[bpf-next V1 PATCH 12/15] xdp: allow page_pool as an allocator type in xdp_return_frame
From: Jesper Dangaard Brouer <hidden>
Date: 2018-03-06 21:48:49
Subsystem:
networking [general], the rest, xdp (express data path) · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Alexei Starovoitov, Daniel Borkmann, David S. Miller, Jesper Dangaard Brouer, John Fastabend
New allocator type MEM_TYPE_PAGE_POOL for page_pool usage. The registered allocator page_pool pointer is not available directly from xdp_rxq_info, but it could be (if needed). For now, the driver should keep separate track of the page_pool pointer, which it should use for RX-ring page allocation. As suggested by Saeed, to maintain a symmetric API it is the drivers responsibility to allocate/create and free/destroy the page_pool. Thus, after the driver have called xdp_rxq_info_unreg(), it is drivers responsibility to free the page_pool, but with a RCU free call. This is done easily via the page_pool helper page_pool_destroy_rcu() (which avoids touching any driver code during the RCU callback, which could happen after the driver have been unloaded). Signed-off-by: Jesper Dangaard Brouer <redacted> --- include/net/xdp.h | 4 +++- net/core/xdp.c | 23 ++++++++++++++++++++--- 2 files changed, 23 insertions(+), 4 deletions(-)
diff --git a/include/net/xdp.h b/include/net/xdp.h
index e82cf91f384a..26eb645c699a 100644
--- a/include/net/xdp.h
+++ b/include/net/xdp.h@@ -36,8 +36,8 @@ enum mem_type { MEM_TYPE_PAGE_SHARED = 0, /* Split-page refcnt based model */ MEM_TYPE_PAGE_ORDER0, /* Orig XDP full page model */ + MEM_TYPE_PAGE_POOL, // Possible new ideas for types: - // MEM_TYPE_PAGE_POOL, /* Will be added later */ // MEM_TYPE_AF_XDP, // MEM_TYPE_DEVICE_OWNED -- invoking an dev->ndo? MEM_TYPE_MAX,
@@ -48,6 +48,8 @@ struct xdp_mem_info { u32 id; }; +struct page_pool; + struct xdp_rxq_info { struct net_device *dev; u32 queue_index;
diff --git a/net/core/xdp.c b/net/core/xdp.c
index 06a5b39491ad..fe8e87abc266 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c@@ -8,6 +8,7 @@ #include <linux/slab.h> #include <linux/idr.h> #include <linux/rhashtable.h> +#include <net/page_pool.h> #include <net/xdp.h>
@@ -27,7 +28,10 @@ static struct rhashtable *mem_id_ht; struct xdp_mem_allocator { struct xdp_mem_info mem; - void *allocator; + union { + void *allocator; + struct page_pool *page_pool; + }; struct rhash_head node; struct rcu_head rcu; };
@@ -74,7 +78,9 @@ void __xdp_mem_allocator_rcu_free(struct rcu_head *rcu) /* Allow this ID to be reused */ ida_simple_remove(&mem_id_pool, xa->mem.id); - /* TODO: Depending on allocator type/pointer free resources */ + /* Notice, driver is expected to free the *allocator, + * e.g. page_pool, and MUST also use RCU free. + */ /* Poison memory */ xa->mem.id = 0xFFFF;
@@ -290,11 +296,21 @@ EXPORT_SYMBOL_GPL(xdp_rxq_info_reg_mem_model); void xdp_return_frame(void *data, struct xdp_mem_info *mem) { - struct xdp_mem_allocator *xa; + struct xdp_mem_allocator *xa = NULL; rcu_read_lock(); if (mem->id) xa = rhashtable_lookup(mem_id_ht, &mem->id, mem_id_rht_params); + + if (mem->type == MEM_TYPE_PAGE_POOL) { + struct page *page = virt_to_head_page(data); + + if (xa) + page_pool_put_page(xa->page_pool, page); + else + put_page(page); + return; + } rcu_read_unlock(); if (mem->type == MEM_TYPE_PAGE_SHARED) {
@@ -306,6 +322,7 @@ void xdp_return_frame(void *data, struct xdp_mem_info *mem) struct page *page = virt_to_page(data); /* Assumes order0 page*/ put_page(page); + return; } } EXPORT_SYMBOL_GPL(xdp_return_frame);