Overload the LSB of struct page* to indicate that it's a page_pool_iov.
Refactor mm calls on struct page* into helpers, and add page_pool_iov handling on those helpers. Modify callers of these mm APIs with calls to these helpers instead.
In areas where struct page* is dereferenced, add a check for special handling of page_pool_iov.
Signed-off-by: Mina Almasry almasrymina@google.com
---
v1: - Disable fragmentation support for iov properly. - fix napi_pp_put_page() path (Yunsheng).
--- include/net/page_pool/helpers.h | 78 ++++++++++++++++++++++++++++++++- net/core/page_pool.c | 67 ++++++++++++++++++++-------- net/core/skbuff.c | 28 +++++++----- 3 files changed, 141 insertions(+), 32 deletions(-)
diff --git a/include/net/page_pool/helpers.h b/include/net/page_pool/helpers.h index 00197f14aa87..2d4e0a2c5620 100644 --- a/include/net/page_pool/helpers.h +++ b/include/net/page_pool/helpers.h @@ -154,6 +154,64 @@ static inline struct page_pool_iov *page_to_page_pool_iov(struct page *page) return NULL; }
+static inline int page_pool_page_ref_count(struct page *page) +{ + if (page_is_page_pool_iov(page)) + return page_pool_iov_refcount(page_to_page_pool_iov(page)); + + return page_ref_count(page); +} + +static inline void page_pool_page_get_many(struct page *page, + unsigned int count) +{ + if (page_is_page_pool_iov(page)) + return page_pool_iov_get_many(page_to_page_pool_iov(page), + count); + + return page_ref_add(page, count); +} + +static inline void page_pool_page_put_many(struct page *page, + unsigned int count) +{ + if (page_is_page_pool_iov(page)) + return page_pool_iov_put_many(page_to_page_pool_iov(page), + count); + + if (count > 1) + page_ref_sub(page, count - 1); + + put_page(page); +} + +static inline bool page_pool_page_is_pfmemalloc(struct page *page) +{ + if (page_is_page_pool_iov(page)) + return false; + + return page_is_pfmemalloc(page); +} + +static inline bool page_pool_page_is_pref_nid(struct page *page, int pref_nid) +{ + /* Assume page_pool_iov are on the preferred node without actually + * checking... + * + * This check is only used to check for recycling memory in the page + * pool's fast paths. Currently the only implementation of page_pool_iov + * is dmabuf device memory. It's a deliberate decision by the user to + * bind a certain dmabuf to a certain netdev, and the netdev rx queue + * would not be able to reallocate memory from another dmabuf that + * exists on the preferred node, so, this check doesn't make much sense + * in this case. Assume all page_pool_iovs can be recycled for now. + */ + if (page_is_page_pool_iov(page)) + return true; + + return page_to_nid(page) == pref_nid; +} + /** * page_pool_dev_alloc_pages() - allocate a page. * @pool: pool from which to allocate @@ -304,6 +362,10 @@ static inline long page_pool_defrag_page(struct page *page, long nr) { long ret;
+ /* fragmentation support hasn't been added to ppiov yet */ + if (WARN_ON_ONCE(page_is_page_pool_iov(page))) + return 0; + /* If nr == pp_frag_count then we have cleared all remaining * references to the page: * 1. 'n == 1': no need to actually overwrite it. @@ -347,7 +409,8 @@ static inline long page_pool_defrag_page(struct page *page, long nr) static inline bool page_pool_is_last_frag(struct page *page) { /* If page_pool_defrag_page() returns 0, we were the last user */ - return page_pool_defrag_page(page, 1) == 0; + return page_is_page_pool_iov(page) || + page_pool_defrag_page(page, 1) == 0; }
