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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 <kaixuxia@tencent.com>
Reviewed-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Kaixu Xia 2022-08-27 17:02:51 +08:00 committed by Andrew Morton
parent 09876ae739
commit 95cd252266
1 changed files with 6 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
mm/damon/vaddr.c
View File

@ -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);
}