I'm investigating: https://bugzilla.kernel.org/show_bug.cgi?id=16337
He is using the new radeon with the new ttm pool wc/uc page allocator. I'm sort of over my head when it comes to mm stuff so forgive me if these are dumb questions... I'm looking at drivers/gpu/drm/ttm/ttm_page_alloc.c.
230 static int set_pages_array_wc(struct page **pages, int addrinarray) 231 { 232 #ifdef TTM_HAS_AGP 233 int i; 234 235 for (i = 0; i < addrinarray; i++) 236 map_page_into_agp(pages[i]); ^^^^^^^^^^^^^^^^^^^^^^^^^^^
This actually sets the pages to uncached and not to write cached. Is that deliberate?
237 #endif 238 return 0; 239 }
[snip]
327 pages_to_free[freed_pages++] = p; 328 /* We can only remove NUM_PAGES_TO_ALLOC at a time. */ 329 if (freed_pages >= NUM_PAGES_TO_ALLOC) { 330 /* remove range of pages from the pool */ 331 __list_del(p->lru.prev, &pool->list);
Why do we use p->lru.prev here when we use &p->lru in other places?
332 333 ttm_pool_update_free_locked(pool, freed_pages); 334 /** 335 * Because changing page caching is costly 336 * we unlock the pool to prevent stalling.
regards, dan carpenter