From: Dennis Zhou <dennis@kernel.org>
To: David Sterba <dsterba@suse.com>, Chris Mason <clm@fb.com>,
Josef Bacik <josef@toxicpanda.com>,
Omar Sandoval <osandov@osandov.com>
Cc: kernel-team@fb.com, linux-btrfs@vger.kernel.org,
Dennis Zhou <dennis@kernel.org>
Subject: [PATCH 13/22] btrfs: calculate discard delay based on number of extents
Date: Mon, 9 Dec 2019 11:45:58 -0800 [thread overview]
Message-ID: <e73a0b58d92cea79ba7dc8784cdaae51f3d203bc.1575919745.git.dennis@kernel.org> (raw)
In-Reply-To: <cover.1575919745.git.dennis@kernel.org>
In-Reply-To: <cover.1575919745.git.dennis@kernel.org>
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>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
---
fs/btrfs/ctree.h | 2 ++
fs/btrfs/discard.c | 53 ++++++++++++++++++++++++++++++++++++++----
fs/btrfs/discard.h | 1 +
fs/btrfs/extent-tree.c | 4 +++-
fs/btrfs/sysfs.c | 31 ++++++++++++++++++++++++
5 files changed, 86 insertions(+), 5 deletions(-)
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 31b15e60f1d3..ae21e5659dd8 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -469,6 +469,8 @@ struct btrfs_discard_ctl {
struct list_head discard_list[BTRFS_NR_DISCARD_LISTS];
atomic_t discardable_extents;
atomic64_t discardable_bytes;
+ u32 delay;
+ u32 iops_limit;
};
/* delayed seq elem */
diff --git a/fs/btrfs/discard.c b/fs/btrfs/discard.c
index e8c2623617fd..160713e04d0c 100644
--- a/fs/btrfs/discard.c
+++ b/fs/btrfs/discard.c
@@ -15,6 +15,11 @@
#define BTRFS_DISCARD_DELAY (120ULL * NSEC_PER_SEC)
#define BTRFS_DISCARD_UNUSED_DELAY (10ULL * NSEC_PER_SEC)
+/* Target completion latency of discarding all discardable extents. */
+#define BTRFS_DISCARD_TARGET_MSEC (6 * 60 * 60UL * MSEC_PER_SEC)
+#define BTRFS_DISCARD_MAX_DELAY (10000UL)
+#define BTRFS_DISCARD_MAX_IOPS (10UL)
+
static struct list_head *get_discard_list(struct btrfs_discard_ctl *discard_ctl,
struct btrfs_block_group *block_group)
{
@@ -239,11 +244,18 @@ void btrfs_discard_schedule_work(struct btrfs_discard_ctl *discard_ctl,
block_group = find_next_block_group(discard_ctl, now);
if (block_group) {
- u64 delay = 0;
+ u32 delay = discard_ctl->delay;
+
+ /*
+ * This timeout is to hopefully prevent immediate discarding
+ * in a recently allocated block group.
+ */
+ if (now < block_group->discard_eligible_time) {
+ u64 bg_timeout = (block_group->discard_eligible_time -
+ now);
- if (now < block_group->discard_eligible_time)
- delay = nsecs_to_jiffies(
- block_group->discard_eligible_time - now);
+ delay = max_t(u64, delay, nsecs_to_jiffies(bg_timeout));
+ }
mod_delayed_work(discard_ctl->discard_workers,
&discard_ctl->work,
@@ -348,6 +360,37 @@ bool btrfs_run_discard_work(struct btrfs_discard_ctl *discard_ctl)
test_bit(BTRFS_FS_DISCARD_RUNNING, &fs_info->flags));
}
+/**
+ * btrfs_discard_calc_delay - recalculate the base delay
+ * @discard_ctl: discard control
+ *
+ * Recalculate the base delay which is based off the total number of
+ * discardable_extents. Clamp this with the iops_limit and
+ * BTRFS_DISCARD_MAX_DELAY.
