| Message ID | 20110505020417.586891398@sli10-conroe.sh.intel.com |
|---|---|
| State | Not Applicable |
| Delegated to: | David Miller |
| Headers | show |
On 05/04/2011 09:59 PM, shaohua.li@intel.com wrote: > flush request isn't queueable in some drives. Add a flag to let driver > notify block layer about this. We can optimize flush performance with the > knowledge. > > Signed-off-by: Shaohua Li<shaohua.li@intel.com> > --- > block/blk-settings.c | 6 ++++++ > include/linux/blkdev.h | 7 +++++++ > 2 files changed, 13 insertions(+) hmmm. This assumes that flush on new hardware, by default, is queueable. I think the sense should be reversed: don't enable the optimization, unless we know the optimization works. That seems safer than always enabling the optimization, unless we know it does not work. That is not a fail-safe mode of operation. Jeff -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, May 05, 2011 at 10:17:39AM +0800, Jeff Garzik wrote: > On 05/04/2011 09:59 PM, shaohua.li@intel.com wrote: > > flush request isn't queueable in some drives. Add a flag to let driver > > notify block layer about this. We can optimize flush performance with the > > knowledge. > > > > Signed-off-by: Shaohua Li<shaohua.li@intel.com> > > --- > > block/blk-settings.c | 6 ++++++ > > include/linux/blkdev.h | 7 +++++++ > > 2 files changed, 13 insertions(+) > > hmmm. > > This assumes that flush on new hardware, by default, is queueable. > > I think the sense should be reversed: don't enable the optimization, > unless we know the optimization works. > > That seems safer than always enabling the optimization, unless we know > it does not work. That is not a fail-safe mode of operation. This assumes flush is queueable by default. but I only enable the optimization for non-queueable flush. So the optimization is off by default, please see the second patch. Thanks, Shaohua -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, May 05, 2011 at 09:59:33AM +0800, shaohua.li@intel.com wrote: > flush request isn't queueable in some drives. Add a flag to let driver > notify block layer about this. We can optimize flush performance with the > knowledge. > > Signed-off-by: Shaohua Li <shaohua.li@intel.com> Acked-by: Tejun Heo <tj@kernel.org> Thanks.
Index: linux/include/linux/blkdev.h =================================================================== --- linux.orig/include/linux/blkdev.h 2011-05-04 14:23:42.000000000 +0800 +++ linux/include/linux/blkdev.h 2011-05-05 09:05:18.000000000 +0800 @@ -364,6 +364,7 @@ struct request_queue * for flush operations */ unsigned int flush_flags; + unsigned int flush_not_queueable:1; unsigned int flush_pending_idx:1; unsigned int flush_running_idx:1; unsigned long flush_pending_since; @@ -843,6 +844,7 @@ extern void blk_queue_softirq_done(struc extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *); extern void blk_queue_rq_timeout(struct request_queue *, unsigned int); extern void blk_queue_flush(struct request_queue *q, unsigned int flush); +extern void blk_queue_flush_queueable(struct request_queue *q, bool queueable); extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev); extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *); @@ -1111,6 +1113,11 @@ static inline unsigned int block_size(st return bdev->bd_block_size; } +static inline bool queue_flush_queueable(struct request_queue *q) +{ + return !q->flush_not_queueable; +} + typedef struct {struct page *v;} Sector; unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *); Index: linux/block/blk-settings.c =================================================================== --- linux.orig/block/blk-settings.c 2011-05-05 08:37:05.000000000 +0800 +++ linux/block/blk-settings.c 2011-05-05 09:02:16.000000000 +0800 @@ -790,6 +790,12 @@ void blk_queue_flush(struct request_queu } EXPORT_SYMBOL_GPL(blk_queue_flush); +void blk_queue_flush_queueable(struct request_queue *q, bool queueable) +{ + q->flush_not_queueable = !queueable; +} +EXPORT_SYMBOL_GPL(blk_queue_flush_queueable); + static int __init blk_settings_init(void) { blk_max_low_pfn = max_low_pfn - 1;
flush request isn't queueable in some drives. Add a flag to let driver notify block layer about this. We can optimize flush performance with the knowledge. Signed-off-by: Shaohua Li <shaohua.li@intel.com> --- block/blk-settings.c | 6 ++++++ include/linux/blkdev.h | 7 +++++++ 2 files changed, 13 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html