Return-Path: Received: from mx2.suse.de ([195.135.220.15]:43883 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754718AbdAIM7O (ORCPT ); Mon, 9 Jan 2017 07:59:14 -0500 Subject: Re: [PATCH 2/8] xfs: abstract PF_FSTRANS to PF_MEMALLOC_NOFS To: Michal Hocko , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org References: <20170106141107.23953-1-mhocko@kernel.org> <20170106141107.23953-3-mhocko@kernel.org> Cc: Andrew Morton , Dave Chinner , djwong@kernel.org, "Theodore Ts'o" , Chris Mason , David Sterba , Jan Kara , ceph-devel@vger.kernel.org, cluster-devel@redhat.com, linux-nfs@vger.kernel.org, logfs@logfs.org, linux-xfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-mtd@lists.infradead.org, reiserfs-devel@vger.kernel.org, linux-ntfs-dev@lists.sourceforge.net, linux-f2fs-devel@lists.sourceforge.net, linux-afs@lists.infradead.org, LKML , Michal Hocko From: Vlastimil Babka Message-ID: Date: Mon, 9 Jan 2017 13:59:05 +0100 MIME-Version: 1.0 In-Reply-To: <20170106141107.23953-3-mhocko@kernel.org> Content-Type: text/plain; charset=utf-8 Sender: linux-nfs-owner@vger.kernel.org List-ID: On 01/06/2017 03:11 PM, Michal Hocko wrote: > From: Michal Hocko > > xfs has defined PF_FSTRANS to declare a scope GFP_NOFS semantic quite > some time ago. We would like to make this concept more generic and use > it for other filesystems as well. Let's start by giving the flag a > more generic name PF_MEMALLOC_NOFS which is in line with an exiting > PF_MEMALLOC_NOIO already used for the same purpose for GFP_NOIO > contexts. Replace all PF_FSTRANS usage from the xfs code in the first > step before we introduce a full API for it as xfs uses the flag directly > anyway. > > This patch doesn't introduce any functional change. > > Signed-off-by: Michal Hocko > Reviewed-by: Brian Foster Acked-by: Vlastimil Babka A nit: > --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -2320,6 +2320,8 @@ extern void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, > #define PF_FREEZER_SKIP 0x40000000 /* Freezer should not count it as freezable */ > #define PF_SUSPEND_TASK 0x80000000 /* this thread called freeze_processes and should not be frozen */ > > +#define PF_MEMALLOC_NOFS PF_FSTRANS /* Transition to a more generic GFP_NOFS scope semantic */ I don't see why this transition is needed, as there are already no users of PF_FSTRANS after this patch. The next patch doesn't remove any more, so this is just extra churn IMHO. But not a strong objection. > + > /* > * Only the _current_ task can read/write to tsk->flags, but other > * tasks can access tsk->flags in readonly mode for example >