From 0aae4ca9e952b83f71ce50af1290f0f5d9ab9df6 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Wed, 28 Apr 2021 13:38:43 -0400 Subject: [PATCH] btrfs: only clamp the first time we have to start flushing We were clamping the threshold for preemptive reclaim any time we added a ticket to wait on, which if we have a lot of threads means we'd essentially max out the clamp the first time we start to flush. Instead of doing this, simply do it every time we have to start flushing, this will make us ramp up gradually instead of going to max clamping as soon as we start needing to do flushing. Signed-off-by: Josef Bacik Signed-off-by: David Sterba --- fs/btrfs/space-info.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/fs/btrfs/space-info.c b/fs/btrfs/space-info.c index c9a5e003bcfa..33edab17af0d 100644 --- a/fs/btrfs/space-info.c +++ b/fs/btrfs/space-info.c @@ -1561,6 +1561,15 @@ static int __reserve_bytes(struct btrfs_fs_info *fs_info, flush == BTRFS_RESERVE_FLUSH_DATA) { list_add_tail(&ticket.list, &space_info->tickets); if (!space_info->flush) { + /* + * We were forced to add a reserve ticket, so + * our preemptive flushing is unable to keep + * up. Clamp down on the threshold for the + * preemptive flushing in order to keep up with + * the workload. + */ + maybe_clamp_preempt(fs_info, space_info); + space_info->flush = 1; trace_btrfs_trigger_flush(fs_info, space_info->flags, @@ -1572,14 +1581,6 @@ static int __reserve_bytes(struct btrfs_fs_info *fs_info, list_add_tail(&ticket.list, &space_info->priority_tickets); } - - /* - * We were forced to add a reserve ticket, so our preemptive - * flushing is unable to keep up. Clamp down on the threshold - * for the preemptive flushing in order to keep up with the - * workload. - */ - maybe_clamp_preempt(fs_info, space_info); } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) { used += orig_bytes; /*