[lkml]   [2010]   [Jun]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH 33/35] libata: take advantage of cmwq and remove concurrency limitations
On 06/28/2010 05:04 PM, Tejun Heo wrote:
> libata has two concurrency related limitations.
> a. ata_wq which is used for polling PIO has single thread per CPU. If
> there are multiple devices doing polling PIO on the same CPU, they
> can't be executed simultaneously.
> b. ata_aux_wq which is used for SCSI probing has single thread. In
> cases where SCSI probing is stalled for extended period of time
> which is possible for ATAPI devices, this will stall all probing.
> #a is solved by increasing maximum concurrency of ata_wq. Please note
> that polling PIO might be used under allocation path and thus needs to
> be served by a separate wq with a rescuer.
> #b is solved by using the default wq instead and achieving exclusion
> via per-port mutex.
> Signed-off-by: Tejun Heo<>
> Cc: Jeff Garzik<>

Acked-by: Jeff Garzik <>

 \ /
  Last update: 2010-06-29 00:35    [W:0.284 / U:0.516 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site