From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756031AbcKWHE1 (ORCPT ); Wed, 23 Nov 2016 02:04:27 -0500 Received: from mail-wj0-f196.google.com ([209.85.210.196]:33178 "EHLO mail-wj0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755562AbcKWHEY (ORCPT ); Wed, 23 Nov 2016 02:04:24 -0500 From: Michal Hocko To: Cc: Tetsuo Handa , Vlastimil Babka , David Rientjes , Johannes Weiner , Mel Gorman , Andrew Morton , LKML Subject: [RFC 0/2] GFP_NOFAIL cleanups Date: Wed, 23 Nov 2016 07:49:23 +0100 Message-Id: <20161123064925.9716-1-mhocko@kernel.org> X-Mailer: git-send-email 2.10.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Tetsuo has noticed [1] that recent changes have changed GFP_NOFAIL semantic for costly order requests. I believe that the primary reason why this happened is that our GFP_NOFAIL checks are too scattered and it is really easy to forget about adding one. That's why I am proposing patch 1 which consolidates all the nofail handling at a single place. This should help to make this code better maintainable. Patch 2 on top is a further attempt to make GFP_NOFAIL semantic less surprising. As things stand currently GFP_NOFAIL overrides the oom killer prevention code which is both subtle and not really needed. The patch 2 has more details about issues this might cause. I would consider both patches more a cleanup than anything else. Any feedback is highly appreciated. [1] http://lkml.kernel.org/r/1479387004-5998-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f72.google.com (mail-wm0-f72.google.com [74.125.82.72]) by kanga.kvack.org (Postfix) with ESMTP id 62B386B0261 for ; Wed, 23 Nov 2016 01:49:36 -0500 (EST) Received: by mail-wm0-f72.google.com with SMTP id w13so2570526wmw.0 for ; Tue, 22 Nov 2016 22:49:36 -0800 (PST) Received: from mail-wj0-f193.google.com (mail-wj0-f193.google.com. [209.85.210.193]) by mx.google.com with ESMTPS id k5si29745696wjo.179.2016.11.22.22.49.35 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 22 Nov 2016 22:49:35 -0800 (PST) Received: by mail-wj0-f193.google.com with SMTP id jb2so310893wjb.3 for ; Tue, 22 Nov 2016 22:49:35 -0800 (PST) From: Michal Hocko Subject: [RFC 0/2] GFP_NOFAIL cleanups Date: Wed, 23 Nov 2016 07:49:23 +0100 Message-Id: <20161123064925.9716-1-mhocko@kernel.org> Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org Cc: Tetsuo Handa , Vlastimil Babka , David Rientjes , Johannes Weiner , Mel Gorman , Andrew Morton , LKML Hi, Tetsuo has noticed [1] that recent changes have changed GFP_NOFAIL semantic for costly order requests. I believe that the primary reason why this happened is that our GFP_NOFAIL checks are too scattered and it is really easy to forget about adding one. That's why I am proposing patch 1 which consolidates all the nofail handling at a single place. This should help to make this code better maintainable. Patch 2 on top is a further attempt to make GFP_NOFAIL semantic less surprising. As things stand currently GFP_NOFAIL overrides the oom killer prevention code which is both subtle and not really needed. The patch 2 has more details about issues this might cause. I would consider both patches more a cleanup than anything else. Any feedback is highly appreciated. [1] http://lkml.kernel.org/r/1479387004-5998-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp -- 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