linux/io_uring/alloc_cache.h, branch v6.3

io_uring: fix poll/netmsg alloc caches

2023-03-30T12:53:42Z

We increase cache->nr_cached when we free into the cache but don't decrease when we take from it, so in some time we'll get an empty cache with cache->nr_cached larger than IO_ALLOC_CACHE_MAX, that fails io_alloc_cache_put() and effectively disables caching. Fixes: 9b797a37c4bd8 ("io_uring: add abstraction around apoll cache") Cc: stable@vger.kernel.org Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe

io_uring: impose max limit on apoll cache

2022-07-25T00:39:17Z

Caches like this tend to grow to the peak size, and then never get any smaller. Impose a max limit on the size, to prevent it from growing too big. A somewhat randomly chosen 512 is the max size we'll allow the cache to get. If a batch of frees come in and would bring it over that, we simply start kfree'ing the surplus. Signed-off-by: Jens Axboe

io_uring: add abstraction around apoll cache

2022-07-25T00:39:17Z

In preparation for adding limits, and one more user, abstract out the core bits of the allocation+free cache. Signed-off-by: Jens Axboe