From: Dennis Zhou <dennis@kernel.org>
To: Josef Bacik <josef@toxicpanda.com>
Cc: David Sterba <dsterba@suse.com>, Chris Mason <clm@fb.com>,
Omar Sandoval <osandov@osandov.com>,
kernel-team@fb.com, linux-btrfs@vger.kernel.org
Subject: Re: [PATCH 10/19] btrfs: calculate discard delay based on number of extents
Date: Fri, 11 Oct 2019 14:07:03 -0400 [thread overview]
Message-ID: <20191011180703.GE29672@dennisz-mbp> (raw)
In-Reply-To: <20191010154133.pk62hvu6pgac3mne@macbook-pro-91.dhcp.thefacebook.com>
On Thu, Oct 10, 2019 at 11:41:33AM -0400, Josef Bacik wrote:
> On Mon, Oct 07, 2019 at 04:17:41PM -0400, Dennis Zhou wrote:
> > Use the number of discardable extents to help guide our discard delay
> > interval. This value is reevaluated every transaction commit.
> >
> > Signed-off-by: Dennis Zhou <dennis@kernel.org>
> > ---
> > fs/btrfs/ctree.h | 2 ++
> > fs/btrfs/discard.c | 31 +++++++++++++++++++++++++++++--
> > fs/btrfs/discard.h | 3 +++
> > fs/btrfs/extent-tree.c | 4 +++-
> > fs/btrfs/sysfs.c | 30 ++++++++++++++++++++++++++++++
> > 5 files changed, 67 insertions(+), 3 deletions(-)
> >
> > diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> > index 8479ab037812..b0823961d049 100644
> > --- a/fs/btrfs/ctree.h
> > +++ b/fs/btrfs/ctree.h
> > @@ -449,6 +449,8 @@ struct btrfs_discard_ctl {
> > struct list_head discard_list[BTRFS_NR_DISCARD_LISTS];
> > atomic_t discard_extents;
> > atomic64_t discardable_bytes;
> > + atomic_t delay;
> > + atomic_t iops_limit;
> > };
> >
> > /* delayed seq elem */
> > diff --git a/fs/btrfs/discard.c b/fs/btrfs/discard.c
> > index 75a2ff14b3c0..c7afb5f8240d 100644
> > --- a/fs/btrfs/discard.c
> > +++ b/fs/btrfs/discard.c
> > @@ -15,6 +15,11 @@
> >
> > #define BTRFS_DISCARD_DELAY (300ULL * NSEC_PER_SEC)
> >
> > +/* target discard delay in milliseconds */
> > +#define BTRFS_DISCARD_TARGET_MSEC (6 * 60 * 60ULL * MSEC_PER_SEC)
> > +#define BTRFS_DISCARD_MAX_DELAY (10000UL)
> > +#define BTRFS_DISCARD_MAX_IOPS (10UL)
> > +
> > static struct list_head *
> > btrfs_get_discard_list(struct btrfs_discard_ctl *discard_ctl,
> > struct btrfs_block_group_cache *cache)
> > @@ -170,10 +175,12 @@ void btrfs_discard_schedule_work(struct btrfs_discard_ctl *discard_ctl,
> >
> > cache = find_next_cache(discard_ctl, now);
> > if (cache) {
> > - u64 delay = 0;
> > + u64 delay = atomic_read(&discard_ctl->delay);
> >
> > if (now < cache->discard_delay)
> > - delay = nsecs_to_jiffies(cache->discard_delay - now);
> > + delay = max_t(u64, delay,
> > + nsecs_to_jiffies(cache->discard_delay -
> > + now));
>
> Small nit, instead
>
> delay = nsecs_to_jiffies(cache->discard_delay - now);
> delay = max_t(u64, delay,
> atomic_read(&discard_ctl->delay);
>
> Looks a little cleaner. Otherwise
Hmmm. Does that work if now > cache->discard_delay? I'm just worried
about the max_t with type u64.
