Messages in this thread | | | Date | Tue, 19 Feb 2008 09:16:08 +0100 | From | Thomas Petazzoni <> | Subject | Re: Question about synchronous write on SSD |
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Hi,
Le Tue, 19 Feb 2008 14:48:18 +0900, "Kyungmin Park" <kmpark@infradead.org> a écrit :
> + /* Write synchronous */ > + bio->bi_rw |= (1 << BIO_RW_SYNC);
Adding BIO_RW_SYNC doesn't make generic_make_request() synchronous as in "generic_make_request() returns only after write completion". BIO_RW_SYNC only asks the I/O layer to unplug immediatly. But generic_make_request() still returns before the completion of the I/O, and the completion is notified asynchronously.
See: http://lxr.free-electrons.com/source/include/linux/bio.h#139
Sincerly,
Thomas -- Thomas Petazzoni, Free Electrons Free Embedded Linux Training Materials on http://free-electrons.com/training (More than 1500 pages!) [unhandled content-type:application/pgp-signature] | |