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 DDAEFC77B75 for ; Tue, 23 May 2023 18:07:49 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5F80C900003; Tue, 23 May 2023 14:07:49 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5A87E900002; Tue, 23 May 2023 14:07:49 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4978F900003; Tue, 23 May 2023 14:07:49 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 3A985900002 for ; Tue, 23 May 2023 14:07:49 -0400 (EDT) Received: from smtpin03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 0C0CD12079E for ; Tue, 23 May 2023 18:07:49 +0000 (UTC) X-FDA: 80822303058.03.A7A0FDB Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf18.hostedemail.com (Postfix) with ESMTP id C634D1C002E for ; Tue, 23 May 2023 18:07:09 +0000 (UTC) Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=Ff5mtWAR; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf18.hostedemail.com: domain of sj@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=sj@kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1684865229; a=rsa-sha256; cv=none; b=OOTZ5BP8Ik+BTczHhVF+EuLPqYJlcHLo3QLHOU2WZFSwhuV5rrWmcbdUzIrH121SPMYESK PSfRmHB6gHSyUgQx8zw02llz3onv73U4K/kiywCdjX/lPi7sNmORk0VSWOT+a/vxpWoW3P KUSilm+lble3rquKdzG8xk+UMOjTDGk= ARC-Authentication-Results: i=1; imf18.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=Ff5mtWAR; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf18.hostedemail.com: domain of sj@kernel.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=sj@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1684865229; 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-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=vf0CeHiZpGPAyht1SjRfwg3G9Uc5t2LEXFJN3uhuRJY=; b=bNhjyivo716aIfGTWoyqIeNHUE7EM0MJAFspdmtCF16q6YHEoVIcU0DPtR0WjPxEHrlMMo xiiUT5Yl/pkGRZsGVixB62AXoyEHPNQDkxak0ZYFAe96SSZ7DDl+kfUkZBC/6/qbvrodNZ itnb3rM1Y16ZCu7QezNxW0nzCrd1GZw= Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id A41FE6189A; Tue, 23 May 2023 18:07:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 64EB0C433EF; Tue, 23 May 2023 18:07:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1684865228; bh=PqO2Ba0azEpR69b5p3AcZhVRdxUYPoFaydPljsZiJ08=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Ff5mtWARZiVsUDm26jYK2NzJV9heOhVdPVGG+GTPzayA+f7KaErquj7YpGPB0tqnS 8Xjw8GhtAZoYaxeEkk/AEcjmW/NpoAe2fjEVBqOy8mDia04zoW/JpOuXzj2QI743Uv 9fg6oXsf99r8rUYjCpbg8WI8E9A4WKITgvK7QQeJO288u0zVR4YCmT4QsbIP+u5Ekj rJxh6oqNS4wCciLQ/4lBz+Xth8Y+V1AubibKcVUGOLYnBDsXsX7KkzpgydzrytMOz+ zgbX2bUTcZ1MD55KVvsL5IBsmReg4CzPE64MeTLF1jtoVVGqC94QbNhjfIhxHZRk3S 5K52MBWNo9fqA== From: SeongJae Park To: Hugh Dickins Cc: Andrew Morton , Mike Rapoport , "Kirill A. Shutemov" , Matthew Wilcox , David Hildenbrand , Suren Baghdasaryan , Qi Zheng , Yang Shi , Mel Gorman , Peter Xu , Peter Zijlstra , Will Deacon , Yu Zhao , Alistair Popple , Ralph Campbell , Ira Weiny , Steven Price , SeongJae Park , Naoya Horiguchi , Christophe Leroy , Zack Rusin , Jason Gunthorpe , Axel Rasmussen , Anshuman Khandual , Pasha Tatashin , Miaohe Lin , Minchan Kim , Christoph Hellwig , Song Liu , Thomas Hellstrom , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 09/31] mm/pagewalkers: ACTION_AGAIN if pte_offset_map_lock() fails Date: Tue, 23 May 2023 18:07:03 +0000 Message-Id: <20230523180703.89902-1-sj@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <6265ac58-6018-a8c6-cf38-69cba698471@google.com> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: C634D1C002E X-Stat-Signature: fym66s35zbges9hqo7xoqoaxx7nandg6 X-HE-Tag: 1684865229-667750 X-HE-Meta: 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 2+rVgsct s1cdbzvLl/ZhTC70HjJtui6On3mgA2PuLYhXy0NHFuEmev8Uz66aEBJqV5O6wxQp0vVLwXSEyjjpnyHB5PyjWBu5zUfuw5xqQQiit2aBEuNzSSgRNM+GuwKjB627ca/FYdOUU5TvQRjdugBppJSaPxThWO74JStqQpeBeKqeTNloyiOsg1BxrNgx93H4+SY8FPRAGFsXPrGNM6pF46XP+03ylF1AMynKvnAofhwQfq8YUoh+ZbO9JTkaGW+CpAP9BpguS/SVbBn3hNBy1h+N8Vm2inhHFRovT+OjSlbLZV/9P2v7WR0ZEyJ8Pt9mhANDbGJMkUWozDy4kEtp0Lgbo66Ydpw2FiZIorYoe8pS8EPfjjm1wIGTvc9mt+gQbhHwsqA4GCkSm1QKpx6aq2L3lYMTEBw== 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: Hello Hugh, On Sun, 21 May 2023 22:00:15 -0700 (PDT) Hugh Dickins wrote: > Simple walk_page_range() users should set ACTION_AGAIN to retry when > pte_offset_map_lock() fails. > > No need to check pmd_trans_unstable(): that was precisely to avoid the > possiblity of calling pte_offset_map() on a racily removed or inserted > THP entry, but such cases are now safely handled inside it. Likewise > there is no need to check pmd_none() or pmd_bad() before calling it. > > Signed-off-by: Hugh Dickins For below mm/damon part, Reviewed-by: SeongJae Park Thanks, SJ > --- > fs/proc/task_mmu.c | 32 ++++++++++++++++---------------- > mm/damon/vaddr.c | 12 ++++++++---- > mm/mempolicy.c | 7 ++++--- > mm/mincore.c | 9 ++++----- > mm/mlock.c | 4 ++++ > 5 files changed, 36 insertions(+), 28 deletions(-) > [...] > diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c > index 1fec16d7263e..b8762ff15c3c 100644 > --- a/mm/damon/vaddr.c > +++ b/mm/damon/vaddr.c > @@ -318,9 +318,11 @@ static int damon_mkold_pmd_entry(pmd_t *pmd, unsigned long addr, > spin_unlock(ptl); > } > > - if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) > - return 0; > pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl); > + if (!pte) { > + walk->action = ACTION_AGAIN; > + return 0; > + } > if (!pte_present(*pte)) > goto out; > damon_ptep_mkold(pte, walk->mm, addr); > @@ -464,9 +466,11 @@ static int damon_young_pmd_entry(pmd_t *pmd, unsigned long addr, > regular_page: > #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ > > - if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) > - return -EINVAL; > pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl); > + if (!pte) { > + walk->action = ACTION_AGAIN; > + return 0; > + } > if (!pte_present(*pte)) > goto out; > folio = damon_get_folio(pte_pfn(*pte)); [...]