On Wed, 17 Jul 2013 00:44:15 +0400 CoolCold <coolthecold@xxxxxxxxx> wrote: > Neil, I've tryed to look around commit logs but failed to find commit > where discard/trim were added. > I was looking via > http://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/log/drivers/md?id=9f2a940965286754f3a34d5737c3097c05db8725&qt=grep&q=discard+support > , tryed just "discard" without support - found commits about dm, not > md, though. > > Can you shed some light here? Thanks in advance. > > (resent in plaintext mode, please reply to this one) Did you try: grep -i discard drivers/md/raid1.c ?? commit 2ff8cc2c6d4e323de71a42affeb3041fa17d5b10 Author: Shaohua Li <shli@xxxxxxxxxxxx> Date: Thu Oct 11 13:28:54 2012 +1100 md: raid 1 supports TRIM is the commit that introduced discard support for md/raid1.c NeilBrown > > > On Tue, Jul 16, 2013 at 11:15 AM, NeilBrown <neilb@xxxxxxx> wrote: > > On Sat, 13 Jul 2013 06:34:19 -0400 "Justin Piszcz" <jpiszcz@xxxxxxxxxxxxxxx> > > wrote: > > > >> Hello, > >> > >> Running 3.10 and I see the following for an md-raid1 of two SSDs: > >> > >> Checking /sys/block/md1/queue: > >> add_random: 0 > >> discard_granularity: 512 > >> discard_max_bytes: 2147450880 > >> discard_zeroes_data: 0 > >> hw_sector_size: 512 > >> iostats: 0 > >> logical_block_size: 512 > >> max_hw_sectors_kb: 32767 > >> max_integrity_segments: 0 > >> max_sectors_kb: 512 > >> max_segment_size: 65536 > >> max_segments: 168 > >> minimum_io_size: 512 > >> nomerges: 0 > >> nr_requests: 128 > >> optimal_io_size: 0 > >> physical_block_size: 512 > >> read_ahead_kb: 8192 > >> rotational: 1 > >> rq_affinity: 0 > >> scheduler: none > >> write_same_max_bytes: 0 > >> > >> What should be seen: > >> rotational: 0 > > > > What has "rotational" got to do with "supports discard"? > > There may be some correlation, but it isn't causal. > > > >> And possibly: > >> discard_zeroes_data: 1 > > > > This should be set as the 'or' of the same value from component devices. And > > does not enable or disable the use of discard. > > > > I don't think that "does this device support discard" appears in sysfs. > > > > I believe trim does work on md/raid1 if the underlying devices all support it. > > > > NeilBrown > > > > > > > >> > >> Can anyone confirm if there is a workaround to allow TRIM when using > >> md-raid1? > >> > >> Some related discussion here: > >> http://us.generation-nt.com/answer/md-rotational-attribute-help-206571222.ht > >> ml > >> http://www.progtown.com/topic343938-ssd-strange-itself-conducts.html > >> > >> > >> Justin. > >> > >> > >> -- > >> To unsubscribe from this list: send the line "unsubscribe linux-raid" in > >> the body of a message to majordomo@xxxxxxxxxxxxxxx > >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > > > >
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