* [PATCH -mm] add a kmem_cache for nsproxy objects
@ 2007-06-18 20:53 Cedric Le Goater
2007-06-19 18:35 ` Andrew Morton
0 siblings, 1 reply; 8+ messages in thread
From: Cedric Le Goater @ 2007-06-18 20:53 UTC (permalink / raw)
To: Linux Kernel Mailing List; +Cc: Andrew Morton, Herbert Poetzl, Pavel Emelianov
It should improve performance in some scenarii where a lot of
these nsproxy objects are created by unsharing namespaces. This is
a typical use of virtual servers that are being created or entered.
This is also a good tool to find leaks and gather statistics on
namespace usage.
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
---
kernel/nsproxy.c | 21 +++++++++++++++++----
1 file changed, 17 insertions(+), 4 deletions(-)
Index: 2.6.22-rc4-mm2/kernel/nsproxy.c
===================================================================
--- 2.6.22-rc4-mm2.orig/kernel/nsproxy.c
+++ 2.6.22-rc4-mm2/kernel/nsproxy.c
@@ -21,6 +21,8 @@
#include <linux/utsname.h>
#include <linux/pid_namespace.h>
+static struct kmem_cache *nsproxy_cachep;
+
struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy);
static inline void get_nsproxy(struct nsproxy *ns)
@@ -43,9 +45,11 @@ static inline struct nsproxy *clone_nspr
{
struct nsproxy *ns;
- ns = kmemdup(orig, sizeof(struct nsproxy), GFP_KERNEL);
- if (ns)
+ ns = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL);
+ if (ns) {
+ memcpy(ns, orig, sizeof(struct nsproxy));
atomic_set(&ns->count, 1);
+ }
return ns;
}
@@ -109,7 +113,7 @@ out_uts:
if (new_nsp->mnt_ns)
put_mnt_ns(new_nsp->mnt_ns);
out_ns:
- kfree(new_nsp);
+ kmem_cache_free(nsproxy_cachep, new_nsp);
return ERR_PTR(err);
}
@@ -160,7 +164,7 @@ void free_nsproxy(struct nsproxy *ns)
put_pid_ns(ns->pid_ns);
if (ns->user_ns)
put_user_ns(ns->user_ns);
- kfree(ns);
+ kmem_cache_free(nsproxy_cachep, ns);
}
/*
@@ -191,3 +195,12 @@ int unshare_nsproxy_namespaces(unsigned
}
return err;
}
+
+static int __init nsproxy_cache_init(void)
+{
+ nsproxy_cachep = kmem_cache_create("nsproxy", sizeof(struct nsproxy),
+ 0, SLAB_PANIC, NULL, NULL);
+ return 0;
+}
+
+module_init(nsproxy_cache_init);
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH -mm] add a kmem_cache for nsproxy objects
2007-06-18 20:53 [PATCH -mm] add a kmem_cache for nsproxy objects Cedric Le Goater
@ 2007-06-19 18:35 ` Andrew Morton
2007-06-19 19:04 ` Christoph Hellwig
2007-06-19 19:24 ` Christoph Lameter
0 siblings, 2 replies; 8+ messages in thread
From: Andrew Morton @ 2007-06-19 18:35 UTC (permalink / raw)
To: Cedric Le Goater, Christoph Lameter
Cc: Linux Kernel Mailing List, Herbert Poetzl, Pavel Emelianov
On Mon, 18 Jun 2007 22:53:13 +0200
Cedric Le Goater <clg@fr.ibm.com> wrote:
> +static int __init nsproxy_cache_init(void)
> +{
> + nsproxy_cachep = kmem_cache_create("nsproxy", sizeof(struct nsproxy),
> + 0, SLAB_PANIC, NULL, NULL);
> + return 0;
> +}
> +
Christoph added this cheesy KMEM_CACHE macro. But I don't immediately recall
the rationale so I'm a bit reluctant to ask people to use-the-cheesy-macro.
Perhaps he can remind us why it is there?
