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In-Reply-To: <20200724152424.GC17209@redhat.com>
From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Fri, 24 Jul 2020 10:32:51 -0700
Message-ID: <CAHk-=whuG+5pUeUqdiW4gk0prvqu7GZSMo-6oWv5PdDC5dBr=A@mail.gmail.com>
Subject: Re: [RFC PATCH] mm: silence soft lockups from unlock_page
To:     Oleg Nesterov <oleg@redhat.com>
Cc:     Hugh Dickins <hughd@google.com>, Michal Hocko <mhocko@kernel.org>,
        Linux-MM <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Tim Chen <tim.c.chen@linux.intel.com>,
        Michal Hocko <mhocko@suse.com>
Content-Type: multipart/mixed; boundary="000000000000bc5df305ab335d94"
Sender: linux-kernel-owner@vger.kernel.org
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--000000000000bc5df305ab335d94
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On Fri, Jul 24, 2020 at 8:24 AM Oleg Nesterov <oleg@redhat.com> wrote:
>
> not sure this makes any sense, but this looks like another user of
> trylock_page_bit_common(), see the patch below on top of 1/2.

Ok, that makes sense. Except you did it on top of the original patch
without the fix to set WQ_FLAG_WOKEN for the non-wakeup case.

And in fact, once you do it on top of that, it becomes obvious that we
can share even more code: move the WQ_FLAG_WOKEN logic _into_ the
trylock_page_bit_common() function.

Then the whole thing becomes something like the attached.

I added your reviewed-by, but maybe you should double-check my changes.

                Linus

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