[PATCH] IPVS: logging sizeof(struct ip_vs_conn) on startup

[PATCH] IPVS: logging sizeof(struct ip_vs_conn) on startup

[Hannes Eder]

No more guessing, how much memory is used by IPVS for a connection.

Signed-off-by: Hannes Eder <heder@google.com>
---
 net/netfilter/ipvs/ip_vs_core.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/net/netfilter/ipvs/ip_vs_core.c b/net/netfilter/ipvs/ip_vs_core.c
index b021464..5b0997c 100644
--- a/net/netfilter/ipvs/ip_vs_core.c
+++ b/net/netfilter/ipvs/ip_vs_core.c
@@ -1475,7 +1475,8 @@ static int __init ip_vs_init(void)
 		goto cleanup_conn;
 	}
 
-	IP_VS_INFO("ipvs loaded.\n");
+	IP_VS_INFO("ipvs loaded (using %Zd bytes/connection).\n",
+	       sizeof(struct ip_vs_conn));
 	return ret;
 
   cleanup_conn:

Re: [PATCH] IPVS: logging sizeof(struct ip_vs_conn) on startup

[Simon Horman]

On Mon, Jul 27, 2009 at 11:08:34AM +0200, Hannes Eder wrote:
> No more guessing, how much memory is used by IPVS for a connection.

I like that.

> Signed-off-by: Hannes Eder <heder@google.com>

Signed-off-by: Simon Horman <horms@verge.net.au>

> ---
>  net/netfilter/ipvs/ip_vs_core.c |    3 ++-
>  1 files changed, 2 insertions(+), 1 deletions(-)
> 
> diff --git a/net/netfilter/ipvs/ip_vs_core.c b/net/netfilter/ipvs/ip_vs_core.c
> index b021464..5b0997c 100644
> --- a/net/netfilter/ipvs/ip_vs_core.c
> +++ b/net/netfilter/ipvs/ip_vs_core.c
> @@ -1475,7 +1475,8 @@ static int __init ip_vs_init(void)
>  		goto cleanup_conn;
>  	}
>  
> -	IP_VS_INFO("ipvs loaded.\n");
> +	IP_VS_INFO("ipvs loaded (using %Zd bytes/connection).\n",
> +	       sizeof(struct ip_vs_conn));
>  	return ret;
>  
>    cleanup_conn:
> 
> --
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Re: [PATCH] IPVS: logging sizeof(struct ip_vs_conn) on startup

[Eric Dumazet]

Hannes Eder a écrit :
> No more guessing, how much memory is used by IPVS for a connection.
> 
> Signed-off-by: Hannes Eder <heder@google.com>
> ---
>  net/netfilter/ipvs/ip_vs_core.c |    3 ++-
>  1 files changed, 2 insertions(+), 1 deletions(-)
> 
> diff --git a/net/netfilter/ipvs/ip_vs_core.c b/net/netfilter/ipvs/ip_vs_core.c
> index b021464..5b0997c 100644
> --- a/net/netfilter/ipvs/ip_vs_core.c
> +++ b/net/netfilter/ipvs/ip_vs_core.c
> @@ -1475,7 +1475,8 @@ static int __init ip_vs_init(void)
>  		goto cleanup_conn;
>  	}
>  
> -	IP_VS_INFO("ipvs loaded.\n");
> +	IP_VS_INFO("ipvs loaded (using %Zd bytes/connection).\n",
> +	       sizeof(struct ip_vs_conn));
>  	return ret;
>  
>    cleanup_conn:

Well, ip_vs_conn_cache uses SLAB_HWCACHE_ALIGN, so this should be rounded up
to L1 cache size. Or add "at least" like in line 1080
of net/netfilter/ipvs/ip_vs_conn.c :

	IP_VS_DBG(0, "Each connection entry needs %Zd bytes at least\n",
		  sizeof(struct ip_vs_conn));

Re: [PATCH] IPVS: logging sizeof(struct ip_vs_conn) on startup

[Hannes Eder]

On Mon, Jul 27, 2009 at 11:25, Eric Dumazet<eric.dumazet@gmail.com> wrote:
> Well, ip_vs_conn_cache uses SLAB_HWCACHE_ALIGN, so this should be rounded up
> to L1 cache size. Or add "at least" like in line 1080
> of net/netfilter/ipvs/ip_vs_conn.c :
>
> IP_VS_DBG(0, "Each connection entry needs %Zd bytes at least\n",
>           sizeof(struct ip_vs_conn));

Good point.  Is there an easy way to figure out how much memory is
wasted for alignment by the slab allocator?  Otherwise I vote for the
"at least" approach.