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH -mm] add a kmem_cache for nsproxy objects
2007-06-19 18:35 ` Andrew Morton
@ 2007-06-19 19:04 ` Christoph Hellwig
2007-06-19 19:27 ` Christoph Lameter
2007-06-19 19:24 ` Christoph Lameter
1 sibling, 1 reply; 8+ messages in thread
From: Christoph Hellwig @ 2007-06-19 19:04 UTC (permalink / raw)
To: Andrew Morton
Cc: Cedric Le Goater, Christoph Lameter, Linux Kernel Mailing List,
Herbert Poetzl, Pavel Emelianov
On Tue, Jun 19, 2007 at 11:35:01AM -0700, Andrew Morton wrote:
> On Mon, 18 Jun 2007 22:53:13 +0200
> Cedric Le Goater <clg@fr.ibm.com> wrote:
>
> > +static int __init nsproxy_cache_init(void)
> > +{
> > + nsproxy_cachep = kmem_cache_create("nsproxy", sizeof(struct nsproxy),
> > + 0, SLAB_PANIC, NULL, NULL);
> > + return 0;
> > +}
> > +
>
> Christoph added this cheesy KMEM_CACHE macro. But I don't immediately recall
> the rationale so I'm a bit reluctant to ask people to use-the-cheesy-macro.
>
> Perhaps he can remind us why it is there?
Hmm, I must have missed the macro going in. Frankly speaking I plain hate
it. It's a rather useless obsfucation.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH -mm] add a kmem_cache for nsproxy objects
2007-06-19 18:35 ` Andrew Morton
2007-06-19 19:04 ` Christoph Hellwig
@ 2007-06-19 19:24 ` Christoph Lameter
2007-06-22 7:48 ` Cedric Le Goater
1 sibling, 1 reply; 8+ messages in thread
From: Christoph Lameter @ 2007-06-19 19:24 UTC (permalink / raw)
To: Andrew Morton
Cc: Cedric Le Goater, Linux Kernel Mailing List, Herbert Poetzl,
Pavel Emelianov
[-- Attachment #1: Type: TEXT/PLAIN, Size: 803 bytes --]
On Tue, 19 Jun 2007, Andrew Morton wrote:
> On Mon, 18 Jun 2007 22:53:13 +0200
> Cedric Le Goater <clg@fr.ibm.com> wrote:
>
> > +static int __init nsproxy_cache_init(void)
> > +{
> > + nsproxy_cachep = kmem_cache_create("nsproxy", sizeof(struct nsproxy),
> > + 0, SLAB_PANIC, NULL, NULL);
> > + return 0;
> > +}
> > +
>
> Christoph added this cheesy KMEM_CACHE macro. But I don't immediately recall
> the rationale so I'm a bit reluctant to ask people to use-the-cheesy-macro.
>
> Perhaps he can remind us why it is there?
Because it simplifies the handling of slabs.
The above will could become:
nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC);
meaning create a cache for the nsproxy struct, the nsproxy name and the
nsproxy size. See include/linux/slab.h.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH -mm] add a kmem_cache for nsproxy objects
2007-06-19 19:04 ` Christoph Hellwig
@ 2007-06-19 19:27 ` Christoph Lameter
2007-06-19 21:14 ` Pekka Enberg
0 siblings, 1 reply; 8+ messages in thread
From: Christoph Lameter @ 2007-06-19 19:27 UTC (permalink / raw)
To: Christoph Hellwig
Cc: Andrew Morton, Cedric Le Goater, Linux Kernel Mailing List,
Herbert Poetzl, Pavel Emelianov
On Tue, 19 Jun 2007, Christoph Hellwig wrote:
> Hmm, I must have missed the macro going in. Frankly speaking I plain hate
> it. It's a rather useless obsfucation.
It makes the code easier to review and reduces errors by establishing a
standard way of defining a slab with minimal effort. You can
still do the old style and create the kmem_cache_create parameter
monsters that span lots of lines.
KMEM_CACHE can do it just by specifying two parameters.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH -mm] add a kmem_cache for nsproxy objects
2007-06-19 19:27 ` Christoph Lameter
@ 2007-06-19 21:14 ` Pekka Enberg
0 siblings, 0 replies; 8+ messages in thread
From: Pekka Enberg @ 2007-06-19 21:14 UTC (permalink / raw)
To: Christoph Lameter
Cc: Christoph Hellwig, Andrew Morton, Cedric Le Goater,
Linux Kernel Mailing List, Herbert Poetzl, Pavel Emelianov
Hi Christoph x 2,
On Tue, 19 Jun 2007, Christoph Hellwig wrote:
> > Hmm, I must have missed the macro going in. Frankly speaking I plain hate
> > it. It's a rather useless obsfucation.
