Re: [PATCH 2/3] Retry page fault when blocking on disk transfer.

[Rik van Riel]

On 10/05/2010 03:53 AM, Michel Lespinasse wrote:
> This change reduces mmap_sem hold times that are caused by waiting for
> disk transfers when accessing file mapped VMAs. It introduces the
> VM_FAULT_ALLOW_RETRY flag, which indicates that the call site wants
> mmap_sem to be released if blocking on a pending disk transfer.
> In that case, filemap_fault() returns the VM_FAULT_RETRY status bit
> and do_page_fault() will then re-acquire mmap_sem and retry the page fault.
> It is expected that the retry will hit the same page which will now be
> cached, and thus it will complete with a low mmap_sem hold time.
>
> Signed-off-by: Michel Lespinasse<walken@xxxxxxxxxx>

Acked-by: Rik van Riel <riel@xxxxxxxxxx>

Looks like it should be relatively easy to do something
similar in do_swap_page also.
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