Re: [PATCH net-next] fix unsafe set_memory_rw from softirq
On Wed, Oct 2, 2013 at 9:57 PM, Eric Dumazet wrote:
> On Wed, 2013-10-02 at 21:53 -0700, Eric Dumazet wrote:
>> On Wed, 2013-10-02 at 21:44 -0700, Alexei Starovoitov wrote:
>>
>> > I think ifdef config_x86 is a bit ugly inside struct sk_filter, but
>> > don't mind whichever way.
>>
>> Its not fair to make sk_filter bigger, because it means that simple (non
>> JIT) filter might need an extra cache line.
>>
>> You could presumably use the following layout instead :
>>
>> struct sk_filter
>> {
>> atomic_trefcnt;
>> struct rcu_head rcu;
>> struct work_struct work;
>>
>> unsigned intlen cacheline_aligned;/* Number of
>> filter blocks */
>> unsigned int(*bpf_func)(const struct sk_buff *skb,
>> const struct sock_filter
>> *filter);
>> struct sock_filter insns[0];
>> };
>
> And since @len is not used by sk_run_filter() use :
>
> struct sk_filter {
> atomic_trefcnt;
> int len; /* number of filter blocks */
> struct rcu_head rcu;
> struct work_struct work;
>
> unsigned int(*bpf_func)(const struct sk_buff *skb,
> const struct sock_filter *filter)
> cacheline_aligned;
> struct sock_filter insns[0];
> };
yes. make sense to avoid first insn cache miss inside sk_run_filter()
at the expense
of 8-byte gap between work and bpf_func (on x86_64 w/o lockdep)
Probably even better to overlap work and insns fields.
Pro: sk_filter size the same, no impact on non-jit case
Con: would be harder to understand the code
another problem is that kfree(sk_filter) inside
sk_filter_release_rcu() needs to move inside bpf_jit_free().
so self nack. Let me fix these issues and respin
Thanks
Alexei
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Re: [PATCH net-next] fix unsafe set_memory_rw from softirq
On Wed, Oct 2, 2013 at 9:57 PM, Eric Dumazet eric.duma...@gmail.com wrote:
On Wed, 2013-10-02 at 21:53 -0700, Eric Dumazet wrote:
On Wed, 2013-10-02 at 21:44 -0700, Alexei Starovoitov wrote:
I think ifdef config_x86 is a bit ugly inside struct sk_filter, but
don't mind whichever way.
Its not fair to make sk_filter bigger, because it means that simple (non
JIT) filter might need an extra cache line.
You could presumably use the following layout instead :
struct sk_filter
{
atomic_trefcnt;
struct rcu_head rcu;
struct work_struct work;
unsigned intlen cacheline_aligned;/* Number of
filter blocks */
unsigned int(*bpf_func)(const struct sk_buff *skb,
const struct sock_filter
*filter);
struct sock_filter insns[0];
};
And since @len is not used by sk_run_filter() use :
struct sk_filter {
atomic_trefcnt;
int len; /* number of filter blocks */
struct rcu_head rcu;
struct work_struct work;
unsigned int(*bpf_func)(const struct sk_buff *skb,
const struct sock_filter *filter)
cacheline_aligned;
struct sock_filter insns[0];
};
yes. make sense to avoid first insn cache miss inside sk_run_filter()
at the expense
of 8-byte gap between work and bpf_func (on x86_64 w/o lockdep)
Probably even better to overlap work and insns fields.
Pro: sk_filter size the same, no impact on non-jit case
Con: would be harder to understand the code
another problem is that kfree(sk_filter) inside
sk_filter_release_rcu() needs to move inside bpf_jit_free().
so self nack. Let me fix these issues and respin
Thanks
Alexei
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH net-next] fix unsafe set_memory_rw from softirq
On Wed, 2013-10-02 at 21:53 -0700, Eric Dumazet wrote:
> On Wed, 2013-10-02 at 21:44 -0700, Alexei Starovoitov wrote:
>
> > I think ifdef config_x86 is a bit ugly inside struct sk_filter, but
> > don't mind whichever way.
