ext4: Remove the logic to trim inode PAs

Earlier, inode PAs were stored in a linked list. This caused a need to
periodically trim the list down inorder to avoid growing it to a very
large size, as this would severly affect performance during list
iteration.

Recent patches changed this list to an rbtree, and since the tree scales
up much better, we no longer need to have the trim functionality, hence
remove it.

Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/c409addceaa3ade4b40328e28e3b54b2f259689e.1679731817.git.ojaswin@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/Documentation/admin-guide/ext4.rst b/Documentation/admin-guide/ext4.rst
index 4c559e08d11ee43c8263888ed9c6770dadc813d0..5740d85439ff508ee128f8d0ea5ab16dca73dc8f 100644 (file)
--- a/Documentation/admin-guide/ext4.rst
+++ b/Documentation/admin-guide/ext4.rst
@@ -489,9 +489,6 @@ Files in /sys/fs/ext4/<devname>:
         multiple of this tuning parameter if the stripe size is not set in the
         ext4 superblock
 
-  mb_max_inode_prealloc
-        The maximum length of per-inode ext4_prealloc_space list.
-
   mb_max_to_scan
         The maximum number of extents the multiblock allocator will search to
         find the best extent.

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 8cf955b1dca5799855acd1446f6dbc99a8df373f..993d3284b430d90590c9cb432739aa5587659b4a 100644 (file)
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1613,7 +1613,6 @@ struct ext4_sb_info {
        unsigned int s_mb_stats;
        unsigned int s_mb_order2_reqs;
        unsigned int s_mb_group_prealloc;
-       unsigned int s_mb_max_inode_prealloc;
        unsigned int s_max_dir_size_kb;
        /* where last allocation was done - for stream allocation */
        unsigned long s_mb_last_group;

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 9b4c6033bd692747bc141e7e8702ffcf2bd4792d..78259bddbc4d614daf5b044149386b965b52bbf4 100644 (file)
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -3417,7 +3417,6 @@ int ext4_mb_init(struct super_block *sb)
        sbi->s_mb_stats = MB_DEFAULT_STATS;
        sbi->s_mb_stream_request = MB_DEFAULT_STREAM_THRESHOLD;
        sbi->s_mb_order2_reqs = MB_DEFAULT_ORDER2_REQS;
-       sbi->s_mb_max_inode_prealloc = MB_DEFAULT_MAX_INODE_PREALLOC;
        /*
         * The default group preallocation is 512, which for 4k block
         * sizes translates to 2 megabytes.  However for bigalloc file
@@ -5601,29 +5600,11 @@ static void ext4_mb_add_n_trim(struct ext4_allocation_context *ac)
        return ;
 }
 
-/*
- * if per-inode prealloc list is too long, trim some PA
- */
-static void ext4_mb_trim_inode_pa(struct inode *inode)
-{
-       struct ext4_inode_info *ei = EXT4_I(inode);
-       struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
-       int count, delta;
-
-       count = atomic_read(&ei->i_prealloc_active);
-       delta = (sbi->s_mb_max_inode_prealloc >> 2) + 1;
-       if (count > sbi->s_mb_max_inode_prealloc + delta) {
-               count -= sbi->s_mb_max_inode_prealloc;
-               ext4_discard_preallocations(inode, count);
-       }
-}
-
 /*
  * release all resource we used in allocation
  */
 static int ext4_mb_release_context(struct ext4_allocation_context *ac)
 {
-       struct inode *inode = ac->ac_inode;
        struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
        struct ext4_prealloc_space *pa = ac->ac_pa;
        if (pa) {
@@ -5659,7 +5640,6 @@ static int ext4_mb_release_context(struct ext4_allocation_context *ac)
        if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)
                mutex_unlock(&ac->ac_lg->lg_mutex);
        ext4_mb_collect_stats(ac);
-       ext4_mb_trim_inode_pa(inode);
        return 0;
 }
 

diff --git a/fs/ext4/mballoc.h b/fs/ext4/mballoc.h
index f8e8ee493867216044666df5985464a2d271e040..6d85ee8674a6469dcacf0613d99e7007e3324fd6 100644 (file)
--- a/fs/ext4/mballoc.h
+++ b/fs/ext4/mballoc.h
@@ -73,11 +73,6 @@
  */
 #define MB_DEFAULT_GROUP_PREALLOC      512
 
-/*
- * maximum length of inode prealloc list
- */
-#define MB_DEFAULT_MAX_INODE_PREALLOC  512
-
 /*
  * Number of groups to search linearly before performing group scanning
  * optimization.

diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c
index 12d6252e3e226dfdf5ee2f61512b23b213c1b503..3042bc605bbf5a9555eecc19889c29061ef2b30c 100644 (file)
--- a/fs/ext4/sysfs.c
+++ b/fs/ext4/sysfs.c
@@ -214,7 +214,6 @@ EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan);
 EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs);
 EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
 EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc);
-EXT4_RW_ATTR_SBI_UI(mb_max_inode_prealloc, s_mb_max_inode_prealloc);
 EXT4_RW_ATTR_SBI_UI(mb_max_linear_groups, s_mb_max_linear_groups);
 EXT4_RW_ATTR_SBI_UI(extent_max_zeroout_kb, s_extent_max_zeroout_kb);
 EXT4_ATTR(trigger_fs_error, 0200, trigger_test_error);
@@ -264,7 +263,6 @@ static struct attribute *ext4_attrs[] = {
        ATTR_LIST(mb_order2_req),
        ATTR_LIST(mb_stream_req),
        ATTR_LIST(mb_group_prealloc),
-       ATTR_LIST(mb_max_inode_prealloc),
        ATTR_LIST(mb_max_linear_groups),
        ATTR_LIST(max_writeback_mb_bump),
        ATTR_LIST(extent_max_zeroout_kb),