Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
net: add skb_defer_disable_key static key
Add a static key to bypass skb_attempt_defer_free() steps
if net.core.skb_defer_max is set to zero.
Main benefit is the atomic_long_inc_return() avoidance.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260311191340.1996888-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
authored by
Eric Dumazet
and committed by
Jakub Kicinski
08dc30de
15abbe7c
+30
-1
+1
net/core/net-sysfs.h
+1
net/core/net-sysfs.h
+5
net/core/skbuff.c
+5
net/core/skbuff.c
···
7256
7256
local_bh_enable();
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}
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7259
+
DEFINE_STATIC_KEY_FALSE(skb_defer_disable_key);
7260
+
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/**
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* skb_attempt_defer_free - queue skb for remote freeing
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* @skb: buffer
···
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unsigned int defer_max;
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bool kick;
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int cpu;
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+
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+
if (static_branch_unlikely(&skb_defer_disable_key))
7276
+
goto nodefer;
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/* zero copy notifications should not be delayed. */
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if (skb_zcopy(skb))
+24
-1
net/core/sysctl_net_core.c
+24
-1
net/core/sysctl_net_core.c
···
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349
return proc_dostring(&fake_table, write, buffer, lenp, ppos);
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}
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+
static int proc_do_skb_defer_max(const struct ctl_table *table, int write,
353
+
void *buffer, size_t *lenp, loff_t *ppos)
354
+
{
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+
static DEFINE_MUTEX(skb_defer_max_mutex);
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+
int ret, oval, nval;
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+
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+
mutex_lock(&skb_defer_max_mutex);
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+
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+
oval = !net_hotdata.sysctl_skb_defer_max;
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+
ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
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+
nval = !net_hotdata.sysctl_skb_defer_max;
363
+
364
+
if (nval != oval) {
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+
if (nval)
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+
static_branch_enable(&skb_defer_disable_key);
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+
else
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+
static_branch_disable(&skb_defer_disable_key);
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+
}
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+
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+
mutex_unlock(&skb_defer_max_mutex);
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+
return ret;
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+
}
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+
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#ifdef CONFIG_BPF_JIT
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static int proc_dointvec_minmax_bpf_enable(const struct ctl_table *table, int write,
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void *buffer, size_t *lenp,
···
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650
.data = &net_hotdata.sysctl_skb_defer_max,
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.maxlen = sizeof(unsigned int),
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652
.mode = 0644,
676
-
.proc_handler = proc_dointvec_minmax,
653
+
.proc_handler = proc_do_skb_defer_max,
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.extra1 = SYSCTL_ZERO,
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},
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};