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 8E592C25B74 for ; Mon, 27 May 2024 04:37:26 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id F1DCD6B0082; Mon, 27 May 2024 00:37:25 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id ECD216B0083; Mon, 27 May 2024 00:37:25 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DBCC76B0085; Mon, 27 May 2024 00:37:25 -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 BF5B06B0082 for ; Mon, 27 May 2024 00:37:25 -0400 (EDT) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 64271412CD for ; Mon, 27 May 2024 04:37:25 +0000 (UTC) X-FDA: 82162916850.06.248EB2F Received: from out-187.mta0.migadu.com (out-187.mta0.migadu.com [91.218.175.187]) by imf02.hostedemail.com (Postfix) with ESMTP id 1E32080005 for ; Mon, 27 May 2024 04:37:22 +0000 (UTC) Authentication-Results: imf02.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=EFeOnbg2; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf02.hostedemail.com: domain of chengming.zhou@linux.dev designates 91.218.175.187 as permitted sender) smtp.mailfrom=chengming.zhou@linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1716784643; 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=EQyD8u11NrOanpKOcWnKj72z9MQcFgIv9avWEkfCemo=; b=mHWB2Kz5q7wdDuJyBJkjXQ98nJgpzGkE+2GR1qJ+9sxMWjT+gxLX8MizVe31VveySWv/+a Lm8bwpKQvkbh5YUweiAOjHfqn11taYBRzIC6+ALbCcb/VGwG647Mr54FBv3KUeSAFxR+Ij 28RQimQ5TvoySXX6kQSbfh0WxWmh7dw= ARC-Authentication-Results: i=1; imf02.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=EFeOnbg2; dmarc=pass (policy=none) header.from=linux.dev; spf=pass (imf02.hostedemail.com: domain of chengming.zhou@linux.dev designates 91.218.175.187 as permitted sender) smtp.mailfrom=chengming.zhou@linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1716784643; a=rsa-sha256; cv=none; b=768xePAPTESHUipTjrj17U/PdVDF9wr+EcciUdvAt5VS1Z/BxuZRhVei2WGXVWzEDDVA2h ngV3ZRDC8z43+EAUsaNf7a1yTv7DM25AJ7YgEqdSusdHll00cvvkEChTwXkpgG9BP1fQbn mJu1TRw3HIOcMtVOyVEX2ZgTZMiTFmU= X-Envelope-To: david@redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1716784641; 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=EQyD8u11NrOanpKOcWnKj72z9MQcFgIv9avWEkfCemo=; b=EFeOnbg2XZXpvVldwuyvIr1GkjGfEao2bYAagv7mmzP6845rsFBQU0mi4apVb1cJ1d+quj ++n6mC1Fedu86yjZb3A8McObuIUxU41Lj8Rj8x5JUGEORDtVRU5EX/3XfQwJCnaOpJjNCt Fk5a38k9L+jkIUbDHKU4mwGcM29pBRU= 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: <36d4f3a6-c426-4455-b5be-2ab503d380ad@linux.dev> Date: Mon, 27 May 2024 12:36:49 +0800 MIME-Version: 1.0 Subject: Re: [PATCH 1/4] mm/ksm: refactor out try_to_merge_with_zero_page() 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> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Chengming Zhou In-Reply-To: <18259f7c-d57e-4504-91ec-90b7c87aad01@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: 1E32080005 X-Stat-Signature: isypzn98re5aoaowibt3odf6pgimgma8 X-Rspam-User: X-Rspamd-Server: rspam04 X-HE-Tag: 1716784642-23244 X-HE-Meta: U2FsdGVkX1+lW/wMxA9ZR4gOCGFrhik8cc7g/AnZ41uDy9VhLsC4Zkm4ClC+TnCq9WUtEmsnRTZWp524Ei8GWL6GlXA8aZJA9canZqrNKHceFOUWkQ/J5UXrHdjg2HLGf6DUVB4fD14czp5YLOO98nOWvv+RIL8wDVQ3KZU+Kpe+mjfisCT/H6l2lE+X8AJNi0Uz3qI22ZKwDlrhGmC/YlDCX5Jr5S5uWQYZkDF3ufDbZ0WMt1C+Botw+4ibb4RJmLONwsNPCf7M8C/O50b8a1KJxKblV4+7pXlXJ0EVxWRjCBHTz0vwhH8tqzKu9Fzpbs7bEXFrKYSNi3e1Y6h65AbF5hn4T7E7eYQyXT1AmW2SmYokVJxpPmlxfAUZ/kEmtC/hWOiMZYMjPw54jN5/szdlcQg7/42FA2Abt6WmYJEiw6/mXwDc/okfq/uo8VDTqzujzaItcgiLIj9QIjWsab475SMkbZGsFmFOKUf9l/FdhdcDrY9dD4NPe9BwkHdiq71vyw3vd2aZzsn6hN0aZBhAqDkvVMUwZ0VUlIR+IEcvWspobSr+AjS4QidAgLyjc6M2YBZJ3uJ6kZI2dOo2C3V85hNlQDnq2OQkyweLhYJQLPqBrDRVl/szksuZbQpDXLRj5N3CXzxyh7HH5LR9z/2yXyC3OWEJfG5zBWidX8QpdbmMZahLiVsodew0Q6gxmFWiG8rpQ8yEaTtjmBYzMbB8YtkeDmbX7R/PCtHvOM0k6Q5MMXoXPlPJLyRVpcQAJUWRnnHloslVaEE8Dola7pKTNb31x7wiNzrhkwjJFYUQROtdwkU+FFAWyCHcmdC58vvWUP6FNgWPy1ed7HEWmqW4z2sa5uXUtndqQJbqptrTHqb9APWKWe0m5dVPqvSlV0AZ9uJhApXnA+OZT0xC09q/wtlAsQbsJBfNp0GeubmVhL37XKaSL84wiWEg3NlOW048cmKoYvGpev2B/7B R40DT9qx mm9uj/tzZkgEXG9M6b+F50SKX6XrTHhys5Sju5qKG7zYPLS8kbtEHfSNgLYUUr7lPbmlJfuqBw7zHi7EvJ2mjmxttgEkyvzLqHMLOs3X6mOhSqEd1Ww2Y/KePkZgGDtretWkb 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 2024/5/24 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.