* [PATCH v2 2/3] f2fs: introduce f2fs_schedule_timeout()
2025-11-12 1:47 [PATCH v2 1/3] f2fs: use memalloc_retry_wait() as much as possible Chao Yu
@ 2025-11-12 1:47 ` Chao Yu
2025-11-12 1:47 ` [PATCH v2 3/3] f2fs: change default schedule timeout value Chao Yu
2025-11-24 18:50 ` [f2fs-dev] [PATCH v2 1/3] f2fs: use memalloc_retry_wait() as much as possible patchwork-bot+f2fs
2 siblings, 0 replies; 4+ messages in thread
From: Chao Yu @ 2025-11-12 1:47 UTC (permalink / raw)
To: jaegeuk; +Cc: linux-f2fs-devel, linux-kernel, Chao Yu
In f2fs retry logic, we will call f2fs_io_schedule_timeout() to sleep as
uninterruptible state (waiting for IO) for a while, however, in several
paths below, we are not blocked by IO:
- f2fs_write_single_data_page() return -EAGAIN due to racing on cp_rwsem.
- f2fs_flush_device_cache() failed to submit preflush command.
- __issue_discard_cmd_range() sleeps periodically in between two in batch
discard submissions.
So, in order to reveal state of task more accurate, let's introduce
f2fs_schedule_timeout() and call it in above paths in where we are waiting
for non-IO reasons.
Then we can get real reason of uninterruptible sleep for a thread in
tracepoint, perfetto, etc.
Signed-off-by: Chao Yu <chao@kernel.org>
---
v2:
- get rid of f2fs_schedule_timeout() replacement in retry logic for no
memory error.
fs/f2fs/checkpoint.c | 4 ++--
fs/f2fs/compress.c | 4 ++--
fs/f2fs/data.c | 4 ++--
fs/f2fs/f2fs.h | 22 +++++++++++++++-------
fs/f2fs/segment.c | 4 ++--
fs/f2fs/super.c | 2 +-
6 files changed, 24 insertions(+), 16 deletions(-)
diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
index bbe07e3a6c75..4c401b5b2933 100644
--- a/fs/f2fs/checkpoint.c
+++ b/fs/f2fs/checkpoint.c
@@ -1318,7 +1318,7 @@ void f2fs_wait_on_all_pages(struct f2fs_sb_info *sbi, int type)
f2fs_submit_merged_write(sbi, DATA);
prepare_to_wait(&sbi->cp_wait, &wait, TASK_UNINTERRUPTIBLE);
- io_schedule_timeout(DEFAULT_IO_TIMEOUT);
+ io_schedule_timeout(DEFAULT_SCHEDULE_TIMEOUT);
}
finish_wait(&sbi->cp_wait, &wait);
}
@@ -1974,7 +1974,7 @@ void f2fs_flush_ckpt_thread(struct f2fs_sb_info *sbi)
/* Let's wait for the previous dispatched checkpoint. */
while (atomic_read(&cprc->queued_ckpt))
- io_schedule_timeout(DEFAULT_IO_TIMEOUT);
+ io_schedule_timeout(DEFAULT_SCHEDULE_TIMEOUT);
}
void f2fs_init_ckpt_req_control(struct f2fs_sb_info *sbi)
diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index 716004ba44dc..148bb925b03b 100644
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c
@@ -1057,7 +1057,7 @@ static void cancel_cluster_writeback(struct compress_ctx *cc,
f2fs_submit_merged_write(F2FS_I_SB(cc->inode), DATA);
while (atomic_read(&cic->pending_pages) !=
(cc->valid_nr_cpages - submitted + 1))
- f2fs_io_schedule_timeout(DEFAULT_IO_TIMEOUT);
+ f2fs_io_schedule_timeout(DEFAULT_SCHEDULE_TIMEOUT);
}
/* Cancel writeback and stay locked. */
@@ -1574,7 +1574,7 @@ static int f2fs_write_raw_pages(struct compress_ctx *cc,
*/
if (IS_NOQUOTA(cc->inode))
goto out;
- f2fs_io_schedule_timeout(DEFAULT_IO_TIMEOUT);
+ f2fs_schedule_timeout(DEFAULT_SCHEDULE_TIMEOUT);
goto retry_write;
}
goto out;
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index d8e163cc7308..48c20386f031 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -3150,8 +3150,8 @@ static int f2fs_write_cache_pages(struct address_space *mapping,
} else if (ret == -EAGAIN) {
ret = 0;
if (wbc->sync_mode == WB_SYNC_ALL) {
- f2fs_io_schedule_timeout(
- DEFAULT_IO_TIMEOUT);
+ f2fs_schedule_timeout(
+ DEFAULT_SCHEDULE_TIMEOUT);
goto retry_write;
}
goto next;
