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 729441CCB4B for ; Mon, 13 Jan 2025 18:43:15 +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=1736793796; cv=none; b=esBU+HkHiRakDuKKHPtxBRGeOceHhOXjWhEnOtPu5Urn4gLIcHa8R2tSqcVsRRGa75ugL97g1wH5qFJXi0bPLMvYnQSSnNCvvTO8FUt9TLHlzSqXaa8f+WstHgbuWFveaRwX/guvkHtvfx8E1szSUDBt8TRjsgWYENtXKcLAorQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736793796; c=relaxed/simple; bh=uPw2sDECkRR33mE3fpDXv7rzwJQNurpTnfV4CbbdCg8=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=MfrYjXk8zHhzg5PkAdZkoT+AaEF3yBjO040jDdCkTZO10fdA6GFu/b/UzFZPadvlbJQZbsEgk3Enb/QKFMdwJFAl2kVqZdBaGFVIx19Y2Ck53KnGDsBCmdv0scTDhbyLOOD3MBbZyQoSKRSuFOtNVjfwcc5YHqjzIwek1kYWrT0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=pslPNXFx; 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="pslPNXFx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D4BFAC4CED6; Mon, 13 Jan 2025 18:43:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1736793795; bh=uPw2sDECkRR33mE3fpDXv7rzwJQNurpTnfV4CbbdCg8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pslPNXFxQWxCpVSFzpmuwnPaNvCYkxDBsQgesKVspmuqkAwKmfGzCanXIZU/7jPUw kjQne8OFofSUdu4+F4H3+NpkiBtc7aPkcswT1JjfG3fA6dIT9HT2R5a/z+rR+PWYON 7Wvd3nNNDsHJQnE+XCYDWgprUIflHbuniWLUA885uqz1VDg6aRNsrR0z+FIclezITW 3NoOo6LaId1tzE2EM20dMNaNWXoJMeNYwD464HYm7LUPpf3n/aMoN8iZRJWHgWvOA6 EdeiDcEjCkvWdUhsHGBrwm3AHbwSXMY3sShKJpVX2yAZlDIuEWEdOKx0ylBIcuCWE8 twUYOtG5CKzkg== From: SeongJae Park To: Usama Arif Cc: SeongJae Park , akpm@linux-foundation.org, damon@lists.linux.dev, linux-mm@kvack.org Subject: Re: [PATCH] mm/damon: increment pa_stat damon address range by folio size Date: Mon, 13 Jan 2025 10:43:11 -0800 Message-Id: <20250113184311.6572-1-sj@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250113180340.805474-1-usamaarif642@gmail.com> References: Precedence: bulk X-Mailing-List: damon@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Hi Usama, Let's use "mm/damon/paddr: " prefix for the patch title, to be more consistent with others. On Mon, 13 Jan 2025 18:03:40 +0000 Usama Arif wrote: > This is to take into account for folios with size > 1 page. > Iterating at PAGE_SIZE increment would increment sz_filter_passed > multiple times for the same folio by folio_size, providing incorrect > stats. damon_get_folio() returns NULL if the page is a tail page. Hence I think it will not increment sz_filter_passed multiple times? > Hence go through the folio only once. I tink this is still nice to do, for more efficiency. Can you post v2 of this patch after updating the commit message and addressing below comments? > > Fixes: 6347f3385dd0 ("mm/damon/paddr: report filter-passed bytes back for DAMOS_STAT action") > Signed-off-by: Usama Arif > --- > mm/damon/paddr.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c > index 6b4397de4199..cc789a97c6f5 100644 > --- a/mm/damon/paddr.c > +++ b/mm/damon/paddr.c > @@ -504,7 +504,8 @@ static unsigned long damon_pa_stat(struct damon_region *r, struct damos *s, > if (!damon_pa_scheme_has_filter(s)) > return 0; > > - for (addr = r->ar.start; addr < r->ar.end; addr += PAGE_SIZE) { > + addr = r->ar.start; > + while (addr < r->ar.end) { > struct folio *folio = damon_get_folio(PHYS_PFN(addr)); > > if (!folio) In this case, the code does "continue". 'addr' is not advanced, so it will result in an infinite loop. Let's do 'addr += PAGE_SIZE' here, to avoid that. > @@ -515,6 +516,7 @@ static unsigned long damon_pa_stat(struct damon_region *r, struct damos *s, > else > *sz_filter_passed += folio_size(folio); > put_folio: > + addr += folio_size(folio); > folio_put(folio); > } > return 0; > -- > 2.43.5 Thanks, SJ