From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751365AbbGOEGn (ORCPT ); Wed, 15 Jul 2015 00:06:43 -0400 Received: from mail-pd0-f176.google.com ([209.85.192.176]:35240 "EHLO mail-pd0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750714AbbGOEGm (ORCPT ); Wed, 15 Jul 2015 00:06:42 -0400 Date: Wed, 15 Jul 2015 13:07:03 +0900 From: Sergey Senozhatsky To: Minchan Kim Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Sergey Senozhatsky , Sergey Senozhatsky Subject: Re: [PATCH 3/3] zsmalloc: do not take class lock in zs_pages_to_compact() Message-ID: <20150715040703.GA545@swordfish> References: <1436607932-7116-1-git-send-email-sergey.senozhatsky@gmail.com> <1436607932-7116-4-git-send-email-sergey.senozhatsky@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1436607932-7116-4-git-send-email-sergey.senozhatsky@gmail.com> User-Agent: Mutt/1.5.23+102 (2ca89bed6448) (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (07/11/15 18:45), Sergey Senozhatsky wrote: [..] > 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; This patch still makes sense. Agree? -ss