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From: Matthew Wilcox <willy@infradead.org>
To: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	David Hildenbrand <david@redhat.com>,
	Oscar Salvador <osalvador@suse.de>, SeongJae Park <sj@kernel.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	damon@lists.linux.dev, vishal.moola@gmail.com
Subject: Re: [PATCH -next 2/8] mm: page_idle: Convert page idle to use folios
Date: Tue, 13 Dec 2022 14:34:48 +0000	[thread overview]
Message-ID: <Y5iNiNUoNlupyhow@casper.infradead.org> (raw)
In-Reply-To: <20221213092735.187924-3-wangkefeng.wang@huawei.com>

On Tue, Dec 13, 2022 at 05:27:29PM +0800, Kefeng Wang wrote:
> -static struct page *page_idle_get_page(unsigned long pfn)
> +static struct folio *folio_idle_get_folio(unsigned long pfn)
>  {
> -	struct page *page = pfn_to_online_page(pfn);
> +	struct folio *folio = pfn_to_online_folio(pfn);
>  
> -	if (!page || !PageLRU(page) ||
> -	    !get_page_unless_zero(page))
> +	if (!folio || !folio_test_lru(folio) || !folio_try_get(folio))
>  		return NULL;

You've changed the semantics here, and I suspect will cause breakage
as a result.  Before if you called page_idle_get_page() on a tail page,
you got a NULL pointer returned.  Now you get the folio that contains
that tail page.

I think you have to continue to call pfn_to_online_page() and do
the conversion to folio manually in this function.  By all means
convert this function to return the folio, but you need to take a
little more care.


  reply	other threads:[~2022-12-13 14:35 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-13  9:27 [PATCH -next 0/8] mm: converted page idle and damon to use folios Kefeng Wang
2022-12-13  9:27 ` [PATCH -next 1/8] mm: memory_hotplug: add pfn_to_online_folio() Kefeng Wang
2022-12-13 11:13   ` kernel test robot
2022-12-13 11:36     ` Kefeng Wang
2022-12-13 11:23   ` kernel test robot
2022-12-13 11:40   ` David Hildenbrand
2022-12-13 12:13     ` Kefeng Wang
2022-12-13 14:42       ` David Hildenbrand
2022-12-13 14:47       ` Matthew Wilcox
2022-12-14  1:10         ` Kefeng Wang
2022-12-13 12:03   ` kernel test robot
2022-12-14  4:15   ` kernel test robot
2022-12-13  9:27 ` [PATCH -next 2/8] mm: page_idle: Convert page idle to use folios Kefeng Wang
2022-12-13 14:34   ` Matthew Wilcox [this message]
2022-12-13 19:14   ` SeongJae Park
2022-12-13  9:27 ` [PATCH -next 3/8] mm: huge_memory: convert split_huge_pages_all() " Kefeng Wang
2022-12-13  9:27 ` [PATCH -next 4/8] mm: damon: add temporary damon_get_folio() Kefeng Wang
2022-12-13 14:40   ` Matthew Wilcox
2022-12-13 19:18     ` SeongJae Park
2022-12-13  9:27 ` [PATCH -next 5/8] mm: damon: convert damon_ptep/pmdp_mkold() to use folios Kefeng Wang
2022-12-13  9:27 ` [PATCH -next 6/8] mm: damon: paddr: convert damon_pa_*() " Kefeng Wang
2022-12-13  9:27 ` [PATCH -next 7/8] mm: damon: vaddr: convert damon_young_pmd_entry() to use folio Kefeng Wang
2022-12-13  9:27 ` [PATCH -next 8/8] mm: damon: remove unneed damon_get_page() Kefeng Wang
2022-12-13 19:26   ` SeongJae Park

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