On 2024/11/22 13:23, Zhiguo Niu wrote:
Chao Yu via Linux-f2fs-devel <linux-f2fs-devel@lists.sourceforge.net>
于2024年11月21日周四 10:01写道:

Quoted:
"at this time, there are still 1086911 extent nodes in this zombie
extent tree that need to be cleaned up.

crash_arm64_sprd_v8.0.3++> extent_tree.node_cnt ffffff80896cc500
   node_cnt = {
     counter = 1086911
   },
"

As reported by Xiuhong, there will be a huge number of extent nodes
in extent tree, it may potentially cause:
- slab memory fragments
- extreme long time shrink on extent tree
- low mapping efficiency

Let's add a sysfs node to limit max read extent count for each inode,
by default, value of this threshold is 10240, it can be updated
according to user's requirement.

Reported-by: Xiuhong Wang <xiuhong.w...@unisoc.com>
Closes: 
https://lore.kernel.org/linux-f2fs-devel/20241112110627.1314632-1-xiuhong.w...@unisoc.com/
Signed-off-by: Xiuhong Wang <xiuhong.w...@unisoc.com>
Signed-off-by: Zhiguo Niu <zhiguo....@unisoc.com>
Signed-off-by: Chao Yu <c...@kernel.org>
---
  Documentation/ABI/testing/sysfs-fs-f2fs | 6 ++++++
  fs/f2fs/extent_cache.c                  | 5 ++++-
  fs/f2fs/f2fs.h                          | 4 ++++
  fs/f2fs/sysfs.c                         | 7 +++++++
  4 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs 
b/Documentation/ABI/testing/sysfs-fs-f2fs
index 513296bb6f29..3e1630c70d8a 100644
--- a/Documentation/ABI/testing/sysfs-fs-f2fs
+++ b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -822,3 +822,9 @@ Description:        It controls the valid block ratio 
threshold not to trigger excessiv
                 for zoned deivces. The initial value of it is 95(%). F2FS will 
stop the
                 background GC thread from intiating GC for sections having 
valid blocks
                 exceeding the ratio.
+
+What:          /sys/fs/f2fs/<disk>/max_read_extent_count
+Date:          November 2024
+Contact:       "Chao Yu" <c...@kernel.org>
+Description:   It controls max read extent count for per-inode, the value of 
threshold
+               is 10240 by default.
diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c
index b7a6817b44b0..347b3b647834 100644
--- a/fs/f2fs/extent_cache.c
+++ b/fs/f2fs/extent_cache.c
@@ -717,7 +717,9 @@ static void __update_extent_tree_range(struct inode *inode,
                 }

                 if (end < org_end && (type != EX_READ ||
-                               org_end - end >= F2FS_MIN_EXTENT_LEN)) {
+                       (org_end - end >= F2FS_MIN_EXTENT_LEN &&
+                       atomic_read(&et->node_cnt) <
+                                       sbi->max_read_extent_count))) {
                         if (parts) {
                                 __set_extent_info(&ei,
                                         end, org_end - end,
@@ -1212,6 +1214,7 @@ void f2fs_init_extent_cache_info(struct f2fs_sb_info *sbi)
         sbi->hot_data_age_threshold = DEF_HOT_DATA_AGE_THRESHOLD;
         sbi->warm_data_age_threshold = DEF_WARM_DATA_AGE_THRESHOLD;
         sbi->last_age_weight = LAST_AGE_WEIGHT;
+       sbi->max_read_extent_count = DEF_MAX_READ_EXTENT_COUNT;
  }

  int __init f2fs_create_extent_cache(void)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index b65b023a588a..6f2cbf4c5740 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -635,6 +635,9 @@ enum {
  #define DEF_HOT_DATA_AGE_THRESHOLD     262144
  #define DEF_WARM_DATA_AGE_THRESHOLD    2621440

+/* default max read extent count per inode */
+#define DEF_MAX_READ_EXTENT_COUNT      10240
+
  /* extent cache type */
  enum extent_type {
         EX_READ,
@@ -1619,6 +1622,7 @@ struct f2fs_sb_info {
         /* for extent tree cache */
         struct extent_tree_info extent_tree[NR_EXTENT_CACHES];
         atomic64_t allocated_data_blocks;       /* for block age extent_cache 
*/
+       unsigned int max_read_extent_count;     /* max read extent count per 
inode */

         /* The threshold used for hot and warm data seperation*/
         unsigned int hot_data_age_threshold;
diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index bdbf24db667b..d1356c656cac 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -787,6 +787,13 @@ static ssize_t __sbi_store(struct f2fs_attr *a,
                 return count;
         }

+       if (!strcmp(a->attr.name, "max_read_extent_count")) {
+               if (t > UINT_MAX)
+                       return -EINVAL;
+               *ui = (unsigned int)t;
+               return count;
+       }
+
Hi Chao,
from Xiuhong remider, it seems miss codes of adding sysfs node
"max_read_extent_count"?
F2FS_SBI_GENERAL_RW_ATTR(max_read_extent_count);
ATTR_LIST(max_read_extent_count);

Oops, let me fix this soon.

Thanks,

thanks!
         if (!strcmp(a->attr.name, "ipu_policy")) {
                 if (t >= BIT(F2FS_IPU_MAX))
                         return -EINVAL;
--
2.40.1



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