To fix:
WARNING: function definition argument 'struct f2fs_attr *' should also have an identifier name
+ ssize_t (*show)(struct f2fs_attr *, struct f2fs_sb_info *, char *);
WARNING: return sysfs_emit(...) formats should include a terminating newline
+ return sysfs_emit(buf, "(none)");
WARNING: Prefer 'unsigned int' to bare use of 'unsigned'
+ unsigned npages = NODE_MAPPING(sbi)->nrpages;
WARNING: Missing a blank line after declarations
+ unsigned npages = COMPRESS_MAPPING(sbi)->nrpages;
+ si->page_mem += (unsigned long long)npages << PAGE_SHIFT;
WARNING: quoted string split across lines
+ seq_printf(s, "CP merge (Queued: %4d, Issued: %4d, Total: %4d, "
+ "Cur time: %4d(ms), Peak time: %4d(ms))\n",
Signed-off-by: Yangtao Li <frank.li@vivo.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This patch introduces a runtime hot/cold data separation method
for f2fs, in order to improve the accuracy for data temperature
classification, reduce the garbage collection overhead after
long-term data updates.
Enhanced hot/cold data separation can record data block update
frequency as "age" of the extent per inode, and take use of the age
info to indicate better temperature type for data block allocation:
- It records total data blocks allocated since mount;
- When file extent has been updated, it calculate the count of data
blocks allocated since last update as the age of the extent;
- Before the data block allocated, it searches for the age info and
chooses the suitable segment for allocation.
Test and result:
- Prepare: create about 30000 files
* 3% for cold files (with cold file extension like .apk, from 3M to 10M)
* 50% for warm files (with random file extension like .FcDxq, from 1K
to 4M)
* 47% for hot files (with hot file extension like .db, from 1K to 256K)
- create(5%)/random update(90%)/delete(5%) the files
* total write amount is about 70G
* fsync will be called for .db files, and buffered write will be used
for other files
The storage of test device is large enough(128G) so that it will not
switch to SSR mode during the test.
Benefit: dirty segment count increment reduce about 14%
- before: Dirty +21110
- after: Dirty +18286
Signed-off-by: qixiaoyu1 <qixiaoyu1@xiaomi.com>
Signed-off-by: xiongping1 <xiongping1@xiaomi.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Through this node, you can control the background discard
to run more aggressively or not aggressively when reach the
utilization rate of the space.
Signed-off-by: Yangtao Li <frank.li@vivo.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Before this patch, the varibale 'readdir_ra' takes effect if it's equal
to '1' or not, so we can change type for it from 'int' to 'bool'.
Signed-off-by: Yuwei Guan <Yuwei.Guan@zeekrlife.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
The user can set the trial count limit for GC urgent and
idle mode with replaced gc_remaining_trials.. If GC thread gets
to the limit, the mode will turn back to GC normal mode finally.
It was applied only to GC_URGENT, while this patch expands it for
GC_IDLE.
Signed-off-by: Yangtao Li <frank.li@vivo.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Revert "f2fs: make gc_urgent and gc_segment_mode sysfs node readable".
Add a gc_mode sysfs node to show the current gc_mode as a string.
Signed-off-by: Yangtao Li <frank.li@vivo.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
The current max_ordered_discard is a fixed value, change it to be
configurable through the sys node.
Signed-off-by: Yangtao Li <frank.li@vivo.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
commit 377224c47118("f2fs: don't split checkpoint in fstrim") obsolete
batch mode and related sysfs entry.
Since this testing sysfs node has been deprecated for a long time, let's
remove it.
Signed-off-by: Yangtao Li <frank.li@vivo.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This patch adds a new sysfs entry named cp_status, it can output
checkpoint flags in real time.
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
introduce the below 4 new sysfs node for atomic write statistics.
- current_atomic_write: the total current atomic write block count,
which is not committed yet.
- peak_atomic_write: the peak value of total current atomic write block
count after boot.
