From: Nick Piggin Slightly change the writeout watermark calculations so we keep background and synchronous writeout watermarks in the same ratios after adjusting them for the amout of mapped memory. This ensures we should always attempt to start background writeout before synchronous writeout and preserves the admin's desired background-versus-forground ratios after we've auto-adjusted one of them. Signed-off-by: Nick Piggin Signed-off-by: Andrew Morton --- 25-akpm/mm/page-writeback.c | 8 +++++--- 1 files changed, 5 insertions(+), 3 deletions(-) diff -puN mm/page-writeback.c~vm-tune-writeback mm/page-writeback.c --- 25/mm/page-writeback.c~vm-tune-writeback 2004-08-06 00:56:17.931967688 -0700 +++ 25-akpm/mm/page-writeback.c 2004-08-06 00:56:17.936966928 -0700 @@ -153,9 +153,11 @@ get_dirty_limits(struct writeback_state if (dirty_ratio < 5) dirty_ratio = 5; - background_ratio = dirty_background_ratio; - if (background_ratio >= dirty_ratio) - background_ratio = dirty_ratio / 2; + /* + * Keep the ratio between dirty_ratio and background_ratio roughly + * what the sysctls are after dirty_ratio has been scaled (above). + */ + background_ratio = dirty_background_ratio * dirty_ratio/vm_dirty_ratio; background = (background_ratio * total_pages) / 100; dirty = (dirty_ratio * total_pages) / 100; _