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| author | Ojaswin Mujoo <ojaswin@linux.ibm.com> | 2023-05-30 18:03:49 +0530 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2023-06-26 19:34:56 -0400 |
| commit | 7e170922f06bf46effa7c57f6035fc463d6edc7e (patch) | |
| tree | 60306c92b8d9cbbbc3764edb53662ad9bd38f9e8 /fs/ext4/ext4.h | |
| parent | 856d865c178b4fbf4c629d5a7d0df9352d123280 (diff) | |
| download | linux-7e170922f06bf46effa7c57f6035fc463d6edc7e.tar.gz linux-7e170922f06bf46effa7c57f6035fc463d6edc7e.tar.bz2 linux-7e170922f06bf46effa7c57f6035fc463d6edc7e.zip | |
ext4: Add allocation criteria 1.5 (CR1_5)
CR1_5 aims to optimize allocations which can't be satisfied in CR1. The
fact that we couldn't find a group in CR1 suggests that it would be
difficult to find a continuous extent to compleltely satisfy our
allocations. So before falling to the slower CR2, in CR1.5 we
proactively trim the the preallocations so we can find a group with
(free / fragments) big enough. This speeds up our allocation at the
cost of slightly reduced preallocation.
The patch also adds a new sysfs tunable:
* /sys/fs/ext4/<partition>/mb_cr1_5_max_trim_order
This controls how much CR1.5 can trim a request before falling to CR2.
For example, for a request of order 7 and max trim order 2, CR1.5 can
trim this upto order 5.
Suggested-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Link: https://lore.kernel.org/r/150fdf65c8e4cc4dba71e020ce0859bcf636a5ff.1685449706.git.ojaswin@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/ext4.h')
| -rw-r--r-- | fs/ext4/ext4.h | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index e4f53947f51f..fb9d2e2a9e42 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -133,13 +133,14 @@ enum SHIFT_DIRECTION { * criteria the slower the allocation. We start at lower criterias and keep * falling back to higher ones if we are not able to find any blocks. */ -#define EXT4_MB_NUM_CRS 4 +#define EXT4_MB_NUM_CRS 5 /* * All possible allocation criterias for mballoc */ enum criteria { CR0, CR1, + CR1_5, CR2, CR3, }; @@ -185,6 +186,9 @@ enum criteria { #define EXT4_MB_CR0_OPTIMIZED 0x8000 /* Avg fragment size rb tree lookup succeeded at least once for cr = 1 */ #define EXT4_MB_CR1_OPTIMIZED 0x00010000 +/* Avg fragment size rb tree lookup succeeded at least once for cr = 1.5 */ +#define EXT4_MB_CR1_5_OPTIMIZED 0x00020000 + struct ext4_allocation_request { /* target inode for block we're allocating */ struct inode *inode; @@ -1549,6 +1553,7 @@ struct ext4_sb_info { unsigned long s_mb_last_start; unsigned int s_mb_prefetch; unsigned int s_mb_prefetch_limit; + unsigned int s_mb_cr1_5_max_trim_order; /* stats for buddy allocator */ atomic_t s_bal_reqs; /* number of reqs with len > 1 */ @@ -1563,6 +1568,7 @@ struct ext4_sb_info { atomic_t s_bal_2orders; /* 2^order hits */ atomic_t s_bal_cr0_bad_suggestions; atomic_t s_bal_cr1_bad_suggestions; + atomic_t s_bal_cr1_5_bad_suggestions; atomic64_t s_bal_cX_groups_considered[EXT4_MB_NUM_CRS]; atomic64_t s_bal_cX_hits[EXT4_MB_NUM_CRS]; atomic64_t s_bal_cX_failed[EXT4_MB_NUM_CRS]; /* cX loop didn't find blocks */ |