- committed_atomic_block: the accumulated total committed atomic write
block count after boot.
- revoked_atomic_block: the accumulated total revoked atomic write block
count after boot.
Signed-off-by: Daeho Jeong <daehojeong@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
We need a mid level of gc urgent mode to do GC forcibly in a period
of given gc_urgent_sleep_time, but not like using greedy GC approach
and switching to SSR mode such as gc urgent high mode. This can be
used for more aggressive periodic storage clean up.
Signed-off-by: Daeho Jeong <daehojeong@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This adds a sysfs entry to call checkpoint during fsync() in order to avoid
long elapsed time to run roll-forward recovery when booting the device.
Default value doesn't enforce the limitation which is same as before.
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This patch exposes max_discard_request, min_discard_issue_time,
mid_discard_issue_time, and max_discard_issue_time in sysfs. This will
allow the user to fine tune discard operations.
Signed-off-by: Konstantin Vyshetsky <vkon@google.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
It needs to assign sbi->gc_mode with GC_IDLE_AT rather than GC_AT when
user tries to enable ATGC via gc_idle sysfs interface, fix it.
Fixes: 093749e296e2 ("f2fs: support age threshold based garbage collection")
Cc: Zhipeng Tan <tanzhipeng@hust.edu.cn>
Signed-off-by: Jicheng Shao <shaojicheng@hust.edu.cn>
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
f2fs rw_semaphores work better if writers can starve readers,
especially for the checkpoint thread, because writers are strictly
more important than reader threads. This prevents significant priority
inversion between low-priority readers that blocked while trying to
acquire the read lock and a second acquisition of the write lock that
might be blocking high priority work.
Signed-off-by: Tim Murray <timmurray@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
https://bugzilla.kernel.org/show_bug.cgi?id=204137
With below script, we will hit panic during new segment allocation:
DISK=bingo.img
MOUNT_DIR=/mnt/f2fs
dd if=/dev/zero of=$DISK bs=1M count=105
mkfs.f2fe -a 1 -o 19 -t 1 -z 1 -f -q $DISK
mount -t f2fs $DISK $MOUNT_DIR -o "noinline_dentry,flush_merge,noextent_cache,mode=lfs,io_bits=7,fsync_mode=strict"
for (( i = 0; i < 4096; i++ )); do
name=`head /dev/urandom | tr -dc A-Za-z0-9 | head -c 10`
mkdir $MOUNT_DIR/$name
done
umount $MOUNT_DIR
rm $DISK
--- Core dump ---
Call Trace:
allocate_segment_by_default+0x9d/0x100 [f2fs]
f2fs_allocate_data_block+0x3c0/0x5c0 [f2fs]
do_write_page+0x62/0x110 [f2fs]
f2fs_outplace_write_data+0x43/0xc0 [f2fs]
f2fs_do_write_data_page+0x386/0x560 [f2fs]
__write_data_page+0x706/0x850 [f2fs]
f2fs_write_cache_pages+0x267/0x6a0 [f2fs]
f2fs_write_data_pages+0x19c/0x2e0 [f2fs]
do_writepages+0x1c/0x70
__filemap_fdatawrite_range+0xaa/0xe0
filemap_fdatawrite+0x1f/0x30
f2fs_sync_dirty_inodes+0x74/0x1f0 [f2fs]
block_operations+0xdc/0x350 [f2fs]
f2fs_write_checkpoint+0x104/0x1150 [f2fs]
f2fs_sync_fs+0xa2/0x120 [f2fs]
f2fs_balance_fs_bg+0x33c/0x390 [f2fs]
f2fs_write_node_pages+0x4c/0x1f0 [f2fs]
do_writepages+0x1c/0x70
__writeback_single_inode+0x45/0x320
writeback_sb_inodes+0x273/0x5c0
wb_writeback+0xff/0x2e0
wb_workfn+0xa1/0x370
process_one_work+0x138/0x350
worker_thread+0x4d/0x3d0
kthread+0x109/0x140
ret_from_fork+0x25/0x30
The root cause here is, with IO alignment feature enables, in worst
case, we need F2FS_IO_SIZE() free blocks space for single one 4k write
due to IO alignment feature will fill dummy pages to make IO being
aligned.
So we will easily run out of free segments during non-inline directory's
data writeback, even in process of foreground GC.
In order to fix this issue, I just propose to reserve additional free
space for IO alignment feature to handle worst case of free space usage
ratio during FGGC.
Fixes: 0a595ebaaa ("f2fs: support IO alignment for DATA and NODE writes")
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Added a new sysfs node called gc_urgent_high_remaining. The user can
set the trial count limit for GC urgent high mode with this value. If
GC thread gets to the limit, the mode will turn back to GC normal mode.
By default, the value is zero, which means there is no limit like before.
Signed-off-by: Daeho Jeong <daehojeong@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This information can be used to check how much time we need to give to issue
all the discard commands.
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Added two options into "mode=" mount option to make it possible for
developers to simulate filesystem fragmentation/after-GC situation
itself. The developers use these modes to understand filesystem
fragmentation/after-GC condition well, and eventually get some
insights to handle them better.
"fragment:segment": f2fs allocates a new segment in ramdom position.
With this, we can simulate the after-GC condition.
"fragment:block" : We can scatter block allocation with
"max_fragment_chunk" and "max_fragment_hole" sysfs
nodes. f2fs will allocate 1..<max_fragment_chunk>
blocks in a chunk and make a hole in the length of
1..<max_fragment_hole> by turns in a newly allocated
free segment. Plus, this mode implicitly enables
"fragment:segment" option for more randomness.
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Daeho Jeong <daehojeong@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Added F2FS_IOSTAT config option to support getting IO statistics through
sysfs and printing out periodic IO statistics tracepoint events and
moved I/O statistics related codes into separate files for better
maintenance.
Signed-off-by: Daeho Jeong <daehojeong@google.com>
Reviewed-by: Chao Yu <chao@kernel.org>
[Jaegeuk Kim: set default=y]
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
To fix:
WARNING: Symbolic permissions 'S_IRUGO' are not preferred. Consider using octal permissions '0444'.
Signed-off-by: Yangtao Li <frank.li@vivo.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
As James Z reported in bugzilla:
https://bugzilla.kernel.org/show_bug.cgi?id=213877
[1.] One-line summary of the problem:
Mount multiple SMR block devices exceed certain number cause system non-response
[2.] Full description of the problem/report:
Created some F2FS on SMR devices (mkfs.f2fs -m), then mounted in sequence. Each device is the same Model: HGST HSH721414AL (Size 14TB).
Empirically, found that when the amount of SMR device * 1.5Gb > System RAM, the system ran out of memory and hung. No dmesg output. For example, 24 SMR Disk need 24*1.5GB = 36GB. A system with 32G RAM can only mount 21 devices, the 22nd device will be a reproducible cause of system hang.
The number of SMR devices with other FS mounted on this system does not interfere with the result above.
[3.] Keywords (i.e., modules, networking, kernel):
F2FS, SMR, Memory
[4.] Kernel information
[4.1.] Kernel version (uname -a):
Linux 5.13.4-200.fc34.x86_64 #1 SMP Tue Jul 20 20:27:29 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
[4.2.] Kernel .config file:
Default Fedora 34 with f2fs-tools-1.14.0-2.fc34.x86_64
[5.] Most recent kernel version which did not have the bug:
None
[6.] Output of Oops.. message (if applicable) with symbolic information
resolved (see Documentation/admin-guide/oops-tracing.rst)
None
[7.] A small shell script or example program which triggers the
problem (if possible)
mount /dev/sdX /mnt/0X
[8.] Memory consumption
With 24 * 14T SMR Block device with F2FS
free -g
total used free shared buff/cache available
Mem: 46 36 0 0 10 10
Swap: 0 0 0
With 3 * 14T SMR Block device with F2FS
free -g
total used free shared buff/cache available
Mem: 7 5 0 0 1 1
Swap: 7 0 7
The root cause is, there are three bitmaps:
- cur_valid_map
- ckpt_valid_map
- discard_map
and each of them will cost ~500MB memory, {cur, ckpt}_valid_map are
necessary, but discard_map is optional, since this bitmap will only be
useful in mountpoint that small discard is enabled.
