From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:57160 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932451AbbIZVHP (ORCPT ); Sat, 26 Sep 2015 17:07:15 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jaewon Kim , Minchan Kim , Mel Gorman , Vlastimil Babka , Andrew Morton , Linus Torvalds Subject: [PATCH 4.2 103/134] vmscan: fix increasing nr_isolated incurred by putback unevictable pages Date: Sat, 26 Sep 2015 13:55:55 -0700 Message-Id: <20150926205318.054221149@linuxfoundation.org> In-Reply-To: <20150926205311.819185658@linuxfoundation.org> References: <20150926205311.819185658@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: stable-owner@vger.kernel.org List-ID: 4.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jaewon Kim commit c54839a722a02818677bcabe57e957f0ce4f841d upstream. 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 increases nr_isolated. To fix this, this patch changes shrink_page_list() to pass unevictable pages back to caller. Caller will take care those pages. Minchan said: 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. Signed-off-by: Jaewon Kim Acked-by: Minchan Kim Cc: Mel Gorman Acked-by: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/vmscan.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1190,7 +1190,7 @@ 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: