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[6.12] Track btrfs patches #36

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[6.12] Track btrfs patches #36

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5e49c78
btrfs: add flags to give an hint to the chunk allocator
kreijack Oct 24, 2021
160344a
btrfs: export dev_item.type in /sys/fs/btrfs/<uuid>/devinfo/<devid>/type
kreijack Oct 24, 2021
29637f2
btrfs: change the DEV_ITEM 'type' field via sysfs
kreijack Oct 24, 2021
970b99e
btrfs: add allocator_hint mode
kreijack Oct 24, 2021
1c1f2e2
btrfs: add allocator_hint for no allocation preferred
kakra Jun 27, 2024
82553ef
btrfs: add allocator_hint to disable allocation completely
kakra Dec 5, 2024
10248db
btrfs: simplify output formatting in btrfs_read_policy_show
asj Jan 1, 2025
4a49a27
btrfs: initialize fs_devices->fs_info earlier
asj Jan 1, 2025
ccb2922
btrfs: add btrfs_read_policy_to_enum helper and refactor read policy …
asj Jan 1, 2025
cf73e90
btrfs: add tracking of read blocks for read policy
asj Jan 1, 2025
7070070
btrfs: introduce CONFIG_BTRFS_EXPERIMENTAL from 6.13
kakra Sep 16, 2024
3efa6c7
btrfs: handle value associated with read policy parameter
asj Jan 1, 2025
6f1b9b1
btrfs: introduce RAID1 round-robin read balancing
kakra May 2, 2025
6fcee9b
btrfs: add RAID1 preferred read device
asj Jan 1, 2025
b627950
btrfs: expose experimental mode in module information
asj Jan 1, 2025
108c5e8
btrfs: enable read policy configuration via modprobe parameter
asj Jan 1, 2025
b2c5980
btrfs: modload to print read policy status
asj Jan 1, 2025
65b747f
btrfs: use the path with the lowest latency for RAID1 reads
asj Oct 11, 2024
a6dfeed
btrfs: move latency-based selection into helper
kakra Apr 9, 2025
c9b6612
btrfs: fix btrfs_read_rr to use the actual number of stripes
kakra Apr 9, 2025
5aa9fb5
btrfs: create a helper instead of open coding device latency calculation
kakra Apr 15, 2025
a451102
btrfs: add filtering by latency to btrfs_read_rr
kakra Apr 14, 2025
9e88f8e
btrfs: add hybrid latency-rr read policy
kakra Apr 18, 2025
eee7666
btrfs: add devinfo read stats to sysfs
kakra Apr 16, 2025
7437625
btrfs: add last IO age to sysfs read_stats
kakra Apr 16, 2025
7c776c2
btrfs: probe read latency if device is 1000 IOs behind its siblings
kakra Apr 16, 2025
fbeb5da
btrfs: allow a short burst of IO for probing read latency
kakra Apr 17, 2025
919eaf1
btrfs: use checkpoint latency instead of cumulative latency
kakra Apr 20, 2025
6f8dc12
btrfs: stat latency checkpoints to get more insight
kakra Apr 20, 2025
18c0ef0
btrfs: rename thresholds to better match with the checkpoint logic
kakra Apr 20, 2025
f4f2455
btrfs: add a stripe ignored counter
kakra Apr 20, 2025
db46d71
btrfs: tune age and burst for latency checkpoint
kakra Apr 21, 2025
504aea7
btrfs: add in-flight queue read policy
kakra Apr 25, 2025
e905c0c
btrfs: guard access to bdev in latency stats and inflight calculation
kakra Apr 27, 2025
740955e
btrfs: reduce atomic reads where possible in btrfs_device_read_latency
kakra May 1, 2025
abf6174
TEST: btrfs: btrfs_backref_resched.patch
fdmanana Jun 23, 2025
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btrfs: use checkpoint latency instead of cumulative latency 
Signed-off-by: Kai Krakow <[email protected]>
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@kakra
kakra committed May 2, 2025
commit 919eaf1aedd76b258e3d40c72e8633d4563151f2
33 changes: 21 additions & 12 deletions fs/btrfs/volumes.c
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Original file line number Diff line number Diff line change
Expand Up @@ -6013,17 +6013,21 @@ static int btrfs_read_preferred(struct btrfs_chunk_map *map, int first,
* Compute the average latency of the device by dividing total latency by
* number of IOs.
*/
#define BTRFS_MAX_AGE_FOR_VALID_LATENCY 1000
#define BTRFS_MAX_AGE_FOR_VALID_LATENCY 10000
static u64 btrfs_device_read_latency(struct btrfs_device *device)
{
u64 read_wait = part_stat_read(device->bdev, nsecs[READ]);
u64 last_nsecs_read = (u64)atomic64_read(&device->last_nsecs_read);
unsigned long read_ios = part_stat_read(device->bdev, ios[READ]);
unsigned long last_ios_read = (unsigned long)atomic64_read(&device->last_ios_read);
u64 last_io_age = (u64)atomic64_read(&device->last_io_age);
u64 avg_wait = 0;
s64 delta_read_wait = read_wait - last_nsecs_read;
s64 delta_read_ios = read_ios - last_ios_read;

