The patch titled
Subject: mm: vmscan: fix missing psi annotation for node_reclaim()
has been added to the -mm tree. Its filename is
mm-vmscan-fix-missing-psi-annotation-for-node_reclaim.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-vmscan-fix-missing-psi-annotation-for-node_reclaim.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-vmscan-fix-missing-psi-annotation-for-node_reclaim.patch
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------------------------------------------------------
From: Johannes Weiner <hannes@xxxxxxxxxxx>
Subject: 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. Although,
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@xxxxxxxxxxxxxxxxxx/)
could soon make this a more common codepath again.
Link: https://lkml.kernel.org/r/20210818152457.35846-1-hannes@xxxxxxxxxxx
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Reported-by: Rik van Riel <riel@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 3 +++
1 file changed, 3 insertions(+)
--- a/mm/vmscan.c~mm-vmscan-fix-missing-psi-annotation-for-node_reclaim
+++ a/mm/vmscan.c
@@ -4424,11 +4424,13 @@ static int __node_reclaim(struct pglist_
.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_
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);
_
Patches currently in -mm which might be from hannes@xxxxxxxxxxx are
mm-memcontrol-fix-occasional-ooms-due-to-proportional-memorylow-reclaim.patch
mm-vmscan-fix-missing-psi-annotation-for-node_reclaim.patch
mm-remove-irqsave-restore-locking-from-contexts-with-irqs-enabled.patch
fs-drop_caches-fix-skipping-over-shadow-cache-inodes.patch
fs-inode-count-invalidated-shadow-pages-in-pginodesteal.patch
vfs-keep-inodes-with-page-cache-off-the-inode-shrinker-lru.patch
