* [PATCH v3] f2fs: fix to freeze GC and discard threads quickly
@ 2026-03-13 16:00 Daeho Jeong
0 siblings, 0 replies; 2+ messages in thread
From: Daeho Jeong @ 2026-03-13 16:00 UTC (permalink / raw)
To: linux-kernel, linux-f2fs-devel, kernel-team; +Cc: Daeho Jeong
From: Daeho Jeong <daehojeong@google.com>
Suspend can fail if kernel threads do not freeze for a while.
f2fs_gc and f2fs_discard threads can perform long-running operations
that prevent them from reaching a freeze point in a timely manner.
This patch adds explicit freezing checks in the following locations:
1. f2fs_gc: Added a check at the 'retry' label to exit the loop quickly
if freezing is requested, especially during heavy GC rounds.
2. __issue_discard_cmd: Added a 'suspended' flag to break both inner and
outer loops during discard command issuance if freezing is detected
after at least one command has been issued.
3. __issue_discard_cmd_orderly: Added a similar check for orderly discard
to ensure responsiveness.
These checks ensure that the threads release locks safely and enter the
frozen state.
Signed-off-by: Daeho Jeong <daehojeong@google.com>
---
v3: removed unnecessary suspended check
v2: add freezing check in do_garbage_collect()
---
fs/f2fs/gc.c | 10 ++++++++++
fs/f2fs/segment.c | 12 +++++++++++-
2 files changed, 21 insertions(+), 1 deletion(-)
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 981eac629fe9..f07746a14aa4 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -1883,12 +1883,18 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
sbi->next_victim_seg[gc_type] =
(cur_segno + 1 < sec_end_segno) ?
cur_segno + 1 : NULL_SEGNO;
+
+ if (unlikely(freezing(current))) {
+ folio_put_refs(sum_folio, 2);
+ goto stop;
+ }
}
next_block:
folio_put_refs(sum_folio, 2);
segno = block_end_segno;
}
+stop:
if (submitted)
f2fs_submit_merged_write(sbi, data_type);
@@ -1962,6 +1968,10 @@ int f2fs_gc(struct f2fs_sb_info *sbi, struct f2fs_gc_control *gc_control)
goto stop;
}
retry:
+ if (unlikely(freezing(current))) {
+ ret = 0;
+ goto stop;
+ }
ret = __get_victim(sbi, &segno, gc_type, gc_control->one_time);
if (ret) {
/* allow to search victim from sections has pinned data */
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index e9b6d774b985..0c4fb4270185 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1606,6 +1606,9 @@ static void __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi,
if (dc->state != D_PREP)
goto next;
+ if (*issued > 0 && unlikely(freezing(current)))
+ break;
+
if (dpolicy->io_aware && !is_idle(sbi, DISCARD_TIME)) {
io_interrupted = true;
break;
@@ -1645,6 +1648,7 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
struct blk_plug plug;
int i, issued;
bool io_interrupted = false;
+ bool suspended = false;
if (dpolicy->timeout)
f2fs_update_time(sbi, UMOUNT_DISCARD_TIMEOUT);
@@ -1675,6 +1679,11 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
list_for_each_entry_safe(dc, tmp, pend_list, list) {
f2fs_bug_on(sbi, dc->state != D_PREP);
+ if (issued > 0 && unlikely(freezing(current))) {
+ suspended = true;
+ break;
+ }
+
if (dpolicy->timeout &&
f2fs_time_over(sbi, UMOUNT_DISCARD_TIMEOUT))
break;
@@ -1694,7 +1703,8 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
next:
mutex_unlock(&dcc->cmd_lock);
- if (issued >= dpolicy->max_requests || io_interrupted)
+ if (issued >= dpolicy->max_requests || io_interrupted ||
+ suspended)
break;
}
--
2.53.0.880.g73c4285caa-goog
^ permalink raw reply related [flat|nested] 2+ messages in thread
* [PATCH v3] f2fs: fix to freeze GC and discard threads quickly
@ 2026-03-16 18:59 Daeho Jeong
0 siblings, 0 replies; 2+ messages in thread
From: Daeho Jeong @ 2026-03-16 18:59 UTC (permalink / raw)
To: linux-kernel, linux-f2fs-devel, kernel-team; +Cc: Daeho Jeong
From: Daeho Jeong <daehojeong@google.com>
Suspend can fail if kernel threads do not freeze for a while.
f2fs_gc and f2fs_discard threads can perform long-running operations
that prevent them from reaching a freeze point in a timely manner.
