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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 12/22] btrfs: keep track of discardable_bytes
Date: Wed, 23 Oct 2019 18:53:06 -0400
Message-ID: <3801afee5fe1a6a81e04e27692e2ded4c5df64ec.1571865774.git.dennis@kernel.org> (raw)
In-Reply-To: <cover.1571865774.git.dennis@kernel.org>
In-Reply-To: <cover.1571865774.git.dennis@kernel.org>

Keep track of this metric so that we can understand how ahead or behind
we are in discarding rate.

Signed-off-by: Dennis Zhou <dennis@kernel.org>
---
 fs/btrfs/ctree.h            |  1 +
 fs/btrfs/discard.c          | 10 +++++++++
 fs/btrfs/free-space-cache.c | 41 +++++++++++++++++++++++++++++--------
 fs/btrfs/free-space-cache.h |  1 +
 fs/btrfs/sysfs.c            | 12 +++++++++++
 5 files changed, 56 insertions(+), 9 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 2cf1dae512aa..43aa355f5c37 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -466,6 +466,7 @@ struct btrfs_discard_ctl {
 	struct btrfs_block_group_cache *cache;
 	struct list_head discard_list[BTRFS_NR_DISCARD_LISTS];
 	atomic_t discardable_extents;
+	atomic64_t discardable_bytes;
 };
 
 /* delayed seq elem */
diff --git a/fs/btrfs/discard.c b/fs/btrfs/discard.c
index 128ba18f2e5e..9c561a561578 100644
--- a/fs/btrfs/discard.c
+++ b/fs/btrfs/discard.c
@@ -351,6 +351,7 @@ void btrfs_discard_update_discardable(struct btrfs_block_group_cache *cache,
 {
 	struct btrfs_discard_ctl *discard_ctl;
 	s32 extents_delta;
+	s64 bytes_delta;
 
 	if (!cache || !btrfs_test_opt(cache->fs_info, DISCARD_ASYNC))
 		return;
@@ -364,6 +365,14 @@ void btrfs_discard_update_discardable(struct btrfs_block_group_cache *cache,
 		ctl->discardable_extents[BTRFS_STAT_PREV] =
 			ctl->discardable_extents[BTRFS_STAT_CURR];
 	}
+
+	bytes_delta = (ctl->discardable_bytes[BTRFS_STAT_CURR] -
+		       ctl->discardable_bytes[BTRFS_STAT_PREV]);
+	if (bytes_delta) {
+		atomic64_add(bytes_delta, &discard_ctl->discardable_bytes);
+		ctl->discardable_bytes[BTRFS_STAT_PREV] =
+			ctl->discardable_bytes[BTRFS_STAT_CURR];
+	}
 }
 
 /**
@@ -453,6 +462,7 @@ void btrfs_discard_init(struct btrfs_fs_info *fs_info)
 		 INIT_LIST_HEAD(&discard_ctl->discard_list[i]);
 
 	atomic_set(&discard_ctl->discardable_extents, 0);
+	atomic64_set(&discard_ctl->discardable_bytes, 0);
 }
 
 void btrfs_discard_cleanup(struct btrfs_fs_info *fs_info)
diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 3a965876aae3..8d4ffd50aee6 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -815,9 +815,11 @@ static int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
 		if (ret)
 			goto free_cache;
 		e->bitmap_extents = count_bitmap_extents(ctl, e);
-		if (!btrfs_free_space_trimmed(e))
+		if (!btrfs_free_space_trimmed(e)) {
 			ctl->discardable_extents[BTRFS_STAT_CURR] +=
 				e->bitmap_extents;
+			ctl->discardable_bytes[BTRFS_STAT_CURR] += e->bytes;
+		}
 	}
 
 	io_ctl_drop_pages(&io_ctl);
@@ -1640,8 +1642,10 @@ __unlink_free_space(struct btrfs_free_space_ctl *ctl,
 	rb_erase(&info->offset_index, &ctl->free_space_offset);
 	ctl->free_extents--;
 
-	if (!info->bitmap && !btrfs_free_space_trimmed(info))
+	if (!info->bitmap && !btrfs_free_space_trimmed(info)) {
 		ctl->discardable_extents[BTRFS_STAT_CURR]--;
+		ctl->discardable_bytes[BTRFS_STAT_CURR] -= info->bytes;
+	}
 }
 
 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
@@ -1662,8 +1666,10 @@ static int link_free_space(struct btrfs_free_space_ctl *ctl,
 	if (ret)
 		return ret;
 
-	if (!info->bitmap && !btrfs_free_space_trimmed(info))
+	if (!info->bitmap && !btrfs_free_space_trimmed(info)) {
 		ctl->discardable_extents[BTRFS_STAT_CURR]++;
+		ctl->discardable_bytes[BTRFS_STAT_CURR] += info->bytes;
+	}
 
 	ctl->free_space += info->bytes;
 	ctl->free_extents++;
@@ -1742,8 +1748,10 @@ static inline void __bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
 		extent_delta++;
 
 	info->bitmap_extents += extent_delta;
-	if (!btrfs_free_space_trimmed(info))
+	if (!btrfs_free_space_trimmed(info)) {
 		ctl->discardable_extents[BTRFS_STAT_CURR] += extent_delta;
+		ctl->discardable_bytes[BTRFS_STAT_CURR] -= bytes;
+	}
 }
 
 static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
@@ -1778,8 +1786,10 @@ static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
 		extent_delta--;
 
 	info->bitmap_extents += extent_delta;
-	if (!btrfs_free_space_trimmed(info))
+	if (!btrfs_free_space_trimmed(info)) {
 		ctl->discardable_extents[BTRFS_STAT_CURR] += extent_delta;
+		ctl->discardable_bytes[BTRFS_STAT_CURR] += bytes;
+	}
 }
 
