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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 16/22] btrfs: make max async discard size tunable
Date: Wed, 23 Oct 2019 18:53:10 -0400
Message-ID: <6b33c5e684690d81dfc7161e0742eb24aa0e3bf1.1571865774.git.dennis@kernel.org> (raw)
In-Reply-To: <cover.1571865774.git.dennis@kernel.org>
In-Reply-To: <cover.1571865774.git.dennis@kernel.org>

Expose max_discard_size as a tunable via sysfs.

Signed-off-by: Dennis Zhou <dennis@kernel.org>
---
 fs/btrfs/ctree.h            |  1 +
 fs/btrfs/discard.c          |  1 +
 fs/btrfs/free-space-cache.c | 19 ++++++++++++-------
 fs/btrfs/sysfs.c            | 31 +++++++++++++++++++++++++++++++
 4 files changed, 45 insertions(+), 7 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index eccfc27e9b83..0a87970c7117 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -468,6 +468,7 @@ struct btrfs_discard_ctl {
 	u64 prev_discard;
 	atomic_t discardable_extents;
 	atomic64_t discardable_bytes;
+	u64 max_discard_size;
 	u32 delay;
 	u32 iops_limit;
 	u64 bps_limit;
diff --git a/fs/btrfs/discard.c b/fs/btrfs/discard.c
index 70873cd884bf..f7799b659d39 100644
--- a/fs/btrfs/discard.c
+++ b/fs/btrfs/discard.c
@@ -521,6 +521,7 @@ void btrfs_discard_init(struct btrfs_fs_info *fs_info)
 	discard_ctl->prev_discard = 0;
 	atomic_set(&discard_ctl->discardable_extents, 0);
 	atomic64_set(&discard_ctl->discardable_bytes, 0);
+	discard_ctl->max_discard_size = BTRFS_ASYNC_DISCARD_MAX_SIZE;
 	discard_ctl->delay = BTRFS_DISCARD_MAX_DELAY;
 	discard_ctl->iops_limit = BTRFS_DISCARD_MAX_IOPS;
 	discard_ctl->bps_limit = 0;
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 186a4243fb7f..c62346b23ca0 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -3406,6 +3406,8 @@ static int trim_no_bitmap(struct btrfs_block_group_cache *block_group,
 			  u64 *total_trimmed, u64 start, u64 end, u64 minlen,
 			  bool async)
 {
+	struct btrfs_discard_ctl *discard_ctl =
+					&block_group->fs_info->discard_ctl;
 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
 	struct btrfs_free_space *entry;
 	struct rb_node *node;
@@ -3414,6 +3416,7 @@ static int trim_no_bitmap(struct btrfs_block_group_cache *block_group,
 	u64 extent_bytes;
 	enum btrfs_trim_state extent_trim_state;
 	u64 bytes;
+	u64 max_discard_size = READ_ONCE(discard_ctl->max_discard_size);
 
 	while (start < end) {
 		struct btrfs_trim_range trim_entry;
@@ -3450,11 +3453,10 @@ static int trim_no_bitmap(struct btrfs_block_group_cache *block_group,
 				goto next;
 			}
 			unlink_free_space(ctl, entry);
-			if (bytes > BTRFS_ASYNC_DISCARD_MAX_SIZE) {
-				bytes = extent_bytes =
-					BTRFS_ASYNC_DISCARD_MAX_SIZE;
-				entry->offset += BTRFS_ASYNC_DISCARD_MAX_SIZE;
-				entry->bytes -= BTRFS_ASYNC_DISCARD_MAX_SIZE;
+			if (max_discard_size && bytes > max_discard_size) {
+				bytes = extent_bytes = max_discard_size;
+				entry->offset += max_discard_size;
+				entry->bytes -= max_discard_size;
 				link_free_space(ctl, entry);
 			} else {
 				kmem_cache_free(btrfs_free_space_cachep, entry);
@@ -3563,12 +3565,15 @@ static int trim_bitmaps(struct btrfs_block_group_cache *block_group,
 			u64 *total_trimmed, u64 start, u64 end, u64 minlen,
 			bool async)
 {
+	struct btrfs_discard_ctl *discard_ctl =
+					&block_group->fs_info->discard_ctl;
 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
 	struct btrfs_free_space *entry;
 	int ret = 0;
 	int ret2;
 	u64 bytes;
 	u64 offset = offset_to_bitmap(ctl, start);
+	u64 max_discard_size = READ_ONCE(discard_ctl->max_discard_size);
 
 	while (offset < end) {
 		bool next_bitmap = false;
@@ -3638,8 +3643,8 @@ static int trim_bitmaps(struct btrfs_block_group_cache *block_group,
 			goto next;
 		}
 
-		if (async && bytes > BTRFS_ASYNC_DISCARD_MAX_SIZE)
-			bytes = BTRFS_ASYNC_DISCARD_MAX_SIZE;
+		if (async && max_discard_size && bytes > max_discard_size)
+			bytes = max_discard_size;
 
 		bitmap_clear_bits(ctl, entry, start, bytes);
 		if (entry->bytes == 0)
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 070fa6223911..c441603b7da1 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -401,11 +401,42 @@ static ssize_t btrfs_discard_bps_limit_store(struct kobject *kobj,
 BTRFS_ATTR_RW(discard, bps_limit, btrfs_discard_bps_limit_show,
 	      btrfs_discard_bps_limit_store);
 
