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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id E5056C433F5 for ; Mon, 30 May 2022 04:04:22 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 15F8B8D0002; Mon, 30 May 2022 00:04:22 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 10DF78D0001; Mon, 30 May 2022 00:04:22 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F3BCD8D0002; Mon, 30 May 2022 00:04:21 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id E4E248D0001 for ; Mon, 30 May 2022 00:04:21 -0400 (EDT) Received: from smtpin12.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id AD96B20CFA for ; Mon, 30 May 2022 04:04:21 +0000 (UTC) X-FDA: 79521067122.12.7E626FC Received: from gandalf.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) by imf31.hostedemail.com (Postfix) with ESMTP id A964E20059 for ; Mon, 30 May 2022 04:03:41 +0000 (UTC) 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 Authentication-Results: imf31.hostedemail.com; dkim=pass header.d=ellerman.id.au header.s=201909 header.b=UCycBCGZ; dmarc=none; spf=pass (imf31.hostedemail.com: domain of mpe@ellerman.id.au designates 150.107.74.76 as permitted sender) smtp.mailfrom=mpe@ellerman.id.au X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: A964E20059 X-Stat-Signature: srk5qcpy1zpmu9zccaahi9x76nz9x934 X-Rspam-User: X-HE-Tag: 1653883421-964940 X-Bogosity: Ham, tests=bogofilter, spamicity=0.111281, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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