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 366816B0038 for ; Tue, 4 Aug 2015 20:52:16 -0400 (EDT) Received: by pdbnt7 with SMTP id nt7so10920388pdb.0 for ; Tue, 04 Aug 2015 17:52:15 -0700 (PDT) Received: from mailout4.samsung.com (mailout4.samsung.com. [203.254.224.34]) by mx.google.com with ESMTPS id yb4si2195290pbb.25.2015.08.04.17.52.14 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Tue, 04 Aug 2015 17:52:15 -0700 (PDT) MIME-version: 1.0 Content-type: text/plain; charset=UTF-8 Received: from epcpsbgr4.samsung.com (u144.gpu120.samsung.co.kr [203.254.230.144]) by mailout4.samsung.com (Oracle Communications Messaging Server 7.0.5.31.0 64bit (built May 5 2014)) with ESMTP id <0NSL00A3D3R0AL90@mailout4.samsung.com> for linux-mm@kvack.org; Wed, 05 Aug 2015 09:52:12 +0900 (KST) Content-transfer-encoding: 8BIT Message-id: <55C15E37.80504@samsung.com> Date: Wed, 05 Aug 2015 09:52:07 +0900 From: Jaewon Kim Subject: Re: [PATCH v2] vmscan: fix increasing nr_isolated incurred by putback unevictable pages References: <1438684808-12707-1-git-send-email-jaewon31.kim@samsung.com> <20150804150937.ee3b62257e77911a2f41a48e@linux-foundation.org> <20150804233108.GA662@bgram> In-reply-to: <20150804233108.GA662@bgram> Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim , Andrew Morton Cc: mgorman@suse.de, linux-mm@kvack.org, linux-kernel@vger.kernel.org, jaewon31.kim@gmail.com On 2015e?? 08i?? 05i? 1/4 08:31, Minchan Kim wrote: > Hello, > > On Tue, Aug 04, 2015 at 03:09:37PM -0700, Andrew Morton wrote: >> On Tue, 04 Aug 2015 19:40:08 +0900 Jaewon Kim wrote: >> >>> reclaim_clean_pages_from_list() assumes that shrink_page_list() returns >>> number of pages removed from the candidate list. But shrink_page_list() >>> puts back mlocked pages without passing it to caller and without >>> counting as nr_reclaimed. This incurrs increasing nr_isolated. >>> To fix this, this patch changes shrink_page_list() to pass unevictable >>> pages back to caller. Caller will take care those pages. >>> >>> .. >>> >>> --- a/mm/vmscan.c >>> +++ b/mm/vmscan.c >>> @@ -1157,7 +1157,7 @@ cull_mlocked: >>> if (PageSwapCache(page)) >>> try_to_free_swap(page); >>> unlock_page(page); >>> - putback_lru_page(page); >>> + list_add(&page->lru, &ret_pages); >>> continue; >>> >>> activate_locked: >> >> Is this going to cause a whole bunch of mlocked pages to be migrated >> whereas in current kernels they stay where they are? >> > > It fixes two issues. > > 1. With unevictable page, cma_alloc will be successful. > > Exactly speaking, cma_alloc of current kernel will fail due to unevictable pages. > > 2. fix leaking of NR_ISOLATED counter of vmstat > > With it, too_many_isolated works. Otherwise, it could make hang until > the process get SIGKILL. > > So, I think it's stable material. > > Acked-by: Minchan Kim > > > Hello Traditional shrink_inactive_list will put back the unevictable pages as it does through putback_inactive_pages. However as Minchan Kim said, cma_alloc will be more successful by migrating unevictable pages. In current kernel, I think, cma_alloc is already trying to migrate unevictable pages except clean page cache. This patch will allow clean page cache also to be migrated in cma_alloc. Thank you -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752561AbbHEAwQ (ORCPT ); Tue, 4 Aug 2015 20:52:16 -0400 Received: from mailout4.samsung.com ([203.254.224.34]:42364 "EHLO mailout4.