Messages in this thread | | | Date | Mon, 26 Sep 2011 05:45:54 -0400 | From | Christoph Hellwig <> | Subject | Re: [patch]mm: add more blk plug |
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On Mon, Sep 26, 2011 at 03:38:47PM +0800, Shaohua Li wrote: > On Mon, 2011-09-26 at 15:30 +0800, Christoph Hellwig wrote: > > On Mon, Sep 26, 2011 at 10:30:26AM +0800, Shaohua Li wrote: > > > Some filesystems implement .writepages. We don't have blk plug > > > in such filesystems for .writepages. > > > > Please add the plugging in the actual ->writepages instances. > there are several filesystems have ->writepages. Can you share an hint > why we don't add plugging in the do_writepages?
Because do_writepages is completely generic code with no knowledge of block I/O. I really don't want to have block plugging be intimately tied into core VM/writeback code all over. We've been there with ->sync_page, and it was a major pain - nevermind the additional (small) overhead for the not block based filesystems.
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