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 13407C433EF for ; Wed, 9 Mar 2022 19:16:02 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 953128D0002; Wed, 9 Mar 2022 14:16:01 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 902058D0001; Wed, 9 Mar 2022 14:16:01 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7C9568D0002; Wed, 9 Mar 2022 14:16:01 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0167.hostedemail.com [216.40.44.167]) by kanga.kvack.org (Postfix) with ESMTP id 6CE2D8D0001 for ; Wed, 9 Mar 2022 14:16:01 -0500 (EST) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 1C741180FF4C3 for ; Wed, 9 Mar 2022 19:16:01 +0000 (UTC) X-FDA: 79225802922.28.EEBF326 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf21.hostedemail.com (Postfix) with ESMTP id 83E931C0019 for ; Wed, 9 Mar 2022 19:16:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1646853360; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=8u+7tNvLmG2m1vlbYy9gZs+lrLcAJdUTzhBQfTfm8/8=; b=XrhhIPk4tk5J0bJoiFIMwvcA5avxRDweRbfqX284b5FG6ZtLocojgNHBILqDkQZEW1d6Rc HAoWLlPql9gCaSC32UBNFNiup+8VxwDxUeqUYyQWHtQZos5r/1B1V77yexcu0Ozb42+J9i +70/aDD5n2oGVz9MYRqbus3Y8ADVURU= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-41-3FUU4tHpMEOVNchgx7KDgw-1; Wed, 09 Mar 2022 14:15:58 -0500 X-MC-Unique: 3FUU4tHpMEOVNchgx7KDgw-1 Received: by mail-wm1-f71.google.com with SMTP id v125-20020a1cac83000000b0037e3d70e7e1so2991128wme.1 for ; Wed, 09 Mar 2022 11:15:57 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:organization:in-reply-to :content-transfer-encoding; bh=8u+7tNvLmG2m1vlbYy9gZs+lrLcAJdUTzhBQfTfm8/8=; b=t/+veDCRAf98F+MBHD5ZPsM94V3EtuBr3XqONPfQQ4X42lUGNI2Nr6sBZ8ETCONrIZ l1KCT8kSMYFGb901yuRlL4SMy2D1ocsczfebL/9Zrl33LTrbfeLy+Ajn+MkL/xT8r6WE bHXQbAmoGOHNem2Q/NsFtSfzJk54cHrru0Dbq8cC6SivgnUUgjU1lUafXS0Il/aJ5ARU u51h5owMEH4EStK9t2OPD19gbyY5pwWOx8ekF/Q/8WQNl0xbd3z4KZoeFqAkZUTn1hS4 lpuZO9L1qdqC1dI7VQflNON30xbwo4KIhgIgYJImeW5rp4707ms9hB9h/a6L50xCXUtf T3cQ== X-Gm-Message-State: AOAM53127d1i8AX2Cd6wF5pro4WC3GhMIN55zP8a5rzGZ280sD/gd+ad RyJO1t42fcsIfmSZnjuMkAzYXfQ757zgu0AhkrNAZvFaoG18FP9MfjA0/iHs+wWXGy5fSRFmyMr tlJzq5L0cA8U= X-Received: by 2002:a5d:59a2:0:b0:1f1:f3af:a069 with SMTP id p2-20020a5d59a2000000b001f1f3afa069mr845959wrr.581.1646853356493; Wed, 09 Mar 2022 11:15:56 -0800 (PST) X-Google-Smtp-Source: ABdhPJxcP9keRv3UQ3cTcwHG1pYQLWUkqChIRH1t4JepaQN83RkcZ7XWUgDLb5f6ntlqfCFWdEszAA== X-Received: by 2002:a5d:59a2:0:b0:1f1:f3af:a069 with SMTP id p2-20020a5d59a2000000b001f1f3afa069mr845925wrr.581.1646853356230; Wed, 09 Mar 2022 11:15:56 -0800 (PST) Received: from ?IPV6:2003:cb:c707:6300:8418:c653:d01f:3bd2? (p200300cbc70763008418c653d01f3bd2.dip0.t-ipconnect.de. [2003:cb:c707:6300:8418:c653:d01f:3bd2]) by smtp.gmail.com with ESMTPSA id n17-20020a05600c3b9100b00389d6331f93sm1085737wms.3.2022.03.09.11.15.54 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 09 Mar 2022 11:15:55 -0800 (PST) Message-ID: Date: Wed, 9 Mar 2022 20:15:54 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH v3 3/9] mm: slightly clarify KSM logic in do_swap_page() To: Yang Shi Cc: Linux Kernel Mailing List , Andrew Morton , Hugh Dickins , Linus Torvalds , David Rientjes , Shakeel Butt , John Hubbard , Jason Gunthorpe , Mike Kravetz , Mike Rapoport , "Kirill A . Shutemov" , Matthew Wilcox , Vlastimil Babka , Jann Horn , Michal Hocko , Nadav Amit , Rik van Riel , Roman Gushchin , Andrea Arcangeli , Peter Xu , Donald Dutile , Christoph Hellwig , Oleg Nesterov , Jan Kara , Liang Zhang , Linux MM References: <20220131162940.210846-1-david@redhat.com> <20220131162940.210846-4-david@redhat.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 83E931C0019 X-Stat-Signature: fxooha685538og5bem34iz543cyq9mzo X-Rspam-User: Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=XrhhIPk4; spf=none (imf21.hostedemail.com: domain of david@redhat.com has no SPF policy when checking 170.10.129.124) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-Rspamd-Server: rspam07 X-HE-Tag: 1646853360-643896 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 09.03.22 19:48, Yang Shi wrote: > On Mon, Jan 31, 2022 at 8:33 AM David Hildenbrand wrote: >> >> Let's make it clearer that KSM might only have to copy a page >> in case we have a page in the swapcache, not if we allocated a fresh >> page and bypassed the swapcache. While at it, add a comment why this is >> usually necessary and merge the two swapcache conditions. >> >> Signed-off-by: David Hildenbrand >> --- >> mm/memory.c | 38 +++++++++++++++++++++++--------------- >> 1 file changed, 23 insertions(+), 15 deletions(-) >> >> diff --git a/mm/memory.c b/mm/memory.c >> index 923165b4c27e..3c91294cca98 100644 >> --- a/mm/memory.c >> +++ b/mm/memory.c >> @@ -3615,21 +3615,29 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) >> goto out_release; >> } >> >> - /* >> - * Make sure try_to_free_swap or reuse_swap_page or swapoff did not > > We could remove the reference to "reuse_swap_page", right? > Yes, I noticed this a couple of days ago as well and already have a patch prepared for that ("mm: adjust stale comment in do_swap_page() mentioning reuse_swap_page()" at https://github.com/davidhildenbrand/linux/commits/cow_fixes_part_3) If Andrew wants, we can fix that up directly before sending upstream or I'll simply include that patch when sending out part2 v2. (I want to avoid sending another series just for this) Thanks! -- Thanks, David / dhildenb