+static ssize_t btrfs_discard_max_discard_size_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, "%llu\n",
+			READ_ONCE(fs_info->discard_ctl.max_discard_size));
+}
+
+static ssize_t btrfs_discard_max_discard_size_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;
+	u64 max_discard_size;
+	int ret;
+
+	ret = kstrtou64(buf, 10, &max_discard_size);
+	if (ret)
+		return -EINVAL;
+
+	WRITE_ONCE(discard_ctl->max_discard_size, max_discard_size);
+
+	return len;
+}
+BTRFS_ATTR_RW(discard, max_discard_size, btrfs_discard_max_discard_size_show,
+	      btrfs_discard_max_discard_size_store);
+
 static const struct attribute *discard_attrs[] = {
 	BTRFS_ATTR_PTR(discard, discardable_extents),
 	BTRFS_ATTR_PTR(discard, discardable_bytes),
 	BTRFS_ATTR_PTR(discard, iops_limit),
 	BTRFS_ATTR_PTR(discard, bps_limit),
+	BTRFS_ATTR_PTR(discard, max_discard_size),
 	NULL,
 };
 
-- 
2.17.1


  parent reply index

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-23 22:52 [PATCH v2 00/22] btrfs: async discard support Dennis Zhou
2019-10-23 22:52 ` [PATCH 01/22] bitmap: genericize percpu bitmap region iterators Dennis Zhou
2019-10-23 22:52 ` [PATCH 02/22] btrfs: rename DISCARD opt to DISCARD_SYNC Dennis Zhou
2019-10-23 22:52 ` [PATCH 03/22] btrfs: keep track of which extents have been discarded Dennis Zhou
2019-11-08 19:05   ` Josef Bacik
2019-11-11 17:20     ` Dennis Zhou
2019-10-23 22:52 ` [PATCH 04/22] btrfs: keep track of cleanliness of the bitmap Dennis Zhou
2019-11-08 19:12   ` Josef Bacik
2019-10-23 22:52 ` [PATCH 05/22] btrfs: add the beginning of async discard, discard workqueue Dennis Zhou
2019-11-11 18:49   ` David Sterba
2019-10-23 22:53 ` [PATCH 06/22] btrfs: handle empty block_group removal Dennis Zhou
2019-11-08 19:19   ` Josef Bacik
2019-10-23 22:53 ` [PATCH 07/22] btrfs: discard one region at a time in async discard Dennis Zhou
2019-11-08 19:27   ` Josef Bacik
2019-10-23 22:53 ` [PATCH 08/22] btrfs: add removal calls for sysfs debug/ Dennis Zhou
2019-11-08 19:28   ` Josef Bacik
2019-10-23 22:53 ` [PATCH 09/22] btrfs: make UUID/debug have its own kobject Dennis Zhou
2019-11-08 19:29   ` Josef Bacik
2019-10-23 22:53 ` [PATCH 10/22] btrfs: add discard sysfs directory Dennis Zhou
2019-11-08 19:29   ` Josef Bacik
2019-10-23 22:53 ` [PATCH 11/22] btrfs: track discardable extents for async discard Dennis Zhou
2019-10-23 22:53 ` [PATCH 12/22] btrfs: keep track of discardable_bytes Dennis Zhou
2019-11-08 19:31   ` Josef Bacik
2019-10-23 22:53 ` [PATCH 13/22] btrfs: calculate discard delay based on number of extents Dennis Zhou
2019-10-23 22:53 ` [PATCH 14/22] btrfs: add bps discard rate limit Dennis Zhou
2019-11-08 19:41   ` Josef Bacik
2019-11-15 17:28     ` David Sterba
2019-10-23 22:53 ` [PATCH 15/22] btrfs: limit max discard size for async discard Dennis Zhou
2019-10-23 22:53 ` Dennis Zhou [this message]
2019-10-23 22:53 ` [PATCH 17/22] btrfs: have multiple discard lists Dennis Zhou
2019-11-08 19:44   ` Josef Bacik
2019-10-23 22:53 ` [PATCH 18/22] btrfs: only keep track of data extents for async discard Dennis Zhou
2019-11-08 19:46   ` Josef Bacik
2019-11-08 20:14     ` Dennis Zhou
2019-11-15 17:31       ` David Sterba
2019-10-23 22:53 ` [PATCH 19/22] btrfs: keep track of discard reuse stats Dennis Zhou
2019-10-23 22:53 ` [PATCH 20/22] btrfs: add async discard header Dennis Zhou
2019-10-23 22:53 ` [PATCH 21/22] btrfs: increase the metadata allowance for the free_space_cache Dennis Zhou
2019-10-23 22:53 ` [PATCH 22/22] btrfs: make smaller extents more likely to go into bitmaps Dennis Zhou
2019-11-15 17:40 ` [PATCH v2 00/22] btrfs: async discard support David Sterba
2019-11-20 21:50 [PATCH v3 " Dennis Zhou
2019-11-20 21:51 ` [PATCH 16/22] btrfs: make max async discard size tunable Dennis Zhou
2019-11-25 19:46 [PATCH v4 00/22] btrfs: async discard support Dennis Zhou
2019-11-25 19:46 ` [PATCH 16/22] btrfs: make max async discard size tunable Dennis Zhou
2019-12-09 19:45 [PATCH v5 00/22] btrfs: async discard support Dennis Zhou
2019-12-09 19:46 ` [PATCH 16/22] btrfs: make max async discard size tunable Dennis Zhou

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