Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Mon, 22 Jun 2020 21:16:13 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Dave Chinner <david@fromorbit.com>
Cc:     Waiman Long <longman@redhat.com>,
        "Darrick J. Wong" <darrick.wong@oracle.com>,
        Ingo Molnar <mingo@redhat.com>,
        Juri Lelli <juri.lelli@redhat.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org,
        Qian Cai <cai@lca.pw>, Eric Sandeen <sandeen@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH v2 1/2] sched: Add PF_MEMALLOC_NOLOCKDEP flag
Message-ID: <20200622191613.GB2483@worktop.programming.kicks-ass.net>
References: <20200617175310.20912-1-longman@redhat.com>
 <20200617175310.20912-2-longman@redhat.com>
 <20200618000110.GF2005@dread.disaster.area>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20200618000110.GF2005@dread.disaster.area>
User-Agent: Mutt/1.10.1 (2018-07-13)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Thu, Jun 18, 2020 at 10:01:10AM +1000, Dave Chinner wrote:

> And, really, if we are playing "re-use existing bits" games because
> we've run out of process flags, all these memalloc flags should be
> moved to a new field in the task, say current->memalloc_flags. You
> could also move PF_SWAPWRITE, PF_LOCAL_THROTTLE, and PF_KSWAPD into
> that field as well as they are all memory allocation context process
> flags...

FWIW

There's still 23 bits free after task_struct::in_memstall. That word has
'current only' semantics, just like PF.