From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750782AbWECUH4 (ORCPT ); Wed, 3 May 2006 16:07:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750797AbWECUH4 (ORCPT ); Wed, 3 May 2006 16:07:56 -0400 Received: from tetsuo.zabbo.net ([207.173.201.20]:6334 "EHLO tetsuo.zabbo.net") by vger.kernel.org with ESMTP id S1750782AbWECUH4 (ORCPT ); Wed, 3 May 2006 16:07:56 -0400 From: Zach Brown To: Nick Piggin , Linus Torvalds , Andrew Morton , linux-kernel@vger.kernel.org Message-Id: <20060503200755.1608.87580.sendpatchset@tetsuo.zabbo.net> Subject: [PATCH] AOP_TRUNCATED_PAGE victims in read_pages() belong in the LRU Date: Wed, 3 May 2006 13:07:55 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org AOP_TRUNCATED_PAGE victims in read_pages() belong in the LRU Nick Piggin rightly pointed out that the introduction of AOP_TRUNCATED_PAGE to read_pages() was wrong to leave A_T_P victim pages in the page cache but not put them in the LRU. Failing to do so hid them from the VM. A_T_P just means that the aop method unlocked the page rather than performing IO. It would be very rare that the page was truncated between the unlock and testing A_T_P. So we leave the pages in the LRU for likely reuse soon rather than backing them back out of the page cache. We do this by matching the behaviour before the A_T_P introduction which added pages to the LRU regardless of what ->readpage() did. This doesn't include the unrelated cleanup in Nick's initial fix which changed read_pages() to return void to match its only caller's behaviour of ignoring errors. Signed-off-by: Nick Piggin Signed-off-by: Zach Brown --- mm/readahead.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) Index: 2.6.17-rc3-git7-read_pages-fix/mm/readahead.c =================================================================== --- 2.6.17-rc3-git7-read_pages-fix.orig/mm/readahead.c +++ 2.6.17-rc3-git7-read_pages-fix/mm/readahead.c @@ -182,14 +182,11 @@ static int read_pages(struct address_spa list_del(&page->lru); if (!add_to_page_cache(page, mapping, page->index, GFP_KERNEL)) { - ret = mapping->a_ops->readpage(filp, page); - if (ret != AOP_TRUNCATED_PAGE) { - if (!pagevec_add(&lru_pvec, page)) - __pagevec_lru_add(&lru_pvec); - continue; - } /* else fall through to release */ - } - page_cache_release(page); + mapping->a_ops->readpage(filp, page); + if (!pagevec_add(&lru_pvec, page)) + __pagevec_lru_add(&lru_pvec); + } else + page_cache_release(page); } pagevec_lru_add(&lru_pvec); ret = 0;