonleaf_pmd_young() && get_cap(LRU_GEN_NONLEAF_YOUNG))
pmdp_test_and_clear_young(vma, addr, pmd + i);
goto next;
}
@@ -4072,12 +4074,11 @@ next:
arch_leave_lazy_mmu_mode();
spin_unlock(ptl);
done:
- *start = -1;
- bitmap_zero(bitmap, MIN_LRU_BATCH);
+ *first = -1;
}
#else
-static void walk_pmd_range_locked(pud_t *pud, unsigned long next, struct vm_area_struct *vma,
- struct mm_walk *args, unsigned long *bitmap, unsigned long *start)
+static void walk_pmd_range_locked(pud_t *pud, unsigned long addr, struct vm_area_struct *vma,
+ struct mm_walk *args, unsigned long *bitmap, unsigned long *first)
{
}
#endif
@@ -4090,9 +4091,9 @@ static void walk_pmd_range(pud_t *pud, u
unsigned long next;
unsigned long addr;
struct vm_area_struct *vma;
- unsigned long pos = -1;
+ unsigned long bitmap[BITS_TO_LONGS(MIN_LRU_BATCH)];
+ unsigned long first = -1;
struct lru_gen_mm_walk *walk = args->private;
- unsigned long bitmap[BITS_TO_LONGS(MIN_LRU_BATCH)] = {};
VM_WARN_ON_ONCE(pud_leaf(*pud));
@@ -4131,18 +4132,17 @@ restart:
if (pfn < pgdat->node_start_pfn || pfn >= pgdat_end_pfn(pgdat))
continue;
- walk_pmd_range_locked(pud, addr, vma, args, bitmap, &pos);
+ walk_pmd_range_locked(pud, addr, vma, args, bitmap, &first);
continue;
}
#endif
walk->mm_stats[MM_NONLEAF_TOTAL]++;
- if (arch_has_hw_nonleaf_pmd_young() &&
- get_cap(LRU_GEN_NONLEAF_YOUNG)) {
+ if (arch_has_hw_nonleaf_pmd_young() && get_cap(LRU_GEN_NONLEAF_YOUNG)) {
if (!pmd_young(val))
continue;
- walk_pmd_range_locked(pud, addr, vma, args, bitmap, &pos);
+ walk_pmd_range_locked(pud, addr, vma, args, bitmap, &first);
}
if (!walk->force_scan && !test_bloom_filter(walk->lruvec, walk->max_seq, pmd + i))
@@ -4159,7 +4159,7 @@ restart:
update_bloom_filter(walk->lruvec, walk->max_seq + 1, pmd + i);
}
- walk_pmd_range_locked(pud, -1, vma, args, bitmap, &pos);
+ walk_pmd_range_locked(pud, -1, vma, args, bitmap, &first);
if (i < PTRS_PER_PMD && get_next_vma(PUD_MASK, PMD_SIZE, args, &start, &end))
goto restart;
_
Patches currently in -mm which might be from talumbau@xxxxxxxxxx are
mm-multi-gen-lru-section-for-working-set-protection.patch
mm-multi-gen-lru-section-for-rmap-pt-walk-feedback.patch
mm-multi-gen-lru-section-for-bloom-filters.patch
mm-multi-gen-lru-section-for-memcg-lru.patch
mm-multi-gen-lru-improve-lru_gen_exit_memcg.patch
mm-multi-gen-lru-improve-walk_pmd_range.patch
mm-multi-gen-lru-simplify-lru_gen_look_around.patch
