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authorJohannes Weiner <hannes@cmpxchg.org>2021-08-20 05:04:27 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2021-08-20 21:31:42 +0300
commit57f29762cdd4687a02f245d1b1e78de046388eac (patch)
tree618d4ae22167aef73c1cb0cd605ff244fcd43326 /mm
parentfcc00621d88b274b5dffd8daeea71d0e4c28b84e (diff)
downloadlinux-57f29762cdd4687a02f245d1b1e78de046388eac.tar.xz
mm: vmscan: fix missing psi annotation for node_reclaim()
In a debugging session the other day, Rik noticed that node_reclaim() was missing memstall annotations. This means we'll miss pressure and lost productivity resulting from reclaim on an overloaded local NUMA node when vm.zone_reclaim_mode is enabled. There haven't been any reports, but that's likely because vm.zone_reclaim_mode hasn't been a commonly used feature recently, and the intersection between such setups and psi users is probably nil. But secondary memory such as CXL-connected DIMMS, persistent memory etc, and the page demotion patches that handle them (https://lore.kernel.org/lkml/20210401183216.443C4443@viggo.jf.intel.com/) could soon make this a more common codepath again. Link: https://lkml.kernel.org/r/20210818152457.35846-1-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reported-by: Rik van Riel <riel@surriel.com> Reviewed-by: Shakeel Butt <shakeelb@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/vmscan.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index b0202ab5e136..eeae2f6bc532 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -4424,11 +4424,13 @@ static int __node_reclaim(struct pglist_data *pgdat, gfp_t gfp_mask, unsigned in
.may_swap = 1,
.reclaim_idx = gfp_zone(gfp_mask),
};
+ unsigned long pflags;
trace_mm_vmscan_node_reclaim_begin(pgdat->node_id, order,
sc.gfp_mask);
cond_resched();
+ psi_memstall_enter(&pflags);
fs_reclaim_acquire(sc.gfp_mask);
/*
* We need to be able to allocate from the reserves for RECLAIM_UNMAP
@@ -4453,6 +4455,7 @@ static int __node_reclaim(struct pglist_data *pgdat, gfp_t gfp_mask, unsigned in
current->flags &= ~PF_SWAPWRITE;
memalloc_noreclaim_restore(noreclaim_flag);
fs_reclaim_release(sc.gfp_mask);
+ psi_memstall_leave(&pflags);
trace_mm_vmscan_node_reclaim_end(sc.nr_reclaimed);