Messages in this thread | | | Date | Tue, 14 Jul 2015 11:23:32 -0400 | From | Mike Snitzer <> | Subject | Re: [PATCH 2/2] block: make /sys/block/<dev>/queue/discard_max_bytes writeable |
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On Tue, Jul 14 2015 at 11:02am -0400, Jens Axboe <axboe@fb.com> wrote:
> Lots of devices support huge discard sizes these days. Depending > on how the device handles them internally, huge discards can > introduce massive latencies (hundreds of msec) on the device side. > > We have a sysfs file, discard_max_bytes, that advertises the max > hardware supported discard size. Make this writeable, and split > the settings into a soft and hard limit. This can be set from > 'discard_granularity' and up to the hardware limit.
Looks pretty good, but we'll lose the original discard_max_bytes once it is changed. That information loss will prevent users from knowing what adjustments are possible over time.
This may be OK, but figured i'd raise it.
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