Commit 16beac87 authored by Naohiro Aota's avatar Naohiro Aota Committed by David Sterba
Browse files

btrfs: zoned: cache reported zone during mount 

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: 5b316468 ("btrfs: get zone information of zoned block devices")
CC: stable@vger.kernel.org
Signed-off-by: default avatarNaohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent d21deec5

fs/btrfs/dev-replace.c

+1 −1
Original line number Diff line number Diff line
@@ -322,7 +322,7 @@ static int btrfs_init_dev_replace_tgtdev(struct btrfs_fs_info *fs_info, 
	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;

fs/btrfs/disk-io.c

+2 −0
Original line number Diff line number Diff line
@@ -3570,6 +3570,8 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device 
		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,

fs/btrfs/volumes.c

+1 −1
Original line number Diff line number Diff line
@@ -2669,7 +2669,7 @@ int btrfs_init_new_device(struct btrfs_fs_info *fs_info, const char *device_path 
	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;

fs/btrfs/zoned.c

+77 −9
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 
#include <linux/blkdev.h>

#include <linux/sched/mm.h>

#include <linux/atomic.h>

#include <linux/vmalloc.h>

#include "ctree.h"

#include "volumes.h"

#include "zoned.h"
@@ -213,6 +214,8 @@ static int emulate_report_zones(struct btrfs_device *device, u64 pos, 
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)
@@ -224,6 +227,34 @@ static int btrfs_get_dev_zones(struct btrfs_device *device, u64 pos, 
		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) {
@@ -237,6 +268,11 @@ static int btrfs_get_dev_zones(struct btrfs_device *device, u64 pos, 
	if (!ret)

		return -EIO;



	/* Populate cache */

	if (zinfo->zone_cache)

		memcpy(zinfo->zone_cache + zno, zones,

		       sizeof(*zinfo->zone_cache) * *nr_zones);



	return 0;

}
@@ -300,7 +336,7 @@ int btrfs_get_dev_zone_info_all_devices(struct btrfs_fs_info *fs_info) 
		if (!device->bdev)

			continue;



		ret = btrfs_get_dev_zone_info(device);

		ret = btrfs_get_dev_zone_info(device, true);

		if (ret)

			break;

	}
@@ -309,7 +345,7 @@ int btrfs_get_dev_zone_info_all_devices(struct btrfs_fs_info *fs_info) 
	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;
@@ -339,6 +375,8 @@ int btrfs_get_dev_zone_info(struct btrfs_device *device) 
	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);
@@ -407,6 +445,23 @@ int btrfs_get_dev_zone_info(struct btrfs_device *device) 
		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 */

	nactive = 0;

	while (sector < nr_sectors) {
@@ -505,8 +560,6 @@ int btrfs_get_dev_zone_info(struct btrfs_device *device) 


	kfree(zones);



	device->zone_info = zone_info;



	switch (bdev_zoned_model(bdev)) {

	case BLK_ZONED_HM:

		model = "host-managed zoned";
@@ -539,11 +592,7 @@ int btrfs_get_dev_zone_info(struct btrfs_device *device) 
out:

	kfree(zones);

out_free_zone_info:

	bitmap_free(zone_info->active_zones);

	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;

}
@@ -558,6 +607,7 @@ void btrfs_destroy_dev_zone_info(struct btrfs_device *device) 
	bitmap_free(zone_info->active_zones);

	bitmap_free(zone_info->seq_zones);

	bitmap_free(zone_info->empty_zones);

	vfree(zone_info->zone_cache);

	kfree(zone_info);

	device->zone_info = NULL;

}
@@ -1975,3 +2025,21 @@ void btrfs_clear_data_reloc_bg(struct btrfs_block_group *bg) 
		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);

}

fs/btrfs/zoned.h

+6 −2
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ struct btrfs_zoned_device_info { 
	unsigned long *seq_zones;

	unsigned long *empty_zones;

	unsigned long *active_zones;

	struct blk_zone *zone_cache;

	struct blk_zone sb_zones[2 * BTRFS_SUPER_MIRROR_MAX];

};
@@ -35,7 +36,7 @@ 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);
@@ -76,6 +77,7 @@ bool btrfs_can_activate_zone(struct btrfs_fs_devices *fs_devices, 
void btrfs_zone_finish_endio(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)
@@ -88,7 +90,8 @@ static inline int btrfs_get_dev_zone_info_all_devices(struct btrfs_fs_info *fs_i 
	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;

}
@@ -232,6 +235,7 @@ static inline void btrfs_zone_finish_endio(struct btrfs_fs_info *fs_info, 


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)