From: Jingbo Xu jefflexu@linux.alibaba.com
mainline inclusion from mainline-v6.7 commit fa151a39a6879144b587f35c0dfcc15e1be9450f category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAN96I
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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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: efc3e6ad53ea ("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 Signed-off-by: Yifan Qiao qiaoyifan4@huawei.com --- mm/page-writeback.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 14192abc4210..b1c73a9fc3c7 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -762,7 +762,8 @@ 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);