[PATCH v2] f2fs: introduce discard_cpuset mount opt
From: Yangtao Li
Date: Thu Mar 02 2023 - 01:02:30 EST
It makes the discard process run faster on a more powerful CPU, or not.
And if bind it to a specific cpu, it is possible to have more cache
locality.
Signed-off-by: Yangtao Li <frank.li@xxxxxxxx>
---
v2:
-fix kernel test robot warn
Documentation/filesystems/f2fs.rst | 2 ++
fs/f2fs/f2fs.h | 1 +
fs/f2fs/segment.c | 8 ++++++-
fs/f2fs/super.c | 36 ++++++++++++++++++++++++++++++
kernel/kthread.c | 1 +
5 files changed, 47 insertions(+), 1 deletion(-)
diff --git a/Documentation/filesystems/f2fs.rst b/Documentation/filesystems/f2fs.rst
index 2055e72871fe..dc005f3b784a 100644
--- a/Documentation/filesystems/f2fs.rst
+++ b/Documentation/filesystems/f2fs.rst
@@ -351,6 +351,8 @@ age_extent_cache Enable an age extent cache based on rb-tree. It records
data block update frequency of the extent per inode, in
order to provide better temperature hints for data block
allocation.
+discard_cpuset=%u Set the cpumask of dicard thread, it makes the discard
+ process run faster on a more powerful CPU, or not.
======================== ============================================================
Debugfs Entries
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index b0ab2062038a..62ce02a87d33 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -183,6 +183,7 @@ struct f2fs_mount_info {
int compress_mode; /* compression mode */
unsigned char extensions[COMPRESS_EXT_NUM][F2FS_EXTENSION_LEN]; /* extensions */
unsigned char noextensions[COMPRESS_EXT_NUM][F2FS_EXTENSION_LEN]; /* extensions */
+ struct cpumask discard_cpumask; /* discard thread cpumask */
};
#define F2FS_FEATURE_ENCRYPT 0x0001
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 227e25836173..2648c564833e 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -2054,11 +2054,17 @@ int f2fs_start_discard_thread(struct f2fs_sb_info *sbi)
if (!f2fs_realtime_discard_enable(sbi))
return 0;
- dcc->f2fs_issue_discard = kthread_run(issue_discard_thread, sbi,
+ dcc->f2fs_issue_discard = kthread_create(issue_discard_thread, sbi,
"f2fs_discard-%u:%u", MAJOR(dev), MINOR(dev));
if (IS_ERR(dcc->f2fs_issue_discard)) {
err = PTR_ERR(dcc->f2fs_issue_discard);
dcc->f2fs_issue_discard = NULL;
+ } else {
+ if (!cpumask_empty(&F2FS_OPTION(sbi).discard_cpumask)) {
+ kthread_bind_mask(dcc->f2fs_issue_discard,
+ &F2FS_OPTION(sbi).discard_cpumask);
+ }
+ wake_up_process(dcc->f2fs_issue_discard);
}
return err;
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index fbaaabbcd6de..8ecbe3595f34 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -164,6 +164,7 @@ enum {
Opt_discard_unit,
Opt_memory_mode,
Opt_age_extent_cache,
+ Opt_discard_cpuset,
Opt_err,
};
@@ -243,6 +244,7 @@ static match_table_t f2fs_tokens = {
{Opt_discard_unit, "discard_unit=%s"},
{Opt_memory_mode, "memory=%s"},
{Opt_age_extent_cache, "age_extent_cache"},
+ {Opt_discard_cpuset, "discard_cpuset=%u"},
{Opt_err, NULL},
};
@@ -1256,6 +1258,22 @@ static int parse_options(struct super_block *sb, char *options, bool is_remount)
case Opt_age_extent_cache:
set_opt(sbi, AGE_EXTENT_CACHE);
break;
+ case Opt_discard_cpuset:
+ if (!f2fs_hw_support_discard(sbi)) {
+ f2fs_warn(sbi, "device does not support discard");
+ break;
+ }
+
+ if (args->from && match_int(args, &arg))
+ return -EINVAL;
+
+ if (!cpu_possible(arg)) {
+ f2fs_err(sbi, "invalid cpu%d for discard_cpuset", arg);
+ return -EINVAL;
+ }
+
+ cpumask_set_cpu(arg, &F2FS_OPTION(sbi).discard_cpumask);
+ break;
default:
f2fs_err(sbi, "Unrecognized mount option \"%s\" or missing value",
p);
@@ -1358,6 +1376,14 @@ static int parse_options(struct super_block *sb, char *options, bool is_remount)
f2fs_err(sbi, "Allow to mount readonly mode only");
return -EROFS;
}
+
+ if (!cpumask_empty(&F2FS_OPTION(sbi).discard_cpumask) &&
+ !cpumask_intersects(cpu_online_mask,
+ &F2FS_OPTION(sbi).discard_cpumask)) {
+ f2fs_err(sbi, "Must include one online CPU for discard_cpuset");
+ return -EINVAL;
+ }
+
return 0;
}
@@ -1884,6 +1910,7 @@ static inline void f2fs_show_compress_options(struct seq_file *seq,
static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
{
struct f2fs_sb_info *sbi = F2FS_SB(root->d_sb);
+ unsigned int cpu;
if (F2FS_OPTION(sbi).bggc_mode == BGGC_MODE_SYNC)
seq_printf(seq, ",background_gc=%s", "sync");
@@ -1909,6 +1936,8 @@ static int f2fs_show_options(struct seq_file *seq, struct dentry *root)
seq_printf(seq, ",discard_unit=%s", "segment");
else if (F2FS_OPTION(sbi).discard_unit == DISCARD_UNIT_SECTION)
seq_printf(seq, ",discard_unit=%s", "section");
+ for_each_cpu(cpu, &F2FS_OPTION(sbi).discard_cpumask)
+ seq_printf(seq, ",discard_cpuset=%u", cpu);
} else {
seq_puts(seq, ",nodiscard");
}
@@ -2340,6 +2369,13 @@ static int f2fs_remount(struct super_block *sb, int *flags, char *data)
goto restore_opts;
}
+ if (!cpumask_equal(&org_mount_opt.discard_cpumask,
+ &F2FS_OPTION(sbi).discard_cpumask)) {
+ err = -EINVAL;
+ f2fs_warn(sbi, "switch discard_cpuset option is not allowed");
+ goto restore_opts;
+ }
+
if ((*flags & SB_RDONLY) && test_opt(sbi, DISABLE_CHECKPOINT)) {
err = -EINVAL;
f2fs_warn(sbi, "disabling checkpoint not compatible with read-only");
diff --git a/kernel/kthread.c b/kernel/kthread.c
index 7e6751b29101..8ddc2cd1b27e 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -541,6 +541,7 @@ void kthread_bind_mask(struct task_struct *p, const struct cpumask *mask)
{
__kthread_bind_mask(p, mask, TASK_UNINTERRUPTIBLE);
}
+EXPORT_SYMBOL_GPL(kthread_bind_mask);
/**
* kthread_bind - bind a just-created kthread to a cpu.
--
2.25.1