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From: Wei Yang <richard.weiyang@gmail.com>
To: Mika Penttil?? <mika.penttila@nextfour.com>
Cc: Wei Yang <richard.weiyang@gmail.com>,
	"Huang, Ying" <ying.huang@intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Dave Hansen <dave.hansen@linux.intel.com>,
	David Hildenbrand <david@redhat.com>,
	Mel Gorman <mgorman@suse.de>, Vlastimil Babka <vbabka@suse.cz>,
	Zi Yan <ziy@nvidia.com>, Michal Hocko <mhocko@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Minchan Kim <minchan@kernel.org>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Hugh Dickins <hughd@google.com>
Subject: Re: [RFC 2/3] mm: Add a new page flag PageLayzyFree() for MADV_FREE
Date: Sun, 15 Mar 2020 12:22:17 +0000	[thread overview]
Message-ID: <20200315122217.45mioaxzuulwvx2f@master> (raw)
In-Reply-To: <92d4b0fe-f592-8da6-0282-2ea8a015b247@nextfour.com>

On Sun, Mar 15, 2020 at 10:54:03AM +0200, Mika Penttil?? wrote:
>
>
>On 15.3.2020 10.18, Wei Yang wrote:
>> On Fri, Feb 28, 2020 at 11:38:18AM +0800, Huang, Ying wrote:
>> > From: Huang Ying <ying.huang@intel.com>
>> > 
>> > Now !PageSwapBacked() is used as the flag for the pages freed lazily
>> > via MADV_FREE.  This isn't obvious enough.  So Dave suggested to add a
>> > new page flag for that to improve the code readability.
>> I am confused with the usage of PageSwapBacked().
>> 
>> Previously I thought this flag means the page is swapin, set in
>> swapin_readahead(). While I found page_add_new_anon_rmap() would set it too.
>> This means every anon page would carry this flag. Then what is this flag
>> means?
>> 
>> 
>
>But not all PageSwapBacked() pages are anon, like shmem.
>

Yes, while it looks shmem is the only exception.

I am still struggling to understand the meaning of this flag.

>
>--Mika

-- 
Wei Yang
Help you, Help me


  reply	other threads:[~2020-03-15 12:22 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-28  3:38 [RFC 0/3] mm: Discard lazily freed pages when migrating Huang, Ying
2020-02-28  3:38 ` [RFC 1/3] mm, migrate: Check return value of try_to_unmap() Huang, Ying
2020-02-28  3:38 ` [RFC 2/3] mm: Add a new page flag PageLayzyFree() for MADV_FREE Huang, Ying
2020-02-28  6:13   ` David Hildenbrand
2020-02-28  6:47     ` Huang, Ying
2020-03-15  8:18   ` Wei Yang
2020-03-15  8:54     ` Mika Penttilä
2020-03-15 12:22       ` Wei Yang [this message]
2020-03-16  1:21         ` Huang, Ying
2020-03-16 22:38           ` Wei Yang
2020-02-28  3:38 ` [RFC 3/3] mm: Discard lazily freed pages when migrating Huang, Ying
2020-02-28  3:42 ` [RFC 0/3] " Matthew Wilcox
2020-02-28  7:25   ` Huang, Ying
2020-02-28  8:22     ` David Hildenbrand
2020-02-28  8:55       ` Huang, Ying
2020-02-28  9:49         ` Mel Gorman
2020-03-02 11:23           ` Huang, Ying
2020-03-02 15:16             ` Mel Gorman
2020-03-03  1:51               ` Huang, Ying
2020-03-03  8:09                 ` Michal Hocko
2020-03-03  8:47                   ` Huang, Ying
2020-03-03  8:58                     ` Michal Hocko
2020-03-03 11:49                       ` Huang, Ying
2020-03-04  9:58                         ` Michal Hocko
2020-03-04 10:56                           ` Mel Gorman
2020-03-05  1:42                             ` Huang, Ying
2020-03-04 11:15                           ` Huang, Ying
2020-03-04 11:26                             ` Michal Hocko
2020-03-05  1:45                               ` Huang, Ying
2020-03-05 10:48                             ` Mel Gorman
2020-03-06  4:05                               ` Huang, Ying
2020-03-09  5:26                               ` Huang, Ying
2020-03-03 13:02                 ` Mel Gorman
2020-03-04  0:33                   ` Huang, Ying
2020-02-28  9:50         ` Michal Hocko
2020-02-28 10:15           ` Michal Hocko
2020-02-28 13:45           ` Johannes Weiner
2020-03-02 14:12           ` Huang, Ying
2020-03-02 14:23             ` David Hildenbrand
2020-03-03  0:25               ` Huang, Ying
2020-03-02 14:25             ` Michal Hocko
2020-03-03  1:30               ` Huang, Ying
2020-03-03  8:19                 ` Michal Hocko
2020-03-03 11:36                   ` Huang, Ying

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