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From: Muchun Song In-Reply-To: <58b1d1f5fbda7db49ca886d9ef6783e3dcbbbc98.1660805030.git.baolin.wang@linux.alibaba.com> Date: Thu, 18 Aug 2022 16:27:41 +0800 Cc: sj@kernel.org, Andrew Morton , Mike Kravetz , damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Message-Id: References: <58b1d1f5fbda7db49ca886d9ef6783e3dcbbbc98.1660805030.git.baolin.wang@linux.alibaba.com> To: Baolin Wang X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1660816018; a=rsa-sha256; cv=none; b=ehYbHKwTL0sFcVRgYJ7D4FzfQ20ckY8OU35H0314VQcYV/B5VWH2Z7BcBBCVmAorWEqDAP 1Uw9Rxrr0v/L87PNXurISd418JbtK1mqY4HV11gAdXX5T+lkfVyEYEE4Zaz7zyNyZ0bjhN F1Oby7qD/7pWjEPZLS9yldwFyozw1mc= ARC-Authentication-Results: i=1; imf13.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=i4uEb4xT; spf=pass (imf13.hostedemail.com: domain of muchun.song@linux.dev designates 94.23.1.103 as permitted sender) smtp.mailfrom=muchun.song@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=1660816018; 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=GmDACFAww771N8QDTZCRoxaYGKF8g2ZcH88LHpMyuOQ=; b=UeZqkjM+BA2DF7WOGOMymk0ZsTFjTIpxQmBqfVb/1WtpkM7rMf/luOdjD1zmy4ANb5EDek kLUn2usRuBw5k7azP58VknqyqAdMtn4aU/+Nyto7QzeVmo31G8KZyJ1s7AjXerTYDoCmGt AgtLg9gnoHQtpYnD8ZK4o5JAcz4O/W0= X-Rspamd-Queue-Id: 9AADB20345 Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=i4uEb4xT; spf=pass (imf13.hostedemail.com: domain of muchun.song@linux.dev designates 94.23.1.103 as permitted sender) smtp.mailfrom=muchun.song@linux.dev; dmarc=pass (policy=none) header.from=linux.dev X-Rspam-User: X-Stat-Signature: 65akfo7q7kxezg6sqbbqmky9s4pe1nf4 X-Rspamd-Server: rspam12 X-HE-Tag: 1660816018-172823 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 Aug 18, 2022, at 15:37, Baolin Wang = wrote: >=20 > The pmd_huge() is used to validate if the pmd entry is mapped by a = huge > page, also including the case of non-present (migration or hwpoisoned) > pmd entry on arm64 or x86 architectures. That means the pmd_pfn() can > not get the correct pfn number for the non-present pmd entry, which > will cause damon_get_page() to get an incorrect page struct (also > may be NULL by pfn_to_online_page()) to make the access statistics > incorrect. >=20 > Moreover it does not make sense that we still waste time to get the > page of the non-present entry, just treat it as not-accessed and skip = it, > that keeps consistent with non-present pte level entry. >=20 > Thus adding a pmd entry present validation to fix above issues. >=20 > Signed-off-by: Baolin Wang > Reviewed-by: SeongJae Park Reviewed-by: Muchun Song Thanks.