 /*
@@ -2050,9 +2060,11 @@ static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
 	 * whole bitmap untrimmed if at any point we add untrimmed regions.
 	 */
 	if (trim_state == BTRFS_TRIM_STATE_UNTRIMMED) {
-		if (btrfs_free_space_trimmed(info))
+		if (btrfs_free_space_trimmed(info)) {
 			ctl->discardable_extents[BTRFS_STAT_CURR] +=
 				info->bitmap_extents;
+			ctl->discardable_bytes[BTRFS_STAT_CURR] += info->bytes;
+		}
 		info->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
 	}
 
@@ -2688,15 +2700,21 @@ __btrfs_return_cluster_to_free_space(
 		bitmap = (entry->bitmap != NULL);
 		if (!bitmap) {
 			/* merging treats extents as if they were new */
-			if (!btrfs_free_space_trimmed(entry))
+			if (!btrfs_free_space_trimmed(entry)) {
 				ctl->discardable_extents[BTRFS_STAT_CURR]--;
+				ctl->discardable_bytes[BTRFS_STAT_CURR] -=
+					entry->bytes;
+			}
 
 			try_merge_free_space(ctl, entry, false);
 			steal_from_bitmap(ctl, entry, false);
 
 			/* as we insert directly, update these statistics */
-			if (!btrfs_free_space_trimmed(entry))
+			if (!btrfs_free_space_trimmed(entry)) {
 				ctl->discardable_extents[BTRFS_STAT_CURR]++;
+				ctl->discardable_bytes[BTRFS_STAT_CURR] +=
+					entry->bytes;
+			}
 		}
 		tree_insert_offset(&ctl->free_space_offset,
 				   entry->offset, &entry->offset_index, bitmap);
@@ -2987,6 +3005,8 @@ u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
 	spin_lock(&ctl->tree_lock);
 
 	ctl->free_space -= bytes;
+	if (!entry->bitmap && !btrfs_free_space_trimmed(entry))
+		ctl->discardable_bytes[BTRFS_STAT_CURR] -= bytes;
 	if (entry->bytes == 0) {
 		ctl->free_extents--;
 		if (entry->bitmap) {
@@ -3493,9 +3513,11 @@ static void reset_trimming_bitmap(struct btrfs_free_space_ctl *ctl, u64 offset)
 
 	entry = tree_search_offset(ctl, offset, 1, 0);
 	if (entry) {
-		if (btrfs_free_space_trimmed(entry))
+		if (btrfs_free_space_trimmed(entry)) {
 			ctl->discardable_extents[BTRFS_STAT_CURR] +=
 				entry->bitmap_extents;
+			ctl->discardable_bytes[BTRFS_STAT_CURR] += entry->bytes;
+		}
 		entry->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
 	}
 
@@ -3509,6 +3531,7 @@ static void end_trimming_bitmap(struct btrfs_free_space_ctl *ctl,
 		entry->trim_state = BTRFS_TRIM_STATE_TRIMMED;
 		ctl->discardable_extents[BTRFS_STAT_CURR] -=
 			entry->bitmap_extents;
+		ctl->discardable_bytes[BTRFS_STAT_CURR] -= entry->bytes;
 	}
 }
 
diff --git a/fs/btrfs/free-space-cache.h b/fs/btrfs/free-space-cache.h
index 5e65899a2afa..1c0ec98da529 100644
--- a/fs/btrfs/free-space-cache.h
+++ b/fs/btrfs/free-space-cache.h
@@ -52,6 +52,7 @@ struct btrfs_free_space_ctl {
 	int unit;
 	u64 start;
 	s32 discardable_extents[BTRFS_STAT_NR_ENTRIES];
+	s64 discardable_bytes[BTRFS_STAT_NR_ENTRIES];
 	const struct btrfs_free_space_op *op;
 	void *private;
 	struct mutex cache_writeout_mutex;
diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 25f3d9062b78..9ebb1f1b1de6 100644
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -330,8 +330,20 @@ static ssize_t btrfs_discardable_extents_show(struct kobject *kobj,
 }
 BTRFS_ATTR(discard, discardable_extents, btrfs_discardable_extents_show);
 
+static ssize_t btrfs_discardable_bytes_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, "%lld\n",
+			atomic64_read(&fs_info->discard_ctl.discardable_bytes));
+}
+BTRFS_ATTR(discard, discardable_bytes, btrfs_discardable_bytes_show);
+
 static const struct attribute *discard_attrs[] = {
 	BTRFS_ATTR_PTR(discard, discardable_extents),
+	BTRFS_ATTR_PTR(discard, discardable_bytes),
 	NULL,
 };
 
-- 
2.17.1


  parent reply index

Thread overview: 44+ 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 ` Dennis Zhou [this message]
2019-11-08 19:31   ` [PATCH 12/22] btrfs: keep track of discardable_bytes 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 ` [PATCH 16/22] btrfs: make max async discard size tunable Dennis Zhou
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 12/22] btrfs: keep track of discardable_bytes Dennis Zhou
2019-11-25 19:46 [PATCH v4 00/22] btrfs: async discard support Dennis Zhou
2019-11-25 19:46 ` [PATCH 12/22] btrfs: keep track of discardable_bytes Dennis Zhou
2019-12-09 19:45 [PATCH v5 00/22] btrfs: async discard support Dennis Zhou
2019-12-09 19:45 ` [PATCH 12/22] btrfs: keep track of discardable_bytes Dennis Zhou
2019-12-14  0:22 [PATCH v6 00/22] btrfs: async discard support Dennis Zhou
2019-12-14  0:22 ` [PATCH 12/22] btrfs: keep track of discardable_bytes Dennis Zhou

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