From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f43.google.com (mail-pa0-f43.google.com [209.85.220.43]) by kanga.kvack.org (Postfix) with ESMTP id 9068F2802F6 for ; Thu, 16 Jul 2015 08:01:52 -0400 (EDT) Received: by pactm7 with SMTP id tm7so42192544pac.2 for ; Thu, 16 Jul 2015 05:01:52 -0700 (PDT) Received: from mail-pd0-x233.google.com (mail-pd0-x233.google.com. [2607:f8b0:400e:c02::233]) by mx.google.com with ESMTPS id i10si12759258pdo.14.2015.07.16.05.01.51 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 16 Jul 2015 05:01:51 -0700 (PDT) Received: by pdjr16 with SMTP id r16so43523780pdj.3 for ; Thu, 16 Jul 2015 05:01:51 -0700 (PDT) From: Sergey Senozhatsky Subject: [PATCH] zsmalloc: do not take class lock in zs_shrinker_count() Date: Thu, 16 Jul 2015 21:00:54 +0900 Message-Id: <1437048054-4916-1-git-send-email-sergey.senozhatsky@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Sergey Senozhatsky , Sergey Senozhatsky We can avoid taking class ->lock around zs_can_compact() in zs_pages_to_compact(), because the number that we return back is outdated in general case, by design. We have different sources that are able to change class's state right after we return from zs_can_compact() -- ongoing I/O operations, manually triggered compaction, or two of them happening simultaneously. We re-do this calculations during compaction on a per class basis anyway. zs_unregister_shrinker() will not return until we have an active shrinker, so classes won't unexpectedly disappear while zs_pages_to_compact(), invoked by zs_shrinker_count(), iterates them. Signed-off-by: Sergey Senozhatsky --- mm/zsmalloc.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c index 1edd8a0..ed64cf5 100644 --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -1836,9 +1836,7 @@ static unsigned long zs_shrinker_count(struct shrinker *shrinker, if (class->index != i) continue; - spin_lock(&class->lock); pages_to_free += zs_can_compact(class); - spin_unlock(&class->lock); } return pages_to_free; -- 2.4.6 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org