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index a4439175eabf..0d0e0a01a659 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -656,8 +656,8 @@ enum {
#define DEFAULT_RETRY_IO_COUNT 8 /* maximum retry read IO or flush count */
-/* congestion wait timeout value, default: 20ms */
-#define DEFAULT_IO_TIMEOUT (msecs_to_jiffies(20))
+/* IO/non-IO congestion wait timeout value, default: 20ms */
+#define DEFAULT_SCHEDULE_TIMEOUT (msecs_to_jiffies(20))
/* timeout value injected, default: 1000ms */
#define DEFAULT_FAULT_TIMEOUT (msecs_to_jiffies(1000))
@@ -4919,22 +4919,30 @@ static inline bool f2fs_block_unit_discard(struct f2fs_sb_info *sbi)
return F2FS_OPTION(sbi).discard_unit == DISCARD_UNIT_BLOCK;
}
-static inline void f2fs_io_schedule_timeout(long timeout)
+static inline void __f2fs_schedule_timeout(long timeout, bool io)
{
set_current_state(TASK_UNINTERRUPTIBLE);
- io_schedule_timeout(timeout);
+ if (io)
+ io_schedule_timeout(timeout);
+ else
+ schedule_timeout(timeout);
}
+#define f2fs_io_schedule_timeout(timeout) \
+ __f2fs_schedule_timeout(timeout, true)
+#define f2fs_schedule_timeout(timeout) \
+ __f2fs_schedule_timeout(timeout, false)
+
static inline void f2fs_io_schedule_timeout_killable(long timeout)
{
while (timeout) {
if (fatal_signal_pending(current))
return;
set_current_state(TASK_UNINTERRUPTIBLE);
- io_schedule_timeout(DEFAULT_IO_TIMEOUT);
- if (timeout <= DEFAULT_IO_TIMEOUT)
+ io_schedule_timeout(DEFAULT_SCHEDULE_TIMEOUT);
+ if (timeout <= DEFAULT_SCHEDULE_TIMEOUT)
return;
- timeout -= DEFAULT_IO_TIMEOUT;
+ timeout -= DEFAULT_SCHEDULE_TIMEOUT;
}
}
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index d968a4250b1a..993ec8afe2db 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -750,7 +750,7 @@ int f2fs_flush_device_cache(struct f2fs_sb_info *sbi)
do {
ret = __submit_flush_wait(sbi, FDEV(i).bdev);
if (ret)
- f2fs_io_schedule_timeout(DEFAULT_IO_TIMEOUT);
+ f2fs_schedule_timeout(DEFAULT_SCHEDULE_TIMEOUT);
} while (ret && --count);
if (ret) {
@@ -3471,7 +3471,7 @@ static unsigned int __issue_discard_cmd_range(struct f2fs_sb_info *sbi,
blk_finish_plug(&plug);
mutex_unlock(&dcc->cmd_lock);
trimmed += __wait_all_discard_cmd(sbi, NULL);
- f2fs_io_schedule_timeout(DEFAULT_IO_TIMEOUT);
+ f2fs_schedule_timeout(DEFAULT_SCHEDULE_TIMEOUT);
goto next;
}
skip:
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 2bd7c2320d4f..d47ec718f3be 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -2652,7 +2652,7 @@ static int f2fs_enable_checkpoint(struct f2fs_sb_info *sbi)
/* we should flush all the data to keep data consistency */
while (get_pages(sbi, F2FS_DIRTY_DATA)) {
writeback_inodes_sb_nr(sbi->sb, nr_pages, WB_REASON_SYNC);
- f2fs_io_schedule_timeout(DEFAULT_IO_TIMEOUT);
+ f2fs_io_schedule_timeout(DEFAULT_SCHEDULE_TIMEOUT);
if (f2fs_time_over(sbi, ENABLE_TIME))
break;
--
2.49.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH v2 3/3] f2fs: change default schedule timeout value
2025-11-12 1:47 [PATCH v2 1/3] f2fs: use memalloc_retry_wait() as much as possible Chao Yu
2025-11-12 1:47 ` [PATCH v2 2/3] f2fs: introduce f2fs_schedule_timeout() Chao Yu
@ 2025-11-12 1:47 ` Chao Yu
2025-11-24 18:50 ` [f2fs-dev] [PATCH v2 1/3] f2fs: use memalloc_retry_wait() as much as possible patchwork-bot+f2fs
2 siblings, 0 replies; 4+ messages in thread
From: Chao Yu @ 2025-11-12 1:47 UTC (permalink / raw)
To: jaegeuk; +Cc: linux-f2fs-devel, linux-kernel, Chao Yu
This patch changes default schedule timeout value from 20ms to 1ms,
in order to give caller more chances to check whether IO or non-IO
congestion condition has already been mitigable.
