From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f177.google.com (mail-pd0-f177.google.com [209.85.192.177]) by kanga.kvack.org (Postfix) with ESMTP id BE623280244 for ; Sat, 11 Jul 2015 05:46:37 -0400 (EDT) Received: by pdbqm3 with SMTP id qm3so53198297pdb.0 for ; Sat, 11 Jul 2015 02:46:37 -0700 (PDT) Received: from mail-pd0-x22b.google.com (mail-pd0-x22b.google.com. [2607:f8b0:400e:c02::22b]) by mx.google.com with ESMTPS id zl8si18570470pac.150.2015.07.11.02.46.36 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 11 Jul 2015 02:46:37 -0700 (PDT) Received: by pdbqm3 with SMTP id qm3so53198233pdb.0 for ; Sat, 11 Jul 2015 02:46:36 -0700 (PDT) From: Sergey Senozhatsky Subject: [PATCH 3/3] zsmalloc: do not take class lock in zs_pages_to_compact() Date: Sat, 11 Jul 2015 18:45:32 +0900 Message-Id: <1436607932-7116-4-git-send-email-sergey.senozhatsky@gmail.com> In-Reply-To: <1436607932-7116-1-git-send-email-sergey.senozhatsky@gmail.com> References: <1436607932-7116-1-git-send-email-sergey.senozhatsky@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.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lock around zs_can_compact() in zs_pages_to_compact(), because the number that we return back is outdated in general case, by design.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 source that are able to change class's state right after we return from zs_can_compact() -- ongoing IO operations, manually triggered compaction or automatic compaction, or all three 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. When called from zram, we are protected by zram's ->init_lock, so, again, classes will be there until zs_pages_to_compact() 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 b10a228..824c182 100644 --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -1811,9 +1811,7 @@ unsigned long zs_pages_to_compact(struct zs_pool *pool) if (class->index != i) continue; - spin_lock(&class->lock); pages_to_free += zs_can_compact(class); - spin_unlock(&class->lock); } return pages_to_free; -- 2.4.5 -- 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