From 95cd2522669243a1804ba8e9583ed10b3b4f51ef Mon Sep 17 00:00:00 2001 From: Kaixu Xia Date: Sat, 27 Aug 2022 17:02:51 +0800 Subject: [PATCH] mm/damon/vaddr: remove comparison between mm and last_mm when checking region accesses The damon regions that belong to the same damon target have the same 'struct mm_struct *mm', so it's unnecessary to compare the mm and last_mm objects among the damon regions in one damon target when checking accesses. But the check is necessary when the target changed in '__damon_va_check_accesses()', so we can simplify the whole operation by using the bool 'same_target' to indicate whether the target changed. Link: https://lkml.kernel.org/r/1661590971-20893-3-git-send-email-kaixuxia@tencent.com Signed-off-by: Kaixu Xia Reviewed-by: SeongJae Park Signed-off-by: Andrew Morton --- mm/damon/vaddr.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c index 34a72f5e13f5..a8505ad47c60 100644 --- a/mm/damon/vaddr.c +++ b/mm/damon/vaddr.c @@ -543,15 +543,14 @@ static bool damon_va_young(struct mm_struct *mm, unsigned long addr, * r the region to be checked */ static void __damon_va_check_access(struct mm_struct *mm, - struct damon_region *r) + struct damon_region *r, bool same_target) { - static struct mm_struct *last_mm; static unsigned long last_addr; static unsigned long last_page_sz = PAGE_SIZE; static bool last_accessed; /* If the region is in the last checked page, reuse the result */ - if (mm == last_mm && (ALIGN_DOWN(last_addr, last_page_sz) == + if (same_target && (ALIGN_DOWN(last_addr, last_page_sz) == ALIGN_DOWN(r->sampling_addr, last_page_sz))) { if (last_accessed) r->nr_accesses++; @@ -562,7 +561,6 @@ static void __damon_va_check_access(struct mm_struct *mm, if (last_accessed) r->nr_accesses++; - last_mm = mm; last_addr = r->sampling_addr; } @@ -572,14 +570,17 @@ static unsigned int damon_va_check_accesses(struct damon_ctx *ctx) struct mm_struct *mm; struct damon_region *r; unsigned int max_nr_accesses = 0; + bool same_target; damon_for_each_target(t, ctx) { mm = damon_get_mm(t); if (!mm) continue; + same_target = false; damon_for_each_region(r, t) { - __damon_va_check_access(mm, r); + __damon_va_check_access(mm, r, same_target); max_nr_accesses = max(r->nr_accesses, max_nr_accesses); + same_target = true; } mmput(mm); } -- 2.11.0