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Message-ID: <20250131222914.1634961-3-jaegeuk@kernel.org>
Date: Fri, 31 Jan 2025 22:27:57 +0000
From: Jaegeuk Kim <jaegeuk@...nel.org>
To: linux-kernel@...r.kernel.org,
linux-f2fs-devel@...ts.sourceforge.net
Cc: Jaegeuk Kim <jaegeuk@...nel.org>
Subject: [PATCH 2/2] f2fs: add a sysfs entry to request donate file-backed pages
1. ioctl(fd1, F2FS_IOC_DONATE_RANGE, {0,3});
2. ioctl(fd2, F2FS_IOC_DONATE_RANGE, {1,2});
3. ioctl(fd3, F2FS_IOC_DONATE_RANGE, {3,1});
4. echo 1024 > /sys/fs/f2fs/tuning/reclaim_caches_kb
This gives a way to reclaim file-backed pages by iterating all f2fs mounts until
reclaiming 1MB page cache ranges, registered by #1, #2, and #3.
5. cat /sys/fs/f2fs/tuning/reclaim_caches_kb
-> gives total number of registered file ranges.
Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
---
Documentation/ABI/testing/sysfs-fs-f2fs | 7 ++
fs/f2fs/f2fs.h | 2 +
fs/f2fs/shrinker.c | 90 +++++++++++++++++++++++++
fs/f2fs/sysfs.c | 63 +++++++++++++++++
4 files changed, 162 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
index 3e1630c70d8a..81deae2af84d 100644
--- a/Documentation/ABI/testing/sysfs-fs-f2fs
+++ b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -828,3 +828,10 @@ Date: November 2024
Contact: "Chao Yu" <chao@...nel.org>
Description: It controls max read extent count for per-inode, the value of threshold
is 10240 by default.
+
+What: /sys/fs/f2fs/tuning/reclaim_caches_kb
+Date: February 2025
+Contact: "Jaegeuk Kim" <jaegeuk@...nel.org>
+Description: It reclaims the given KBs of file-backed pages registered by
+ ioctl(F2FS_IOC_DONATE_RANGE).
+ For example, writing N tries to drop N KBs spaces in LRU.
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 805585a7d2b6..bd0d8138b71d 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -4241,6 +4241,8 @@ unsigned long f2fs_shrink_count(struct shrinker *shrink,
struct shrink_control *sc);
unsigned long f2fs_shrink_scan(struct shrinker *shrink,
struct shrink_control *sc);
+unsigned int f2fs_donate_files(void);
+void f2fs_reclaim_caches(unsigned int reclaim_caches_kb);
void f2fs_join_shrinker(struct f2fs_sb_info *sbi);
void f2fs_leave_shrinker(struct f2fs_sb_info *sbi);
diff --git a/fs/f2fs/shrinker.c b/fs/f2fs/shrinker.c
index 83d6fb97dcae..45efff635d8e 100644
--- a/fs/f2fs/shrinker.c
+++ b/fs/f2fs/shrinker.c
@@ -130,6 +130,96 @@ unsigned long f2fs_shrink_scan(struct shrinker *shrink,
return freed;
}
+unsigned int f2fs_donate_files(void)
+{
+ struct f2fs_sb_info *sbi;
+ struct list_head *p;
+ unsigned int donate_files = 0;
+
+ spin_lock(&f2fs_list_lock);
+ p = f2fs_list.next;
+ while (p != &f2fs_list) {
+ sbi = list_entry(p, struct f2fs_sb_info, s_list);
+
+ /* stop f2fs_put_super */
+ if (!mutex_trylock(&sbi->umount_mutex)) {
+ p = p->next;
+ continue;
+ }
+ spin_unlock(&f2fs_list_lock);
+
+ donate_files += sbi->donate_files;
+
+ spin_lock(&f2fs_list_lock);
+ p = p->next;
+ mutex_unlock(&sbi->umount_mutex);
+ }
+ spin_unlock(&f2fs_list_lock);
+
+ return donate_files;
+}
+
+static unsigned int do_reclaim_caches(struct f2fs_sb_info *sbi,
+ unsigned int reclaim_caches_kb)
+{
+ struct inode *inode;
+ struct f2fs_inode_info *fi;
+ unsigned int nfiles = sbi->donate_files;
+ pgoff_t npages = reclaim_caches_kb >> (PAGE_SHIFT - 10);
+
+ while (npages && nfiles--) {
+ pgoff_t len;
+
+ spin_lock(&sbi->inode_lock[DONATE_INODE]);
+ if (list_empty(&sbi->inode_list[DONATE_INODE])) {
+ spin_unlock(&sbi->inode_lock[DONATE_INODE]);
+ break;
+ }
+ fi = list_first_entry(&sbi->inode_list[DONATE_INODE],
+ struct f2fs_inode_info, gdonate_list);
+ list_move_tail(&fi->gdonate_list, &sbi->inode_list[DONATE_INODE]);
+ inode = igrab(&fi->vfs_inode);