In addition, default interval of periodical discard submission is
kept to 20ms.
Signed-off-by: Chao Yu <chao@kernel.org>
---
v2:
- no changes
fs/f2fs/f2fs.h | 6 ++++--
fs/f2fs/segment.c | 2 +-
2 files changed, 5 insertions(+), 3 deletions(-)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 0d0e0a01a659..74cbbd84f39b 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -407,6 +407,8 @@ struct discard_entry {
#define DEFAULT_DISCARD_GRANULARITY 16
/* default maximum discard granularity of ordered discard, unit: block count */
#define DEFAULT_MAX_ORDERED_DISCARD_GRANULARITY 16
+/* default interval of periodical discard submission */
+#define DEFAULT_DISCARD_INTERVAL (msecs_to_jiffies(20))
/* max discard pend list number */
#define MAX_PLIST_NUM 512
@@ -656,8 +658,8 @@ enum {
#define DEFAULT_RETRY_IO_COUNT 8 /* maximum retry read IO or flush count */
-/* IO/non-IO congestion wait timeout value, default: 20ms */
-#define DEFAULT_SCHEDULE_TIMEOUT (msecs_to_jiffies(20))
+/* IO/non-IO congestion wait timeout value, default: 1ms */
+#define DEFAULT_SCHEDULE_TIMEOUT (msecs_to_jiffies(1))
/* timeout value injected, default: 1000ms */
#define DEFAULT_FAULT_TIMEOUT (msecs_to_jiffies(1000))
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 993ec8afe2db..8375dca7ed9e 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -3471,7 +3471,7 @@ static unsigned int __issue_discard_cmd_range(struct f2fs_sb_info *sbi,
blk_finish_plug(&plug);
mutex_unlock(&dcc->cmd_lock);
trimmed += __wait_all_discard_cmd(sbi, NULL);
- f2fs_schedule_timeout(DEFAULT_SCHEDULE_TIMEOUT);
+ f2fs_schedule_timeout(DEFAULT_DISCARD_INTERVAL);
goto next;
}
skip:
--
2.49.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [f2fs-dev] [PATCH v2 1/3] f2fs: use memalloc_retry_wait() as much as possible
2025-11-12 1:47 [PATCH v2 1/3] f2fs: use memalloc_retry_wait() as much as possible Chao Yu
2025-11-12 1:47 ` [PATCH v2 2/3] f2fs: introduce f2fs_schedule_timeout() Chao Yu
2025-11-12 1:47 ` [PATCH v2 3/3] f2fs: change default schedule timeout value Chao Yu
@ 2025-11-24 18:50 ` patchwork-bot+f2fs
2 siblings, 0 replies; 4+ messages in thread
From: patchwork-bot+f2fs @ 2025-11-24 18:50 UTC (permalink / raw)
To: Chao Yu; +Cc: jaegeuk, linux-kernel, linux-f2fs-devel
Hello:
This series was applied to jaegeuk/f2fs.git (dev)
by Jaegeuk Kim <jaegeuk@kernel.org>:
On Wed, 12 Nov 2025 09:47:47 +0800 you wrote:
> memalloc_retry_wait() is recommended in memory allocation retry logic,
> use it as much as possible.
>
> Signed-off-by: Chao Yu <chao@kernel.org>
> ---
> use memalloc_retry_wait() instead of f2fs_io_schedule_timeout()
> fs/f2fs/segment.c | 2 +-
> fs/f2fs/super.c | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
Here is the summary with links:
- [f2fs-dev,v2,1/3] f2fs: use memalloc_retry_wait() as much as possible
https://git.kernel.org/jaegeuk/f2fs/c/00e24c488596
- [f2fs-dev,v2,2/3] f2fs: introduce f2fs_schedule_timeout()
https://git.kernel.org/jaegeuk/f2fs/c/517eb4747ad8
- [f2fs-dev,v2,3/3] f2fs: change default schedule timeout value
https://git.kernel.org/jaegeuk/f2fs/c/2f4c126cc08b
You are awesome, thank you!
--
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^ permalink raw reply [flat|nested] 4+ messages in thread