On Wed, 4 Dec 2024 09:21:46 -0800 David Wei wrote:
> +/*
> + * page_pool_mp_return_in_cache() - return a netmem to the allocation cache.
> + * @pool: pool from which pages were allocated
> + * @netmem: netmem to return
> + *
> + * Return already allocated and accounted netmem to the page pool's allocation
> + * cache. The function doesn't provide synchronisation and must only be called
> + * from the napi context.
NAPI is irrelevant, this helper, IIUC, has to be called down the call
chain from mp_ops->alloc().
> + */
> +void page_pool_mp_return_in_cache(struct page_pool *pool, netmem_ref netmem)
> +{
> + if (WARN_ON_ONCE(pool->alloc.count >= PP_ALLOC_CACHE_REFILL))
> + return;
I'd
return false;
without a warning.
> + page_pool_dma_sync_for_device(pool, netmem, -1);
> + page_pool_fragment_netmem(netmem, 1);
> + pool->alloc.cache[pool->alloc.count++] = netmem;
and here:
return true;
this say mps can use return value as a stop condition in a do {} while()
loop, without having to duplicate the check.
do {
netmem = alloc...
... logic;
} while (page_pool_mp_alloc_refill(pp, netmem));
/* last netmem didn't fit in the cache */
return netmem;
