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Message-Id: <08dd249c9522c001313f520796faa777c4089e1c.1605267335.git.lorenzo@kernel.org>
Date: Fri, 13 Nov 2020 12:48:29 +0100
From: Lorenzo Bianconi <lorenzo@...nel.org>
To: netdev@...r.kernel.org
Cc: bpf@...r.kernel.org, lorenzo.bianconi@...hat.com,
davem@...emloft.net, kuba@...nel.org, brouer@...hat.com,
ilias.apalodimas@...aro.org, john.fastabend@...il.com
Subject: [PATCH v6 net-nex 2/5] net: page_pool: add bulk support for ptr_ring
Introduce the capability to batch page_pool ptr_ring refill since it is
usually run inside the driver NAPI tx completion loop.
Suggested-by: Jesper Dangaard Brouer <brouer@...hat.com>
Co-developed-by: Jesper Dangaard Brouer <brouer@...hat.com>
Signed-off-by: Jesper Dangaard Brouer <brouer@...hat.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@...nel.org>
---
include/net/page_pool.h | 26 +++++++++++++++
net/core/page_pool.c | 70 +++++++++++++++++++++++++++++++++++------
net/core/xdp.c | 9 ++----
3 files changed, 88 insertions(+), 17 deletions(-)
diff --git a/include/net/page_pool.h b/include/net/page_pool.h
index 81d7773f96cd..b5b195305346 100644
--- a/include/net/page_pool.h
+++ b/include/net/page_pool.h
@@ -152,6 +152,8 @@ struct page_pool *page_pool_create(const struct page_pool_params *params);
void page_pool_destroy(struct page_pool *pool);
void page_pool_use_xdp_mem(struct page_pool *pool, void (*disconnect)(void *));
void page_pool_release_page(struct page_pool *pool, struct page *page);
+void page_pool_put_page_bulk(struct page_pool *pool, void **data,
+ int count);
#else
static inline void page_pool_destroy(struct page_pool *pool)
{
@@ -165,6 +167,11 @@ static inline void page_pool_release_page(struct page_pool *pool,
struct page *page)
{
}
+
+static inline void page_pool_put_page_bulk(struct page_pool *pool, void **data,
+ int count)
+{
+}
#endif
void page_pool_put_page(struct page_pool *pool, struct page *page,
@@ -215,4 +222,23 @@ static inline void page_pool_nid_changed(struct page_pool *pool, int new_nid)
if (unlikely(pool->p.nid != new_nid))
page_pool_update_nid(pool, new_nid);
}
+
+static inline void page_pool_ring_lock(struct page_pool *pool)
+ __acquires(&pool->ring.producer_lock)
+{
+ if (in_serving_softirq())
+ spin_lock(&pool->ring.producer_lock);
+ else
+ spin_lock_bh(&pool->ring.producer_lock);
+}
+
+static inline void page_pool_ring_unlock(struct page_pool *pool)
+ __releases(&pool->ring.producer_lock)
+{
+ if (in_serving_softirq())
+ spin_unlock(&pool->ring.producer_lock);
+ else
+ spin_unlock_bh(&pool->ring.producer_lock);
+}
+
#endif /* _NET_PAGE_POOL_H */
diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index ef98372facf6..f3c690b8c8e3 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
@@ -11,6 +11,8 @@
#include <linux/device.h>
#include <net/page_pool.h>
+#include <net/xdp.h>
+
#include <linux/dma-direction.h>
#include <linux/dma-mapping.h>
#include <linux/page-flags.h>
@@ -362,8 +364,9 @@ static bool pool_page_reusable(struct page_pool *pool, struct page *page)
* If the page refcnt != 1, then the page will be returned to memory
* subsystem.
