On 07/22/2010 07:56 AM, Dan Carpenter wrote:
> 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
>
This is because it use __list_del to remove a whole part of the list.
/*
* Delete a list entry by making the prev/next entries
* point to each other.
*
* This is only for internal list manipulation where we know
* the prev/next entries already!
*/
static inline void __list_del(struct list_head * prev, struct list_head * next)
{
????????next->prev = prev;
????????prev->next = next;
}
Cheers,
Jerome
