Re: [PATCH RFC net-next 2/3] net: page_pool: use alloc_pages_bulk in refill code path
flat view
From: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Date: 2021-02-24 20:18:16
Also in:
linux-mm, linux-nfs, lkml
Hi Jesper, On Wed, Feb 24, 2021 at 07:56:46PM +0100, Jesper Dangaard Brouer wrote:
There are cases where the page_pool need to refill with pages from the page allocator. Some workloads cause the page_pool to release pages instead of recycling these pages. For these workload it can improve performance to bulk alloc pages from the page-allocator to refill the alloc cache. For XDP-redirect workload with 100G mlx5 driver (that use page_pool) redirecting xdp_frame packets into a veth, that does XDP_PASS to create an SKB from the xdp_frame, which then cannot return the page to the page_pool. In this case, we saw[1] an improvement of 18.8% from using the alloc_pages_bulk API (3,677,958 pps -> 4,368,926 pps). [1] https://github.com/xdp-project/xdp-project/blob/master/areas/mem/page_pool06_alloc_pages_bulk.org Signed-off-by: Jesper Dangaard Brouer <redacted>
[...]
quoted hunk ↗ jump to hunk
+ /* Remaining pages store in alloc.cache */ + list_for_each_entry_safe(page, next, &page_list, lru) { + list_del(&page->lru); + if (pp_flags & PP_FLAG_DMA_MAP) { + page = page_pool_dma_map(pool, page); + if (!page)
As I commented on the previous patch, i'd prefer the put_page() here to be explicitly called, instead of hiding in the page_pool_dma_map()
quoted hunk ↗ jump to hunk
+ continue; + } + if (likely(pool->alloc.count < PP_ALLOC_CACHE_SIZE)) { + pool->alloc.cache[pool->alloc.count++] = page; + pool->pages_state_hold_cnt++; + trace_page_pool_state_hold(pool, page, + pool->pages_state_hold_cnt); + } else { + put_page(page); + } + } +out: if (pool->p.flags & PP_FLAG_DMA_MAP) { - page = page_pool_dma_map(pool, page); - if (!page) + first_page = page_pool_dma_map(pool, first_page); + if (!first_page) return NULL; }
[...] Cheers /Ilias