*/
-void page_pool_put_page(struct page_pool *pool, struct page *page,
- unsigned int dma_sync_size, bool allow_direct)
+static __always_inline struct page *
+__page_pool_put_page(struct page_pool *pool, struct page *page,
+ unsigned int dma_sync_size, bool allow_direct)
{
/* This allocator is optimized for the XDP mode that uses
* one-frame-per-page, but have fallbacks that act like the
@@ -379,15 +382,12 @@ void page_pool_put_page(struct page_pool *pool, struct page *page,
page_pool_dma_sync_for_device(pool, page,
dma_sync_size);
- if (allow_direct && in_serving_softirq())
- if (page_pool_recycle_in_cache(page, pool))
- return;
+ if (allow_direct && in_serving_softirq() &&
+ page_pool_recycle_in_cache(page, pool))
+ return NULL;
- if (!page_pool_recycle_in_ring(pool, page)) {
- /* Cache full, fallback to free pages */
- page_pool_return_page(pool, page);
- }
- return;
+ /* Page found as candidate for recycling */
+ return page;
}
/* Fallback/non-XDP mode: API user have elevated refcnt.
*
@@ -405,9 +405,59 @@ void page_pool_put_page(struct page_pool *pool, struct page *page,
/* Do not replace this with page_pool_return_page() */
page_pool_release_page(pool, page);
put_page(page);
+
+ return NULL;
+}
+
+void page_pool_put_page(struct page_pool *pool, struct page *page,
+ unsigned int dma_sync_size, bool allow_direct)
+{
+ page = __page_pool_put_page(pool, page, dma_sync_size, allow_direct);
+ if (page && !page_pool_recycle_in_ring(pool, page)) {
+ /* Cache full, fallback to free pages */
+ page_pool_return_page(pool, page);
+ }
}
EXPORT_SYMBOL(page_pool_put_page);
+/* Caller must not use data area after call, as this function overwrites it */
+void page_pool_put_page_bulk(struct page_pool *pool, void **data,
+ int count)
+{
+ int i, bulk_len = 0;
+
+ for (i = 0; i < count; i++) {
+ struct page *page = virt_to_head_page(data[i]);
+
+ page = __page_pool_put_page(pool, page, -1, false);
+ /* Approved for bulk recycling in ptr_ring cache */
+ if (page)
+ data[bulk_len++] = page;
+ }
+
+ if (unlikely(!bulk_len))
+ return;
+
+ /* Bulk producer into ptr_ring page_pool cache */
+ page_pool_ring_lock(pool);
+ for (i = 0; i < bulk_len; i++) {
+ if (__ptr_ring_produce(&pool->ring, data[i]))
+ break; /* ring full */
+ }
+ page_pool_ring_unlock(pool);
+
+ /* Hopefully all pages was return into ptr_ring */
+ if (likely(i == bulk_len))
+ return;
+
+ /* ptr_ring cache full, free remaining pages outside producer lock
+ * since put_page() with refcnt == 1 can be an expensive operation
+ */
+ for (; i < bulk_len; i++)
+ page_pool_return_page(pool, data[i]);
+}
+EXPORT_SYMBOL(page_pool_put_page_bulk);
+
static void page_pool_empty_ring(struct page_pool *pool)
{
struct page *page;
diff --git a/net/core/xdp.c b/net/core/xdp.c
index bbaee7fdd44f..3d330ebda893 100644
--- a/net/core/xdp.c
+++ b/net/core/xdp.c
@@ -393,16 +393,11 @@ EXPORT_SYMBOL_GPL(xdp_return_frame_rx_napi);
void xdp_flush_frame_bulk(struct xdp_frame_bulk *bq)
{
struct xdp_mem_allocator *xa = bq->xa;
- int i;
- if (unlikely(!xa))
+ if (unlikely(!xa || !bq->count))
return;
- for (i = 0; i < bq->count; i++) {
- struct page *page = virt_to_head_page(bq->q[i]);
-
- page_pool_put_full_page(xa->page_pool, page, false);
- }
+ page_pool_put_page_bulk(xa->page_pool, bq->q, bq->count);
/* bq->xa is not cleared to save lookup, if mem.id same in next bulk */
bq->count = 0;
}
--
2.26.2
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