Re: Question about synchronous write on SSD

[Thomas Petazzoni]

Hi,

Le Tue, 19 Feb 2008 14:48:18 +0900,
"Kyungmin Park" <kmpark@xxxxxxxxxxxxx> a Ãcrit :

> +               /* 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!)

Attachment: signature.asc
Description: PGP signature