* xfrm: avoid spinlock in get_acqseq() used by xfrm user
@ 2010-02-16 12:01 jamal
2010-02-16 13:09 ` Eric Dumazet
2010-02-17 4:20 ` David Miller
0 siblings, 2 replies; 3+ messages in thread
From: jamal @ 2010-02-16 12:01 UTC (permalink / raw)
To: David Miller; +Cc: Eric Dumazet, netdev
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Eric's version fixed it for pfkey. This one is for xfrm user.
I thought about amortizing those two get_acqseq()s but it seems
reasonable to have two of these sequence spaces for the two different
interfaces.
cheers,
jamal
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commit d5168d5addbc999c94aacda8f28a4a173756a72b
Author: Jamal Hadi Salim <hadi@cyberus.ca>
Date: Tue Feb 16 06:51:22 2010 -0500
xfrm: avoid spinlock in get_acqseq() used by xfrm user
This is in the same spirit as commit 28aecb9d7728dc26bf03ce7925fe622023a83a2a
by Eric Dumazet.
Use atomic_inc_return() in get_acqseq() to avoid taking a spinlock
Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
index f50ee9b..96f2088 100644
--- a/net/xfrm/xfrm_state.c
+++ b/net/xfrm/xfrm_state.c
@@ -1462,12 +1462,12 @@ EXPORT_SYMBOL(xfrm_find_acq_byseq);
u32 xfrm_get_acqseq(void)
{
u32 res;
- static u32 acqseq;
- static DEFINE_SPINLOCK(acqseq_lock);
+ static atomic_t acqseq;
+
+ do {
+ res = atomic_inc_return(&acqseq);
+ } while (!res);
- spin_lock_bh(&acqseq_lock);
- res = (++acqseq ? : ++acqseq);
- spin_unlock_bh(&acqseq_lock);
return res;
}
EXPORT_SYMBOL(xfrm_get_acqseq);
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: xfrm: avoid spinlock in get_acqseq() used by xfrm user
2010-02-16 12:01 xfrm: avoid spinlock in get_acqseq() used by xfrm user jamal
@ 2010-02-16 13:09 ` Eric Dumazet
2010-02-17 4:20 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: Eric Dumazet @ 2010-02-16 13:09 UTC (permalink / raw)
To: hadi; +Cc: David Miller, netdev
Le mardi 16 février 2010 à 07:01 -0500, jamal a écrit :
> Eric's version fixed it for pfkey. This one is for xfrm user.
> I thought about amortizing those two get_acqseq()s but it seems
> reasonable to have two of these sequence spaces for the two different
> interfaces.
>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Thanks !
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: xfrm: avoid spinlock in get_acqseq() used by xfrm user
2010-02-16 12:01 xfrm: avoid spinlock in get_acqseq() used by xfrm user jamal
2010-02-16 13:09 ` Eric Dumazet
@ 2010-02-17 4:20 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: David Miller @ 2010-02-17 4:20 UTC (permalink / raw)
To: hadi; +Cc: eric.dumazet, netdev
From: jamal <hadi@cyberus.ca>
Date: Tue, 16 Feb 2010 07:01:22 -0500
> Eric's version fixed it for pfkey. This one is for xfrm user.
> I thought about amortizing those two get_acqseq()s but it seems
> reasonable to have two of these sequence spaces for the two different
> interfaces.
Applied, thanks Jamal.
^ permalink raw reply [flat|nested] 3+ messages in thread
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