lkml.org 
[lkml]   [2020]   [Jul]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH bpf-next v7 2/7] bpf: Generalize caching for sk_storage.
Date
From: KP Singh <kpsingh@google.com>

Provide the a ability to define local storage caches on a per-object
type basis. The caches and caching indices for different objects should
not be inter-mixed as suggested in:

https://lore.kernel.org/bpf/20200630193441.kdwnkestulg5erii@kafai-mbp.dhcp.thefacebook.com/

"Caching a sk-storage at idx=0 of a sk should not stop an
inode-storage to be cached at the same idx of a inode."

Signed-off-by: KP Singh <kpsingh@google.com>
---
include/net/bpf_sk_storage.h | 19 +++++++++++++++++++
net/core/bpf_sk_storage.c | 31 +++++++++++++++----------------
2 files changed, 34 insertions(+), 16 deletions(-)

diff --git a/include/net/bpf_sk_storage.h b/include/net/bpf_sk_storage.h
index 5036c94c0503..950c5aaba15e 100644
--- a/include/net/bpf_sk_storage.h
+++ b/include/net/bpf_sk_storage.h
@@ -3,6 +3,9 @@
#ifndef _BPF_SK_STORAGE_H
#define _BPF_SK_STORAGE_H

+#include <linux/types.h>
+#include <linux/spinlock.h>
+
struct sock;

void bpf_sk_storage_free(struct sock *sk);
@@ -15,6 +18,22 @@ struct sk_buff;
struct nlattr;
struct sock;

+#define BPF_LOCAL_STORAGE_CACHE_SIZE 16
+
+struct bpf_local_storage_cache {
+ spinlock_t idx_lock;
+ u64 idx_usage_counts[BPF_LOCAL_STORAGE_CACHE_SIZE];
+};
+
+#define DEFINE_BPF_STORAGE_CACHE(name) \
+static struct bpf_local_storage_cache name = { \
+ .idx_lock = __SPIN_LOCK_UNLOCKED(name.idx_lock), \
+}
+
+u16 bpf_local_storage_cache_idx_get(struct bpf_local_storage_cache *cache);
+void bpf_local_storage_cache_idx_free(struct bpf_local_storage_cache *cache,
+ u16 idx);
+
#ifdef CONFIG_BPF_SYSCALL
int bpf_sk_storage_clone(const struct sock *sk, struct sock *newsk);
struct bpf_sk_storage_diag *
diff --git a/net/core/bpf_sk_storage.c b/net/core/bpf_sk_storage.c
index a5cc218834ee..99dde7b74767 100644
--- a/net/core/bpf_sk_storage.c
+++ b/net/core/bpf_sk_storage.c
@@ -14,6 +14,8 @@

#define BPF_LOCAL_STORAGE_CREATE_FLAG_MASK (BPF_F_NO_PREALLOC | BPF_F_CLONE)

+DEFINE_BPF_STORAGE_CACHE(sk_cache);
+
struct bpf_local_storage_map_bucket {
struct hlist_head list;
raw_spinlock_t lock;
@@ -78,10 +80,6 @@ struct bpf_local_storage_elem {
#define SELEM(_SDATA) \
container_of((_SDATA), struct bpf_local_storage_elem, sdata)
#define SDATA(_SELEM) (&(_SELEM)->sdata)
-#define BPF_LOCAL_STORAGE_CACHE_SIZE 16
-
-static DEFINE_SPINLOCK(cache_idx_lock);
-static u64 cache_idx_usage_counts[BPF_LOCAL_STORAGE_CACHE_SIZE];

struct bpf_local_storage {
struct bpf_local_storage_data __rcu *cache[BPF_LOCAL_STORAGE_CACHE_SIZE];
@@ -517,16 +515,16 @@ static int sk_storage_delete(struct sock *sk, struct bpf_map *map)
return 0;
}

-static u16 cache_idx_get(void)
+u16 bpf_local_storage_cache_idx_get(struct bpf_local_storage_cache *cache)
{
u64 min_usage = U64_MAX;
u16 i, res = 0;

- spin_lock(&cache_idx_lock);
+ spin_lock(&cache->idx_lock);

for (i = 0; i < BPF_LOCAL_STORAGE_CACHE_SIZE; i++) {
- if (cache_idx_usage_counts[i] < min_usage) {
- min_usage = cache_idx_usage_counts[i];
+ if (cache->idx_usage_counts[i] < min_usage) {
+ min_usage = cache->idx_usage_counts[i];
res = i;

/* Found a free cache_idx */
@@ -534,18 +532,19 @@ static u16 cache_idx_get(void)
break;
}
}
- cache_idx_usage_counts[res]++;
+ cache->idx_usage_counts[res]++;

- spin_unlock(&cache_idx_lock);
+ spin_unlock(&cache->idx_lock);

return res;
}

-static void cache_idx_free(u16 idx)
+void bpf_local_storage_cache_idx_free(struct bpf_local_storage_cache *cache,
+ u16 idx)
{
- spin_lock(&cache_idx_lock);
- cache_idx_usage_counts[idx]--;
- spin_unlock(&cache_idx_lock);
+ spin_lock(&cache->idx_lock);
+ cache->idx_usage_counts[idx]--;
+ spin_unlock(&cache->idx_lock);
}

/* Called by __sk_destruct() & bpf_sk_storage_clone() */
@@ -597,7 +596,7 @@ static void bpf_local_storage_map_free(struct bpf_map *map)

smap = (struct bpf_local_storage_map *)map;

- cache_idx_free(smap->cache_idx);
+ bpf_local_storage_cache_idx_free(&sk_cache, smap->cache_idx);

/* Note that this map might be concurrently cloned from
* bpf_sk_storage_clone. Wait for any existing bpf_sk_storage_clone
@@ -713,7 +712,7 @@ static struct bpf_map *bpf_local_storage_map_alloc(union bpf_attr *attr)
}

smap->elem_size = sizeof(struct bpf_local_storage_elem) + attr->value_size;
- smap->cache_idx = cache_idx_get();
+ smap->cache_idx = bpf_local_storage_cache_idx_get(&sk_cache);

return &smap->map;
}
--
2.28.0.rc0.142.g3c755180ce-goog
\
 
 \ /
  Last update: 2020-07-30 16:09    [W:0.124 / U:1.388 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site