diff options
| author | Yang Yang <[email protected]> | 2022-03-22 14:46:33 -0700 |
|---|---|---|
| committer | Linus Torvalds <[email protected]> | 2022-03-22 15:57:09 -0700 |
| commit | 4d45c3aff5ebf80d329eba0f90544d20224f612d (patch) | |
| tree | fc2d0043a99fe44608ed8f01da3cfa3e4f7365cb | |
| parent | d8c47cc7bf602ef73384a00869a70148146c1191 (diff) | |
mm/vmstat: add event for ksm swapping in copy
When faults in from swap what used to be a KSM page and that page had been
swapped in before, system has to make a copy, and leaves remerging the
pages to a later pass of ksmd.
That is not good for performace, we'd better to reduce this kind of copy.
There are some ways to reduce it, for example lessen swappiness or
madvise(, , MADV_MERGEABLE) range. So add this event to support doing
this tuning. Just like this patch: "mm, THP, swap: add THP swapping out
fallback counting".
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Yang Yang <[email protected]>
Reviewed-by: Ran Xiaokai <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Yang Shi <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Saravanan D <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
| -rw-r--r-- | include/linux/vm_event_item.h | 3 | ||||
| -rw-r--r-- | mm/ksm.c | 3 | ||||
| -rw-r--r-- | mm/vmstat.c | 3 |
3 files changed, 9 insertions, 0 deletions
diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h index 7b2363388bfa..16a0a4fd000b 100644 --- a/include/linux/vm_event_item.h +++ b/include/linux/vm_event_item.h @@ -129,6 +129,9 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT, #ifdef CONFIG_SWAP SWAP_RA, SWAP_RA_HIT, +#ifdef CONFIG_KSM + KSM_SWPIN_COPY, +#endif #endif #ifdef CONFIG_X86 DIRECT_MAP_LEVEL2_SPLIT, @@ -2595,6 +2595,9 @@ struct page *ksm_might_need_to_copy(struct page *page, SetPageDirty(new_page); __SetPageUptodate(new_page); __SetPageLocked(new_page); +#ifdef CONFIG_SWAP + count_vm_event(KSM_SWPIN_COPY); +#endif } return new_page; diff --git a/mm/vmstat.c b/mm/vmstat.c index 846b670dd346..d5cc8d739fac 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -1388,6 +1388,9 @@ const char * const vmstat_text[] = { #ifdef CONFIG_SWAP "swap_ra", "swap_ra_hit", +#ifdef CONFIG_KSM + "ksm_swpin_copy", +#endif #endif #ifdef CONFIG_X86 "direct_map_level2_splits", |