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Message-ID: <20191016225028.2100206-8-jonathan.lemon@gmail.com>
Date: Wed, 16 Oct 2019 15:50:25 -0700
From: Jonathan Lemon <jonathan.lemon@...il.com>
To: <brouer@...hat.com>, <ilias.apalodimas@...aro.org>,
<saeedm@...lanox.com>, <tariqt@...lanox.com>
CC: <netdev@...r.kernel.org>, <kernel-team@...com>
Subject: [PATCH 07/10 net-next] page_pool: allow configurable linear cache size
Some drivers may utilize more than one page per RX work entry.
Allow a configurable cache size, with the same defaults if the
size is zero.
Convert magic numbers into descriptive entries.
Re-arrange the page_pool structure for efficiency.
Signed-off-by: Jonathan Lemon <jonathan.lemon@...il.com>
---
include/net/page_pool.h | 50 ++++++++++++++++++++---------------------
net/core/page_pool.c | 49 +++++++++++++++++++++++-----------------
2 files changed, 54 insertions(+), 45 deletions(-)
diff --git a/include/net/page_pool.h b/include/net/page_pool.h
index 89bc91294b53..fc340db42f9a 100644
--- a/include/net/page_pool.h
+++ b/include/net/page_pool.h
@@ -51,41 +51,34 @@
* cache is already full (or partly full) then the XDP_DROP recycles
* would have to take a slower code path.
*/
-#define PP_ALLOC_CACHE_SIZE 128
#define PP_ALLOC_CACHE_REFILL 64
-struct pp_alloc_cache {
- u32 count;
- void *cache[PP_ALLOC_CACHE_SIZE];
-};
+#define PP_ALLOC_CACHE_DEFAULT (2 * PP_ALLOC_CACHE_REFILL)
+#define PP_ALLOC_CACHE_LIMIT 512
+#define PP_ALLOC_POOL_DEFAULT 1024
+#define PP_ALLOC_POOL_LIMIT 32768
struct page_pool_params {
unsigned int flags;
unsigned int order;
unsigned int pool_size;
+ unsigned int cache_size;
int nid; /* Numa node id to allocate from pages from */
- struct device *dev; /* device, for DMA pre-mapping purposes */
enum dma_data_direction dma_dir; /* DMA mapping direction */
+ struct device *dev; /* device, for DMA pre-mapping purposes */
};
struct page_pool {
struct page_pool_params p;
+ u32 alloc_count;
u32 pages_state_hold_cnt;
+ atomic_t pages_state_release_cnt;
- /*
- * Data structure for allocation side
- *
- * Drivers allocation side usually already perform some kind
- * of resource protection. Piggyback on this protection, and
- * require driver to protect allocation side.
- *
- * For NIC drivers this means, allocate a page_pool per
- * RX-queue. As the RX-queue is already protected by
- * Softirq/BH scheduling and napi_schedule. NAPI schedule
- * guarantee that a single napi_struct will only be scheduled
- * on a single CPU (see napi_schedule).
+ /* A page_pool is strictly tied to a single RX-queue being
+ * protected by NAPI, due to above pp_alloc_cache. This
+ * refcnt serves purpose is to simplify drivers error handling.
*/
- struct pp_alloc_cache alloc ____cacheline_aligned_in_smp;
+ refcount_t user_cnt;
/* Data structure for storing recycled pages.
*
@@ -100,13 +93,20 @@ struct page_pool {
*/
struct ptr_ring ring;
- atomic_t pages_state_release_cnt;
-
- /* A page_pool is strictly tied to a single RX-queue being
- * protected by NAPI, due to above pp_alloc_cache. This
- * refcnt serves purpose is to simplify drivers error handling.
+ /*
+ * Data structure for allocation side
+ *
+ * Drivers allocation side usually already perform some kind
+ * of resource protection. Piggyback on this protection, and
+ * require driver to protect allocation side.
+ *
+ * For NIC drivers this means, allocate a page_pool per
+ * RX-queue. As the RX-queue is already protected by
+ * Softirq/BH scheduling and napi_schedule. NAPI schedule
+ * guarantee that a single napi_struct will only be scheduled
+ * on a single CPU (see napi_schedule).
