Re: [PATCH v7 3/6] zswap: make shrinking memcg-aware

On Mon, Nov 27, 2023 at 03:45:57PM -0800, Nhat Pham wrote:

static void shrink_worker(struct work_struct *w) { struct zswap_pool *pool = container_of(w, typeof(*pool), shrink_work);

• struct mem_cgroup *memcg; int ret, failures = 0;

• /* global reclaim will select cgroup in a round-robin fashion. */ do {

• ret = zswap_reclaim_entry(pool);
  

• if (ret) {
  

• 	zswap_reject_reclaim_fail++;
  

• 	if (ret != -EAGAIN)
  

• 		break;
  

• spin_lock(&zswap_pools_lock);
  

• memcg = pool->next_shrink =
  

• 	mem_cgroup_iter_online(NULL, pool->next_shrink, NULL, true);
  

• /* full round trip */
  

• if (!memcg) {
  

• 	spin_unlock(&zswap_pools_lock);
  if (++failures == MAX_RECLAIM_RETRIES)
  	break;
  

• 	goto resched;
  

  }

• /*
  

•  * Acquire an extra reference to the iterated memcg in case the
  

•  * original reference is dropped by the zswap offlining callback.
  

•  */
  

• css_get(&memcg->css);
  

struct mem_cgroup isn't defined when !CONFIG_MEMCG. This needs a mem_cgroup_get() wrapper and a dummy function for no-memcg builds.

With that fixed, though, everything else looks good to me:

Acked-by: Johannes Weiner hannes@cmpxchg.org