>
> Reviewed-by: Josef Bacik <josef@toxicpanda.com>
>
> Thanks,
>
> Josef
Thanks,
Dennis
next prev parent reply other threads:[~2019-10-11 18:07 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-07 20:17 [RFC PATCH 00/19] btrfs: async discard support Dennis Zhou
2019-10-07 20:17 ` [PATCH 01/19] bitmap: genericize percpu bitmap region iterators Dennis Zhou
2019-10-07 20:26 ` Josef Bacik
2019-10-07 22:24 ` Dennis Zhou
2019-10-15 12:11 ` David Sterba
2019-10-15 18:35 ` Dennis Zhou
2019-10-07 20:17 ` [PATCH 02/19] btrfs: rename DISCARD opt to DISCARD_SYNC Dennis Zhou
2019-10-07 20:27 ` Josef Bacik
2019-10-08 11:12 ` Johannes Thumshirn
2019-10-11 9:19 ` Nikolay Borisov
2019-10-07 20:17 ` [PATCH 03/19] btrfs: keep track of which extents have been discarded Dennis Zhou
2019-10-07 20:37 ` Josef Bacik
2019-10-07 22:38 ` Dennis Zhou
2019-10-10 13:40 ` Josef Bacik
2019-10-11 16:15 ` Dennis Zhou
2019-10-08 12:46 ` Nikolay Borisov
2019-10-11 16:08 ` Dennis Zhou
2019-10-15 12:17 ` David Sterba
2019-10-15 19:58 ` Dennis Zhou
2019-10-07 20:17 ` [PATCH 04/19] btrfs: keep track of cleanliness of the bitmap Dennis Zhou
2019-10-10 14:16 ` Josef Bacik
2019-10-11 16:17 ` Dennis Zhou
2019-10-15 12:23 ` David Sterba
2019-10-07 20:17 ` [PATCH 05/19] btrfs: add the beginning of async discard, discard workqueue Dennis Zhou
2019-10-10 14:38 ` Josef Bacik
2019-10-15 12:49 ` David Sterba
2019-10-15 19:57 ` Dennis Zhou
2019-10-07 20:17 ` [PATCH 06/19] btrfs: handle empty block_group removal Dennis Zhou
2019-10-10 15:00 ` Josef Bacik
2019-10-11 16:52 ` Dennis Zhou
2019-10-07 20:17 ` [PATCH 07/19] btrfs: discard one region at a time in async discard Dennis Zhou
2019-10-10 15:22 ` Josef Bacik
2019-10-14 19:42 ` Dennis Zhou
2019-10-07 20:17 ` [PATCH 08/19] btrfs: track discardable extents for asnyc discard Dennis Zhou
2019-10-10 15:36 ` Josef Bacik
2019-10-14 19:50 ` Dennis Zhou
2019-10-15 13:12 ` David Sterba
2019-10-15 18:41 ` Dennis Zhou
2019-10-07 20:17 ` [PATCH 09/19] btrfs: keep track of discardable_bytes Dennis Zhou
2019-10-10 15:38 ` Josef Bacik
2019-10-07 20:17 ` [PATCH 10/19] btrfs: calculate discard delay based on number of extents Dennis Zhou
2019-10-10 15:41 ` Josef Bacik
2019-10-11 18:07 ` Dennis Zhou [this message]
2019-10-07 20:17 ` [PATCH 11/19] btrfs: add bps discard rate limit Dennis Zhou
2019-10-10 15:47 ` Josef Bacik
2019-10-14 19:56 ` Dennis Zhou
2019-10-07 20:17 ` [PATCH 12/19] btrfs: limit max discard size for async discard Dennis Zhou
2019-10-10 16:16 ` Josef Bacik
2019-10-14 19:57 ` Dennis Zhou
2019-10-07 20:17 ` [PATCH 13/19] btrfs: have multiple discard lists Dennis Zhou
2019-10-10 16:51 ` Josef Bacik
2019-10-14 20:04 ` Dennis Zhou
2019-10-07 20:17 ` [PATCH 14/19] btrfs: only keep track of data extents for async discard Dennis Zhou
2019-10-10 16:53 ` Josef Bacik
2019-10-07 20:17 ` [PATCH 15/19] btrfs: load block_groups into discard_list on mount Dennis Zhou
2019-10-10 17:11 ` Josef Bacik
2019-10-14 20:17 ` Dennis Zhou
2019-10-14 23:38 ` David Sterba
2019-10-15 15:42 ` Dennis Zhou
2019-10-07 20:17 ` [PATCH 16/19] btrfs: keep track of discard reuse stats Dennis Zhou
2019-10-10 17:13 ` Josef Bacik
2019-10-07 20:17 ` [PATCH 17/19] btrfs: add async discard header Dennis Zhou
2019-10-10 17:13 ` Josef Bacik
2019-10-07 20:17 ` [PATCH 18/19] btrfs: increase the metadata allowance for the free_space_cache Dennis Zhou
2019-10-10 17:16 ` Josef Bacik
2019-10-07 20:17 ` [PATCH 19/19] btrfs: make smaller extents more likely to go into bitmaps Dennis Zhou
2019-10-10 17:17 ` Josef Bacik
2019-10-11 7:49 ` [RFC PATCH 00/19] btrfs: async discard support Nikolay Borisov
2019-10-14 21:05 ` Dennis Zhou
2019-10-15 12:08 ` David Sterba
2019-10-15 15:41 ` Dennis Zhou
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