The patch titled
Subject: mm: handle lru_add_drain_all for UP properly
has been added to the -mm tree. Its filename is
mm-handle-lru_add_drain_all-for-up-properly.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-handle-lru_add_drain_all-for-up-properly.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-handle-lru_add_drain_all-for-up-properly.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Michal Hocko <mhocko@xxxxxxxx>
Subject: mm: handle lru_add_drain_all for UP properly
Since for_each_cpu(cpu, mask) added by commit 2d3854a37e8b767a ("cpumask:
introduce new API, without changing anything") did not evaluate the mask
argument if NR_CPUS == 1 due to CONFIG_SMP=n, lru_add_drain_all() is
hitting WARN_ON() at __flush_work() added by commit 4d43d395fed12463
("workqueue: Try to catch flush_work() without INIT_WORK().") by
unconditionally calling flush_work() [1].
Workaround this issue by using CONFIG_SMP=n specific lru_add_drain_all
implementation. There is no real need to defer the implementation to the
workqueue as the draining is going to happen on the local cpu. So alias
lru_add_drain_all to lru_add_drain which does all the necessary work.
[1] https://lkml.kernel.org/r/18a30387-6aa5-6123-e67c-57579ecc3f38@xxxxxxxxxxxx
Link: http://lkml.kernel.org/r/20190213124334.GH4525@xxxxxxxxxxxxxx
Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Debugged-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/swap.c | 7 +++++++
1 file changed, 7 insertions(+)
--- a/mm/swap.c~mm-handle-lru_add_drain_all-for-up-properly
+++ a/mm/swap.c
@@ -660,6 +660,7 @@ static void lru_add_drain_per_cpu(struct
static DEFINE_PER_CPU(struct work_struct, lru_add_drain_work);
+#ifdef CONFIG_SMP
/*
* Doesn't need any cpu hotplug locking because we do rely on per-cpu
* kworkers being shut down before our page_alloc_cpu_dead callback is
@@ -702,6 +703,12 @@ void lru_add_drain_all(void)
mutex_unlock(&lock);
}
+#else
+void lru_add_drain_all(void)
+{
+ lru_add_drain();
+}
+#endif
/**
* release_pages - batched put_page()
_
Patches currently in -mm which might be from mhocko@xxxxxxxx are
proc-oom-do-not-report-alien-mms-when-setting-oom_score_adj.patch
mm-handle-lru_add_drain_all-for-up-properly.patch
