@@ -82,6 +82,65 @@ static inline struct page *page_pool_dev_alloc_frag(struct page_pool *pool,
return page_pool_alloc_frag(pool, offset, size, gfp);
}
+static inline struct page *page_pool_alloc(struct page_pool *pool,
+ unsigned int *offset,
+ unsigned int *size, gfp_t gfp)
+{
+ unsigned int max_size = PAGE_SIZE << pool->p.order;
+ struct page *page;
+
+ if ((*size << 1) > max_size) {
+ *size = max_size;
+ *offset = 0;
+ return page_pool_alloc_pages(pool, gfp);
+ }
+
+ page = page_pool_alloc_frag(pool, offset, *size, gfp);
+ if (unlikely(!page))
+ return NULL;
+
+ /* There is very likely not enough space for another fragment, so append
+ * the remaining size to the current fragment to avoid truesize
+ * underestimate problem.
+ */
+ if (pool->frag_offset + *size > max_size) {
+ *size = max_size - *offset;
+ pool->frag_offset = max_size;
+ }
+
+ return page;
+}
+
+static inline struct page *page_pool_dev_alloc(struct page_pool *pool,
+ unsigned int *offset,
+ unsigned int *size)
+{
+ gfp_t gfp = (GFP_ATOMIC | __GFP_NOWARN);
+
+ return page_pool_alloc(pool, offset, size, gfp);
+}
+
+static inline void *page_pool_cache_alloc(struct page_pool *pool,
+ unsigned int *size, gfp_t gfp)
+{
+ unsigned int offset;
+ struct page *page;
+
+ page = page_pool_alloc(pool, &offset, size, gfp);
+ if (unlikely(!page))
+ return NULL;
+
+ return page_address(page) + offset;
+}
+
+static inline void *page_pool_dev_cache_alloc(struct page_pool *pool,
+ unsigned int *size)
+{
+ gfp_t gfp = (GFP_ATOMIC | __GFP_NOWARN);
+
+ return page_pool_cache_alloc(pool, size, gfp);
+}
+
/**
* page_pool_get_dma_dir() - Retrieve the stored DMA direction.
* @pool: pool from which page was allocated
@@ -221,6 +280,12 @@ static inline void page_pool_recycle_direct(struct page_pool *pool,
#define PAGE_POOL_32BIT_ARCH_WITH_64BIT_DMA \
(sizeof(dma_addr_t) > sizeof(unsigned long))
+static inline void page_pool_cache_free(struct page_pool *pool, void *data,
+ bool allow_direct)
+{
+ page_pool_put_page(pool, virt_to_head_page(data), -1, allow_direct);
+}
+
/**
* page_pool_get_dma_addr() - Retrieve the stored DMA address.
* @page: page allocated from a page pool
@@ -809,7 +809,7 @@ static void page_pool_empty_ring(struct page_pool *pool)
}
}
-static void page_pool_free(struct page_pool *pool)
+static void __page_pool_destroy(struct page_pool *pool)
{
if (pool->disconnect)
pool->disconnect(pool);
@@ -860,7 +860,7 @@ static int page_pool_release(struct page_pool *pool)
page_pool_scrub(pool);
inflight = page_pool_inflight(pool);
if (!inflight)
- page_pool_free(pool);
+ __page_pool_destroy(pool);
return inflight;
}
Currently page pool supports the below use cases: use case 1: allocate page without page splitting using page_pool_alloc_pages() API if the driver knows that the memory it need is always bigger than half of the page allocated from page pool. use case 2: allocate page frag with page splitting using page_pool_alloc_frag() API if the driver knows that the memory it need is always smaller than or equal to the half of the page allocated from page pool. There is emerging use case [1] & [2] that is a mix of the above two case: the driver doesn't know the size of memory it need beforehand, so the driver may use something like below to allocate memory with least memory utilization and performance penalty: if (size << 1 > max_size) page = page_pool_alloc_pages(); else page = page_pool_alloc_frag(); To avoid the driver doing something like above, add the page_pool[_cache]_alloc() API to support the above use case, and update the true size of memory that is acctually allocated by updating '*size' back to the driver in order to avoid exacerbating truesize underestimate problem. Rename page_pool_free() which is used in the destroy process to __page_pool_destroy() to avoid confusion with the newly added API. 1. https://lore.kernel.org/all/d3ae6bd3537fbce379382ac6a42f67e22f27ece2.1683896626.git.lorenzo@kernel.org/ 2. https://lore.kernel.org/all/20230526054621.18371-3-liangchen.linux@gmail.com/ Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com> CC: Lorenzo Bianconi <lorenzo@kernel.org> CC: Alexander Duyck <alexander.duyck@gmail.com> CC: Liang Chen <liangchen.linux@gmail.com> CC: Alexander Lobakin <aleksander.lobakin@intel.com> --- include/net/page_pool/helpers.h | 65 +++++++++++++++++++++++++++++++++ net/core/page_pool.c | 4 +- 2 files changed, 67 insertions(+), 2 deletions(-)