This patch adds explicit freezing checks in the following locations:
1. f2fs_gc: Added a check at the 'retry' label to exit the loop quickly
if freezing is requested, especially during heavy GC rounds.
2. __issue_discard_cmd: Added a 'suspended' flag to break both inner and
outer loops during discard command issuance if freezing is detected
after at least one command has been issued.
3. __issue_discard_cmd_orderly: Added a similar check for orderly discard
to ensure responsiveness.
These checks ensure that the threads release locks safely and enter the
frozen state.
Signed-off-by: Daeho Jeong <daehojeong@google.com>
---
v3: removed unnecessary suspended check
v2: add freezing check in do_garbage_collect()
---
fs/f2fs/gc.c | 10 ++++++++++
fs/f2fs/segment.c | 12 +++++++++++-
2 files changed, 21 insertions(+), 1 deletion(-)
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 246496fbe5e5..2305f16cbabb 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -1889,12 +1889,18 @@ static int do_garbage_collect(struct f2fs_sb_info *sbi,
sbi->next_victim_seg[gc_type] =
(cur_segno + 1 < sec_end_segno) ?
cur_segno + 1 : NULL_SEGNO;
+
+ if (unlikely(freezing(current))) {
+ folio_put_refs(sum_folio, 2);
+ goto stop;
+ }
}
next_block:
folio_put_refs(sum_folio, 2);
segno = block_end_segno;
}
+stop:
if (submitted)
f2fs_submit_merged_write(sbi, data_type);
@@ -1968,6 +1974,10 @@ int f2fs_gc(struct f2fs_sb_info *sbi, struct f2fs_gc_control *gc_control)
goto stop;
}
retry:
+ if (unlikely(freezing(current))) {
+ ret = 0;
+ goto stop;
+ }
ret = __get_victim(sbi, &segno, gc_type, gc_control->one_time);
if (ret) {
/* allow to search victim from sections has pinned data */
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index e9b6d774b985..0c4fb4270185 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1606,6 +1606,9 @@ static void __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi,
if (dc->state != D_PREP)
goto next;
+ if (*issued > 0 && unlikely(freezing(current)))
+ break;
+
if (dpolicy->io_aware && !is_idle(sbi, DISCARD_TIME)) {
io_interrupted = true;
break;
@@ -1645,6 +1648,7 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
struct blk_plug plug;
int i, issued;
bool io_interrupted = false;
+ bool suspended = false;
if (dpolicy->timeout)
f2fs_update_time(sbi, UMOUNT_DISCARD_TIMEOUT);
@@ -1675,6 +1679,11 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
list_for_each_entry_safe(dc, tmp, pend_list, list) {
f2fs_bug_on(sbi, dc->state != D_PREP);
+ if (issued > 0 && unlikely(freezing(current))) {
+ suspended = true;
+ break;
+ }
+
if (dpolicy->timeout &&
f2fs_time_over(sbi, UMOUNT_DISCARD_TIMEOUT))
break;
@@ -1694,7 +1703,8 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
next:
mutex_unlock(&dcc->cmd_lock);
- if (issued >= dpolicy->max_requests || io_interrupted)
+ if (issued >= dpolicy->max_requests || io_interrupted ||
+ suspended)
break;
}
--
2.53.0.851.ga537e3e6e9-goog
^ permalink raw reply related [flat|nested] 2+ messages in thread
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