The patch titled Subject: mm: fix ratelimit_pages update error in dirty_ratio_handler() has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-fix-ratelimit_pages-update-error-in-dirty_ratio_handler.patch

This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...

This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------ From: Jinliang Zheng alexjlzheng@tencent.com Subject: mm: fix ratelimit_pages update error in dirty_ratio_handler() Date: Tue, 15 Apr 2025 17:02:32 +0800

In dirty_ratio_handler(), vm_dirty_bytes must be set to zero before calling writeback_set_ratelimit(), as global_dirty_limits() always prioritizes the value of vm_dirty_bytes.

That causes ratelimit_pages to still use the value calculated based on vm_dirty_bytes, which is wrong now.

Link: https://lkml.kernel.org/r/20250415090232.7544-1-alexjlzheng@tencent.com Fixes: 9d823e8f6b1b ("writeback: per task dirty rate limit") Signed-off-by: Jinliang Zheng alexjlzheng@tencent.com Reviewed-by: MengEn Sun mengensun@tencent.com Cc: Andrea Righi andrea@betterlinux.com Cc: Fenggaung Wu fengguang.wu@intel.com Cc: Jinliang Zheng alexjlzheng@tencent.com Cc: Matthew Wilcox (Oracle) willy@infradead.org Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

mm/page-writeback.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/page-writeback.c~mm-fix-ratelimit_pages-update-error-in-dirty_ratio_handler +++ a/mm/page-writeback.c @@ -520,8 +520,8 @@ static int dirty_ratio_handler(const str

ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos); if (ret == 0 && write && vm_dirty_ratio != old_ratio) { - writeback_set_ratelimit(); vm_dirty_bytes = 0; + writeback_set_ratelimit(); } return ret; } _

Patches currently in -mm which might be from alexjlzheng@tencent.com are

mm-fix-ratelimit_pages-update-error-in-dirty_ratio_handler.patch