Messages in this thread | | | Date | Tue, 2 Apr 2024 10:09:59 -0700 | From | Boris Burkov <> | Subject | Re: [PATCH RFC PATCH 3/3] btrfs: zoned: kick cleaner kthread if low on space |
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On Thu, Mar 28, 2024 at 02:56:33PM +0100, Johannes Thumshirn wrote: > From: Johannes Thumshirn <johannes.thumshirn@wdc.com> > > Kick the cleaner kthread on chunk allocation if we're slowly running out > of usable space on a zoned filesystem.
I'm really excited about this and think it probably makes sense on not-zoned as well.
Have you found that this is a fast enough to help real allocations that are in trouble? I'd be worried that it's a lot faster than waiting 30 seconds but still not urgent enough to save the day for someone trying to allocate right now.
Not a blocking request for this patch, which I think is a definite improvement, but we could do something like add a pass to find_free_extent (before allocating a fresh BG?!?) that blocks on reclaim running if we have kicked it (or errors out in a way that signals to the outer loop that we can wait for reclaim, if needed for locking or whatever)
> > Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> > --- > fs/btrfs/zoned.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c > index fb8707f4cab5..25c1a17873db 100644 > --- a/fs/btrfs/zoned.c > +++ b/fs/btrfs/zoned.c > @@ -1040,6 +1040,7 @@ int btrfs_reset_sb_log_zones(struct block_device *bdev, int mirror) > u64 btrfs_find_allocatable_zones(struct btrfs_device *device, u64 hole_start, > u64 hole_end, u64 num_bytes) > { > + struct btrfs_fs_info *fs_info = device->fs_info; > struct btrfs_zoned_device_info *zinfo = device->zone_info; > const u8 shift = zinfo->zone_size_shift; > u64 nzones = num_bytes >> shift; > @@ -1051,6 +1052,11 @@ u64 btrfs_find_allocatable_zones(struct btrfs_device *device, u64 hole_start, > ASSERT(IS_ALIGNED(hole_start, zinfo->zone_size)); > ASSERT(IS_ALIGNED(num_bytes, zinfo->zone_size)); > > + if (!test_bit(BTRFS_FS_CLEANER_RUNNING, &fs_info->flags) && > + btrfs_zoned_should_reclaim(fs_info)) { > + wake_up_process(fs_info->cleaner_kthread); > + } > + > while (pos < hole_end) { > begin = pos >> shift; > end = begin + nzones; > > -- > 2.35.3 >
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