[PATCH v2 08/28] list: add a new LRU list type
Glauber Costa
glommer at parallels.com
Fri Apr 5 08:01:01 UTC 2013
On 04/05/2013 05:20 AM, Dave Chinner wrote:
> On Thu, Apr 04, 2013 at 02:53:49PM -0700, Greg Thelen wrote:
>> On Fri, Mar 29 2013, Glauber Costa wrote:
>>> From: Dave Chinner <dchinner at redhat.com>
>>> +long
>>> +list_lru_walk(
>>> + struct list_lru *lru,
>>> + list_lru_walk_cb isolate,
>>> + void *cb_arg,
>>> + long nr_to_walk)
>>> +{
>>> + struct list_head *item, *n;
>>> + long removed = 0;
>>> +restart:
>>> + spin_lock(&lru->lock);
>>> + list_for_each_safe(item, n, &lru->list) {
>>> + int ret;
>>> +
>>> + if (nr_to_walk-- < 0)
>>> + break;
>>> +
>>> + ret = isolate(item, &lru->lock, cb_arg);
>>> + switch (ret) {
>>> + case 0: /* item removed from list */
>>> + lru->nr_items--;
>>> + removed++;
>>> + break;
>>> + case 1: /* item referenced, give another pass */
>>> + list_move_tail(item, &lru->list);
>>> + break;
>>> + case 2: /* item cannot be locked, skip */
>>> + break;
>>> + case 3: /* item not freeable, lock dropped */
>>> + goto restart;
>>
>> These four magic return values might benefit from an enum (or #define)
>> for clarity.
>
> Obviously, and it was stated that this needed to be done by miself
> when I last posted the patch set many months ago. I've been rather
> busy since then, and so haven't had time to do anything with it.
>
>> Maybe the names would be LRU_OK, LRU_REMOVED, LRU_ROTATE, LRU_RETRY.
>
> Something like that...
>
I can handle that and fold it with credits as usual if you don't mind.
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