Messages in this thread | | | Date | Wed, 11 Apr 2012 16:13:44 -0700 | From | Andrew Morton <> | Subject | Re: [RESEND][PATCH v2] block: remove plugging at buffered write time |
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On Mon, 09 Apr 2012 10:34:44 -0400 Jeff Moyer <jmoyer@redhat.com> wrote:
> Wu Fengguang <fengguang.wu@intel.com> writes: > > > Buffered write(2) is not directly tied to IO, so it's not suitable to > > handle plug in generic_file_aio_write(). > [snip, moved] > > Note that plugging for O_SYNC writes is also removed. The user may pass > > arbitrary @size arguments, which may be much larger than the preferable > > I/O size, or may cross extent/device boundaries. Let the lower layers > > handle the plugging. Otherwise the plugging code here will turn the > > low level plugging into no-ops. > > I assume you have some numbers to back this up, right? Care to share > those?
Yes please.
We've broken this stuff a few times recently - we should review and test carefully.
> > Also moves unplugging for direct I/O from around ->direct_IO() down to > > do_blockdev_direct_IO(). > > This could be handled in a separate patch.
I think that would be better.
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