From: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
hch@infradead.org, david@fromorbit.com,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, cl@linux.com, mike.kravetz@oracle.com
Subject: Re: [RFC PATCH V2 0/9] Introduce attach/clear_page_private to cleanup code
Date: Sat, 2 May 2020 10:56:51 +0200 [thread overview]
Message-ID: <e4d5ddc0-877f-6499-f697-2b7c0ddbf386@cloud.ionos.com> (raw)
In-Reply-To: <20200502004158.GD29705@bombadil.infradead.org>
On 5/2/20 2:41 AM, Matthew Wilcox wrote:
> On Sat, May 02, 2020 at 12:42:15AM +0200, Guoqing Jiang wrote:
>> On 5/2/20 12:16 AM, Matthew Wilcox wrote:
>>> On Thu, Apr 30, 2020 at 11:44:41PM +0200, Guoqing Jiang wrote:
>>>> include/linux/pagemap.h: introduce attach/clear_page_private
>>>> md: remove __clear_page_buffers and use attach/clear_page_private
>>>> btrfs: use attach/clear_page_private
>>>> fs/buffer.c: use attach/clear_page_private
>>>> f2fs: use attach/clear_page_private
>>>> iomap: use attach/clear_page_private
>>>> ntfs: replace attach_page_buffers with attach_page_private
>>>> orangefs: use attach/clear_page_private
>>>> buffer_head.h: remove attach_page_buffers
>>> I think mm/migrate.c could also use this:
>>>
>>> ClearPagePrivate(page);
>>> set_page_private(newpage, page_private(page));
>>> set_page_private(page, 0);
>>> put_page(page);
>>> get_page(newpage);
>>>
>> Thanks for checking! Assume the below change is appropriate.
>>
>> diff --git a/mm/migrate.c b/mm/migrate.c
>> index 7160c1556f79..f214adfb3fa4 100644
>> --- a/mm/migrate.c
>> +++ b/mm/migrate.c
>> @@ -797,10 +797,7 @@ static int __buffer_migrate_page(struct address_space
>> *mapping,
>> if (rc != MIGRATEPAGE_SUCCESS)
>> goto unlock_buffers;
>>
>> - ClearPagePrivate(page);
>> - set_page_private(newpage, page_private(page));
>> - set_page_private(page, 0);
>> - put_page(page);
>> + set_page_private(newpage, detach_page_private(page));
>> get_page(newpage);
> I think you can do:
>
> @@ -797,11 +797,7 @@ static int __buffer_migrate_page(struct address_space *mapping,
> if (rc != MIGRATEPAGE_SUCCESS)
> goto unlock_buffers;
>
> - ClearPagePrivate(page);
> - set_page_private(newpage, page_private(page));
> - set_page_private(page, 0);
> - put_page(page);
> - get_page(newpage);
> + attach_page_private(newpage, detach_page_private(page));
>
> bh = head;
> do {
> @@ -810,8 +806,6 @@ static int __buffer_migrate_page(struct address_space *mapping,
>
> } while (bh != head);
>
> - SetPagePrivate(newpage);
> -
> if (mode != MIGRATE_SYNC_NO_COPY)
>
> ... but maybe there's a subtlety to the ordering of the setup of the bh
> and setting PagePrivate that means what you have there is a better patch.
Yes, it is better but not sure if the order can be changed here. And seems
the original commit is this one.
commit e965f9630c651fa4249039fd4b80c9392d07a856
Author: Christoph Lameter <clameter@sgi.com>
Date: Wed Feb 1 03:05:41 2006 -0800
[PATCH] Direct Migration V9: Avoid writeback / page_migrate() method
Migrate a page with buffers without requiring writeback
This introduces a new address space operation migratepage() that
may be used
by a filesystem to implement its own version of page migration.
A version is provided that migrates buffers attached to pages. Some
filesystems (ext2, ext3, xfs) are modified to utilize this feature.
The swapper address space operation are modified so that a regular
migrate_page() will occur for anonymous pages without writeback
(migrate_pages
forces every anonymous page to have a swap entry).
Hope mm experts could take a look, so CC more people and mm list. And
the question is that if we can setting PagePrivate before setup bh in the
__buffer_migrate_page, thanks for your any further input.
Thanks,
Guoqing
prev parent reply other threads:[~2020-05-02 8:57 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-30 21:44 [RFC PATCH V2 0/9] Introduce attach/clear_page_private to cleanup code Guoqing Jiang
2020-04-30 21:44 ` [RFC PATCH V2 1/9] include/linux/pagemap.h: introduce attach/clear_page_private Guoqing Jiang
2020-04-30 22:10 ` Andreas Grünbacher
2020-05-01 6:38 ` Guoqing Jiang
2020-04-30 22:13 ` Matthew Wilcox
2020-05-01 1:42 ` Al Viro
2020-05-01 1:49 ` Al Viro
2020-05-01 6:41 ` Guoqing Jiang
2020-05-01 6:39 ` Guoqing Jiang
2020-04-30 21:44 ` [RFC PATCH V2 2/9] md: remove __clear_page_buffers and use attach/clear_page_private Guoqing Jiang
2020-04-30 21:44 ` [RFC PATCH V2 3/9] btrfs: " Guoqing Jiang
2020-04-30 21:44 ` [RFC PATCH V2 4/9] fs/buffer.c: " Guoqing Jiang
2020-04-30 21:44 ` [RFC PATCH V2 5/9] f2fs: " Guoqing Jiang
2020-04-30 21:44 ` [RFC PATCH V2 6/9] iomap: " Guoqing Jiang
2020-04-30 21:44 ` [RFC PATCH V2 7/9] ntfs: replace attach_page_buffers with attach_page_private Guoqing Jiang
2020-04-30 21:44 ` [RFC PATCH V2 8/9] orangefs: use attach/clear_page_private Guoqing Jiang
2020-04-30 21:44 ` [RFC PATCH V2 9/9] buffer_head.h: remove attach_page_buffers Guoqing Jiang
2020-05-01 22:16 ` [RFC PATCH V2 0/9] Introduce attach/clear_page_private to cleanup code Matthew Wilcox
2020-05-01 22:42 ` Guoqing Jiang
2020-05-02 0:41 ` Matthew Wilcox
2020-05-02 8:56 ` Guoqing Jiang [this message]
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