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 3 > /sys/fs/f2fs/blk/donate_caches will reclaim 3 page cache ranges, registered by #1, #2, and #3. Signed-off-by: Jaegeuk Kim <[email protected]>
jaegeuk · Jan 8, 2025 · 9ea74b4 · 9ea74b4
1 parent d2e7bc7
commit 9ea74b4
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diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -828,3 +828,10 @@ Date:		November 2024
 Contact:	"Chao Yu" <[email protected]>
 Description:	It controls max read extent count for per-inode, the value of threshold
 		is 10240 by default.
+
+What:		/sys/fs/f2fs/<disk>/donate_caches
+Date:		December 2024
+Contact:	"Jaegeuk Kim" <[email protected]>
+Description:	It reclaims the certian file-backed pages registered by
+		ioctl(F2FS_IOC_DONATE_RANGE).
+		For example, writing N tries to drop N address spaces in LRU.
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
@@ -1635,6 +1635,9 @@ struct f2fs_sb_info {
 	unsigned int warm_data_age_threshold;
 	unsigned int last_age_weight;
 
+	/* control donate caches */
+	unsigned int donate_caches;
+
 	/* basic filesystem units */
 	unsigned int log_sectors_per_block;	/* log2 sectors per block */
 	unsigned int log_blocksize;		/* log2 block size */
@@ -4256,6 +4259,7 @@ unsigned long f2fs_shrink_count(struct shrinker *shrink,
 			struct shrink_control *sc);
 unsigned long f2fs_shrink_scan(struct shrinker *shrink,
 			struct shrink_control *sc);
+void f2fs_donate_caches(struct f2fs_sb_info *sbi);
 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
@@ -130,6 +130,33 @@ unsigned long f2fs_shrink_scan(struct shrinker *shrink,
 	return freed;
 }
 
+void f2fs_donate_caches(struct f2fs_sb_info *sbi)
+{
+	struct inode *inode = NULL;
+	struct f2fs_inode_info *fi;
+	int nfiles = sbi->donate_caches;
+next:
+	spin_lock(&sbi->inode_lock[DONATE_INODE]);
+	if (list_empty(&sbi->inode_list[DONATE_INODE]) || !nfiles) {
+		spin_unlock(&sbi->inode_lock[DONATE_INODE]);
+		return;
+	}
+
+	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) {
+		invalidate_inode_pages2_range(inode->i_mapping,
+			fi->donate_start, fi->donate_end);
+		iput(inode);
+	}
+	if (nfiles--)
+		goto next;
+}
+
 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
@@ -811,6 +811,12 @@ static ssize_t __sbi_store(struct f2fs_attr *a,
 		return count;
 	}
 
+	if (!strcmp(a->attr.name, "donate_caches")) {
+		sbi->donate_caches = min(t, sbi->ndirty_inode[DONATE_INODE]);
+		f2fs_donate_caches(sbi);
+		return count;
+	}
+
 	*ui = (unsigned int)t;
 
 	return count;
@@ -1030,6 +1036,7 @@ F2FS_SBI_GENERAL_RW_ATTR(max_victim_search);
 F2FS_SBI_GENERAL_RW_ATTR(migration_granularity);
 F2FS_SBI_GENERAL_RW_ATTR(migration_window_granularity);
 F2FS_SBI_GENERAL_RW_ATTR(dir_level);
+F2FS_SBI_GENERAL_RW_ATTR(donate_caches);
 #ifdef CONFIG_F2FS_IOSTAT
 F2FS_SBI_GENERAL_RW_ATTR(iostat_enable);
 F2FS_SBI_GENERAL_RW_ATTR(iostat_period_ms);
@@ -1178,6 +1185,7 @@ static struct attribute *f2fs_attrs[] = {
 	ATTR_LIST(migration_granularity),
 	ATTR_LIST(migration_window_granularity),
 	ATTR_LIST(dir_level),
+	ATTR_LIST(donate_caches),
 	ATTR_LIST(ram_thresh),
 	ATTR_LIST(ra_nid_pages),
 	ATTR_LIST(dirty_nats_ratio),