For a blkzoned device such as SMR or ZNS devices, f2fs will only issue
discard for a section(zone) when all blocks of that section are invalid,
so, for such device, we don't need small discard functionality at all.
This patch introduces a new mountoption "discard_unit=block|segment|
section" to support issuing discard with different basic unit which is
aligned to block, segment or section, so that user can specify
"discard_unit=segment" or "discard_unit=section" to disable small
discard functionality.
Note that this mount option can not be changed by remount() due to
related metadata need to be initialized during mount().
In order to save memory, let's use "discard_unit=section" for blkzoned
device by default.
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
When creating a file, we need to set the temperature based on
extension_list. If the empty string is a valid extension_list,
the is_extension_exist will always returns true,
which affects the separation of hot and cold.
Signed-off-by: Wang Xiaojun <wangxiaojun11@huawei.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Added gc_reclaimed_segments and gc_segment_mode sysfs nodes.
1) "gc_reclaimed_segments" shows how many segments have been
reclaimed by GC during a specific GC mode.
2) "gc_segment_mode" is used to control for which gc mode
the "gc_reclaimed_segments" node shows.
Signed-off-by: Daeho Jeong <daehojeong@google.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Let's create /sys/fs/f2fs/<disk>/feature_list/ to meet sysfs rule.
Note that there are three feature list entries:
1) /sys/fs/f2fs/features
: shows runtime features supported by in-kernel f2fs along with Kconfig.
- ref. F2FS_FEATURE_RO_ATTR()
2) /sys/fs/f2fs/$s_id/features <deprecated>
: shows on-disk features enabled by mkfs.f2fs, used for old kernels. This
won't add new feature anymore, and thus, users should check entries in 3)
instead of this 2).
3) /sys/fs/f2fs/$s_id/feature_list
: shows on-disk features enabled by mkfs.f2fs per instance, which follows
sysfs entry rule where each entry should expose single value.
This list covers old feature list provided by 2) and beyond. Therefore,
please add new on-disk feature in this list only.
- ref. F2FS_SB_FEATURE_RO_ATTR()
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Older kernels don't support encryption with casefolding. This adds
the sysfs entry encrypted_casefold to show support for those combined
features. Support for this feature was originally added by
commit 7ad08a58bf67 ("f2fs: Handle casefolding with Encryption")
Fixes: 7ad08a58bf67 ("f2fs: Handle casefolding with Encryption")
Cc: stable@vger.kernel.org # v5.11+
Signed-off-by: Daniel Rosenberg <drosen@google.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
The casefolding feature is only supported when CONFIG_UNICODE is set.
This modifies the feature list f2fs presents under sysfs accordingly.
Fixes: 5aba54302a46 ("f2fs: include charset encoding information in the superblock")
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Daniel Rosenberg <drosen@google.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Given RO feature in superblock, we don't need to check provisioning/reserve
spaces and SSA area.
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
I've added new sysfs nodes to show runtime compression stat since mount.
compr_written_block - show the block count written after compression
compr_saved_block - show the saved block count with compression
compr_new_inode - show the count of inode newly enabled for compression
Signed-off-by: Daeho Jeong <daehojeong@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This is useful when checking conditions during checkpoint=disable in Android.