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751073AbbHEAwO (ORCPT ); Tue, 4 Aug 2015 20:52:14 -0400 MIME-version: 1.0 Content-type: text/plain; charset=UTF-8 X-AuditID: cbfee690-f796f6d000005054-16-55c15e3cd595 Content-transfer-encoding: 8BIT Message-id: <55C15E37.80504@samsung.com> Date: Wed, 05 Aug 2015 09:52:07 +0900 From: Jaewon Kim User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 To: Minchan Kim , Andrew Morton Cc: mgorman@suse.de, linux-mm@kvack.org, linux-kernel@vger.kernel.org, jaewon31.kim@gmail.com Subject: Re: [PATCH v2] vmscan: fix increasing nr_isolated incurred by putback unevictable pages References: <1438684808-12707-1-git-send-email-jaewon31.kim@samsung.com> <20150804150937.ee3b62257e77911a2f41a48e@linux-foundation.org> <20150804233108.GA662@bgram> In-reply-to: <20150804233108.GA662@bgram> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprPIsWRmVeSWpSXmKPExsVy+t8zTV2buIOhBou3yljMWb+GzaJ780xG i8u75rBZ3Fvzn9Vi8rtnjBbLvr5nd2Dz2DnrLrvHplWdbB6bPk1i9zgx4zeLx+bT1R6fN8kF sEVx2aSk5mSWpRbp2yVwZRz/PYm9YC1/xc15n5kbGDfzdDFyckgImEi8mL+BFcIWk7hwbz1b FyMXh5DASkaJh09bmGGKlh35zAJiCwnMYpS4uSAaxOYVEJT4MfkeUJyDg1lAXuLIpWyQMLOA usSkeYuYIcrvM0rM+W8DUa4h8XX3J7AxLAKqEgfXLQerYRPQlni/YBLYDaICERIfVn1lA7FF BPwlZk+azwgxM16i8cY6sHphgSSJe8f7GSHmr2CUONyTBGJzCmhK9F88xw5yv4TAKXaJCwvv MEMsE5D4NvkQ2J0SArISmw5AvSUpcXDFDZYJjGKzkHwzC+GbWUi+WcDIvIpRNLUguaA4Kb3I RK84Mbe4NC9dLzk/dxMjJN4m7GC8d8D6EKMAB6MSD+8H54OhQqyJZcWVuYcYTYGOmMgsJZqc D4zqvJJ4Q2MzIwtTE1NjI3NLMyVx3tdSP4OFBNITS1KzU1MLUovii0pzUosPMTJxcEo1MHbr f53xLM9gtbug7dzW+VvTF56s2PCA+U/hPpNzCnEnD666svCpyqefew80mPD13Okxu/bQ1fzS r6qGCMaHZ5cGzuOIXCZ9iZc/6G+h+oSwC6cPZrS83L7bc93iCLetrsFVktw3JZSviG10/q2T qq13c5V8ROulbvNWO/Y9nRk7/d9nbBHWdVRiKc5INNRiLipOBABEjq5usgIAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrDIsWRmVeSWpSXmKPExsVy+t9jQV2buIOhBo/aJCzmrF/DZtG9eSaj xeVdc9gs7q35z2ox+d0zRotlX9+zO7B57Jx1l91j06pONo9Nnyaxe5yY8ZvFY/Ppao/Pm+QC 2KIaGG0yUhNTUosUUvOS81My89JtlbyD453jTc0MDHUNLS3MlRTyEnNTbZVcfAJ03TJzgM5Q UihLzCkFCgUkFhcr6dthmhAa4qZrAdMYoesbEgTXY2SABhLWMWYc/z2JvWAtf8XNeZ+ZGxg3 83QxcnJICJhILDvymQXCFpO4cG89G4gtJDCLUeLmgmgQm1dAUOLH5HtANRwczALyEkcuZYOE mQXUJSbNW8QMUX6fUWLOfxuIcg2Jr7s/gY1kEVCVOLhuOVgNm4C2xPsFk1hBbFGBCIkPq76C rRIR8JeYPWk+I8TMeInGG+vA6oUFkiTuHe9nhJi/glHicE8SiM0poCnRf/Ec+wRGoBsRrpuF cN0sJNctYGRexSiRWpBcUJyUnmuUl1quV5yYW1yal66XnJ+7iREc08+kdzAe3uV+iFGAg1GJ h/eD88FQIdbEsuLK3EOMEhzMSiK8O6KAQrwpiZVVqUX58UWlOanFhxhNgf6byCwlmpwPTDd5 JfGGxiZmRpZGZsYm5sbGSuK8+iabQoUE0hNLUrNTUwtSi2D6mDg4pRoYDz16xWO5f29qV8Y3 xb4HEx34ZC4WZl2qs9v7WP/cRUv1v7uc2Sc52+2v3M6welfZNNFl8leF9pjpLY7dvDRvX0yi atlKrh+/HUK+pB98W3Wo7qBNd5Zzx+FKocKJjJP3d26oeHHijmxH9ObFh2ftMU5VPTbl55fU D8XPn58J6leMOuq4x4FtsxJLcUaioRZzUXEiAHZXMNb/AgAA DLP-Filter: Pass X-MTR: 20000000000000000@CPGS X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2015년 08월 05일 08:31, Minchan Kim wrote: > Hello, > > On Tue, Aug 04, 2015 at 03:09:37PM -0700, Andrew Morton wrote: >> On Tue, 04 Aug 2015 19:40:08 +0900 Jaewon Kim wrote: >> >>> reclaim_clean_pages_from_list() assumes that shrink_page_list() returns >>> number of pages removed from the candidate list. But shrink_page_list() >>> puts back mlocked pages without passing it to caller and without >>> counting as nr_reclaimed. This incurrs increasing nr_isolated. >>> To fix this, this patch changes shrink_page_list() to pass unevictable >>> pages back to caller. Caller will take care those pages. >>> >>> .. >>> >>> --- a/mm/vmscan.c >>> +++ b/mm/vmscan.c >>> @@ -1157,7 +1157,7 @@ cull_mlocked: >>> if (PageSwapCache(page)) >>> try_to_free_swap(page); >>> unlock_page(page); >>> - putback_lru_page(page); >>> + list_add(&page->lru, &ret_pages); >>> continue; >>> >>> activate_locked: >> >> Is this going to cause a whole bunch of mlocked pages to be migrated >> whereas in current kernels they stay where they are? >> > > It fixes two issues. > > 1. With unevictable page, cma_alloc will be successful. > > Exactly speaking, cma_alloc of current kernel will fail due to unevictable pages. > > 2. fix leaking of NR_ISOLATED counter of vmstat > > With it, too_many_isolated works. Otherwise, it could make hang until > the process get SIGKILL. > > So, I think it's stable material. > > Acked-by: Minchan Kim > > > Hello Traditional shrink_inactive_list will put back the unevictable pages as it does through putback_inactive_pages. However as Minchan Kim said, cma_alloc will be more successful by migrating unevictable pages. In current kernel, I think, cma_alloc is already trying to migrate unevictable pages except clean page cache. This patch will allow clean page cache also to be migrated in cma_alloc. Thank you