From: Jérôme Glisse <jgli...@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 at redhat.com>
Reviewed-by: Mario Kleiner <mario.kleiner.de at gmail.com>
Reviewed-and-Tested-by: Michel Dänzer <michel at daenzer.net>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk at oracle.com>
Cc: Thomas Hellstrom <thellstrom at vmware.com>
---
drivers/gpu/drm/ttm/ttm_page_alloc_dma.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
index af23080..624d941 100644
--- a/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
+++ b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
@@ -963,13 +963,13 @@ 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;
- /* free at least NUM_PAGES_TO_ALLOC number of pages
- * to reduce calls to set_memory_wb */
- if (npages < NUM_PAGES_TO_ALLOC)
- npages = NUM_PAGES_TO_ALLOC;
- }
}
spin_unlock_irqrestore(&pool->lock, irq_flags);
--
1.8.3.1
