diff options
Diffstat (limited to 'mm/page_alloc.c')
-rw-r--r-- | mm/page_alloc.c | 35 |
1 files changed, 27 insertions, 8 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 18490f3bd7f1..1cbbac2b0492 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -207,8 +207,21 @@ static char * const zone_names[MAX_NR_ZONES] = { "Movable", }; +/* + * Try to keep at least this much lowmem free. Do not allow normal + * allocations below this point, only high priority ones. Automatically + * tuned according to the amount of memory in the system. + */ int min_free_kbytes = 1024; int user_min_free_kbytes = -1; +int min_free_order_shift = 1; + +/* + * Extra memory for the system to try freeing. Used to temporarily + * free memory, to make space for new workloads. Anyone can allocate + * down to the min watermarks controlled by min_free_kbytes above. + */ +int extra_free_kbytes = 0; static unsigned long __meminitdata nr_kernel_pages; static unsigned long __meminitdata nr_all_pages; @@ -1876,7 +1889,7 @@ static bool __zone_watermark_ok(struct zone *z, unsigned int order, free_pages -= z->free_area[o].nr_free << o; /* Require fewer higher order pages to be free */ - min >>= 1; + min >>= min_free_order_shift; if (free_pages <= min) return false; @@ -5740,6 +5753,7 @@ static void setup_per_zone_lowmem_reserve(void) static void __setup_per_zone_wmarks(void) { unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10); + unsigned long pages_low = extra_free_kbytes >> (PAGE_SHIFT - 10); unsigned long lowmem_pages = 0; struct zone *zone; unsigned long flags; @@ -5751,11 +5765,14 @@ static void __setup_per_zone_wmarks(void) } for_each_zone(zone) { - u64 tmp; + u64 min, low; spin_lock_irqsave(&zone->lock, flags); - tmp = (u64)pages_min * zone->managed_pages; - do_div(tmp, lowmem_pages); + min = (u64)pages_min * zone->managed_pages; + do_div(min, lowmem_pages); + low = (u64)pages_low * zone->managed_pages; + do_div(low, vm_total_pages); + if (is_highmem(zone)) { /* * __GFP_HIGH and PF_MEMALLOC allocations usually don't @@ -5776,11 +5793,13 @@ static void __setup_per_zone_wmarks(void) * If it's a lowmem zone, reserve a number of pages * proportionate to the zone's size. */ - zone->watermark[WMARK_MIN] = tmp; + zone->watermark[WMARK_MIN] = min; } - zone->watermark[WMARK_LOW] = min_wmark_pages(zone) + (tmp >> 2); - zone->watermark[WMARK_HIGH] = min_wmark_pages(zone) + (tmp >> 1); + zone->watermark[WMARK_LOW] = min_wmark_pages(zone) + + low + (min >> 2); + zone->watermark[WMARK_HIGH] = min_wmark_pages(zone) + + low + (min >> 1); __mod_zone_page_state(zone, NR_ALLOC_BATCH, high_wmark_pages(zone) - low_wmark_pages(zone) - @@ -5904,7 +5923,7 @@ module_init(init_per_zone_wmark_min) /* * min_free_kbytes_sysctl_handler - just a wrapper around proc_dointvec() so * that we can call two helper functions whenever min_free_kbytes - * changes. + * or extra_free_kbytes changes. */ int min_free_kbytes_sysctl_handler(struct ctl_table *table, int write, void __user *buffer, size_t *length, loff_t *ppos) |