dm bufio: when done scanning return from __scan immediately
commit 0e825862f3
upstream.
When __scan frees the required number of buffer entries that the
shrinker requested (nr_to_scan becomes zero) it must return. Before
this fix the __scan code exited only the inner loop and continued in the
outer loop -- which could result in reduced performance due to extra
buffers being freed (e.g. unnecessarily evicted thinp metadata needing
to be synchronously re-read into bufio's cache).
Also, move dm_bufio_cond_resched to __scan's inner loop, so that
iterating the bufio client's lru lists doesn't result in scheduling
latency.
Reported-by: Joe Thornber <thornber@redhat.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
07321b43e0
commit
7f6c5d82bf
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@ -1486,9 +1486,9 @@ static long __scan(struct dm_bufio_client *c, unsigned long nr_to_scan,
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list_for_each_entry_safe_reverse(b, tmp, &c->lru[l], lru_list) {
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freed += __cleanup_old_buffer(b, gfp_mask, 0);
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if (!--nr_to_scan)
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break;
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return freed;
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dm_bufio_cond_resched();
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}
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dm_bufio_cond_resched();
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}
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return freed;
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}
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