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From: SeongJae Park <sj@kernel.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	SeongJae Park <sj@kernel.org>,
	damon@lists.linux.dev, linux-mm@kvack.org,
	vishal.moola@gmail.com, david@redhat.com
Subject: Re: [PATCH -next v3 5/7] mm/damon/vaddr: convert damon_young_pmd_entry() to use folio
Date: Thu, 29 Dec 2022 21:31:11 +0000	[thread overview]
Message-ID: <20221229213111.163524-1-sj@kernel.org> (raw)
In-Reply-To: <Y64BRAL90fZA7gIe@casper.infradead.org>

On Thu, 29 Dec 2022 21:06:12 +0000 Matthew Wilcox <willy@infradead.org> wrote:

> On Wed, Dec 28, 2022 at 07:34:11PM +0800, Kefeng Wang wrote:
> > -		if (pmd_young(*pmd) || !page_is_idle(page) ||
> > +		if (pmd_young(*pmd) || !folio_test_idle(folio) ||
> >  					mmu_notifier_test_young(walk->mm,
> >  						addr)) {
> >  			*priv->page_sz = HPAGE_PMD_SIZE;
> 
> hmm ...
> 
> >  	pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
> >  	if (!pte_present(*pte))
> >  		goto out;
> > -	page = damon_get_page(pte_pfn(*pte));
> > -	if (!page)
> > +	folio = damon_get_folio(pte_pfn(*pte));
> > +	if (!folio)
> >  		goto out;
> > -	if (pte_young(*pte) || !page_is_idle(page) ||
> > +	if (pte_young(*pte) || !folio_test_idle(folio) ||
> >  			mmu_notifier_test_young(walk->mm, addr)) {
> >  		*priv->page_sz = PAGE_SIZE;
> 
> hmm ...
> 
> So why aren't we doing '*priv->page_sz = folio_size(folio)'?  What does
> DAMON want to do when encountering folios that are neither PAGE_SIZE
> nor HPAGE_PMD_SIZE?

Good point.  We use the field to know if next address to check access is in
same folio and therefore if we could reuse the last access check result.  So it
would be better to use 'folio_size(folio)' here.  The field name would also
better to be 'folio_sz'.  I will make the change, unless others do.


Thanks,
SJ

  reply	other threads:[~2022-12-29 21:31 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-28 11:34 [PATCH -next v3 0/7] mm: convert page_idle/damon to use folios Kefeng Wang
2022-12-28 11:34 ` [PATCH -next v3 1/7] mm: page_idle: convert page idle " Kefeng Wang
2022-12-28 17:46   ` SeongJae Park
2022-12-28 11:34 ` [PATCH -next v3 2/7] mm/damon: introduce damon_get_folio() Kefeng Wang
2022-12-28 22:36   ` Matthew Wilcox
2022-12-28 23:14     ` SeongJae Park
2022-12-28 11:34 ` [PATCH -next v3 3/7] mm/damon: convert damon_ptep/pmdp_mkold() to use folios Kefeng Wang
2022-12-28 11:34 ` [PATCH -next v3 4/7] mm/damon/paddr: convert damon_pa_*() " Kefeng Wang
2022-12-29 20:36   ` Matthew Wilcox
2022-12-30  6:40     ` Kefeng Wang
2022-12-28 11:34 ` [PATCH -next v3 5/7] mm/damon/vaddr: convert damon_young_pmd_entry() to use folio Kefeng Wang
2022-12-29 21:06   ` Matthew Wilcox
2022-12-29 21:31     ` SeongJae Park [this message]
2022-12-28 11:34 ` [PATCH -next v3 6/7] mm/damon: remove unneed damon_get_page() Kefeng Wang
2022-12-28 17:49   ` SeongJae Park
2022-12-28 11:34 ` [PATCH -next v3 7/7] mm/damon/vaddr: convert hugetlb related function to use folios Kefeng Wang
2022-12-28 17:51   ` SeongJae Park
2022-12-28 17:55 ` [PATCH -next v3 0/7] mm: convert page_idle/damon " SeongJae Park
2022-12-29  2:16   ` Kefeng Wang

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