From: Jérôme Glisse jglisse@redhat.com
Calls to set_memory_wb() incure heavy TLB flush and IPI cost. To minimize those wait until pool grow beyond batch size before draining the pool.
Signed-off-by: Jérôme Glisse jglisse@redhat.com Reviewed-by: Mario Kleiner mario.kleiner.de@gmail.com Cc: Michel Dänzer michel@daenzer.net Cc: Thomas Hellstrom thellstrom@vmware.com Cc: Konrad Rzeszutek Wilk konrad.wilk@oracle.com --- drivers/gpu/drm/ttm/ttm_page_alloc_dma.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c index 0194a93..8028dd6 100644 --- a/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c +++ b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c @@ -953,7 +953,12 @@ void ttm_dma_unpopulate(struct ttm_dma_tt *ttm_dma, struct device *dev) } else { pool->npages_free += count; list_splice(&ttm_dma->pages_list, &pool->free_list); - if (pool->npages_free > _manager->options.max_size) + /* + * Wait to have at at least NUM_PAGES_TO_ALLOC number of pages + * to free in order to minimize calls to set_memory_wb(). + */ + if (pool->npages_free >= (_manager->options.max_size + + NUM_PAGES_TO_ALLOC)) npages = pool->npages_free - _manager->options.max_size; } spin_unlock_irqrestore(&pool->lock, irq_flags);