Re: [PATCH 0/2] Add support to aio ring pages migration

From: Gu Zheng
Date: Thu Jul 11 2013 - 06:14:58 EST


ping...

On 07/08/2013 06:38 PM, Gu Zheng wrote:

> Currently aio ring pages use get_user_pages() to allocate pages from movable
> zone,as discussed in thread https://lkml.org/lkml/2012/11/29/69, it is easy to
> pin user pages for a long time, which is fatal for memory hotplug/remove framework.
>
> As Mel Gorman suggested, "Implement a callback for migration to unpin pages,
> barrier operations until migration completes and pin the new pfns" can soloved
> this issue. And the best palce to hold the callbacks is address space operations
> which can be found via page->mapping.
>
> But the current aio ring pages are anonymous pages, they don't have
> address_space_operations, so we use an anon inode file as the aio ring file to
> manage the aio ring pages, so that we can implement the callback and register it
> to page->mmapping->a_ops->migratepage.
>
> But there's a ploblem that all files created by anon_inode_getfile() share the
> same inode, so mutil aio context will share the same aio ring pages, it'll lead
> to io events chaos. In order to solve this issus, we introduce a new fucntion
> anon_inode_getfile_private() which is samilar to anon_inode_getfile(), but each
> new file has its own anon inode.
>
> This work is based on Benjamin's patch,
> http://www.spinics.net/lists/linux-fsdevel/msg66014.html
>
> Gu Zheng (2):
> fs/anon_inode: Introduce a new lib function
> anon_inode_getfile_private()
> fs/aio: Add support to aio ring pages migration
>
> fs/aio.c | 120 +++++++++++++++++++++++++++++++++++++++----
> fs/anon_inodes.c | 66 +++++++++++++++++++++++
> include/linux/anon_inodes.h | 3 +
> include/linux/migrate.h | 3 +
> mm/migrate.c | 2 +-
> 5 files changed, 182 insertions(+), 12 deletions(-)
>


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