From b5ff4133617d0eced35b685da0bd0929dd9fabb7 Mon Sep 17 00:00:00 2001 From: "T.J. Alumbaugh" Date: Wed, 18 Jan 2023 00:18:26 +0000 Subject: [PATCH] mm: multi-gen LRU: improve walk_pmd_range() Improve readability of walk_pmd_range() and walk_pmd_range_locked(). Link: https://lkml.kernel.org/r/20230118001827.1040870-7-talumbau@google.com Signed-off-by: T.J. Alumbaugh Cc: Yu Zhao Signed-off-by: Andrew Morton --- mm/vmscan.c | 40 ++++++++++++++++++++-------------------- 1 file changed, 20 insertions(+), 20 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index c2e6ad53447b..ff3b4aa3c31f 100644 --- a/mm/vmscan.c +++ b/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 *pud, unsigned long next, struct vm_area 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 *pud, unsigned long next, struct vm_area 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, unsigned long start, unsigned long end, 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;