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 489023191D4 for ; Mon, 5 Jan 2026 16:49:28 +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=1767631768; cv=none; b=JbDc7DDlLxUqd2Z6K3Fvu3Ugj8q6tvBpCGFi/iG3eZjyVoUz8ktSOqEAz6O6GFvgmdieeM3T8d0zGl4huqErR610hRpYcRcAvIEqtYYVLl1Ty9MaZXb8JcVe4Gsapf0PMhWJOEkZ9PxP/qv9qCam/KQNemZ9CEXeVbkUvzFb0yA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767631768; c=relaxed/simple; bh=q4jProQTOr60sLsG+h2XK+ynEstH6XLCXVz8oALa8gY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=mCHYdkrABoG5jisciOkNmmaEFxA1hPvrtRa8B8VCgoiGFVtPdAve2SaV664vJrBSjezHPt0BszyuBcNoJGjeR9xwl1jgbmVq+coohPJPRIACzEDafXplPoInqcNJM9vlqBDDN4PPCKnTSN+miFUkVxhyHUph8ZOxjBQfZDvZIIo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bfAKs4/B; 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="bfAKs4/B" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 32254C116D0; Mon, 5 Jan 2026 16:49:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1767631767; bh=q4jProQTOr60sLsG+h2XK+ynEstH6XLCXVz8oALa8gY=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=bfAKs4/BGFyCRwCH+PUoi6dKBrSOT1OFhGke+NhSx+WHx0963FCJyFW9CzbIfyul0 hOaELtLEe+yU5C6nghjzsZ6zR6U2DWzOpHJOwEoXQG8AEulvCx1D0ObpkA7/jHr6OT xOoDoUl51JNPx5ccOEpxo2YuH04x9+m4mqhdP81qLxKKadekAhvUgBlb+S9F+OpZ3t JuEH9aIcSI1hdd6QRsU1vhw5eekBF8of1d8GaKhp9DH8rW2x3dWE6pFMjjnoqS1Odr I5qX/9KyfZDx8lDcpND3h+qGgAWlruBELpSZXJNsbe25wY42iV+4pZmnYFSviuU4oQ lUKBIxiULVFUQ== Message-ID: <69c9ac59-4fb2-42fc-a8ae-32f583e47de4@kernel.org> Date: Mon, 5 Jan 2026 17:49:22 +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: [PATCH v3 2/6] mm: khugepaged: refine scan progress number To: Vernon Yang , akpm@linux-foundation.org Cc: lorenzo.stoakes@oracle.com, ziy@nvidia.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, richard.weiyang@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Vernon Yang References: <20260104054112.4541-1-yanglincheng@kylinos.cn> <20260104054112.4541-3-yanglincheng@kylinos.cn> From: "David Hildenbrand (Red Hat)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 1/4/26 06:41, Vernon Yang wrote: > Currently, each PMD scan always increases `progress` by HPAGE_PMD_NR, > even if only scanning a single page. By counting the actual number of "... a single pmd" ? > pages scanned, the `progress` is tracked accurately. "page table entries / pages scanned" ? > > Signed-off-by: Vernon Yang > --- > mm/khugepaged.c | 31 +++++++++++++++++++++++-------- > 1 file changed, 23 insertions(+), 8 deletions(-) > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index 9f99f61689f8..4b124e854e2e 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -1247,7 +1247,7 @@ static int collapse_huge_page(struct mm_struct *mm, unsigned long address, > static int hpage_collapse_scan_pmd(struct mm_struct *mm, > struct vm_area_struct *vma, > unsigned long start_addr, bool *mmap_locked, > - struct collapse_control *cc) > + int *progress, struct collapse_control *cc) > { > pmd_t *pmd; > pte_t *pte, *_pte; > @@ -1258,23 +1258,28 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm, > unsigned long addr; > spinlock_t *ptl; > int node = NUMA_NO_NODE, unmapped = 0; > + int _progress = 0; "cur_progress" ? > > VM_BUG_ON(start_addr & ~HPAGE_PMD_MASK); > > result = find_pmd_or_thp_or_none(mm, start_addr, &pmd); > - if (result != SCAN_SUCCEED) > + if (result != SCAN_SUCCEED) { > + _progress = HPAGE_PMD_NR; > goto out; > + } > > memset(cc->node_load, 0, sizeof(cc->node_load)); > nodes_clear(cc->alloc_nmask); > pte = pte_offset_map_lock(mm, pmd, start_addr, &ptl); > if (!pte) { > + _progress = HPAGE_PMD_NR; > result = SCAN_NO_PTE_TABLE; > goto out; > } > > for (addr = start_addr, _pte = pte; _pte < pte + HPAGE_PMD_NR; > _pte++, addr += PAGE_SIZE) { > + _progress++; > pte_t pteval = ptep_get(_pte); > if (pte_none_or_zero(pteval)) { > ++none_or_zero; > @@ -1410,6 +1415,9 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm, > *mmap_locked = false; > } > out: > + if (progress) > + *progress += _progress; > + > trace_mm_khugepaged_scan_pmd(mm, folio, referenced, > none_or_zero, result, unmapped); > return result; > @@ -2287,7 +2295,7 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr, > > static int hpage_collapse_scan_file(struct mm_struct *mm, unsigned long addr, > struct file *file, pgoff_t start, > - struct collapse_control *cc) > + int *progress, struct collapse_control *cc) > { > struct folio *folio = NULL; > struct address_space *mapping = file->f_mapping; > @@ -2295,6 +2303,7 @@ static int hpage_collapse_scan_file(struct mm_struct *mm, unsigned long addr, > int present, swap; > int node = NUMA_NO_NODE; > int result = SCAN_SUCCEED; > + int _progress = 0; Same here. Not sure if it would be cleaner to just let the parent increment its counter and returning instead the "cur_progress" from the function. -- Cheers David