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 E73A52E3AF0; Wed, 30 Jul 2025 17:56:55 +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=1753898216; cv=none; b=lYQZRuN1TI8wmJzj+omahINP6Xo86223K4a0cKMlOpxjz7AZoRZgtrVZuGdSn/uCJbTaLHEsil5rMP4vibS3UVA4TnlVpdPFQIKNYf0sRsXB1w3/2XZ/4DqUnorUBUPS2prx8cKBr5Hn/26RChj4nDVVZFneRPWGABsAzLWv3+g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753898216; c=relaxed/simple; bh=LxlL3e6vR/HG4aAeNYWdTWRtYhjSKsDeB3n9zodRNKc=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=MY6rRIke8nU58NwKbBA7+Qwgmwqz1c3NUrNYUsCKr6rupXwNs9mp14EVxaU1JL4rJQH6Aq2fN6Hdq8LCl7YHyRQWgFYu5zWTu34Ak0coRcFKHVEk8WL5ZnnAXUE/Aj4SKR0WsCqd7oa44gg/H4huKwIPgMRAdyghba56Vh8dwoY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=FmhIB6rw; 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="FmhIB6rw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A1176C4CEE7; Wed, 30 Jul 2025 17:56:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1753898215; bh=LxlL3e6vR/HG4aAeNYWdTWRtYhjSKsDeB3n9zodRNKc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FmhIB6rwEPaQO/Kz2XplzMkph3aNpT/mO8O9r3oM07r1u2d/KSkOmLDTwvIIVGs+9 qrS9w9JcKtrEzhSH1eZVWTCgNdV9WqCbiFnGSf7fpfPJ9a1uXtQg2rnucfQbXyH7vt YpWeppA9eHbXki8P8Kpsuduy5rbUCSW7J3KH6wJ2gIXeNhmmVgjlC+aUguWjnEBVpI Kw5w8z0hcK/sfavGU6AsLX39TbLvXrJ+6c0x9xv3m/kukaKKBgFDqbSLuU1VS9paIp Mv37T8M6Bslm1zXa+gB5/ar0I71926sLzi6DcZRFjDj3mqUvRiMt2PyTVVnlwai9uj aqDRnYn18lDrQ== From: SeongJae Park To: Yueyang Pan Cc: SeongJae Park , Andrew Morton , Usama Arif , damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/2] mm/damon: Add damos_stat support for vaddr Date: Wed, 30 Jul 2025 10:56:52 -0700 Message-Id: <20250730175652.60173-1-sj@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: References: Precedence: bulk X-Mailing-List: damon@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Wed, 30 Jul 2025 10:19:56 -0700 Yueyang Pan wrote: > This patch adds support for damos_stat in virtual address space. > It leverages the walk_page_range to walk the page table and gets > the folio from page table. The last folio scanned is stored in > damos->last_applied to prevent double counting. > > Signed-off-by: Yueyang Pan > --- > mm/damon/vaddr.c | 105 ++++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 104 insertions(+), 1 deletion(-) > > diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c > index 87e825349bdf..6ed919e817e2 100644 > --- a/mm/damon/vaddr.c > +++ b/mm/damon/vaddr.c > @@ -890,6 +890,109 @@ static unsigned long damos_va_migrate(struct damon_target *target, > return applied * PAGE_SIZE; > } > > +struct damos_va_stat_private { > + struct damos *scheme; > + unsigned long *sz_filter_passed; > +}; > + > +static inline bool damon_va_invalid_damos_folio(struct folio *folio, struct damos *s) Weirdly DAMON code usually keeps the 80 columns limit. Could you please break down this line? Also, the name feels long to me. What about damos_va_invalid_folio()? > +{ > + return !folio || folio == s->last_applied; > +} > + > +static int damos_va_stat_pmd_entry(pmd_t *pmd, unsigned long addr, > + unsigned long next, struct mm_walk *walk) > +{ > + struct damos_va_stat_private *priv = walk->private; > + struct damos *s = priv->scheme; > + unsigned long *sz_filter_passed = priv->sz_filter_passed; > + struct vm_area_struct *vma = walk->vma; > + struct folio *folio; > + spinlock_t *ptl; > + pte_t *start_pte, *pte, ptent; > + int nr; > + > +#ifdef CONFIG_TRANSPARENT_HUGEPAGE > + if (pmd_trans_huge(*pmd)) { > + pmd_t pmde; > + > + ptl = pmd_trans_huge_lock(pmd, vma); > + if (!ptl) > + return 0; > + pmde = pmdp_get(pmd); > + if (!pmd_present(pmde)) > + goto huge_unlock; > + > + folio = vm_normal_folio_pmd(vma, addr, pmde); > + > + if (damon_va_invalid_damos_folio(folio, s)) > + goto huge_unlock; > + > + if (!damos_va_filter_out(s, folio, vma, addr, NULL, pmd)) > + *sz_filter_passed += folio_size(folio); > + s->last_applied = folio; > + > +huge_unlock: > + spin_unlock(ptl); > + return 0; > + } > +#endif > + start_pte = pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); > + if (!start_pte) > + return 0; > + > + for (; addr < next; pte += nr, addr += nr * PAGE_SIZE) { > + nr = 1; > + ptent = ptep_get(pte); > + > + if (pte_none(ptent) || !pte_present(ptent)) > + continue; > + > + folio = vm_normal_folio(vma, addr, ptent); > + > + if (damon_va_invalid_damos_folio(folio, s)) > + continue; > + > + if (!damos_va_filter_out(s, folio, vma, addr, pte, NULL)) > + *sz_filter_passed += folio_size(folio); > + nr = folio_nr_pages(folio); > + s->last_applied = folio; > + } > + > + pte_unmap_unlock(start_pte, ptl); > + No strong opinion, but I'd like to drop above two blank lines (one after the for loop, and one after pte_unmap_unlock() if you don't mind. > + return 0; > +} > + > +static unsigned long damos_va_stat(struct damon_target *target, > + struct damon_region *r, struct damos *s, > + unsigned long *sz_filter_passed) > +{ > + Seems this is unnecessary blank line. Let's remove it. > + struct damos_va_stat_private priv; > + struct mm_struct *mm; > + struct mm_walk_ops walk_ops = { > + .pmd_entry = damos_va_stat_pmd_entry, > + .walk_lock = PGWALK_RDLOCK, > + }; > + > + priv.scheme = s; > + priv.sz_filter_passed = sz_filter_passed; > + > + if (!damon_scheme_has_filter(s)) > + return 0; > + > + mm = damon_get_mm(target); > + if (!mm) > + return 0; > + > + mmap_read_lock(mm); > + walk_page_range(mm, r->ar.start, r->ar.end, &walk_ops, &priv); > + mmap_read_unlock(mm); > + mmput(mm); > + return 0; > +} > + > static unsigned long damon_va_apply_scheme(struct damon_ctx *ctx, > struct damon_target *t, struct damon_region *r, > struct damos *scheme, unsigned long *sz_filter_passed) > @@ -916,7 +1019,7 @@ static unsigned long damon_va_apply_scheme(struct damon_ctx *ctx, > case DAMOS_MIGRATE_COLD: > return damos_va_migrate(t, r, scheme, sz_filter_passed); > case DAMOS_STAT: > - return 0; > + return damos_va_stat(t, r, scheme, sz_filter_passed); > default: > /* > * DAMOS actions that are not yet supported by 'vaddr'. > -- > 2.47.3 Thanks, SJ