f2fs: Add bggc_io_aware to adjust the priority of BG_GC when issuing IO

Currently, we have encountered some issues while testing ZUFS. In
situations near the storage limit (e.g., 50GB remaining), and after
simulating fragmentation by repeatedly writing and deleting data, we found
that application installation and startup tests conducted after idling for
a few minutes take significantly longer several times that of traditional
UFS. Tracing the operations revealed that the majority of I/Os were issued
by background GC, which blocks normal I/O operations.

Under normal circumstances, ZUFS indeed requires more background GC and
employs a more aggressive GC strategy. However, I aim to find a way to
minimize the impact on regular I/O operations under these near-limit
conditions. To address this, I have introduced a bggc_io_aware feature,
which controls the prioritization of background GC in the presence of I/Os.
This switch can be adjusted at the framework level to implement different
strategies. If set to AWARE_ALL_IO, all background GC operations will be
skipped during active I/O issuance. The default option remains consistent
with the current strategy, ensuring no change in behavior.

Signed-off-by: Liao Yuanhong <liaoyuanhong@vivo.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
index ce189acd1908530aec979208e57ed7dba1081669..66ee156819839f9db5a0c1991c83aed6cf793b8b 100644 (file)
--- a/Documentation/ABI/testing/sysfs-fs-f2fs
+++ b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -898,3 +898,16 @@ Description:
                - "compat": Hash-based lookup with a linear search fallback enabled
                - "auto:perf": lookup_mode is auto and fallback is disabled on-disk
                - "auto:compat": lookup_mode is auto and fallback is enabled on-disk
+
+What:          /sys/fs/f2fs/<disk>/bggc_io_aware
+Date:          August 2025
+Contact:       "Liao Yuanhong" <liaoyuanhong@vivo.com>
+Description:   Used to adjust the BG_GC priority when pending IO, with a default value
+               of 0. Specifically, for ZUFS, the default value is 1.
+
+               ==================  ======================================================
+               value                           description
+               bggc_io_aware = 0   skip background GC if there is any kind of pending IO
+               bggc_io_aware = 1   skip background GC if there is pending read IO
+               bggc_io_aware = 2   don't aware IO for background GC
+               ==================  ======================================================

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 0655c5c20eee3c2be7d5bb428b2bfa840f61b604..dba391b72119adf44111ec7b5df1df3039ba563a 100644 (file)
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -155,6 +155,12 @@ enum blkzone_allocation_policy {
        BLKZONE_ALLOC_PRIOR_CONV,       /* Prioritize writing to conventional zones */
 };
 
+enum bggc_io_aware_policy {
+       AWARE_ALL_IO,           /* skip background GC if there is any kind of pending IO */
+       AWARE_READ_IO,          /* skip background GC if there is pending read IO */
+       AWARE_NONE,                     /* don't aware IO for background GC */
+};
+
 /*
  * An implementation of an rwsem that is explicitly unfair to readers. This
  * prevents priority inversion when a low-priority reader acquires the read lock
@@ -1841,6 +1847,7 @@ struct f2fs_sb_info {
        spinlock_t dev_lock;                    /* protect dirty_device */
        bool aligned_blksize;                   /* all devices has the same logical blksize */
        unsigned int first_seq_zone_segno;      /* first segno in sequential zone */
+       unsigned int bggc_io_aware;             /* For adjust the BG_GC priority when pending IO */
 
        /* For write statistics */
        u64 sectors_written_start;
@@ -3033,13 +3040,10 @@ static inline bool is_idle(struct f2fs_sb_info *sbi, int type)
        if (sbi->gc_mode == GC_URGENT_HIGH)
                return true;
 
-       if (zoned_gc) {
-               if (is_inflight_read_io(sbi))
-                       return false;
-       } else {
-               if (is_inflight_io(sbi, type))
-                       return false;
-       }
+       if (sbi->bggc_io_aware == AWARE_READ_IO && is_inflight_read_io(sbi))
+               return false;
+       if (sbi->bggc_io_aware == AWARE_ALL_IO && is_inflight_io(sbi, type))
+               return false;
 
        if (sbi->gc_mode == GC_URGENT_MID)
                return true;

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 87f6490d92477361a5e263cff1cf407faa97baad..2000880b7dca9ff08b068e2a8c52eb5fcdb17796 100644 (file)
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -4683,9 +4683,11 @@ static int f2fs_scan_devices(struct f2fs_sb_info *sbi)
 
        logical_blksize = bdev_logical_block_size(sbi->sb->s_bdev);
        sbi->aligned_blksize = true;
+       sbi->bggc_io_aware = AWARE_ALL_IO;
 #ifdef CONFIG_BLK_DEV_ZONED
        sbi->max_open_zones = UINT_MAX;
        sbi->blkzone_alloc_policy = BLKZONE_ALLOC_PRIOR_SEQ;
+       sbi->bggc_io_aware = AWARE_READ_IO;
 #endif
 
        for (i = 0; i < max_devices; i++) {

diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index 82489c78aeda581535b8def05750db4c12c86098..1ffaf9e74ce9fbd3993b43e2ca5c027832f115c5 100644 (file)
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -882,6 +882,13 @@ out:
                return count;
        }
 
+       if (!strcmp(a->attr.name, "bggc_io_aware")) {
+               if (t < AWARE_ALL_IO || t > AWARE_NONE)
+                       return -EINVAL;
+               sbi->bggc_io_aware = t;
+               return count;
+       }
+
        *ui = (unsigned int)t;
 
        return count;
@@ -1191,6 +1198,7 @@ F2FS_SBI_GENERAL_RW_ATTR(blkzone_alloc_policy);
 #endif
 F2FS_SBI_GENERAL_RW_ATTR(carve_out);
 F2FS_SBI_GENERAL_RW_ATTR(reserved_pin_section);
+F2FS_SBI_GENERAL_RW_ATTR(bggc_io_aware);
 
 /* STAT_INFO ATTR */
 #ifdef CONFIG_F2FS_STAT_FS
@@ -1320,6 +1328,7 @@ static struct attribute *f2fs_attrs[] = {
        ATTR_LIST(discard_idle_interval),
        ATTR_LIST(gc_idle_interval),
        ATTR_LIST(umount_discard_timeout),
+       ATTR_LIST(bggc_io_aware),
 #ifdef CONFIG_F2FS_IOSTAT
        ATTR_LIST(iostat_enable),
        ATTR_LIST(iostat_period_ms),