+ */
+void btrfs_discard_calc_delay(struct btrfs_discard_ctl *discard_ctl)
+{
+ s32 discardable_extents =
+ atomic_read(&discard_ctl->discardable_extents);
+ s32 iops_limit;
+ unsigned long delay;
+
+ if (!discardable_extents)
+ return;
+
+ spin_lock(&discard_ctl->lock);
+
+ iops_limit = READ_ONCE(discard_ctl->iops_limit);
+ if (iops_limit)
+ iops_limit = MSEC_PER_SEC / iops_limit;
+
+ delay = BTRFS_DISCARD_TARGET_MSEC / discardable_extents;
+ delay = clamp_t(s32, delay, iops_limit, BTRFS_DISCARD_MAX_DELAY);
+ discard_ctl->delay = msecs_to_jiffies(delay);
+
+ spin_unlock(&discard_ctl->lock);
+}
+
/**
* btrfs_discard_update_discardable - propagate discard counters
* @block_group: block_group of interest
@@ -476,6 +519,8 @@ void btrfs_discard_init(struct btrfs_fs_info *fs_info)
atomic_set(&discard_ctl->discardable_extents, 0);
atomic64_set(&discard_ctl->discardable_bytes, 0);
+ discard_ctl->delay = BTRFS_DISCARD_MAX_DELAY;
+ discard_ctl->iops_limit = BTRFS_DISCARD_MAX_IOPS;
}
void btrfs_discard_cleanup(struct btrfs_fs_info *fs_info)
diff --git a/fs/btrfs/discard.h b/fs/btrfs/discard.h
index 7e3680dd82ce..3ed6855e24da 100644
--- a/fs/btrfs/discard.h
+++ b/fs/btrfs/discard.h
@@ -17,6 +17,7 @@ void btrfs_discard_schedule_work(struct btrfs_discard_ctl *discard_ctl,
bool btrfs_run_discard_work(struct btrfs_discard_ctl *discard_ctl);
/* Update operations. */
+void btrfs_discard_calc_delay(struct btrfs_discard_ctl *discard_ctl);
void btrfs_discard_update_discardable(struct btrfs_block_group *block_group,
struct btrfs_free_space_ctl *ctl);
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 574be68e9659..dd51ea6a21e7 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2935,8 +2935,10 @@ int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans)
cond_resched();
}
- if (btrfs_test_opt(fs_info, DISCARD_ASYNC))
+ if (btrfs_test_opt(fs_info, DISCARD_ASYNC)) {
+ btrfs_discard_calc_delay(&fs_info->discard_ctl);
btrfs_discard_schedule_work(&fs_info->discard_ctl, true);
+ }
/*
* Transaction is finished. We don't need the lock anymore. We
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index e799d4488d72..79139b4b4f0a 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -344,6 +344,36 @@ static const struct attribute_group btrfs_static_feature_attr_group = {
*/
#define discard_to_fs_info(_kobj) to_fs_info((_kobj)->parent->parent)
+static ssize_t btrfs_discard_iops_limit_show(struct kobject *kobj,
+ struct kobj_attribute *a,
+ char *buf)
+{
+ struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
+
+ return snprintf(buf, PAGE_SIZE, "%u\n",
+ READ_ONCE(fs_info->discard_ctl.iops_limit));
+}
+
+static ssize_t btrfs_discard_iops_limit_store(struct kobject *kobj,
+ struct kobj_attribute *a,
+ const char *buf, size_t len)
+{
+ struct btrfs_fs_info *fs_info = discard_to_fs_info(kobj);
+ struct btrfs_discard_ctl *discard_ctl = &fs_info->discard_ctl;
+ u32 iops_limit;
+ int ret;
+
+ ret = kstrtou32(buf, 10, &iops_limit);
+ if (ret)
+ return -EINVAL;
+
+ WRITE_ONCE(discard_ctl->iops_limit, iops_limit);
+
+ return len;
+}
+BTRFS_ATTR_RW(discard, iops_limit, btrfs_discard_iops_limit_show,
+ btrfs_discard_iops_limit_store);
+
static ssize_t btrfs_discardable_extents_show(struct kobject *kobj,
struct kobj_attribute *a,
char *buf)
@@ -367,6 +397,7 @@ static ssize_t btrfs_discardable_bytes_show(struct kobject *kobj,
BTRFS_ATTR(discard, discardable_bytes, btrfs_discardable_bytes_show);
static const struct attribute *discard_debug_attrs[] = {
+ BTRFS_ATTR_PTR(discard, iops_limit),
