Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755479AbaKYLbF (ORCPT ); Tue, 25 Nov 2014 06:31:05 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:58544 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752492AbaKYKls (ORCPT ); Tue, 25 Nov 2014 05:41:48 -0500 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Mikulas Patocka , Mike Snitzer , Luis Henriques Subject: [PATCH 3.16.y-ckt 110/254] dm bufio: when done scanning return from __scan immediately Date: Tue, 25 Nov 2014 10:37:40 +0000 Message-Id: <1416912004-5928-111-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1416912004-5928-1-git-send-email-luis.henriques@canonical.com> References: <1416912004-5928-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.16 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.7-ckt2 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Mikulas Patocka commit 0e825862f3c04cee40e25f55680333728a4ffa9b 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 Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer Signed-off-by: Luis Henriques --- drivers/md/dm-bufio.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c index da2ebac231b9..598ba99d2e15 100644 --- a/drivers/md/dm-bufio.c +++ b/drivers/md/dm-bufio.c @@ -1486,9 +1486,9 @@ static long __scan(struct dm_bufio_client *c, unsigned long nr_to_scan, list_for_each_entry_safe_reverse(b, tmp, &c->lru[l], lru_list) { freed += __cleanup_old_buffer(b, gfp_mask, 0); if (!--nr_to_scan) - break; + return freed; + dm_bufio_cond_resched(); } - dm_bufio_cond_resched(); } return freed; } -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/