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[2620:137:e000::1:20]) by mx.google.com with ESMTP id b24-20020a170902d89800b00163b98f6047si6950869plz.116.2022.05.29.23.09.45; Sun, 29 May 2022 23:10:08 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@ellerman.id.au header.s=201909 header.b=UCycBCGZ; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231519AbiE3EE2 (ORCPT + 99 others); Mon, 30 May 2022 00:04:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57008 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229533AbiE3EEZ (ORCPT ); Mon, 30 May 2022 00:04:25 -0400 Received: from gandalf.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B5F1DBC3A for ; Sun, 29 May 2022 21:04:21 -0700 (PDT) Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4LBMH50Q5zz4xD2; Mon, 30 May 2022 14:04:16 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ellerman.id.au; s=201909; t=1653883457; bh=x0svsTO+jOFwH/KVWpk821pyzNznqc/zH685jsc3xAo=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=UCycBCGZN4FwwG9NtPjTOTY9Z6WdyBcbaCY1PV8XmA12shhVCHuzIe5pdqh2qYFyk PvtxE+XWmWXjkR889bgopN8vT1jB3UHEMi7kCJEHHylLZwHJy4YWI6hcRkKXK3da3R kqDNRTvZol2gq/YWneJ5EK/RWA4uYCtAO1l2ZY3ixLtsy3wr87J4ZWsCsNQDfZ8MJk qQTb9AyVIt7AFnTWq0hZOGBdZY0as/KlU0ZmYbT6HjW2OB2YKu0E8IB1/VqHkWB0z6 u6COQPyxQl+Wdp58uKjrK4Dj8FYXNKb93F/LQ7zUWabwIGqegG1utiF9qIwyF5SzSU a+TD/72hO8qWA== From: Michael Ellerman To: Peter Xu , linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH v4] mm: Avoid unnecessary page fault retires on shared memory types In-Reply-To: <20220527193936.30678-1-peterx@redhat.com> References: <20220527193936.30678-1-peterx@redhat.com> Date: Mon, 30 May 2022 14:04:12 +1000 Message-ID: <87mtezll8j.fsf@mpe.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_PASS,SPF_PASS, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Peter Xu writes: > I observed that for each of the shared file-backed page faults, we're very > likely to retry one more time for the 1st write fault upon no page. It's > because we'll need to release the mmap lock for dirty rate limit purpose > with balance_dirty_pages_ratelimited() (in fault_dirty_shared_page()). > ... > arch/powerpc/mm/copro_fault.c | 5 +++++ > arch/powerpc/mm/fault.c | 5 +++++ Acked-by: Michael Ellerman (powerpc) cheers