*/
- refcount_t user_cnt;
+ void *alloc_cache[];
};
struct page *page_pool_alloc_pages(struct page_pool *pool, gfp_t gfp);
diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index ea56823236c5..f8fedecddb6f 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
@@ -18,22 +18,18 @@
#include <trace/events/page_pool.h>
-static int page_pool_init(struct page_pool *pool,
- const struct page_pool_params *params)
+static int page_pool_init(struct page_pool *pool)
{
- unsigned int ring_qsize = 1024; /* Default */
-
- memcpy(&pool->p, params, sizeof(pool->p));
/* Validate only known flags were used */
if (pool->p.flags & ~(PP_FLAG_ALL))
return -EINVAL;
- if (pool->p.pool_size)
- ring_qsize = pool->p.pool_size;
+ if (!pool->p.pool_size)
+ pool->p.pool_size = PP_ALLOC_POOL_DEFAULT;
/* Sanity limit mem that can be pinned down */
- if (ring_qsize > 32768)
+ if (pool->p.pool_size > PP_ALLOC_POOL_LIMIT)
return -E2BIG;
/* DMA direction is either DMA_FROM_DEVICE or DMA_BIDIRECTIONAL.
@@ -44,7 +40,7 @@ static int page_pool_init(struct page_pool *pool,
(pool->p.dma_dir != DMA_BIDIRECTIONAL))
return -EINVAL;
- if (ptr_ring_init(&pool->ring, ring_qsize, GFP_KERNEL) < 0)
+ if (ptr_ring_init(&pool->ring, pool->p.pool_size, GFP_KERNEL) < 0)
return -ENOMEM;
atomic_set(&pool->pages_state_release_cnt, 0);
@@ -61,13 +57,26 @@ static int page_pool_init(struct page_pool *pool,
struct page_pool *page_pool_create(const struct page_pool_params *params)
{
struct page_pool *pool;
+ u32 cache_size, size;
int err;
- pool = kzalloc_node(sizeof(*pool), GFP_KERNEL, params->nid);
+ cache_size = params->cache_size;
+ if (!cache_size)
+ cache_size = PP_ALLOC_CACHE_DEFAULT;
+
+ /* Sanity limit mem that can be pinned down */
+ if (cache_size > PP_ALLOC_CACHE_LIMIT)
+ return ERR_PTR(-E2BIG);
+
+ size = sizeof(*pool) + cache_size * sizeof(void *);
+ pool = kzalloc_node(size, GFP_KERNEL, params->nid);
if (!pool)
return ERR_PTR(-ENOMEM);
- err = page_pool_init(pool, params);
+ memcpy(&pool->p, params, sizeof(pool->p));
+ pool->p.cache_size = cache_size;
+
+ err = page_pool_init(pool);
if (err < 0) {
pr_warn("%s() gave up with errno %d\n", __func__, err);
kfree(pool);
@@ -87,9 +96,9 @@ static struct page *__page_pool_get_cached(struct page_pool *pool)
/* Test for safe-context, caller should provide this guarantee */
if (likely(in_serving_softirq())) {
- if (likely(pool->alloc.count)) {
+ if (likely(pool->alloc_count)) {
/* Fast-path */
- page = pool->alloc.cache[--pool->alloc.count];
+ page = pool->alloc_cache[--pool->alloc_count];
return page;
}
refill = true;
@@ -105,8 +114,8 @@ static struct page *__page_pool_get_cached(struct page_pool *pool)
spin_lock(&r->consumer_lock);
page = __ptr_ring_consume(r);
if (refill)
- pool->alloc.count = __ptr_ring_consume_batched(r,
- pool->alloc.cache,
+ pool->alloc_count = __ptr_ring_consume_batched(r,
+ pool->alloc_cache,
PP_ALLOC_CACHE_REFILL);
spin_unlock(&r->consumer_lock);
return page;
@@ -276,11 +285,11 @@ static bool __page_pool_recycle_into_ring(struct page_pool *pool,
static bool __page_pool_recycle_into_cache(struct page *page,
struct page_pool *pool)
{
- if (unlikely(pool->alloc.count == PP_ALLOC_CACHE_SIZE))
+ if (unlikely(pool->alloc_count == pool->p.cache_size))
return false;
/* Caller MUST have verified/know (page_ref_count(page) == 1) */
- pool->alloc.cache[pool->alloc.count++] = page;
+ pool->alloc_cache[pool->alloc_count++] = page;
return true;
}
@@ -365,7 +374,7 @@ void __page_pool_free(struct page_pool *pool)
if (!page_pool_put(pool))
return;
- WARN(pool->alloc.count, "API usage violation");
+ WARN(pool->alloc_count, "API usage violation");
WARN(!ptr_ring_empty(&pool->ring), "ptr_ring is not empty");
/* Can happen due to forced shutdown */
@@ -389,8 +398,8 @@ static void page_pool_flush(struct page_pool *pool)
* no-longer in use, and page_pool_alloc_pages() cannot be
* called concurrently.
*/
- while (pool->alloc.count) {
- page = pool->alloc.cache[--pool->alloc.count];
+ while (pool->alloc_count) {
+ page = pool->alloc_cache[--pool->alloc_count];
__page_pool_return_page(pool, page);
}
--
2.17.1
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