On 13.08.2014 12:52, Jérôme Glisse wrote:
From: Jérôme Glisse jglisse@redhat.com
Due to bug in code it appear that some of the pool where never properly use and always empty. Before fixing that bug this patch set sensible limit on pool size. The magic 64MB number was nominated.
This is obviously a some what arbitrary number but the intend of ttm pool is to minimize page alloc cost especialy when allocating page that will be mark to be excluded from cpu cache mecanisms. We assume that mostly small buffer that are constantly allocated/deallocated might suffer from core memory allocation overhead as well as cache status change. This are the assumptions behind the 64MB value.
This obviously need some serious testing including monitoring pool size.
Signed-off-by: Jérôme Glisse jglisse@redhat.com
[...]
@@ -393,8 +404,9 @@ int ttm_mem_global_init(struct ttm_mem_global *glob) pr_info("Zone %7s: Available graphics memory: %llu kiB\n", zone->name, (unsigned long long)zone->max_mem >> 10); }
- ttm_page_alloc_init(glob, glob->zone_kernel->max_mem/(2*PAGE_SIZE));
- ttm_dma_page_alloc_init(glob, glob->zone_kernel->max_mem/(2*PAGE_SIZE));
- max_pool_size = min(glob->zone_kernel->max_mem >> 3UL, MAX_POOL_SIZE);
This introduces a 'comparison of distinct pointer types lacks a cast' warning for me.