/** @@ -434,7 +497,12 @@ static inline void page_pool_free_va(struct page_pool *pool, void *va, */ static inline dma_addr_t page_pool_get_dma_addr(struct page *page) { - dma_addr_t ret = page->dma_addr; + dma_addr_t ret; + + if (page_is_page_pool_iov(page)) + return page_pool_iov_dma_addr(page_to_page_pool_iov(page)); + + ret = page->dma_addr;
if (PAGE_POOL_32BIT_ARCH_WITH_64BIT_DMA) ret <<= PAGE_SHIFT; @@ -444,6 +512,12 @@ static inline dma_addr_t page_pool_get_dma_addr(struct page *page)
static inline bool page_pool_set_dma_addr(struct page *page, dma_addr_t addr) { + /* page_pool_iovs are mapped and their dma-addr can't be modified. */ + if (page_is_page_pool_iov(page)) { + DEBUG_NET_WARN_ON_ONCE(true); + return false; + } + if (PAGE_POOL_32BIT_ARCH_WITH_64BIT_DMA) { page->dma_addr = addr >> PAGE_SHIFT;
diff --git a/net/core/page_pool.c b/net/core/page_pool.c index 423c88564a00..f0148d66371b 100644 --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -346,7 +346,7 @@ static struct page *page_pool_refill_alloc_cache(struct page_pool *pool) if (unlikely(!page)) break;
- if (likely(page_to_nid(page) == pref_nid)) { + if (likely(page_pool_page_is_pref_nid(page, pref_nid))) { pool->alloc.cache[pool->alloc.count++] = page; } else { /* NUMA mismatch; @@ -391,7 +391,15 @@ static void page_pool_dma_sync_for_device(struct page_pool *pool, struct page *page, unsigned int dma_sync_size) { - dma_addr_t dma_addr = page_pool_get_dma_addr(page); + dma_addr_t dma_addr; + + /* page_pool_iov memory provider do not support PP_FLAG_DMA_SYNC_DEV */ + if (page_is_page_pool_iov(page)) { + DEBUG_NET_WARN_ON_ONCE(true); + return; + } + + dma_addr = page_pool_get_dma_addr(page);
dma_sync_size = min(dma_sync_size, pool->p.max_len); dma_sync_single_range_for_device(pool->p.dev, dma_addr, @@ -403,6 +411,12 @@ static bool page_pool_dma_map(struct page_pool *pool, struct page *page) { dma_addr_t dma;
+ if (page_is_page_pool_iov(page)) { + /* page_pool_iovs are already mapped */ + DEBUG_NET_WARN_ON_ONCE(true); + return true; + } + /* Setup DMA mapping: use 'struct page' area for storing DMA-addr * since dma_addr_t can be either 32 or 64 bits and does not always fit * into page private data (i.e 32bit cpu with 64bit DMA caps) @@ -434,22 +448,33 @@ static bool page_pool_dma_map(struct page_pool *pool, struct page *page) static void page_pool_set_pp_info(struct page_pool *pool, struct page *page) { - page->pp = pool; - page->pp_magic |= PP_SIGNATURE; - - /* Ensuring all pages have been split into one fragment initially: - * page_pool_set_pp_info() is only called once for every page when it - * is allocated from the page allocator and page_pool_fragment_page() - * is dirtying the same cache line as the page->pp_magic above, so - * the overhead is negligible. - */ - page_pool_fragment_page(page, 1); + if (!page_is_page_pool_iov(page)) { + page->pp = pool; + page->pp_magic |= PP_SIGNATURE; + + /* Ensuring all pages have been split into one fragment + * initially: + * page_pool_set_pp_info() is only called once for every page + * when it is allocated from the page allocator and + * page_pool_fragment_page() is dirtying the same cache line as + * the page->pp_magic above, so * the overhead is negligible. + */ + page_pool_fragment_page(page, 1); + } else { + page_to_page_pool_iov(page)->pp = pool; + } + if (pool->has_init_callback) pool->slow.init_callback(page, pool->slow.init_arg); }
static void page_pool_clear_pp_info(struct page *page) { + if (page_is_page_pool_iov(page)) { + page_to_page_pool_iov(page)->pp = NULL; + return; + } + page->pp_magic = 0; page->pp = NULL; } @@ -664,7 +689,7 @@ static bool page_pool_recycle_in_cache(struct page *page, return false; }
