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Message-Id: <20220221084930.993153960@linuxfoundation.org>
Date: Mon, 21 Feb 2022 09:47:15 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Naohiro Aota <naohiro.aota@....com>,
David Sterba <dsterba@...e.com>
Subject: [PATCH 5.15 003/196] btrfs: zoned: cache reported zone during mount
From: Naohiro Aota <naohiro.aota@....com>
commit 16beac87e95e2fb278b552397c8260637f8a63f7 upstream.
When mounting a device, we are reporting the zones twice: once for
checking the zone attributes in btrfs_get_dev_zone_info and once for
loading block groups' zone info in
btrfs_load_block_group_zone_info(). With a lot of block groups, that
leads to a lot of REPORT ZONE commands and slows down the mount
process.
This patch introduces a zone info cache in struct
btrfs_zoned_device_info. The cache is populated while in
btrfs_get_dev_zone_info() and used for
btrfs_load_block_group_zone_info() to reduce the number of REPORT ZONE
commands. The zone cache is then released after loading the block
groups, as it will not be much effective during the run time.
Benchmark: Mount an HDD with 57,007 block groups
Before patch: 171.368 seconds
After patch: 64.064 seconds
While it still takes a minute due to the slowness of loading all the
block groups, the patch reduces the mount time by 1/3.
Link: https://lore.kernel.org/linux-btrfs/CAHQ7scUiLtcTqZOMMY5kbWUBOhGRwKo6J6wYPT5WY+C=cD49nQ@mail.gmail.com/
Fixes: 5b316468983d ("btrfs: get zone information of zoned block devices")
CC: stable@...r.kernel.org
Signed-off-by: Naohiro Aota <naohiro.aota@....com>
Signed-off-by: David Sterba <dsterba@...e.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
fs/btrfs/dev-replace.c | 2 -
fs/btrfs/disk-io.c | 2 +
fs/btrfs/volumes.c | 2 -
fs/btrfs/zoned.c | 85 ++++++++++++++++++++++++++++++++++++++++++++-----
fs/btrfs/zoned.h | 8 +++-
5 files changed, 87 insertions(+), 12 deletions(-)
--- a/fs/btrfs/dev-replace.c
+++ b/fs/btrfs/dev-replace.c
@@ -325,7 +325,7 @@ static int btrfs_init_dev_replace_tgtdev
set_blocksize(device->bdev, BTRFS_BDEV_BLOCKSIZE);
device->fs_devices = fs_info->fs_devices;
- ret = btrfs_get_dev_zone_info(device);
+ ret = btrfs_get_dev_zone_info(device, false);
if (ret)
goto error;
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -3565,6 +3565,8 @@ int __cold open_ctree(struct super_block
goto fail_sysfs;
}
+ btrfs_free_zone_cache(fs_info);
+
if (!sb_rdonly(sb) && fs_info->fs_devices->missing_devices &&
!btrfs_check_rw_degradable(fs_info, NULL)) {
btrfs_warn(fs_info,
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -2596,7 +2596,7 @@ int btrfs_init_new_device(struct btrfs_f
device->fs_info = fs_info;
device->bdev = bdev;
- ret = btrfs_get_dev_zone_info(device);
+ ret = btrfs_get_dev_zone_info(device, false);
if (ret)
goto error_free_device;
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -4,6 +4,7 @@
#include <linux/slab.h>
#include <linux/blkdev.h>
#include <linux/sched/mm.h>
+#include <linux/vmalloc.h>
#include "ctree.h"
#include "volumes.h"
#include "zoned.h"
@@ -195,6 +196,8 @@ static int emulate_report_zones(struct b
static int btrfs_get_dev_zones(struct btrfs_device *device, u64 pos,
struct blk_zone *zones, unsigned int *nr_zones)
{
+ struct btrfs_zoned_device_info *zinfo = device->zone_info;
+ u32 zno;
int ret;
if (!*nr_zones)
@@ -206,6 +209,34 @@ static int btrfs_get_dev_zones(struct bt
return 0;
}
+ /* Check cache */
+ if (zinfo->zone_cache) {
+ unsigned int i;
+
+ ASSERT(IS_ALIGNED(pos, zinfo->zone_size));
+ zno = pos >> zinfo->zone_size_shift;
+ /*
+ * We cannot report zones beyond the zone end. So, it is OK to
+ * cap *nr_zones to at the end.
+ */
+ *nr_zones = min_t(u32, *nr_zones, zinfo->nr_zones - zno);
+
+ for (i = 0; i < *nr_zones; i++) {
+ struct blk_zone *zone_info;
+
+ zone_info = &zinfo->zone_cache[zno + i];
+ if (!zone_info->len)
+ break;
+ }
+
+ if (i == *nr_zones) {
+ /* Cache hit on all the zones */
+ memcpy(zones, zinfo->zone_cache + zno,
+ sizeof(*zinfo->zone_cache) * *nr_zones);
+ return 0;
+ }
+ }
+
ret = blkdev_report_zones(device->bdev, pos >> SECTOR_SHIFT, *nr_zones,
copy_zone_info_cb, zones);
if (ret < 0) {
@@ -219,6 +250,11 @@ static int btrfs_get_dev_zones(struct bt
if (!ret)
return -EIO;
+ /* Populate cache */
+ if (zinfo->zone_cache)
+ memcpy(zinfo->zone_cache + zno, zones,
+ sizeof(*zinfo->zone_cache) * *nr_zones);
+
return 0;
}
@@ -282,7 +318,7 @@ int btrfs_get_dev_zone_info_all_devices(
if (!device->bdev)
continue;
- ret = btrfs_get_dev_zone_info(device);
+ ret = btrfs_get_dev_zone_info(device, true);
if (ret)
break;
}
@@ -291,7 +327,7 @@ int btrfs_get_dev_zone_info_all_devices(
return ret;
}
-int btrfs_get_dev_zone_info(struct btrfs_device *device)
+int btrfs_get_dev_zone_info(struct btrfs_device *device, bool populate_cache)
{
struct btrfs_fs_info *fs_info = device->fs_info;
struct btrfs_zoned_device_info *zone_info = NULL;
@@ -318,6 +354,8 @@ int btrfs_get_dev_zone_info(struct btrfs
if (!zone_info)
return -ENOMEM;
+ device->zone_info = zone_info;
+
if (!bdev_is_zoned(bdev)) {
if (!fs_info->zone_size) {
ret = calculate_emulated_zone_size(fs_info);
@@ -369,6 +407,23 @@ int btrfs_get_dev_zone_info(struct btrfs
goto out;
}
+ /*
+ * Enable zone cache only for a zoned device. On a non-zoned device, we
+ * fill the zone info with emulated CONVENTIONAL zones, so no need to
+ * use the cache.
