From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 39F9F239099 for ; Fri, 6 Feb 2026 08:18:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770365933; cv=none; b=jb8i9Ep2TxvUJZN+SO546PK/n3goiL92rnlg8h8sdBGzUbSpl1ZjB17/152aN1K5YsP6Q1qnxshiNzUlW8XOGI5JCKpkc66YkZH1FTUCnzRVrdMt9QHyJhsTKHMUT08YKIXo4O6Kz+bDENp0Vm1eovqSPgZnieZYET28R2+medM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770365933; c=relaxed/simple; bh=syvH/EQhTARDq0ntPLE1YxFDXePP+tcEqlK28YM5SKA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=jFbcwxE+fWFgCYUxcnRk3MqvTVEGigucoD4utmG6NJe7Jqhm1jgG7s5mGu9yWcbq50A5ThR6A8mybjD7F8Nwe9XaXFh2/6WSw8CsSrX89kBg3gHDjBJ8dQ1qQXu+qUODlS3PN3c8a19y98AC2/ODoqPe3dYT0a816mrUHGLmSEs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=rkm+DJ+n; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="rkm+DJ+n" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 01BF4C116C6; Fri, 6 Feb 2026 08:18:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770365933; bh=syvH/EQhTARDq0ntPLE1YxFDXePP+tcEqlK28YM5SKA=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=rkm+DJ+nul/EhvQz9DIjFMuvbWLKUMga0qkpo6yRynLo49ahf8C7xCbDruBozImLe 543u02WvzmVpgrM46UIs9g9E2qBfy9GchB+EpTDM/6e2z6WcTeTBIv5Blh6X10yyQH j47lD2Ih0XpJBSYJr2DDGHRXqPsLLfhyqoN7+AdBpAP4dzkwJ8Ku0D5sC4OJC6kjz3 BVzC2HWM+MCTpta7hTpOf7gSPGFkQQpnCuocMKeJGzVHJu3a+UwZSd2r+2WzA9R7bB 7Ccl6k9mtDsml3l3qmmb20hzAy8p6T5tCEzrnmMF/o154D/1s8CQ3XcyEhcaG3pc60 fpj5Pa5yJ6JTA== Message-ID: Date: Fri, 6 Feb 2026 09:18:49 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: ksm: initialize rmap values directly and make them const To: xu.xin16@zte.com.cn, akpm@linux-foundation.org Cc: chengming.zhou@linux.dev, hughd@google.com, wang.yaxin@zte.com.cn, yang.yang29@zte.com.cn, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <202602061522548871ohgXN8z0qq87sTSX-yZc@zte.com.cn> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2/6/26 08:22, xu.xin16@zte.com.cn wrote: > From: xu xin > > Considering that commit 06fbd555dea8 ("ksm: optimize rmap_walk_ksm by passing > a suitable addressrange") seems to have already been merged, this new patch is > proposed to address the issue raised by David at: > > https://lore.kernel.org/all/ba03780a-fd65-4a03-97de-bc0905106260@kernel.org/ > > This initialize rmap values (addr, pgoff_start, pgoff_end) directly and > make them const to make code more robust. Besides, since KSM folios are always > order-0, so folio_nr_pages(KSM folio) is always 1, so the line: > > "pgoff_end = pgoff_start + folio_nr_pages(folio) - 1;" > > becomes directly: > > "pgoff_end = pgoff_start;" > > The test reproducer of rmap_walk_ksm can be found at: > https://lore.kernel.org/all/20260206151424734QIyWL_pA-1QeJPbJlUxsO@zte.com.cn/ Thanks! > > Fixes: 06fbd555dea8 ("ksm: optimize rmap_walk_ksm by passing a suitable addressrange") > Signed-off-by: xu xin The patch does not seem to be upstream / in mm-stable yet. Can you resend the original patch with these changes included and the reproducer referenced in the updated patch description? Thanks! > --- > mm/ksm.c | 13 +++++-------- > 1 file changed, 5 insertions(+), 8 deletions(-) > > diff --git a/mm/ksm.c b/mm/ksm.c > index 031c17e4ada6..c7ca117024a4 100644 > --- a/mm/ksm.c > +++ b/mm/ksm.c > @@ -3171,8 +3171,11 @@ void rmap_walk_ksm(struct folio *folio, struct rmap_walk_control *rwc) > struct anon_vma *anon_vma = rmap_item->anon_vma; > struct anon_vma_chain *vmac; > struct vm_area_struct *vma; > - unsigned long addr; > - pgoff_t pgoff_start, pgoff_end; > + /* Ignore the stable/unstable/sqnr flags */ > + const unsigned long addr = rmap_item->address & PAGE_MASK; > + const pgoff_t pgoff_start = rmap_item->address >> PAGE_SHIFT; > + /* KSM folios are always order-0 normal pages */ > + const pgoff_t pgoff_end = pgoff_start; I would move them all the way up, above the "struct anon_vma *anon_vma = rmap_item->anon_vma;" -- Cheers, David