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authorJoe Damato <jdamato@fastly.com>2022-03-01 23:55:47 -0800
committerDavid S. Miller <davem@davemloft.net>2022-03-03 09:55:28 +0000
commit8610037e8106b48c79cfe0afb92b2b2466e51c3d (patch)
tree32f1b4cdbf620845dcf8f6af2a37319bc0b1f311 /net
parent42f0c1934c7cb3e94c2fe8f5771245fa5631d0e7 (diff)
page_pool: Add allocation stats
Add per-pool statistics counters for the allocation path of a page pool. These stats are incremented in softirq context, so no locking or per-cpu variables are needed. This code is disabled by default and a kernel config option is provided for users who wish to enable them. The statistics added are: - fast: successful fast path allocations - slow: slow path order-0 allocations - slow_high_order: slow path high order allocations - empty: ptr ring is empty, so a slow path allocation was forced. - refill: an allocation which triggered a refill of the cache - waive: pages obtained from the ptr ring that cannot be added to the cache due to a NUMA mismatch. Signed-off-by: Joe Damato <jdamato@fastly.com> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/Kconfig13
-rw-r--r--net/core/page_pool.c24
2 files changed, 33 insertions, 4 deletions
diff --git a/net/Kconfig b/net/Kconfig
index 8a1f9d0287de..6b78f695caa6 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -434,6 +434,19 @@ config NET_DEVLINK
config PAGE_POOL
bool
+config PAGE_POOL_STATS
+ default n
+ bool "Page pool stats"
+ depends on PAGE_POOL
+ help
+ Enable page pool statistics to track page allocation and recycling
+ in page pools. This option incurs additional CPU cost in allocation
+ and recycle paths and additional memory cost to store the statistics.
+ These statistics are only available if this option is enabled and if
+ the driver using the page pool supports exporting this data.
+
+ If unsure, say N.
+
config FAILOVER
tristate "Generic failover module"
help
diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index e25d359d84d9..0fa4b76798d9 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
@@ -26,6 +26,13 @@
#define BIAS_MAX LONG_MAX
+#ifdef CONFIG_PAGE_POOL_STATS
+/* alloc_stat_inc is intended to be used in softirq context */
+#define alloc_stat_inc(pool, __stat) (pool->alloc_stats.__stat++)
+#else
+#define alloc_stat_inc(pool, __stat)
+#endif
+
static int page_pool_init(struct page_pool *pool,
const struct page_pool_params *params)
{
@@ -117,8 +124,10 @@ static struct page *page_pool_refill_alloc_cache(struct page_pool *pool)
int pref_nid; /* preferred NUMA node */
/* Quicker fallback, avoid locks when ring is empty */
- if (__ptr_ring_empty(r))
+ if (__ptr_ring_empty(r)) {
+ alloc_stat_inc(pool, empty);
return NULL;
+ }
/* Softirq guarantee CPU and thus NUMA node is stable. This,
* assumes CPU refilling driver RX-ring will also run RX-NAPI.
@@ -145,14 +154,17 @@ static struct page *page_pool_refill_alloc_cache(struct page_pool *pool)
* This limit stress on page buddy alloactor.
*/
page_pool_return_page(pool, page);
+ alloc_stat_inc(pool, waive);
page = NULL;
break;
}
} while (pool->alloc.count < PP_ALLOC_CACHE_REFILL);
/* Return last page */
- if (likely(pool->alloc.count > 0))
+ if (likely(pool->alloc.count > 0)) {
page = pool->alloc.cache[--pool->alloc.count];
+ alloc_stat_inc(pool, refill);
+ }
return page;
}
@@ -166,6 +178,7 @@ static struct page *__page_pool_get_cached(struct page_pool *pool)
if (likely(pool->alloc.count)) {
/* Fast-path */
page = pool->alloc.cache[--pool->alloc.count];
+ alloc_stat_inc(pool, fast);
} else {
page = page_pool_refill_alloc_cache(pool);
}
@@ -239,6 +252,7 @@ static struct page *__page_pool_alloc_page_order(struct page_pool *pool,
return NULL;
}
+ alloc_stat_inc(pool, slow_high_order);
page_pool_set_pp_info(pool, page);
/* Track how many pages are held 'in-flight' */
@@ -293,10 +307,12 @@ static struct page *__page_pool_alloc_pages_slow(struct page_pool *pool,
}
/* Return last page */
- if (likely(pool->alloc.count > 0))
+ if (likely(pool->alloc.count > 0)) {
page = pool->alloc.cache[--pool->alloc.count];
- else
+ alloc_stat_inc(pool, slow);
+ } else {
page = NULL;
+ }
/* When page just alloc'ed is should/must have refcnt 1. */
return page;