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[209.85.220.65]) by mx.google.com with SMTPS id x186sor2086123ybg.209.2019.07.10.14.40.07 for (Google Transport Security); Wed, 10 Jul 2019 14:40:07 -0700 (PDT) Received-SPF: pass (google.com: domain of shakeelb@google.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=ianG8POe; spf=pass (google.com: domain of shakeelb@google.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=shakeelb@google.com; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=klmpTKMRhJk0PWQQA2dmLgLN6yYzHWA+paLC90wMAwo=; b=ianG8POesm7I23H2706WLKaOHcIeSM/jbJvK3rX1MbMAkRdwmns8fy1bKZC7i9oc3k ohbiQFPpzrqOOrzzv+XhRdRFx+/2IAbaOBKTcRklRc+xSnIjtv158DtXLkElnFJIEZQM TzWEnN+zO218EByyOBpYZTflZ2HqTf6TV6LFwmZjK1voTtyFxX18k/9gYaEuUuk3J4k+ K2qKaAYPaowUKNlcmGN4ToMAGbqL6DJO3BYiRM2quEj3iw0xeLuCN0mw/mYqFS+c4/GU Zq2v67KPnQzfEEFsI1vt0c2DxD+a+avQP8g97zcsXYKmfHt8Zml5XHrtaheM02XN5BnG PdBg== X-Google-Smtp-Source: APXvYqw4iXskw6yoB+U4UXJRAYJgfQB2zmNYQyo/PSJcnmTZ3tvplyN8EfCsh0Hao7Yc0XZMOxUHsuZHdRdZtD5D0sE= X-Received: by 2002:a25:7c05:: with SMTP id x5mr20528ybc.358.1562794807061; Wed, 10 Jul 2019 14:40:07 -0700 (PDT) MIME-Version: 1.0 References: <20190710213238.91835-1-henryburns@google.com> In-Reply-To: <20190710213238.91835-1-henryburns@google.com> From: Shakeel Butt Date: Wed, 10 Jul 2019 14:39:55 -0700 Message-ID: Subject: Re: [PATCH] mm/z3fold.c: remove z3fold_migration trylock To: Henry Burns Cc: Vitaly Wool , Andrew Morton , Vitaly Vul , Jonathan Adams , Greg Kroah-Hartman , Snild Dolkow , Thomas Gleixner , Linux MM , LKML Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Jul 10, 2019 at 2:32 PM Henry Burns wrote: > > z3fold_page_migrate() will never succeed because it attempts to acquire a > lock that has already been taken by migrate.c in __unmap_and_move(). > > __unmap_and_move() migrate.c > trylock_page(oldpage) > move_to_new_page(oldpage_newpage) > a_ops->migrate_page(oldpage, newpage) > z3fold_page_migrate(oldpage, newpage) > trylock_page(oldpage) > > > Signed-off-by: Henry Burns Reviewed-by: Shakeel Butt Please add the Fixes tag as well. > --- > mm/z3fold.c | 6 ------ > 1 file changed, 6 deletions(-) > > diff --git a/mm/z3fold.c b/mm/z3fold.c > index 985732c8b025..9fe9330ab8ae 100644 > --- a/mm/z3fold.c > +++ b/mm/z3fold.c > @@ -1335,16 +1335,11 @@ static int z3fold_page_migrate(struct address_space *mapping, struct page *newpa > zhdr = page_address(page); > pool = zhdr_to_pool(zhdr); > > - if (!trylock_page(page)) > - return -EAGAIN; > - > if (!z3fold_page_trylock(zhdr)) { > - unlock_page(page); > return -EAGAIN; > } > if (zhdr->mapped_count != 0) { > z3fold_page_unlock(zhdr); > - unlock_page(page); > return -EBUSY; > } > new_zhdr = page_address(newpage); > @@ -1376,7 +1371,6 @@ static int z3fold_page_migrate(struct address_space *mapping, struct page *newpa > queue_work_on(new_zhdr->cpu, pool->compact_wq, &new_zhdr->work); > > page_mapcount_reset(page); > - unlock_page(page); > put_page(page); > return 0; > } > -- > 2.22.0.410.gd8fdbe21b5-goog >