>
> Its not fair to make sk_filter bigger, because it means that simple (non
> JIT) filter might need an extra cache line.
>
> You could presumably use the following layout instead :
>
> struct sk_filter
> {
> atomic_trefcnt;
> struct rcu_head rcu;
> struct work_struct work;
>
> unsigned intlen cacheline_aligned;/* Number of
> filter blocks */
> unsigned int(*bpf_func)(const struct sk_buff *skb,
> const struct sock_filter *filter);
> struct sock_filter insns[0];
> };
And since @len is not used by sk_run_filter() use :
struct sk_filter {
atomic_trefcnt;
int len; /* number of filter blocks */
struct rcu_head rcu;
struct work_struct work;
unsigned int(*bpf_func)(const struct sk_buff *skb,
const struct sock_filter *filter)
cacheline_aligned;
struct sock_filter insns[0];
};
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH net-next] fix unsafe set_memory_rw from softirq
On Wed, 2013-10-02 at 21:44 -0700, Alexei Starovoitov wrote:
> I think ifdef config_x86 is a bit ugly inside struct sk_filter, but
> don't mind whichever way.
Its not fair to make sk_filter bigger, because it means that simple (non
JIT) filter might need an extra cache line.
You could presumably use the following layout instead :
struct sk_filter
{
atomic_trefcnt;
struct rcu_head rcu;
struct work_struct work;
unsigned intlen cacheline_aligned;/* Number of
filter blocks */
unsigned int(*bpf_func)(const struct sk_buff *skb,
const struct sock_filter *filter);
struct sock_filter insns[0];
};
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH net-next] fix unsafe set_memory_rw from softirq
On Wed, Oct 2, 2013 at 9:23 PM, Eric Dumazet wrote: > On Wed, 2013-10-02 at 20:50 -0700, Alexei Starovoitov wrote: >> on x86 system with net.core.bpf_jit_enable = 1 > >> diff --git a/include/linux/filter.h b/include/linux/filter.h >> index a6ac848..378fa03 100644 >> --- a/include/linux/filter.h >> +++ b/include/linux/filter.h >> @@ -27,6 +27,7 @@ struct sk_filter >> unsigned intlen;/* Number of filter blocks */ >> unsigned int(*bpf_func)(const struct sk_buff *skb, >> const struct sock_filter *filter); >> + struct work_struct work; >> struct rcu_head rcu; >> struct sock_filter insns[0]; >> }; > > Nice catch ! > > It seems only x86 and s390 needs this work_struct. I think ifdef config_x86 is a bit ugly inside struct sk_filter, but don't mind whichever way. > (and you might CC Heiko Carstens to ask him > to make the s390 part, of Ack it if you plan to do it) set_memory_rw() on s390 is a simple page table walker that doesn't do any IPI unlike x86 Heiko, please confirm that it's not an issue there. Thanks Alexei -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH net-next] fix unsafe set_memory_rw from softirq
On Wed, 2013-10-02 at 20:50 -0700, Alexei Starovoitov wrote: > on x86 system with net.core.bpf_jit_enable = 1 > diff --git a/include/linux/filter.h b/include/linux/filter.h > index a6ac848..378fa03 100644 > --- a/include/linux/filter.h > +++ b/include/linux/filter.h > @@ -27,6 +27,7 @@ struct sk_filter > unsigned intlen;/* Number of filter blocks */ > unsigned int(*bpf_func)(const struct sk_buff *skb, > const struct sock_filter *filter); > + struct work_struct work; > struct rcu_head rcu; > struct sock_filter insns[0]; > }; Nice catch ! It seems only x86 and s390 needs this work_struct. (and you might CC Heiko Carstens to ask him to make the s390 part, of Ack it if you plan to do it) Thanks -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH net-next] fix unsafe set_memory_rw from softirq