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
bd_part is never NULL for a block device in use by a file system, so
remove the checks.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Added "ckpt_thread_ioprio" sysfs node to give a way to change checkpoint
merge daemon's io priority. Its default value is "be,3", which means
"BE" I/O class and I/O priority "3". We can select the class between "rt"
and "be", and set the I/O priority within valid range of it.
"," delimiter is necessary in between I/O class and priority number.
Signed-off-by: Daeho Jeong <daehojeong@google.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Introduce /sys/fs/f2fs/<devname>/stat/sb_status to show superblock
status in real time as a hexadecimal value.
value sb status macro description
0x1 SBI_IS_DIRTY, /* dirty flag for checkpoint */
0x2 SBI_IS_CLOSE, /* specify unmounting */
0x4 SBI_NEED_FSCK, /* need fsck.f2fs to fix */
0x8 SBI_POR_DOING, /* recovery is doing or not */
0x10 SBI_NEED_SB_WRITE, /* need to recover superblock */
0x20 SBI_NEED_CP, /* need to checkpoint */
0x40 SBI_IS_SHUTDOWN, /* shutdown by ioctl */
0x80 SBI_IS_RECOVERED, /* recovered orphan/data */
0x100 SBI_CP_DISABLED, /* CP was disabled last mount */
0x200 SBI_CP_DISABLED_QUICK, /* CP was disabled quickly */
0x400 SBI_QUOTA_NEED_FLUSH, /* need to flush quota info in CP */
0x800 SBI_QUOTA_SKIP_FLUSH, /* skip flushing quota in current CP */
0x1000 SBI_QUOTA_NEED_REPAIR, /* quota file may be corrupted */
0x2000 SBI_IS_RESIZEFS, /* resizefs is in process */
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Add a new directory 'stat' in path of /sys/fs/f2fs/<devname>/, later
we can add new readonly stat sysfs file into this directory, it will
make <devname> directory less mess.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This patch adds max_io_bytes to limit bio size when f2fs tries to merge
consecutive IOs. This can give a testing point to split out bios and check
end_io handles those bios correctly. This is used to capture a recent bug
on the decompression and fsverity flow.
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
For multi-device case, one f2fs image includes multi devices, so it
needs to account bytes written of all block devices belong to the image
rather than one main block device, fix it.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
syzkaller found that with CONFIG_DEBUG_KOBJECT_RELEASE=y, unmounting an
f2fs filesystem could result in the following splat:
kobject: 'loop5' ((____ptrval____)): kobject_release, parent 0000000000000000 (delayed 250)
kobject: 'f2fs_xattr_entry-7:5' ((____ptrval____)): kobject_release, parent 0000000000000000 (delayed 750)
------------[ cut here ]------------
ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x98
WARNING: CPU: 0 PID: 699 at lib/debugobjects.c:485 debug_print_object+0x180/0x240
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 699 Comm: syz-executor.5 Tainted: G S 5.9.0-rc8+ #101
Hardware name: linux,dummy-virt (DT)
Call trace:
dump_backtrace+0x0/0x4d8
show_stack+0x34/0x48
dump_stack+0x174/0x1f8
panic+0x360/0x7a0
__warn+0x244/0x2ec
report_bug+0x240/0x398
bug_handler+0x50/0xc0
call_break_hook+0x160/0x1d8
brk_handler+0x30/0xc0
do_debug_exception+0x184/0x340
el1_dbg+0x48/0xb0
el1_sync_handler+0x170/0x1c8
el1_sync+0x80/0x100
debug_print_object+0x180/0x240
debug_check_no_obj_freed+0x200/0x430
slab_free_freelist_hook+0x190/0x210
kfree+0x13c/0x460
f2fs_put_super+0x624/0xa58
generic_shutdown_super+0x120/0x300
kill_block_super+0x94/0xf8
kill_f2fs_super+0x244/0x308
deactivate_locked_super+0x104/0x150
deactivate_super+0x118/0x148
cleanup_mnt+0x27c/0x3c0
__cleanup_mnt+0x28/0x38
task_work_run+0x10c/0x248
do_notify_resume+0x9d4/0x1188
work_pending+0x8/0x34c
Like the error handling for f2fs_register_sysfs(), we need to wait for
the kobject to be destroyed before returning to prevent a potential
use-after-free.
