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Message-Id: <20240826174116.5008-9-konishi.ryusuke@gmail.com>
Date: Tue, 27 Aug 2024 02:41:16 +0900
From: Ryusuke Konishi <konishi.ryusuke@...il.com>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: linux-nilfs@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH 8/8] nilfs2: refactor nilfs_segctor_thread()
Simplify nilfs_segctor_thread(), the main loop function of the log
writer thread, to make the basic structure easier to understand.
In particular, the acquisition and release of the sc_state_lock spinlock
was scattered throughout the function, so extract the determination of
whether log writing is required into a helper function and make the
spinlock lock sections clearer.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@...il.com>
---
fs/nilfs2/segment.c | 85 +++++++++++++++++++++------------------------
1 file changed, 40 insertions(+), 45 deletions(-)
diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
index 013262ab5169..587251830897 100644
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -2629,6 +2629,32 @@ static int nilfs_segctor_flush_mode(struct nilfs_sc_info *sci)
return SC_LSEG_SR;
}
+/**
+ * nilfs_log_write_required - determine whether log writing is required
+ * @sci: nilfs_sc_info struct
+ * @modep: location for storing log writing mode
+ *
+ * Return: true if log writing is required, false otherwise. If log writing
+ * is required, the mode is stored in the location pointed to by @modep.
+ */
+static bool nilfs_log_write_required(struct nilfs_sc_info *sci, int *modep)
+{
+ bool timedout, ret = true;
+
+ spin_lock(&sci->sc_state_lock);
+ timedout = ((sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
+ time_after_eq(jiffies, sci->sc_timer.expires));
+ if (timedout || sci->sc_seq_request != sci->sc_seq_done)
+ *modep = SC_LSEG_SR;
+ else if (sci->sc_flush_request)
+ *modep = nilfs_segctor_flush_mode(sci);
+ else
+ ret = false;
+
+ spin_unlock(&sci->sc_state_lock);
+ return ret;
+}
+
/**
* nilfs_segctor_thread - main loop of the log writer thread
* @arg: pointer to a struct nilfs_sc_info.
@@ -2644,70 +2670,39 @@ static int nilfs_segctor_thread(void *arg)
{
struct nilfs_sc_info *sci = (struct nilfs_sc_info *)arg;
struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
- int timeout = 0;
nilfs_info(sci->sc_super,
"segctord starting. Construction interval = %lu seconds, CP frequency < %lu seconds",
sci->sc_interval / HZ, sci->sc_mjcp_freq / HZ);
set_freezable();
- spin_lock(&sci->sc_state_lock);
- loop:
- for (;;) {
- int mode;
-
- if (kthread_should_stop())
- goto end_thread;
-
- if (timeout || sci->sc_seq_request != sci->sc_seq_done)
- mode = SC_LSEG_SR;
- else if (sci->sc_flush_request)
- mode = nilfs_segctor_flush_mode(sci);
- else
- break;
-
- spin_unlock(&sci->sc_state_lock);
- nilfs_segctor_thread_construct(sci, mode);
- spin_lock(&sci->sc_state_lock);
- timeout = 0;
- }
-
- if (freezing(current)) {
- spin_unlock(&sci->sc_state_lock);
- try_to_freeze();
- spin_lock(&sci->sc_state_lock);
- } else {
+ while (!kthread_should_stop()) {
DEFINE_WAIT(wait);
- int should_sleep = 1;
+ bool should_write;
+ int mode;
+
+ if (freezing(current)) {
+ try_to_freeze();
+ continue;
+ }
prepare_to_wait(&sci->sc_wait_daemon, &wait,
TASK_INTERRUPTIBLE);
-
- if (sci->sc_seq_request != sci->sc_seq_done)
- should_sleep = 0;
- else if (sci->sc_flush_request)
- should_sleep = 0;
- else if (sci->sc_state & NILFS_SEGCTOR_COMMIT)
- should_sleep = time_before(jiffies,
- sci->sc_timer.expires);
-
- if (should_sleep) {
- spin_unlock(&sci->sc_state_lock);
+ should_write = nilfs_log_write_required(sci, &mode);
+ if (!should_write)
schedule();
- spin_lock(&sci->sc_state_lock);
- }
finish_wait(&sci->sc_wait_daemon, &wait);
- timeout = ((sci->sc_state & NILFS_SEGCTOR_COMMIT) &&
- time_after_eq(jiffies, sci->sc_timer.expires));
if (nilfs_sb_dirty(nilfs) && nilfs_sb_need_update(nilfs))
set_nilfs_discontinued(nilfs);
+
+ if (should_write)
+ nilfs_segctor_thread_construct(sci, mode);
}
- goto loop;
- end_thread:
/* end sync. */
+ spin_lock(&sci->sc_state_lock);
sci->sc_task = NULL;
timer_shutdown_sync(&sci->sc_timer);
spin_unlock(&sci->sc_state_lock);
--
2.34.1
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