6.6-stable review patch. If anyone has any objections, please let me know.
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From: Jingbo Xu jefflexu@linux.alibaba.com
commit fa151a39a6879144b587f35c0dfcc15e1be9450f upstream.
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: Greg Kroah-Hartman gregkh@linuxfoundation.org --- mm/page-writeback.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -750,7 +750,8 @@ static int __bdi_set_max_ratio(struct ba 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);