+ spin_unlock(&sbi->inode_lock[DONATE_INODE]);
+
+ if (!inode)
+ continue;
+
+ len = fi->donate_end - fi->donate_start + 1;
+ npages = npages < len ? 0 : npages - len;
+ invalidate_inode_pages2_range(inode->i_mapping,
+ fi->donate_start, fi->donate_end);
+ iput(inode);
+ cond_resched();
+ }
+ return npages << (PAGE_SHIFT - 10);
+}
+
+void f2fs_reclaim_caches(unsigned int reclaim_caches_kb)
+{
+ struct f2fs_sb_info *sbi;
+ struct list_head *p;
+
+ spin_lock(&f2fs_list_lock);
+ p = f2fs_list.next;
+ while (p != &f2fs_list && reclaim_caches_kb) {
+ sbi = list_entry(p, struct f2fs_sb_info, s_list);
+
+ /* stop f2fs_put_super */
+ if (!mutex_trylock(&sbi->umount_mutex)) {
+ p = p->next;
+ continue;
+ }
+ spin_unlock(&f2fs_list_lock);
+
+ reclaim_caches_kb = do_reclaim_caches(sbi, reclaim_caches_kb);
+
+ spin_lock(&f2fs_list_lock);
+ p = p->next;
+ mutex_unlock(&sbi->umount_mutex);
+ }
+ spin_unlock(&f2fs_list_lock);
+}
+
void f2fs_join_shrinker(struct f2fs_sb_info *sbi)
{
spin_lock(&f2fs_list_lock);
diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index 4bd7b17a20c8..579226a05a69 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -916,6 +916,39 @@ static struct f2fs_base_attr f2fs_base_attr_##_name = { \
.show = f2fs_feature_show, \
}
+static ssize_t f2fs_tune_show(struct f2fs_base_attr *a, char *buf)
+{
+ unsigned int res;
+
+ if (!strcmp(a->attr.name, "reclaim_caches_kb"))
+ res = f2fs_donate_files();
+
+ return sysfs_emit(buf, "%u\n", res);
+}
+
+static ssize_t f2fs_tune_store(struct f2fs_base_attr *a,
+ const char *buf, size_t count)
+{
+ unsigned long t;
+ int ret;
+
+ ret = kstrtoul(skip_spaces(buf), 0, &t);
+ if (ret)
+ return ret;
+
+ if (!strcmp(a->attr.name, "reclaim_caches_kb"))
+ f2fs_reclaim_caches(t);
+
+ return ret ? ret : count;
+}
+
+#define F2FS_TUNE_RW_ATTR(_name) \
+static struct f2fs_base_attr f2fs_base_attr_##_name = { \
+ .attr = {.name = __stringify(_name), .mode = 0644 }, \
+ .show = f2fs_tune_show, \
+ .store = f2fs_tune_store, \
+}
+
static ssize_t f2fs_sb_feature_show(struct f2fs_attr *a,
struct f2fs_sb_info *sbi, char *buf)
{
@@ -1368,6 +1401,14 @@ static struct attribute *f2fs_sb_feat_attrs[] = {
};
ATTRIBUTE_GROUPS(f2fs_sb_feat);
+F2FS_TUNE_RW_ATTR(reclaim_caches_kb);
+
+static struct attribute *f2fs_tune_attrs[] = {
+ BASE_ATTR_LIST(reclaim_caches_kb),
+ NULL,
+};
+ATTRIBUTE_GROUPS(f2fs_tune);
+
static const struct sysfs_ops f2fs_attr_ops = {
.show = f2fs_attr_show,
.store = f2fs_attr_store,
@@ -1401,6 +1442,20 @@ static struct kobject f2fs_feat = {
.kset = &f2fs_kset,
};
+static const struct sysfs_ops f2fs_tune_attr_ops = {
+ .show = f2fs_base_attr_show,
+ .store = f2fs_base_attr_store,
+};
+
+static const struct kobj_type f2fs_tune_ktype = {
+ .default_groups = f2fs_tune_groups,
+ .sysfs_ops = &f2fs_tune_attr_ops,
+};
+
+static struct kobject f2fs_tune = {
+ .kset = &f2fs_kset,
+};
+
static ssize_t f2fs_stat_attr_show(struct kobject *kobj,
struct attribute *attr, char *buf)
{
@@ -1637,6 +1692,11 @@ int __init f2fs_init_sysfs(void)
if (ret)
goto unregister_out;
+ ret = kobject_init_and_add(&f2fs_tune, &f2fs_tune_ktype,
+ NULL, "tuning");
+ if (ret)
+ goto put_feat;
+
f2fs_proc_root = proc_mkdir("fs/f2fs", NULL);
if (!f2fs_proc_root) {
ret = -ENOMEM;
@@ -1645,6 +1705,8 @@ int __init f2fs_init_sysfs(void)
return 0;
put_kobject:
+ kobject_put(&f2fs_tune);
+put_feat:
kobject_put(&f2fs_feat);
unregister_out:
kset_unregister(&f2fs_kset);
@@ -1653,6 +1715,7 @@ int __init f2fs_init_sysfs(void)
void f2fs_exit_sysfs(void)
{
+ kobject_put(&f2fs_tune);
kobject_put(&f2fs_feat);
kset_unregister(&f2fs_kset);
remove_proc_entry("fs/f2fs", NULL);
--
2.48.1.362.g079036d154-goog
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