- /* Caller MUST have verified/know (page_ref_count(page) == 1) */ + /* Caller MUST have verified/know (page_pool_page_ref_count(page) == 1) */ pool->alloc.cache[pool->alloc.count++] = page; recycle_stat_inc(pool, cached); return true; @@ -689,9 +714,10 @@ __page_pool_put_page(struct page_pool *pool, struct page *page, * refcnt == 1 means page_pool owns page, and can recycle it. * * page is NOT reusable when allocated when system is under - * some pressure. (page_is_pfmemalloc) + * some pressure. (page_pool_page_is_pfmemalloc) */ - if (likely(page_ref_count(page) == 1 && !page_is_pfmemalloc(page))) { + if (likely(page_pool_page_ref_count(page) == 1 && + !page_pool_page_is_pfmemalloc(page))) { /* Read barrier done in page_ref_count / READ_ONCE */
if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV) @@ -806,7 +832,8 @@ static struct page *page_pool_drain_frag(struct page_pool *pool, if (likely(page_pool_defrag_page(page, drain_count))) return NULL;
- if (page_ref_count(page) == 1 && !page_is_pfmemalloc(page)) { + if (page_pool_page_ref_count(page) == 1 && + !page_pool_page_is_pfmemalloc(page)) { if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV) page_pool_dma_sync_for_device(pool, page, -1);
@@ -840,6 +867,10 @@ struct page *page_pool_alloc_frag(struct page_pool *pool, if (WARN_ON(size > max_size)) return NULL;
+ /* page_pool_iov's don't currently support fragmentation */ + if (WARN_ON_ONCE(pool->mp_ops == &dmabuf_devmem_ops)) + return NULL; + size = ALIGN(size, dma_get_cache_alignment()); *offset = pool->frag_offset;
@@ -882,9 +913,9 @@ static void page_pool_empty_ring(struct page_pool *pool) /* Empty recycle ring */ while ((page = ptr_ring_consume_bh(&pool->ring))) { /* Verify the refcnt invariant of cached pages */ - if (!(page_ref_count(page) == 1)) + if (!(page_pool_page_ref_count(page) == 1)) pr_crit("%s() page_pool refcnt %d violation\n", - __func__, page_ref_count(page)); + __func__, page_pool_page_ref_count(page));
page_pool_return_page(pool, page); } diff --git a/net/core/skbuff.c b/net/core/skbuff.c index b157efea5dea..07f802f1adf1 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -896,19 +896,23 @@ bool napi_pp_put_page(struct page *page, bool napi_safe) bool allow_direct = false; struct page_pool *pp;
- page = compound_head(page); - - /* page->pp_magic is OR'ed with PP_SIGNATURE after the allocation - * in order to preserve any existing bits, such as bit 0 for the - * head page of compound page and bit 1 for pfmemalloc page, so - * mask those bits for freeing side when doing below checking, - * and page_is_pfmemalloc() is checked in __page_pool_put_page() - * to avoid recycling the pfmemalloc page. - */ - if (unlikely((page->pp_magic & ~0x3UL) != PP_SIGNATURE)) - return false; + if (!page_is_page_pool_iov(page)) { + page = compound_head(page); + + /* page->pp_magic is OR'ed with PP_SIGNATURE after the allocation + * in order to preserve any existing bits, such as bit 0 for the + * head page of compound page and bit 1 for pfmemalloc page, so + * mask those bits for freeing side when doing below checking, + * and page_is_pfmemalloc() is checked in __page_pool_put_page() + * to avoid recycling the pfmemalloc page. + */ + if (unlikely((page->pp_magic & ~0x3UL) != PP_SIGNATURE)) + return false;
- pp = page->pp; + pp = page->pp; + } else { + pp = page_to_page_pool_iov(page)->pp; + }
/* Allow direct recycle if we have reasons to believe that we are * in the same context as the consumer would run, so there's