projects / pve-kernel.git / blame
| Commit | Line | Data |
|---|---|---|
| 5dde66b4 | 1 | From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 |
| 0ec9138f | 2 | From: Ojaswin Mujoo <ojaswin@linux.ibm.com> |
| 0ec9138f | 3 | Date: Fri, 15 Dec 2023 16:49:50 +0530 |
| 5dde66b4 | 4 | Subject: [PATCH] ext4: fallback to complex scan if aligned scan doesn't work |
| 0ec9138f FG |
5 | |
| 6 | Currently in case the goal length is a multiple of stripe size we use | |
| 7 | ext4_mb_scan_aligned() to find the stripe size aligned physical blocks. | |
| 8 | In case we are not able to find any, we again go back to calling | |
| 9 | ext4_mb_choose_next_group() to search for a different suitable block | |
| 10 | group. However, since the linear search always begins from the start, | |
| 11 | most of the times we end up with the same BG and the cycle continues. | |
| 12 | ||
| 13 | With large fliesystems, the CPU can be stuck in this loop for hours | |
| 14 | which can slow down the whole system. Hence, until we figure out a | |
| 15 | better way to continue the search (rather than starting from beginning) | |
| 16 | in ext4_mb_choose_next_group(), lets just fallback to | |
| 17 | ext4_mb_complex_scan_group() in case aligned scan fails, as it is much | |
| 18 | more likely to find the needed blocks. | |
| 19 | ||
| 20 | Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> | |
| 21 | --- | |
| 22 | fs/ext4/mballoc.c | 21 +++++++++++++-------- | |
| 23 | 1 file changed, 13 insertions(+), 8 deletions(-) | |
| 24 | ||
| 25 | diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c | |
| 4cf5a7d9 | 26 | index 5246b408cf0c..e3b942664842 100644 |
| 0ec9138f FG |
27 | --- a/fs/ext4/mballoc.c |
| 28 | +++ b/fs/ext4/mballoc.c | |
| 5dde66b4 | 29 | @@ -2894,14 +2894,19 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac) |
| 0ec9138f FG |
30 | ac->ac_groups_scanned++; |
| 31 | if (cr == CR_POWER2_ALIGNED) | |
| 32 | ext4_mb_simple_scan_group(ac, &e4b); | |
| 33 | - else if ((cr == CR_GOAL_LEN_FAST || | |
| 34 | - cr == CR_BEST_AVAIL_LEN) && | |
| 35 | - sbi->s_stripe && | |
| 36 | - !(ac->ac_g_ex.fe_len % | |
| 37 | - EXT4_B2C(sbi, sbi->s_stripe))) | |
| 38 | - ext4_mb_scan_aligned(ac, &e4b); | |
| 39 | - else | |
| 40 | - ext4_mb_complex_scan_group(ac, &e4b); | |
| 41 | + else { | |
| 42 | + bool is_stripe_aligned = sbi->s_stripe && | |
| 43 | + !(ac->ac_g_ex.fe_len % | |
| 44 | + EXT4_B2C(sbi, sbi->s_stripe)); | |
| 45 | + | |
| 46 | + if ((cr == CR_GOAL_LEN_FAST || | |
| 47 | + cr == CR_BEST_AVAIL_LEN) && | |
| 48 | + is_stripe_aligned) | |
| 49 | + ext4_mb_scan_aligned(ac, &e4b); | |
| 50 | + | |
| 51 | + if (ac->ac_status == AC_STATUS_CONTINUE) | |
| 52 | + ext4_mb_complex_scan_group(ac, &e4b); | |
| 53 | + } | |
| 54 | ||
| 55 | ext4_unlock_group(sb, group); | |
| 56 | ext4_mb_unload_buddy(&e4b); |