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| author | Charan Teja Reddy <charante@codeaurora.org> | 2021-05-05 04:36:51 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-05-05 21:27:24 +0300 |
| commit | 06dac2f467fe9269a433aa5056dd2ee1d20475e9 (patch) | |
| tree | 95f275981034d644d9a329e8bfe00dd8c2dc39ff /mm | |
| parent | ef4984384172e93cc95e0e8cd102536d67e8a787 (diff) | |
| download | linux-06dac2f467fe9269a433aa5056dd2ee1d20475e9.tar.xz | |
mm: compaction: update the COMPACT[STALL|FAIL] events properly
By definition, COMPACT[STALL|FAIL] events needs to be counted when there
is 'At least in one zone compaction wasn't deferred or skipped from the
direct compaction'. And when compaction is skipped or deferred,
COMPACT_SKIPPED will be returned but it will still go and update these
compaction events which is wrong in the sense that COMPACT[STALL|FAIL]
is counted without even trying the compaction.
Correct this by skipping the counting of these events when
COMPACT_SKIPPED is returned for compaction. This indirectly also avoid
the unnecessary try into the get_page_from_freelist() when compaction is
not even tried.
There is a corner case where compaction is skipped but still count
COMPACTSTALL event, which is that IRQ came and freed the page and the
same is captured in capture_control.
Link: https://lkml.kernel.org/r/1613151184-21213-1-git-send-email-charante@codeaurora.org
Signed-off-by: Charan Teja Reddy <charante@codeaurora.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/compaction.c | 8 | ||||
| -rw-r--r-- | mm/page_alloc.c | 2 |
2 files changed, 10 insertions, 0 deletions
diff --git a/mm/compaction.c b/mm/compaction.c index 027eb794e747..1be7928af62b 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -2529,6 +2529,14 @@ static enum compact_result compact_zone_order(struct zone *zone, int order, */ WRITE_ONCE(current->capture_control, NULL); *capture = READ_ONCE(capc.page); + /* + * Technically, it is also possible that compaction is skipped but + * the page is still captured out of luck(IRQ came and freed the page). + * Returning COMPACT_SUCCESS in such cases helps in properly accounting + * the COMPACT[STALL|FAIL] when compaction is skipped. + */ + if (*capture) + ret = COMPACT_SUCCESS; return ret; } diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 19cdd8a829dc..64d4aae2a78a 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -4204,6 +4204,8 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order, memalloc_noreclaim_restore(noreclaim_flag); psi_memstall_leave(&pflags); + if (*compact_result == COMPACT_SKIPPED) + return NULL; /* * At least in one zone compaction wasn't deferred or skipped, so let's * count a compaction stall |