mm: fix arithmetic for max_prop_frac when setting max_ratio

Since now bdi->max_ratio is part per million, fix the wrong arithmetic for
max_prop_frac when setting max_ratio.  Otherwise the miscalculated
max_prop_frac will affect the incrementing of writeout completion count
when max_ratio is not 100%.

Link: https://lkml.kernel.org/r/20231219142508.86265-3-jefflexu@linux.alibaba.com
Fixes: efc3e6ad53 ("mm: split off __bdi_set_max_ratio() function")
Signed-off-by: Jingbo Xu <jefflexu@linux.alibaba.com>
Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Stefan Roesch <shr@devkernel.io>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Jingbo Xu 2023-12-19 22:25:08 +08:00 committed by Andrew Morton
parent e0646b7590
commit fa151a39a6
1 changed files with 2 additions and 1 deletions

View File

@ -728,7 +728,8 @@ static int __bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ra
ret = -EINVAL;
} else {
bdi->max_ratio = max_ratio;
bdi->max_prop_frac = (FPROP_FRAC_BASE * max_ratio) / 100;
bdi->max_prop_frac = (FPROP_FRAC_BASE * max_ratio) /
(100 * BDI_RATIO_SCALE);
}
spin_unlock_bh(&bdi_lock);