linux-kernel - Re: [PATCH v2] net: fix sk_page_frag() recursion from memory reclaim

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Message-ID: <CALvZod7Lm5d-84wWubTUOFWo4XU2cgqBpFw84QzFdiokX86COQ@mail.gmail.com>
Date:   Thu, 31 Oct 2019 11:51:57 -0700
From:   Shakeel Butt <shakeelb@...gle.com>
To:     Tejun Heo <tj@...nel.org>
Cc:     Eric Dumazet <eric.dumazet@...il.com>,
        Michal Hocko <mhocko@...nel.org>,
        "David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
        Kernel Team <kernel-team@...com>,
        LKML <linux-kernel@...r.kernel.org>,
        Josef Bacik <josef@...icpanda.com>,
        Jakub Kicinski <jakub.kicinski@...ronome.com>,
        Johannes Weiner <hannes@...xchg.org>,
        Linux MM <linux-mm@...ck.org>, Mel Gorman <mgorman@...e.de>,
        Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH v2] net: fix sk_page_frag() recursion from memory reclaim

On Thu, Oct 31, 2019 at 11:43 AM Tejun Heo <tj@...nel.org> wrote:
>
> Hello,
>
> On Thu, Oct 31, 2019 at 11:30:57AM -0700, Shakeel Butt wrote:
> > Basically what I wanted to say that MM treats PF_MEMALLOC as the
> > reclaim context while __GFP_MEMALLOC just tells to give access to the
> > reserves. As gfpflags_allow_blocking() can be used beyond net
> > subsystem, my only concern is its potential usage under PF_MEMALLOC
> > context but without __GFP_MEMALLOC.
>
> Yeah, PF_MEMALLOC is likely the better condition to check here as we
> primarily want to know whether %current might be recursing and that
> should be indicated reliably with PF_MEMALLOC.  Wanna prep a patch for
> it?

Sure, I will keep your commit message and authorship (if you are ok with it).

>
> Thanks.
>
> --
> tejun