kernel: use bulk free in kfree_skb_list to improve performance

Signed-off-by: Felix Fietkau <nbd@nbd.name>
master
Felix Fietkau 5 years ago
parent 085141dc5b
commit 98b654de2e

@ -0,0 +1,61 @@
From: Felix Fietkau <nbd@nbd.name>
Date: Sat, 23 Mar 2019 18:26:10 +0100
Subject: [PATCH] net: use bulk free in kfree_skb_list
Since we're freeing multiple skbs, we might as well use bulk free to save a
few cycles. Use the same conditions for bulk free as in napi_consume_skb.
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -666,12 +666,44 @@ EXPORT_SYMBOL(kfree_skb);
void kfree_skb_list(struct sk_buff *segs)
{
- while (segs) {
- struct sk_buff *next = segs->next;
+ struct sk_buff *next = segs;
+ void *skbs[16];
+ int n_skbs = 0;
- kfree_skb(segs);
- segs = next;
+ while ((segs = next) != NULL) {
+ next = segs->next;
+
+ if (segs->fclone != SKB_FCLONE_UNAVAILABLE) {
+ kfree_skb(segs);
+ continue;
+ }
+
+ if (!skb_unref(segs))
+ continue;
+
+ trace_kfree_skb(segs, __builtin_return_address(0));
+
+ /* drop skb->head and call any destructors for packet */
+ skb_release_all(segs);
+
+#ifdef CONFIG_SLUB
+ /* SLUB writes into objects when freeing */
+ prefetchw(segs);
+#endif
+
+ skbs[n_skbs++] = segs;
+
+ if (n_skbs < ARRAY_SIZE(skbs))
+ continue;
+
+ kmem_cache_free_bulk(skbuff_head_cache, n_skbs, skbs);
+ n_skbs = 0;
}
+
+ if (!n_skbs)
+ return;
+
+ kmem_cache_free_bulk(skbuff_head_cache, n_skbs, skbs);
}
EXPORT_SYMBOL(kfree_skb_list);

@ -0,0 +1,61 @@
From: Felix Fietkau <nbd@nbd.name>
Date: Sat, 23 Mar 2019 18:26:10 +0100
Subject: [PATCH] net: use bulk free in kfree_skb_list
Since we're freeing multiple skbs, we might as well use bulk free to save a
few cycles. Use the same conditions for bulk free as in napi_consume_skb.
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -666,12 +666,44 @@ EXPORT_SYMBOL(kfree_skb);
void kfree_skb_list(struct sk_buff *segs)
{
- while (segs) {
- struct sk_buff *next = segs->next;
+ struct sk_buff *next = segs;
+ void *skbs[16];
+ int n_skbs = 0;
- kfree_skb(segs);
- segs = next;
+ while ((segs = next) != NULL) {
+ next = segs->next;
+
+ if (segs->fclone != SKB_FCLONE_UNAVAILABLE) {
+ kfree_skb(segs);
+ continue;
+ }
+
+ if (!skb_unref(segs))
+ continue;
+
+ trace_kfree_skb(segs, __builtin_return_address(0));
+
+ /* drop skb->head and call any destructors for packet */
+ skb_release_all(segs);
+
+#ifdef CONFIG_SLUB
+ /* SLUB writes into objects when freeing */
+ prefetchw(segs);
+#endif
+
+ skbs[n_skbs++] = segs;
+
+ if (n_skbs < ARRAY_SIZE(skbs))
+ continue;
+
+ kmem_cache_free_bulk(skbuff_head_cache, n_skbs, skbs);
+ n_skbs = 0;
}
+
+ if (!n_skbs)
+ return;
+
+ kmem_cache_free_bulk(skbuff_head_cache, n_skbs, skbs);
}
EXPORT_SYMBOL(kfree_skb_list);
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