diff options
| -rw-r--r-- | mm/page-writeback.c | 41 |
1 files changed, 18 insertions, 23 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 1d2fc89ca56..be0efbde499 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -133,11 +133,9 @@ get_dirty_limits(long *pbackground, long *pdirty, #ifdef CONFIG_HIGHMEM /* - * If this mapping can only allocate from low memory, - * we exclude high memory from our count. + * We always exclude high memory from our count. */ - if (mapping && !(mapping_gfp_mask(mapping) & __GFP_HIGHMEM)) - available_memory -= totalhigh_pages; + available_memory -= totalhigh_pages; #endif @@ -526,28 +524,25 @@ static struct notifier_block __cpuinitdata ratelimit_nb = { }; /* - * If the machine has a large highmem:lowmem ratio then scale back the default - * dirty memory thresholds: allowing too much dirty highmem pins an excessive - * number of buffer_heads. + * Called early on to tune the page writeback dirty limits. + * + * We used to scale dirty pages according to how total memory + * related to pages that could be allocated for buffers (by + * comparing nr_free_buffer_pages() to vm_total_pages. + * + * However, that was when we used "dirty_ratio" to scale with + * all memory, and we don't do that any more. "dirty_ratio" + * is now applied to total non-HIGHPAGE memory (by subtracting + * totalhigh_pages from vm_total_pages), and as such we can't + * get into the old insane situation any more where we had + * large amounts of dirty pages compared to a small amount of + * non-HIGHMEM memory. + * + * But we might still want to scale the dirty_ratio by how + * much memory the box has.. */ void __init page_writeback_init(void) { - long buffer_pages = nr_free_buffer_pages(); - long correction; - - correction = (100 * 4 * buffer_pages) / vm_total_pages; - - if (correction < 100) { - dirty_background_ratio *= correction; - dirty_background_ratio /= 100; - vm_dirty_ratio *= correction; - vm_dirty_ratio /= 100; - - if (dirty_background_ratio <= 0) - dirty_background_ratio = 1; - if (vm_dirty_ratio <= 0) - vm_dirty_ratio = 1; - } mod_timer(&wb_timer, jiffies + dirty_writeback_interval); writeback_set_ratelimit(); register_cpu_notifier(&ratelimit_nb); |