From patchwork Wed Mar 21 22:44:27 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Goldwyn Rodrigues X-Patchwork-Id: 10300501 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id B6A5B600F6 for ; Wed, 21 Mar 2018 22:44:48 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A3F0D2903D for ; Wed, 21 Mar 2018 22:44:48 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 97C4F29917; Wed, 21 Mar 2018 22:44:48 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id F188C2903D for ; Wed, 21 Mar 2018 22:44:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754019AbeCUWoq (ORCPT ); Wed, 21 Mar 2018 18:44:46 -0400 Received: from mx2.suse.de ([195.135.220.15]:34938 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753715AbeCUWoo (ORCPT ); Wed, 21 Mar 2018 18:44:44 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id B42F7AB39; Wed, 21 Mar 2018 22:44:42 +0000 (UTC) From: Goldwyn Rodrigues To: linux-fsdevel@vger.kernel.org Cc: linux-mm@kvack.org, willy@infradead.org, david@fromorbit.com, Goldwyn Rodrigues Subject: [PATCH 1/3] fs: Perform writebacks under memalloc_nofs Date: Wed, 21 Mar 2018 17:44:27 -0500 Message-Id: <20180321224429.15860-2-rgoldwyn@suse.de> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180321224429.15860-1-rgoldwyn@suse.de> References: <20180321224429.15860-1-rgoldwyn@suse.de> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Goldwyn Rodrigues writebacks can recurse into itself under low memory situations. Set memalloc_nofs_save() in order to make sure it does not recurse. Since writeouts are performed for fdatawrites as well, set memalloc_nofs_save while performing fdatawrites. Signed-off-by: Goldwyn Rodrigues --- fs/fs-writeback.c | 8 ++++++++ fs/xfs/xfs_aops.c | 7 ------- mm/filemap.c | 3 +++ 3 files changed, 11 insertions(+), 7 deletions(-) diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index d4d04fee568a..42f7f4c2063b 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -28,6 +28,7 @@ #include #include #include +#include #include "internal.h" /* @@ -1713,7 +1714,12 @@ static long wb_writeback(struct bdi_writeback *wb, struct inode *inode; long progress; struct blk_plug plug; + unsigned flags; + if (current->flags & PF_MEMALLOC_NOFS) + return 0; + + flags = memalloc_nofs_save(); oldest_jif = jiffies; work->older_than_this = &oldest_jif; @@ -1797,6 +1803,8 @@ static long wb_writeback(struct bdi_writeback *wb, spin_unlock(&wb->list_lock); blk_finish_plug(&plug); + memalloc_nofs_restore(flags); + return nr_pages - work->nr_pages; } diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c index 9c6a830da0ee..943ade03489a 100644 --- a/fs/xfs/xfs_aops.c +++ b/fs/xfs/xfs_aops.c @@ -1086,13 +1086,6 @@ xfs_do_writepage( PF_MEMALLOC)) goto redirty; - /* - * Given that we do not allow direct reclaim to call us, we should - * never be called while in a filesystem transaction. - */ - if (WARN_ON_ONCE(current->flags & PF_MEMALLOC_NOFS)) - goto redirty; - /* * Is this page beyond the end of the file? * diff --git a/mm/filemap.c b/mm/filemap.c index 693f62212a59..3c9ead9a1e32 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -430,6 +430,7 @@ int __filemap_fdatawrite_range(struct address_space *mapping, loff_t start, loff_t end, int sync_mode) { int ret; + unsigned flags; struct writeback_control wbc = { .sync_mode = sync_mode, .nr_to_write = LONG_MAX, @@ -440,9 +441,11 @@ int __filemap_fdatawrite_range(struct address_space *mapping, loff_t start, if (!mapping_cap_writeback_dirty(mapping)) return 0; + flags = memalloc_nofs_save(); wbc_attach_fdatawrite_inode(&wbc, mapping->host); ret = do_writepages(mapping, &wbc); wbc_detach_inode(&wbc); + memalloc_nofs_restore(flags); return ret; }