+ */
+ if (populate_cache && bdev_is_zoned(device->bdev)) {
+ zone_info->zone_cache = vzalloc(sizeof(struct blk_zone) *
+ zone_info->nr_zones);
+ if (!zone_info->zone_cache) {
+ btrfs_err_in_rcu(device->fs_info,
+ "zoned: failed to allocate zone cache for %s",
+ rcu_str_deref(device->name));
+ ret = -ENOMEM;
+ goto out;
+ }
+ }
+
/* Get zones type */
while (sector < nr_sectors) {
nr_zones = BTRFS_REPORT_NR_ZONES;
@@ -444,8 +499,6 @@ int btrfs_get_dev_zone_info(struct btrfs
kfree(zones);
- device->zone_info = zone_info;
-
switch (bdev_zoned_model(bdev)) {
case BLK_ZONED_HM:
model = "host-managed zoned";
@@ -478,10 +531,7 @@ int btrfs_get_dev_zone_info(struct btrfs
out:
kfree(zones);
out_free_zone_info:
- bitmap_free(zone_info->empty_zones);
- bitmap_free(zone_info->seq_zones);
- kfree(zone_info);
- device->zone_info = NULL;
+ btrfs_destroy_dev_zone_info(device);
return ret;
}
@@ -495,6 +545,7 @@ void btrfs_destroy_dev_zone_info(struct
bitmap_free(zone_info->seq_zones);
bitmap_free(zone_info->empty_zones);
+ vfree(zone_info->zone_cache);
kfree(zone_info);
device->zone_info = NULL;
}
@@ -1551,3 +1602,21 @@ void btrfs_clear_data_reloc_bg(struct bt
fs_info->data_reloc_bg = 0;
spin_unlock(&fs_info->relocation_bg_lock);
}
+
+void btrfs_free_zone_cache(struct btrfs_fs_info *fs_info)
+{
+ struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
+ struct btrfs_device *device;
+
+ if (!btrfs_is_zoned(fs_info))
+ return;
+
+ mutex_lock(&fs_devices->device_list_mutex);
+ list_for_each_entry(device, &fs_devices->devices, dev_list) {
+ if (device->zone_info) {
+ vfree(device->zone_info->zone_cache);
+ device->zone_info->zone_cache = NULL;
+ }
+ }
+ mutex_unlock(&fs_devices->device_list_mutex);
+}
--- a/fs/btrfs/zoned.h
+++ b/fs/btrfs/zoned.h
@@ -25,6 +25,7 @@ struct btrfs_zoned_device_info {
u32 nr_zones;
unsigned long *seq_zones;
unsigned long *empty_zones;
+ struct blk_zone *zone_cache;
struct blk_zone sb_zones[2 * BTRFS_SUPER_MIRROR_MAX];
};
@@ -32,7 +33,7 @@ struct btrfs_zoned_device_info {
int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
struct blk_zone *zone);
int btrfs_get_dev_zone_info_all_devices(struct btrfs_fs_info *fs_info);
-int btrfs_get_dev_zone_info(struct btrfs_device *device);
+int btrfs_get_dev_zone_info(struct btrfs_device *device, bool populate_cache);
void btrfs_destroy_dev_zone_info(struct btrfs_device *device);
int btrfs_check_zoned_mode(struct btrfs_fs_info *fs_info);
int btrfs_check_mountopts_zoned(struct btrfs_fs_info *info);
@@ -67,6 +68,7 @@ int btrfs_sync_zone_write_pointer(struct
struct btrfs_device *btrfs_zoned_get_device(struct btrfs_fs_info *fs_info,
u64 logical, u64 length);
void btrfs_clear_data_reloc_bg(struct btrfs_block_group *bg);
+void btrfs_free_zone_cache(struct btrfs_fs_info *fs_info);
#else /* CONFIG_BLK_DEV_ZONED */
static inline int btrfs_get_dev_zone(struct btrfs_device *device, u64 pos,
struct blk_zone *zone)
@@ -79,7 +81,8 @@ static inline int btrfs_get_dev_zone_inf
return 0;
}
-static inline int btrfs_get_dev_zone_info(struct btrfs_device *device)
+static inline int btrfs_get_dev_zone_info(struct btrfs_device *device,
+ bool populate_cache)
{
return 0;
}
@@ -202,6 +205,7 @@ static inline struct btrfs_device *btrfs
static inline void btrfs_clear_data_reloc_bg(struct btrfs_block_group *bg) { }
+static inline void btrfs_free_zone_cache(struct btrfs_fs_info *fs_info) { }
#endif
static inline bool btrfs_dev_is_sequential(struct btrfs_device *device, u64 pos)
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