From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 31986C433EF for ; Mon, 30 May 2022 04:04:56 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4LBMHp3CqCz3bTR for ; Mon, 30 May 2022 14:04:54 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=ellerman.id.au header.i=@ellerman.id.au header.a=rsa-sha256 header.s=201909 header.b=UCycBCGZ; dkim-atps=neutral Received: from gandalf.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4LBMH55hm1z2xXV for ; Mon, 30 May 2022 14:04:17 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=ellerman.id.au header.i=@ellerman.id.au header.a=rsa-sha256 header.s=201909 header.b=UCycBCGZ; dkim-atps=neutral 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 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-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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