Commit 361eb69f authored by Ojaswin Mujoo's avatar Ojaswin Mujoo Committed by Theodore Ts'o
Browse files

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: default avatarOjaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: default avatarRitesh Harjani (IBM) <ritesh.list@gmail.com>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/c409addceaa3ade4b40328e28e3b54b2f259689e.1679731817.git.ojaswin@linux.ibm.com


Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 38727786

Documentation/admin-guide/ext4.rst

+0 −3
Original line number Diff line number Diff line
@@ -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.

fs/ext4/ext4.h

+0 −1
Original line number Diff line number Diff line
@@ -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;

fs/ext4/mballoc.c

+0 −20
Original line number Diff line number Diff line
@@ -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;

}

fs/ext4/mballoc.h

+0 −5
Original line number Diff line number Diff line
@@ -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.

fs/ext4/sysfs.c

+0 −2
Original line number Diff line number Diff line
@@ -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),