On 08/16/2017 02:53 PM, Kirill Tkhai wrote:
> This patch completes splitting of ni->lock into ni->lock and pni->lock.
> Now, global ni->lock is used for inserting in tcache_nodeinfo::reclaim_tree,
> which happen just on every 1024 inserting or erasing of pages.
> For other LRU operations is used pni->lock, which is per-filesystem
> (i.e., per-container), and does not affect other containers.
>
> Also, lock order is changed:
>
> spin_lock(&pni->lock);
> spin_lock(&ni->lock);
>
> Signed-off-by: Kirill Tkhai <ktk...@virtuozzo.com>
> ---
> mm/tcache.c | 27 ++++++++++++++-------------
> 1 file changed, 14 insertions(+), 13 deletions(-)
>
> static int tcache_create_pool(void)
> @@ -1064,7 +1064,6 @@ tcache_lru_isolate(int nid, struct page **pages, int
> nr_to_isolate)
> }
> rcu_read_unlock();
>
> - spin_lock_irq(&ni->lock);
> spin_lock(&pni->lock);
spin_lock_irq(&pni->lock)
> nr_isolated = __tcache_lru_isolate(pni, pages, nr_to_isolate);
>
> @@ -1073,17 +1072,19 @@ tcache_lru_isolate(int nid, struct page **pages, int
> nr_to_isolate)
>
> atomic_long_sub(nr_isolated, &ni->nr_pages);
>
> - if (!RB_EMPTY_NODE(rbn)) {
> - rb_erase(rbn, &ni->reclaim_tree);
> - RB_CLEAR_NODE(rbn);
> + if (!RB_EMPTY_NODE(rbn) || !list_empty(&pni->lru)) {
> + spin_lock(&ni->lock);
> + if (!RB_EMPTY_NODE(rbn))
> + rb_erase(rbn, &ni->reclaim_tree);
> + if (!list_empty(&pni->lru))
> + __tcache_insert_reclaim_node(ni, pni);
> + else
> + RB_CLEAR_NODE(rbn);
Didn't get this part. Shouldn't we have something like this?
if (!RB_EMPTY_NODE(rbn)) {
rb_erase(rbn, &ni->reclaim_tree);
RB_CLEAR_NODE(rbn);
}
if (!list_empty(&pni->lru))
__tcache_insert_reclaim_node(ni, pni);
> + update_ni_rb_first(ni);
> + spin_unlock(&ni->lock);
> }
> - if (!list_empty(&pni->lru))
> - __tcache_insert_reclaim_node(ni, pni);
> - update_ni_rb_first(ni);
> -
> unlock:
> spin_unlock(&pni->lock);
spin_unlock_irq(&pni->lock)
> - spin_unlock_irq(&ni->lock);
> tcache_put_pool(pni->pool);
> out:
> return nr_isolated;
>
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