BTRFS_ATTR_PTR(discard, discardable_extents),
BTRFS_ATTR_PTR(discard, discardable_bytes),
NULL,
--
2.17.1
next prev parent reply other threads:[~2019-12-09 19:46 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-09 19:45 [PATCH v5 00/22] btrfs: async discard support Dennis Zhou
2019-12-09 19:45 ` [PATCH 01/22] bitmap: genericize percpu bitmap region iterators Dennis Zhou
2019-12-09 19:45 ` [PATCH 02/22] btrfs: rename DISCARD opt to DISCARD_SYNC Dennis Zhou
2019-12-09 19:45 ` [PATCH 03/22] btrfs: keep track of which extents have been discarded Dennis Zhou
2019-12-09 19:45 ` [PATCH 04/22] btrfs: keep track of cleanliness of the bitmap Dennis Zhou
2019-12-09 19:45 ` [PATCH 05/22] btrfs: add the beginning of async discard, discard workqueue Dennis Zhou
2019-12-09 19:45 ` [PATCH 06/22] btrfs: handle empty block_group removal Dennis Zhou
2019-12-09 19:45 ` [PATCH 07/22] btrfs: discard one region at a time in async discard Dennis Zhou
2019-12-09 19:45 ` [PATCH 08/22] btrfs: add removal calls for sysfs debug/ Dennis Zhou
2019-12-09 19:45 ` [PATCH 09/22] btrfs: make UUID/debug have its own kobject Dennis Zhou
2019-12-09 19:45 ` [PATCH 10/22] btrfs: add discard sysfs directory Dennis Zhou
2019-12-09 19:45 ` [PATCH 11/22] btrfs: track discardable extents for async discard Dennis Zhou
2019-12-09 19:45 ` [PATCH 12/22] btrfs: keep track of discardable_bytes Dennis Zhou
2019-12-09 19:45 ` Dennis Zhou [this message]
2019-12-09 19:45 ` [PATCH 14/22] btrfs: add bps discard rate limit Dennis Zhou
2019-12-09 19:46 ` [PATCH 15/22] btrfs: limit max discard size for async discard Dennis Zhou
2019-12-09 19:46 ` [PATCH 16/22] btrfs: make max async discard size tunable Dennis Zhou
2019-12-09 19:46 ` [PATCH 17/22] btrfs: have multiple discard lists Dennis Zhou
2019-12-09 19:46 ` [PATCH 18/22] btrfs: only keep track of data extents for async discard Dennis Zhou
2019-12-09 19:46 ` [PATCH 19/22] btrfs: keep track of discard reuse stats Dennis Zhou
2019-12-09 19:46 ` [PATCH 20/22] btrfs: add async discard header Dennis Zhou
2019-12-09 19:46 ` [PATCH 21/22] btrfs: increase the metadata allowance for the free_space_cache Dennis Zhou
2019-12-09 19:46 ` [PATCH 22/22] btrfs: make smaller extents more likely to go into bitmaps Dennis Zhou
2019-12-10 14:04 ` [PATCH v5 00/22] btrfs: async discard support David Sterba
-- strict thread matches above, loose matches on Subject: below --
2019-12-14 0:22 [PATCH v6 " Dennis Zhou
2019-12-14 0:22 ` [PATCH 13/22] btrfs: calculate discard delay based on number of extents Dennis Zhou
2019-12-30 16:50 ` David Sterba
2020-01-02 16:45 ` Dennis Zhou
2019-11-25 19:46 [PATCH v4 00/22] btrfs: async discard support Dennis Zhou
2019-11-25 19:46 ` [PATCH 13/22] btrfs: calculate discard delay based on number of extents Dennis Zhou
2019-11-20 21:50 [PATCH v3 00/22] btrfs: async discard support Dennis Zhou
2019-11-20 21:51 ` [PATCH 13/22] btrfs: calculate discard delay based on number of extents Dennis Zhou
2019-10-23 22:52 [PATCH v2 00/22] btrfs: async discard support Dennis Zhou
2019-10-23 22:53 ` [PATCH 13/22] btrfs: calculate discard delay based on number of extents Dennis Zhou
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=e73a0b58d92cea79ba7dc8784cdaae51f3d203bc.1575919745.git.dennis@kernel.org \
--to=dennis@kernel.org \
--cc=clm@fb.com \
--cc=dsterba@suse.com \
--cc=josef@toxicpanda.com \
--cc=kernel-team@fb.com \
--cc=linux-btrfs@vger.kernel.org \
--cc=osandov@osandov.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).