Re: questions about ttm_page_alloc.c

From: Dan Carpenter
Date: Thu Jul 22 2010 - 07:57:05 EST


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

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