Re: questions about ttm_page_alloc.c

On Mon, Jul 12, 2010 at 07:12:37PM -0400, Jerome Glisse wrote:

On 07/12/2010 06:39 PM, Dan Carpenter wrote:

...

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.

Thanks for answering about the wb vs uncached, but I'm still confused why we use &p->lru in most places and p->lru.prev in this place.

regards, dan carpenter