diff options
Diffstat (limited to 'mm/page-writeback.c')
| -rw-r--r-- | mm/page-writeback.c | 93 |
1 files changed, 47 insertions, 46 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 9ab6de8..433fa99 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -146,6 +146,7 @@ static struct prop_descriptor vm_completions; * We make sure that the background writeout level is below the adjusted * clamping level. */ + static unsigned long highmem_dirtyable_memory(unsigned long total) { #ifdef CONFIG_HIGHMEM @@ -172,12 +173,12 @@ static unsigned long highmem_dirtyable_memory(unsigned long total) } /** - * determine_dirtyable_memory - amount of memory that may be used + * global_dirtyable_memory - number of globally dirtyable pages * - * Returns the numebr of pages that can currently be freed and used - * by the kernel for direct mappings. + * Returns the global number of pages potentially available for dirty + * page cache. This is the base value for the global dirty limits. */ -static unsigned long determine_dirtyable_memory(void) +unsigned long global_dirtyable_memory(void) { unsigned long x; @@ -191,6 +192,47 @@ static unsigned long determine_dirtyable_memory(void) } /* + * global_dirty_limits - background-writeback and dirty-throttling thresholds + * + * Calculate the dirty thresholds based on sysctl parameters + * - vm.dirty_background_ratio or vm.dirty_background_bytes + * - vm.dirty_ratio or vm.dirty_bytes + * The dirty limits will be lifted by 1/4 for PF_LESS_THROTTLE (ie. nfsd) and + * real-time tasks. + */ +void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty) +{ + unsigned long background; + unsigned long dirty; + unsigned long uninitialized_var(available_memory); + struct task_struct *tsk; + + if (!vm_dirty_bytes || !dirty_background_bytes) + available_memory = global_dirtyable_memory(); + + if (vm_dirty_bytes) + dirty = DIV_ROUND_UP(vm_dirty_bytes, PAGE_SIZE); + else + dirty = (vm_dirty_ratio * available_memory) / 100; + + if (dirty_background_bytes) + background = DIV_ROUND_UP(dirty_background_bytes, PAGE_SIZE); + else + background = (dirty_background_ratio * available_memory) / 100; + + if (background >= dirty) + background = dirty / 2; + tsk = current; + if (tsk->flags & PF_LESS_THROTTLE || rt_task(tsk)) { + background += background / 4; + dirty += dirty / 4; + } + *pbackground = background; + *pdirty = dirty; + trace_global_dirty_state(background, dirty); +} + +/* * couple the period to the dirty_ratio: * * period/2 ~ roundup_pow_of_two(dirty limit) @@ -202,7 +244,7 @@ static int calc_period_shift(void) if (vm_dirty_bytes) dirty_total = vm_dirty_bytes / PAGE_SIZE; else - dirty_total = (vm_dirty_ratio * determine_dirtyable_memory()) / + dirty_total = (vm_dirty_ratio * global_dirtyable_memory()) / 100; return 2 + ilog2(dirty_total - 1); } @@ -362,47 +404,6 @@ static unsigned long hard_dirty_limit(unsigned long thresh) return max(thresh, global_dirty_limit); } -/* - * global_dirty_limits - background-writeback and dirty-throttling thresholds - * - * Calculate the dirty thresholds based on sysctl parameters - * - vm.dirty_background_ratio or vm.dirty_background_bytes - * - vm.dirty_ratio or vm.dirty_bytes - * The dirty limits will be lifted by 1/4 for PF_LESS_THROTTLE (ie. nfsd) and - * real-time tasks. - */ -void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty) -{ - unsigned long background; - unsigned long dirty; - unsigned long uninitialized_var(available_memory); - struct task_struct *tsk; - - if (!vm_dirty_bytes || !dirty_background_bytes) - available_memory = determine_dirtyable_memory(); - - if (vm_dirty_bytes) - dirty = DIV_ROUND_UP(vm_dirty_bytes, PAGE_SIZE); - else - dirty = (vm_dirty_ratio * available_memory) / 100; - - if (dirty_background_bytes) - background = DIV_ROUND_UP(dirty_background_bytes, PAGE_SIZE); - else - background = (dirty_background_ratio * available_memory) / 100; - - if (background >= dirty) - background = dirty / 2; - tsk = current; - if (tsk->flags & PF_LESS_THROTTLE || rt_task(tsk)) { - background += background / 4; - dirty += dirty / 4; - } - *pbackground = background; - *pdirty = dirty; - trace_global_dirty_state(background, dirty); -} - /** * bdi_dirty_limit - @bdi's share of dirty throttling threshold * @bdi: the backing_dev_info to query |