if (last_io_age >= 0 && last_io_age < BTRFS_MAX_AGE_FOR_VALID_LATENCY
&& read_wait && read_ios && read_wait >= read_ios)
avg_wait = div_u64(read_wait, read_ios);
&& delta_read_wait > 0 && delta_read_ios > 0 && delta_read_wait >= delta_read_ios)
avg_wait = div_u64(delta_read_wait, delta_read_ios);

return avg_wait;
}
Expand Down Expand Up @@ -6174,7 +6178,7 @@ static int btrfs_read_fastest_rr(struct btrfs_fs_info *fs_info,
}
#endif

#define BTRFS_OLD_AGE_IO_BURST 20
#define BTRFS_OLD_AGE_IO_BURST 100
static int find_live_mirror(struct btrfs_fs_info *fs_info,
struct btrfs_chunk_map *map, int first,
int dev_replace_is_ongoing)
Expand Down Expand Up @@ -6256,19 +6260,24 @@ static int find_live_mirror(struct btrfs_fs_info *fs_info,

out:
#ifdef CONFIG_BTRFS_EXPERIMENTAL
/* reset age of selected stripe */
s64 current_age, new_age;
do {
current_age = atomic64_read(&map->stripes[preferred_mirror].dev->last_io_age);
/* reset age of selected stripe */
s64 current_age;
struct btrfs_device *pref_dev = map->stripes[preferred_mirror].dev;

spin_lock(&pref_dev->latency_lock);

current_age = atomic64_read(&pref_dev->last_io_age);
if (current_age >= BTRFS_MAX_AGE_FOR_VALID_LATENCY) {
new_age = -BTRFS_OLD_AGE_IO_BURST;
atomic64_set(&pref_dev->last_io_age, -BTRFS_OLD_AGE_IO_BURST);
atomic64_set(&pref_dev->last_nsecs_read, part_stat_read(pref_dev->bdev, nsecs[READ]));
atomic64_set(&pref_dev->last_ios_read, part_stat_read(pref_dev->bdev, ios[READ]));
} else if (current_age >= 0) {
new_age = 0;
} else {
return preferred_mirror;
atomic64_set(&pref_dev->last_io_age, 0);
}
} while (unlikely(atomic64_cmpxchg(&map->stripes[preferred_mirror].dev->last_io_age, current_age, new_age) != current_age));

spin_unlock(&pref_dev->latency_lock);
} while (0);
#endif

/* we couldn't find one that doesn't fail. Just return something
Expand Down
7 changes: 7 additions & 0 deletions fs/btrfs/volumes.h
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Original file line number Diff line number Diff line change
Expand Up @@ -201,6 +201,13 @@ struct btrfs_device {
#ifdef CONFIG_BTRFS_EXPERIMENTAL
/* store an age of last read access */
atomic64_t last_io_age;

/* lock while updating values */
spinlock_t latency_lock;

/* last latency values for short term latency calculation */
atomic64_t last_nsecs_read;
atomic64_t last_ios_read;
#endif
};

Expand Down