Commit 2caffb6a authored by Kemeng Shi's avatar Kemeng Shi Committed by Theodore Ts'o
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ext4: use correct criteria name instead stale integer number in comment 



Use correct criteria name instead stale integer number in comment

Signed-off-by: default avatarKemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: default avatarOjaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20240424061904.987525-5-shikemeng@huaweicloud.com


Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent d1a3924e

fs/ext4/ext4.h

+6 −3
Original line number Diff line number Diff line
@@ -213,11 +213,14 @@ enum criteria { 
#define EXT4_MB_USE_RESERVED		0x2000

/* Do strict check for free blocks while retrying block allocation */

#define EXT4_MB_STRICT_CHECK		0x4000

/* Large fragment size list lookup succeeded at least once for cr = 0 */

/* Large fragment size list lookup succeeded at least once for

 * CR_POWER2_ALIGNED */

#define EXT4_MB_CR_POWER2_ALIGNED_OPTIMIZED		0x8000

/* Avg fragment size rb tree lookup succeeded at least once for cr = 1 */

/* Avg fragment size rb tree lookup succeeded at least once for

 * CR_GOAL_LEN_FAST */

#define EXT4_MB_CR_GOAL_LEN_FAST_OPTIMIZED		0x00010000

/* Avg fragment size rb tree lookup succeeded at least once for cr = 1.5 */

/* Avg fragment size rb tree lookup succeeded at least once for

 * CR_BEST_AVAIL_LEN */

#define EXT4_MB_CR_BEST_AVAIL_LEN_OPTIMIZED		0x00020000



struct ext4_allocation_request {

fs/ext4/mballoc.c

+9 −7
Original line number Diff line number Diff line
@@ -1135,8 +1135,9 @@ static void ext4_mb_choose_next_group(struct ext4_allocation_context *ac, 
		ext4_mb_choose_next_group_best_avail(ac, new_cr, group);

	} else {

		/*

		 * TODO: For CR=2, we can arrange groups in an rb tree sorted by

		 * bb_free. But until that happens, we should never come here.

		 * TODO: For CR_GOAL_LEN_SLOW, we can arrange groups in an

		 * rb tree sorted by bb_free. But until that happens, we should

		 * never come here.

		 */

		WARN_ON(1);

	}
@@ -2683,7 +2684,7 @@ static int ext4_mb_good_group_nolock(struct ext4_allocation_context *ac, 
		int ret;



		/*

		 * cr=CR_POWER2_ALIGNED/CR_GOAL_LEN_FAST is a very optimistic

		 * CR_POWER2_ALIGNED/CR_GOAL_LEN_FAST is a very optimistic

		 * search to find large good chunks almost for free. If buddy

		 * data is not ready, then this optimization makes no sense. But

		 * we never skip the first block group in a flex_bg, since this
@@ -3448,10 +3449,11 @@ static int ext4_mb_init_backend(struct super_block *sb) 
	}

	if (sbi->s_mb_prefetch > ext4_get_groups_count(sb))

		sbi->s_mb_prefetch = ext4_get_groups_count(sb);

	/* now many real IOs to prefetch within a single allocation at cr=0

	 * given cr=0 is an CPU-related optimization we shouldn't try to

	 * load too many groups, at some point we should start to use what

	 * we've got in memory.

	/*

	 * now many real IOs to prefetch within a single allocation at

	 * CR_POWER2_ALIGNED. Given CR_POWER2_ALIGNED is an CPU-related

	 * optimization we shouldn't try to load too many groups, at some point

	 * we should start to use what we've got in memory.

	 * with an average random access time 5ms, it'd take a second to get

	 * 200 groups (* N with flex_bg), so let's make this limit 4

	 */

fs/ext4/mballoc.h

+2 −2
Original line number Diff line number Diff line
@@ -187,8 +187,8 @@ struct ext4_allocation_context { 
	struct ext4_free_extent ac_f_ex;



	/*

	 * goal len can change in CR1.5, so save the original len. This is

	 * used while adjusting the PA window and for accounting.

	 * goal len can change in CR_BEST_AVAIL_LEN, so save the original len.

	 * This is used while adjusting the PA window and for accounting.

	 */

	ext4_grpblk_t	ac_orig_goal_len;