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 E3A10C25B78 for ; Mon, 27 May 2024 07:41:56 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 661876B0082; Mon, 27 May 2024 03:41:56 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5C3906B0083; Mon, 27 May 2024 03:41:56 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 48B056B0085; Mon, 27 May 2024 03:41:56 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 294F36B0082 for ; Mon, 27 May 2024 03:41:56 -0400 (EDT) Received: from smtpin26.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 90F4CC14A9 for ; Mon, 27 May 2024 07:41:55 +0000 (UTC) X-FDA: 82163381790.26.D02C647 Received: from out-178.mta1.migadu.com (out-178.mta1.migadu.com [95.215.58.178]) by imf21.hostedemail.com (Postfix) with ESMTP id 4A7EF1C001B for ; Mon, 27 May 2024 07:41:52 +0000 (UTC) Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b="CLJCQTE/"; spf=pass (imf21.hostedemail.com: domain of chengming.zhou@linux.dev designates 95.215.58.178 as permitted sender) smtp.mailfrom=chengming.zhou@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1716795712; h=from:from:sender: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:dkim-signature; bh=A8ih7vz66Rx+ZxVaMPrr50Ps6h1emlB7JWpOfQ6g6+8=; b=NR7yZYzSZwGgLHi+4HCUqIjDlfoWoNUKNqhffpQebKQT0O+ztw3c6ONGdhuT5dulH+W66t U7FbZjR4a9aPNzAxAogidKxe4XaEKfcLI9L3MJGbb1kmgRGy3VHv37vzpBd8I7ZOPM+OxY hymkwP2M5soMO3k6dMIrWl535m6zqbg= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b="CLJCQTE/"; spf=pass (imf21.hostedemail.com: domain of chengming.zhou@linux.dev designates 95.215.58.178 as permitted sender) smtp.mailfrom=chengming.zhou@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1716795712; a=rsa-sha256; cv=none; b=1KJp9fbMOJ8B92v3CSHm58q/mwARKdBUgxC2M2EVjX81xkaKqygZP57kzl0nuuCl1x0YVw UgbhapWdIEAtaMUmDb/FYQUGrX5WROej9EVIb1a37csDAd919RpfxxHyfixC3FLsRUDV0j A0UNo/Jp6HDwVUwEogzsW0vTK+aTakU= X-Envelope-To: david@redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1716795709; 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=A8ih7vz66Rx+ZxVaMPrr50Ps6h1emlB7JWpOfQ6g6+8=; b=CLJCQTE/vly7FuFm/O96eANqAlO1xjq4WZyQtTRg7+o7S3z8nAA/pw9hHG7z8v6UmUVWEj DAsGh4R23PM3h1mMP9uGubp94rSQC5EifT1BGP+atzIxVzxjwpG8oi+kRoBoe5dQpL7jAO QeQn9+WSoa/zkivs6BVf4vfdAZon4Es= X-Envelope-To: akpm@linux-foundation.org X-Envelope-To: aarcange@redhat.com X-Envelope-To: hughd@google.com X-Envelope-To: shr@devkernel.io X-Envelope-To: linux-mm@kvack.org X-Envelope-To: linux-kernel@vger.kernel.org X-Envelope-To: zhouchengming@bytedance.com Message-ID: Date: Mon, 27 May 2024 15:41:21 +0800 MIME-Version: 1.0 Subject: Re: [PATCH 1/4] mm/ksm: refactor out try_to_merge_with_zero_page() Content-Language: en-US To: David Hildenbrand , Andrew Morton , aarcange@redhat.com, hughd@google.com, shr@devkernel.io Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, zhouchengming@bytedance.com References: <20240524-b4-ksm-scan-optimize-v1-0-053b31bd7ab4@linux.dev> <20240524-b4-ksm-scan-optimize-v1-1-053b31bd7ab4@linux.dev> <18259f7c-d57e-4504-91ec-90b7c87aad01@redhat.com> <36d4f3a6-c426-4455-b5be-2ab503d380ad@linux.dev> <18ad1a9f-8f00-41c1-9c77-ac3252061852@redhat.com> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Chengming Zhou In-Reply-To: <18ad1a9f-8f00-41c1-9c77-ac3252061852@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 4A7EF1C001B X-Stat-Signature: frrrybdiiim8cmom5q5huaaegr5ju8gt X-HE-Tag: 1716795712-546073 X-HE-Meta: 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 IoIr08cs 3FayPyZ1O/xEcjOXJPqWg2iZ9djTDhHhKY+fYAEmffv6juJh7oNVAhl77ePJm7f60A8SQpwZuQT2p3/+34hKTD8+PTLCm+Mm7T1ciK0cXBeWREtcB69I0MEIyCLxRs/qsbAopadwxH4UYuwF4ddKONC+ky/Gv8xH1zeG7 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: List-Subscribe: List-Unsubscribe: On 2024/5/27 15:18, David Hildenbrand wrote: > Am 27.05.24 um 06:36 schrieb Chengming Zhou: >> On 2024/5/24 23:12, David Hildenbrand wrote: >>> On 24.05.24 10:56, Chengming Zhou wrote: >>>> In preparation for later changes, refactor out a new function called >>>> try_to_merge_with_zero_page(), which tries to merge with zero page. >>>> >>>> Signed-off-by: Chengming Zhou >>>> --- >>>>    mm/ksm.c | 67 +++++++++++++++++++++++++++++++++++----------------------------- >>>>    1 file changed, 37 insertions(+), 30 deletions(-) >>>> >>>> diff --git a/mm/ksm.c b/mm/ksm.c >>>> index 4dc707d175fa..cbd4ba7ea974 100644 >>>> --- a/mm/ksm.c >>>> +++ b/mm/ksm.c >>>> @@ -1531,6 +1531,41 @@ static int try_to_merge_one_page(struct vm_area_struct *vma, >>>>        return err; >>>>    } >>>>    +/* This function returns 0 if the pages were merged, -EFAULT otherwise. */ >>> >>> No it doesn't. Check the "err = 0" case. >>> >> >> Right, how about this: This function returns 0 if the page were merged or the vma >> is out of date, which means we don't need to continue, -EFAULT otherwise. > > Maybe slightly adjusted: > > This function returns 0 if the pages were merged or if they are no longer merging candidates (e.g., VMA stale), -EFAULT otherwise. > Great, will change to this. Thanks!