I hate the name, but the macro is far from useless.
On 6/19/07, Christoph Lameter <clameter@sgi.com> wrote:
> It makes the code easier to review and reduces errors by establishing a
> standard way of defining a slab with minimal effort. You can
> still do the old style and create the kmem_cache_create parameter
> monsters that span lots of lines.
>
> KMEM_CACHE can do it just by specifying two parameters.
Yes and if you look at existing callers of kmem_cache_create(), you'll
notice that most of them work _exactly_ the way the macro does. Most
of the time you want to use default alignment and not define a
constructor.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH -mm] add a kmem_cache for nsproxy objects
2007-06-19 19:24 ` Christoph Lameter
@ 2007-06-22 7:48 ` Cedric Le Goater
2007-06-22 16:22 ` Christoph Lameter
0 siblings, 1 reply; 8+ messages in thread
From: Cedric Le Goater @ 2007-06-22 7:48 UTC (permalink / raw)
To: Christoph Lameter
Cc: Andrew Morton, Linux Kernel Mailing List, Herbert Poetzl,
Pavel Emelianov
Christoph Lameter wrote:
> On Tue, 19 Jun 2007, Andrew Morton wrote:
>
>> On Mon, 18 Jun 2007 22:53:13 +0200
>> Cedric Le Goater <clg@fr.ibm.com> wrote:
>>
>>> +static int __init nsproxy_cache_init(void)
>>> +{
>>> + nsproxy_cachep = kmem_cache_create("nsproxy", sizeof(struct nsproxy),
>>> + 0, SLAB_PANIC, NULL, NULL);
>>> + return 0;
>>> +}
>>> +
>> Christoph added this cheesy KMEM_CACHE macro. But I don't immediately recall
>> the rationale so I'm a bit reluctant to ask people to use-the-cheesy-macro.
>>
>> Perhaps he can remind us why it is there?
>
> Because it simplifies the handling of slabs.
>
> The above will could become:
>
> nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC);
>
> meaning create a cache for the nsproxy struct, the nsproxy name and the
> nsproxy size. See include/linux/slab.h.
yes, I should probably use that for the nsproxy struct.
my 2cts :
the macro sets the align parameter to "__alignof__(struct)" by default.
is that something we want to do all the time ? if so, why not change
kmem_cache_create() directly ?
Most of the complexity is in flags. I did a grep and picked what i thought
was the most aggressive. The macro would probably be more useful if we could
identify by it's name in which context it can be used.
C.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH -mm] add a kmem_cache for nsproxy objects
2007-06-22 7:48 ` Cedric Le Goater
@ 2007-06-22 16:22 ` Christoph Lameter
0 siblings, 0 replies; 8+ messages in thread
From: Christoph Lameter @ 2007-06-22 16:22 UTC (permalink / raw)
To: Cedric Le Goater
Cc: Andrew Morton, Linux Kernel Mailing List, Herbert Poetzl,
Pavel Emelianov
On Fri, 22 Jun 2007, Cedric Le Goater wrote:
> the macro sets the align parameter to "__alignof__(struct)" by default.
> is that something we want to do all the time ? if so, why not change
> kmem_cache_create() directly ?
Its a safety net. If there is some reason that the structure needs a
larger alignment than ARCH_KMALLOC_MINALIGN then that alignment will be
applied.
> Most of the complexity is in flags. I did a grep and picked what i thought
> was the most aggressive. The macro would probably be more useful if we could
> identify by it's name in which context it can be used.
What context are you thinking about and how would it influence
the macro?
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2007-06-22 16:23 UTC | newest]
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2007-06-18 20:53 [PATCH -mm] add a kmem_cache for nsproxy objects Cedric Le Goater
2007-06-19 18:35 ` Andrew Morton
2007-06-19 19:04 ` Christoph Hellwig
2007-06-19 19:27 ` Christoph Lameter
2007-06-19 21:14 ` Pekka Enberg
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