-Hannes

[PATCH v2] IPVS: logging sizeof(struct ip_vs_conn) on startup

[Hannes Eder]

No more guessing, how much memory used by IPVS for a connection.

[ The number printed is a lower bound, as ip_vs_conn_cache uses
SLAB_HWCACHE_ALIGN. ]

Signed-off-by: Hannes Eder <heder@google.com>
Signed-off-by: Simon Horman <horms@verge.net.au>

 net/netfilter/ipvs/ip_vs_core.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/net/netfilter/ipvs/ip_vs_core.c b/net/netfilter/ipvs/ip_vs_core.c
index b021464..b6bb4a0 100644
--- a/net/netfilter/ipvs/ip_vs_core.c
+++ b/net/netfilter/ipvs/ip_vs_core.c
@@ -1475,7 +1475,8 @@ static int __init ip_vs_init(void)
 		goto cleanup_conn;
 	}
 
-	IP_VS_INFO("ipvs loaded.\n");
+	IP_VS_INFO("ipvs loaded (using at least %Zd bytes/connection).\n",
+	       sizeof(struct ip_vs_conn));
 	return ret;
 
   cleanup_conn:

Re: [PATCH v2] IPVS: logging sizeof(struct ip_vs_conn) on startup

[David Miller]

From: Hannes Eder <heder@google.com>
Date: Mon, 27 Jul 2009 15:13:57 +0200

> No more guessing, how much memory used by IPVS for a connection.
> 
> [ The number printed is a lower bound, as ip_vs_conn_cache uses
> SLAB_HWCACHE_ALIGN. ]
> 
> Signed-off-by: Hannes Eder <heder@google.com>
> Signed-off-by: Simon Horman <horms@verge.net.au>

Who needs to know this?  A developer?

They can run tools such as 'pahole' et al. to fish out this
information even when only a kernel binary is available.

For the user, it's just noise.

I'm not applying this, sorry.

Re: [PATCH v2] IPVS: logging sizeof(struct ip_vs_conn) on startup

[Simon Horman]

On Mon, Jul 27, 2009 at 11:48:45AM -0700, David Miller wrote:
> From: Hannes Eder <heder@google.com>
> Date: Mon, 27 Jul 2009 15:13:57 +0200
> 
> > No more guessing, how much memory used by IPVS for a connection.
> > 
> > [ The number printed is a lower bound, as ip_vs_conn_cache uses
> > SLAB_HWCACHE_ALIGN. ]
> > 
> > Signed-off-by: Hannes Eder <heder@google.com>
> > Signed-off-by: Simon Horman <horms@verge.net.au>
> 
> Who needs to know this?  A developer?
> 
> They can run tools such as 'pahole' et al. to fish out this
> information even when only a kernel binary is available.
> 
> For the user, it's just noise.
> 
> I'm not applying this, sorry.

Surprisingly its a very common question amongst users,
because they want to know how much memory they need.
It is of course all a bit silly, because the amount of
memory used by the connection table is usually very small,
but people still ask.

Re: [PATCH v2] IPVS: logging sizeof(struct ip_vs_conn) on startup

[Eric Dumazet]

Simon Horman a écrit :
> 
> Surprisingly its a very common question amongst users,
> because they want to know how much memory they need.
> It is of course all a bit silly, because the amount of
> memory used by the connection table is usually very small,
> but people still ask.
> 

If SLUB is used 

$ cat /sys/kernel/slab/ip_vs_conn/object_size

If SLAB is used, take fourth column of :

$ grep ip_vs_conn /proc/slabinfo

BTW these take into account L1 cache size alignment