diff options
| -rw-r--r-- | mm/page_alloc.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index c73dbbc1cd8f..08e8627361a0 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1671,6 +1671,18 @@ static void __init free_area_init_core(struct pglist_data *pgdat, if (batch < 1) batch = 1; + /* + * Clamp the batch to a 2^n - 1 value. Having a power + * of 2 value was found to be more likely to have + * suboptimal cache aliasing properties in some cases. + * + * For example if 2 tasks are alternately allocating + * batches of pages, one task can end up with a lot + * of pages of one half of the possible page colors + * and the other with pages of the other colors. + */ + batch = (1 << fls(batch + batch/2)) - 1; + for (cpu = 0; cpu < NR_CPUS; cpu++) { struct per_cpu_pages *pcp; |