Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753407AbdHPCNp (ORCPT ); Tue, 15 Aug 2017 22:13:45 -0400 Received: from LGEAMRELO12.lge.com ([156.147.23.52]:60755 "EHLO lgeamrelo12.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752992AbdHPCNo (ORCPT ); Tue, 15 Aug 2017 22:13:44 -0400 X-Original-SENDERIP: 156.147.1.121 X-Original-MAILFROM: minchan@kernel.org X-Original-SENDERIP: 10.177.220.163 X-Original-MAILFROM: minchan@kernel.org Date: Wed, 16 Aug 2017 11:13:39 +0900 From: Minchan Kim To: Hui Zhu Cc: ngupta@vflare.org, sergey.senozhatsky.work@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, teawater@gmail.com Subject: Re: [PATCH v2] zsmalloc: zs_page_migrate: schedule free_work if zspage is ZS_EMPTY Message-ID: <20170816021339.GA23451@blaptop> References: <1502704590-3129-1-git-send-email-zhuhui@xiaomi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1502704590-3129-1-git-send-email-zhuhui@xiaomi.com> User-Agent: Mutt/1.8.3 (2017-05-23) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3052 Lines: 81 Hi Hui, On Mon, Aug 14, 2017 at 05:56:30PM +0800, Hui Zhu wrote: > After commit e2846124f9a2 ("zsmalloc: zs_page_migrate: skip unnecessary This patch is not merged yet so the hash is invalid. That means we may fold this patch to [1] in current mmotm. [1] zsmalloc-zs_page_migrate-skip-unnecessary-loops-but-not-return-ebusy-if-zspage-is-not-inuse-fix.patch > loops but not return -EBUSY if zspage is not inuse") zs_page_migrate > can handle the ZS_EMPTY zspage. > > But I got some false in zs_page_isolate: > if (get_zspage_inuse(zspage) == 0) { > spin_unlock(&class->lock); > return false; > } I also realized we should make zs_page_isolate succeed on empty zspage because we allow the empty zspage migration from now on. Could you send a patch for that as well? > The page of this zspage was migrated in before. > > The reason is commit e2846124f9a2 ("zsmalloc: zs_page_migrate: skip > unnecessary loops but not return -EBUSY if zspage is not inuse") just > handle the "page" but not "newpage" then it keep the "newpage" with > a empty zspage inside system. > Root cause is zs_page_isolate remove it from ZS_EMPTY list but not > call zs_page_putback "schedule_work(&pool->free_work);". Because > zs_page_migrate done the job without "schedule_work(&pool->free_work);" > > Make this patch let zs_page_migrate wake up free_work if need. > > Fixes: e2846124f9a2 ("zsmalloc: zs_page_migrate: skip unnecessary loops but not return -EBUSY if zspage is not inuse") > Signed-off-by: Hui Zhu > --- > mm/zsmalloc.c | 13 +++++++++++-- > 1 file changed, 11 insertions(+), 2 deletions(-) > > diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c > index 62457eb..c6cc77c 100644 > --- a/mm/zsmalloc.c > +++ b/mm/zsmalloc.c > @@ -2035,8 +2035,17 @@ int zs_page_migrate(struct address_space *mapping, struct page *newpage, > * Page migration is done so let's putback isolated zspage to > * the list if @page is final isolated subpage in the zspage. > */ > - if (!is_zspage_isolated(zspage)) > - putback_zspage(class, zspage); > + if (!is_zspage_isolated(zspage)) { > + /* > + * Page will be freed in following part. But newpage and > + * zspage will stay in system if zspage is in ZS_EMPTY > + * list. So call free_work to free it. > + * The page and class is locked, we cannot free zspage > + * immediately so let's defer. > + */ How about this? /* * Since we allow empty zspage migration, putback of zspage * should free empty zspage. Otherwise, it could make a leak * until upcoming free_work is done, which isn't guaranteed. */ > + if (putback_zspage(class, zspage) == ZS_EMPTY) > + schedule_work(&pool->free_work); > + } > > reset_page(page); > put_page(page); > -- > 1.9.1 > > -- > 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