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authorJohannes Weiner <hannes@cmpxchg.org>2018-10-26 15:06:08 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-10-26 16:26:32 -0700
commitb1d29ba82cf2bc784f4c963ddd6a2cf29e229b33 (patch)
tree4fc15315a4c1f8c1d1e99968a3077dcf1ac45407 /kernel
parent1899ad18c6072d689896badafb81267b0a1092a4 (diff)
delayacct: track delays from thrashing cache pages
Delay accounting already measures the time a task spends in direct reclaim and waiting for swapin, but in low memory situations tasks spend can spend a significant amount of their time waiting on thrashing page cache. This isn't tracked right now. To know the full impact of memory contention on an individual task, measure the delay when waiting for a recently evicted active cache page to read back into memory. Also update tools/accounting/getdelays.c: [hannes@computer accounting]$ sudo ./getdelays -d -p 1 print delayacct stats ON PID 1 CPU count real total virtual total delay total delay average 50318 745000000 847346785 400533713 0.008ms IO count delay total delay average 435 122601218 0ms SWAP count delay total delay average 0 0 0ms RECLAIM count delay total delay average 0 0 0ms THRASHING count delay total delay average 19 12621439 0ms Link: http://lkml.kernel.org/r/20180828172258.3185-4-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Daniel Drake <drake@endlessm.com> Tested-by: Suren Baghdasaryan <surenb@google.com> Cc: Christopher Lameter <cl@linux.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Johannes Weiner <jweiner@fb.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Enderborg <peter.enderborg@sony.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Shakeel Butt <shakeelb@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vinayak Menon <vinmenon@codeaurora.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/delayacct.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/kernel/delayacct.c b/kernel/delayacct.c
index ca8ac2824f0b..2a12b988c717 100644
--- a/kernel/delayacct.c
+++ b/kernel/delayacct.c
@@ -135,9 +135,12 @@ int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
d->swapin_delay_total = (tmp < d->swapin_delay_total) ? 0 : tmp;
tmp = d->freepages_delay_total + tsk->delays->freepages_delay;
d->freepages_delay_total = (tmp < d->freepages_delay_total) ? 0 : tmp;
+ tmp = d->thrashing_delay_total + tsk->delays->thrashing_delay;
+ d->thrashing_delay_total = (tmp < d->thrashing_delay_total) ? 0 : tmp;
d->blkio_count += tsk->delays->blkio_count;
d->swapin_count += tsk->delays->swapin_count;
d->freepages_count += tsk->delays->freepages_count;
+ d->thrashing_count += tsk->delays->thrashing_count;
raw_spin_unlock_irqrestore(&tsk->delays->lock, flags);
return 0;
@@ -169,3 +172,15 @@ void __delayacct_freepages_end(void)
&current->delays->freepages_count);
}
+void __delayacct_thrashing_start(void)
+{
+ current->delays->thrashing_start = ktime_get_ns();
+}
+
+void __delayacct_thrashing_end(void)
+{
+ delayacct_end(&current->delays->lock,
+ &current->delays->thrashing_start,
+ &current->delays->thrashing_delay,
+ &current->delays->thrashing_count);
+}