On Wed, 2013-10-02 at 20:50 -0700, Alexei Starovoitov wrote: on x86 system with net.core.bpf_jit_enable = 1 diff --git a/include/linux/filter.h b/include/linux/filter.h index a6ac848..378fa03 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -27,6 +27,7 @@ struct sk_filter unsigned intlen;/* Number of filter blocks */ unsigned int(*bpf_func)(const struct sk_buff *skb, const struct sock_filter *filter); + struct work_struct work; struct rcu_head rcu; struct sock_filter insns[0]; }; Nice catch ! It seems only x86 and s390 needs this work_struct. (and you might CC Heiko Carstens heiko.carst...@de.ibm.com to ask him to make the s390 part, of Ack it if you plan to do it) Thanks -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH net-next] fix unsafe set_memory_rw from softirq
On Wed, Oct 2, 2013 at 9:23 PM, Eric Dumazet eric.duma...@gmail.com wrote: On Wed, 2013-10-02 at 20:50 -0700, Alexei Starovoitov wrote: on x86 system with net.core.bpf_jit_enable = 1 diff --git a/include/linux/filter.h b/include/linux/filter.h index a6ac848..378fa03 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -27,6 +27,7 @@ struct sk_filter unsigned intlen;/* Number of filter blocks */ unsigned int(*bpf_func)(const struct sk_buff *skb, const struct sock_filter *filter); + struct work_struct work; struct rcu_head rcu; struct sock_filter insns[0]; }; Nice catch ! It seems only x86 and s390 needs this work_struct. I think ifdef config_x86 is a bit ugly inside struct sk_filter, but don't mind whichever way. (and you might CC Heiko Carstens heiko.carst...@de.ibm.com to ask him to make the s390 part, of Ack it if you plan to do it) set_memory_rw() on s390 is a simple page table walker that doesn't do any IPI unlike x86 Heiko, please confirm that it's not an issue there. Thanks Alexei -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH net-next] fix unsafe set_memory_rw from softirq
On Wed, 2013-10-02 at 21:44 -0700, Alexei Starovoitov wrote:
I think ifdef config_x86 is a bit ugly inside struct sk_filter, but
don't mind whichever way.
Its not fair to make sk_filter bigger, because it means that simple (non
JIT) filter might need an extra cache line.
You could presumably use the following layout instead :
struct sk_filter
{
atomic_trefcnt;
struct rcu_head rcu;
struct work_struct work;
unsigned intlen cacheline_aligned;/* Number of
filter blocks */
unsigned int(*bpf_func)(const struct sk_buff *skb,
const struct sock_filter *filter);
struct sock_filter insns[0];
};
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH net-next] fix unsafe set_memory_rw from softirq
On Wed, 2013-10-02 at 21:53 -0700, Eric Dumazet wrote:
On Wed, 2013-10-02 at 21:44 -0700, Alexei Starovoitov wrote:
I think ifdef config_x86 is a bit ugly inside struct sk_filter, but
don't mind whichever way.
Its not fair to make sk_filter bigger, because it means that simple (non
JIT) filter might need an extra cache line.
You could presumably use the following layout instead :
struct sk_filter
{
atomic_trefcnt;
struct rcu_head rcu;
struct work_struct work;
unsigned intlen cacheline_aligned;/* Number of
filter blocks */
unsigned int(*bpf_func)(const struct sk_buff *skb,
const struct sock_filter *filter);
struct sock_filter insns[0];
};
And since @len is not used by sk_run_filter() use :
struct sk_filter {
atomic_trefcnt;
int len; /* number of filter blocks */
struct rcu_head rcu;
struct work_struct work;
unsigned int(*bpf_func)(const struct sk_buff *skb,
const struct sock_filter *filter)
cacheline_aligned;
struct sock_filter insns[0];
};
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
