From: Ojaswin Mujoo <ojaswin@linux.ibm.com> mainline inclusion from mainline-v6.8-rc1 commit 1f6bc02f18489b9c9ea39b068d0695fb0e4567e9 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/ICN2MB Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- Currently in case the goal length is a multiple of stripe size we use ext4_mb_scan_aligned() to find the stripe size aligned physical blocks. In case we are not able to find any, we again go back to calling ext4_mb_choose_next_group() to search for a different suitable block group. However, since the linear search always begins from the start, most of the times we end up with the same BG and the cycle continues. With large fliesystems, the CPU can be stuck in this loop for hours which can slow down the whole system. Hence, until we figure out a better way to continue the search (rather than starting from beginning) in ext4_mb_choose_next_group(), lets just fallback to ext4_mb_complex_scan_group() in case aligned scan fails, as it is much more likely to find the needed blocks. Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/ee033f6dfa0a7f2934437008a909c3788233950f.170245501... Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Baokun Li <libaokun1@huawei.com> --- fs/ext4/mballoc.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index dcad2d88df6b..19c7a3cfae49 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -2935,14 +2935,19 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac) ac->ac_groups_scanned++; if (cr == CR_POWER2_ALIGNED) ext4_mb_simple_scan_group(ac, &e4b); - else if ((cr == CR_GOAL_LEN_FAST || - cr == CR_BEST_AVAIL_LEN) && - sbi->s_stripe && - !(ac->ac_g_ex.fe_len % - EXT4_B2C(sbi, sbi->s_stripe))) - ext4_mb_scan_aligned(ac, &e4b); - else - ext4_mb_complex_scan_group(ac, &e4b); + else { + bool is_stripe_aligned = sbi->s_stripe && + !(ac->ac_g_ex.fe_len % + EXT4_B2C(sbi, sbi->s_stripe)); + + if ((cr == CR_GOAL_LEN_FAST || + cr == CR_BEST_AVAIL_LEN) && + is_stripe_aligned) + ext4_mb_scan_aligned(ac, &e4b); + + if (ac->ac_status == AC_STATUS_CONTINUE) + ext4_mb_complex_scan_group(ac, &e4b); + } ext4_unlock_group(sb, group); ext4_mb_unload_buddy(&e4b); -- 2.46.1