Fixes: bf9e697ecd ("f2fs: expose features to sysfs entry")
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Chao Yu <chao@kernel.org>
Signed-off-by: Jamie Iles <jamie@nuviainc.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
There are several issues in current background GC algorithm:
- valid blocks is one of key factors during cost overhead calculation,
so if segment has less valid block, however even its age is young or
it locates hot segment, CB algorithm will still choose the segment as
victim, it's not appropriate.
- GCed data/node will go to existing logs, no matter in-there datas'
update frequency is the same or not, it may mix hot and cold data
again.
- GC alloctor mainly use LFS type segment, it will cost free segment
more quickly.
This patch introduces a new algorithm named age threshold based
garbage collection to solve above issues, there are three steps
mainly:
1. select a source victim:
- set an age threshold, and select candidates beased threshold:
e.g.
0 means youngest, 100 means oldest, if we set age threshold to 80
then select dirty segments which has age in range of [80, 100] as
candiddates;
- set candidate_ratio threshold, and select candidates based the
ratio, so that we can shrink candidates to those oldest segments;
- select target segment with fewest valid blocks in order to
migrate blocks with minimum cost;
2. select a target victim:
- select candidates beased age threshold;
- set candidate_radius threshold, search candidates whose age is
around source victims, searching radius should less than the
radius threshold.
- select target segment with most valid blocks in order to avoid
migrating current target segment.
3. merge valid blocks from source victim into target victim with
SSR alloctor.
Test steps:
- create 160 dirty segments:
* half of them have 128 valid blocks per segment
* left of them have 384 valid blocks per segment
- run background GC
Benefit: GC count and block movement count both decrease obviously:
- Before:
- Valid: 86
- Dirty: 1
- Prefree: 11
- Free: 6001 (6001)
GC calls: 162 (BG: 220)
- data segments : 160 (160)
- node segments : 2 (2)
Try to move 41454 blocks (BG: 41454)
- data blocks : 40960 (40960)
- node blocks : 494 (494)
IPU: 0 blocks
SSR: 0 blocks in 0 segments
LFS: 41364 blocks in 81 segments
- After:
- Valid: 87
- Dirty: 0
- Prefree: 4
- Free: 6008 (6008)
GC calls: 75 (BG: 76)
- data segments : 74 (74)
- node segments : 1 (1)
Try to move 12813 blocks (BG: 12813)
- data blocks : 12544 (12544)
- node blocks : 269 (269)
IPU: 0 blocks
SSR: 12032 blocks in 77 segments
LFS: 855 blocks in 2 segments
Signed-off-by: Chao Yu <yuchao0@huawei.com>
[Jaegeuk Kim: fix a bug along with pinfile in-mem segment]
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This switches f2fs over to the generic support provided in
the previous patch.
Since casefolded dentries behave the same in ext4 and f2fs, we decrease
the maintenance burden by unifying them, and any optimizations will
immediately apply to both.
Signed-off-by: Daniel Rosenberg <drosen@google.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This fixes the missing change.
Note that, the below commit id is from mainline, original patch to catch up.
Fixes: 0e5e81114de1 ("f2fs: add GC_URGENT_LOW mode in gc_urgent")
Signed-off-by: Jaegeuk Kim <jaegeuk@google.com>
Just for code style, no logic change
1. delete useless space
2. change spaces into tab
Signed-off-by: Jack Qiu <jack.qiu@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Added a new gc_urgent mode, GC_URGENT_LOW, in which mode
F2FS will lower the bar of checking idle in order to
process outstanding discard commands and GC a little bit
aggressively.
Signed-off-by: Daeho Jeong <daehojeong@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
