2015-04-18 09:25:03

by Gavin Guo

[permalink] [raw]
Subject: [PATCH] mm/slab_common: Support the slub_debug boot option on specific object size

The slub_debug=PU,kmalloc-xx cannot work because in the
create_kmalloc_caches() the s->name is created after the
create_kmalloc_cache() is called. The name is NULL in the
create_kmalloc_cache() so the kmem_cache_flags() would not set the
slub_debug flags to the s->flags. The fix here set up a temporary
kmalloc_names string array for the initialization purpose. After the
kmalloc_caches are already it can be used to create s->name in the
kasprintf.

Signed-off-by: Gavin Guo <[email protected]>
---
mm/slab_common.c | 29 ++++++++++++++++++++++++++---
1 file changed, 26 insertions(+), 3 deletions(-)

diff --git a/mm/slab_common.c b/mm/slab_common.c
index 999bb34..c7d7d54 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -793,6 +793,26 @@ void __init create_kmalloc_caches(unsigned long flags)
int i;

/*
+ * The kmalloc_names is for temporary usage to make
+ * slub_debug=,kmalloc-xx option work in the boot time. The
+ * kmalloc_index() support to 2^26=64MB. So, the final entry of the
+ * table is kmalloc-67108864.
+ */
+ static char __initdata kmalloc_names[][17] = {
+ "0", "kmalloc-96", "kmalloc-192",
+ "kmalloc-8", "kmalloc-16", "kmalloc-32",
+ "kmalloc-64", "kmalloc-128", "kmalloc-256",
+ "kmalloc-512", "kmalloc-1024", "kmalloc-2048",
+ "kmalloc-4196", "kmalloc-8192", "kmalloc-16384",
+ "kmalloc-32768", "kmalloc-65536",
+ "kmalloc-131072", "kmalloc-262144",
+ "kmalloc-524288", "kmalloc-1048576",
+ "kmalloc-2097152", "kmalloc-4194304",
+ "kmalloc-8388608", "kmalloc-16777216",
+ "kmalloc-33554432", "kmalloc-67108864"
+ };
+
+ /*
* Patch up the size_index table if we have strange large alignment
* requirements for the kmalloc array. This is only the case for
* MIPS it seems. The standard arches will not generate any code here.
@@ -835,7 +855,8 @@ void __init create_kmalloc_caches(unsigned long flags)
}
for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {
if (!kmalloc_caches[i]) {
- kmalloc_caches[i] = create_kmalloc_cache(NULL,
+ kmalloc_caches[i] = create_kmalloc_cache(
+ kmalloc_names[i],
1 << i, flags);
}

@@ -845,10 +866,12 @@ void __init create_kmalloc_caches(unsigned long flags)
* earlier power of two caches
*/
if (KMALLOC_MIN_SIZE <= 32 && !kmalloc_caches[1] && i == 6)
- kmalloc_caches[1] = create_kmalloc_cache(NULL, 96, flags);
+ kmalloc_caches[1] = create_kmalloc_cache(
+ kmalloc_names[1], 96, flags);

if (KMALLOC_MIN_SIZE <= 64 && !kmalloc_caches[2] && i == 7)
- kmalloc_caches[2] = create_kmalloc_cache(NULL, 192, flags);
+ kmalloc_caches[2] = create_kmalloc_cache(
+ kmalloc_names[2], 192, flags);
}

/* Kmalloc array is now usable */
--
2.0.0


Subject: Re: [PATCH] mm/slab_common: Support the slub_debug boot option on specific object size

On Sat, 18 Apr 2015, Gavin Guo wrote:

> The slub_debug=PU,kmalloc-xx cannot work because in the
> create_kmalloc_caches() the s->name is created after the
> create_kmalloc_cache() is called. The name is NULL in the
> create_kmalloc_cache() so the kmem_cache_flags() would not set the
> slub_debug flags to the s->flags. The fix here set up a temporary
> kmalloc_names string array for the initialization purpose. After the
> kmalloc_caches are already it can be used to create s->name in the
> kasprintf.

Ok if you do that then the dynamic creation of the kmalloc hostname can
also be removed. This patch should do that as well.

2015-04-21 02:27:12

by Gavin Guo

[permalink] [raw]
Subject: Re: [PATCH] mm/slab_common: Support the slub_debug boot option on specific object size

Hi Christoph,

On Mon, Apr 20, 2015 at 11:40 PM, Christoph Lameter <[email protected]> wrote:
> On Sat, 18 Apr 2015, Gavin Guo wrote:
>
>> The slub_debug=PU,kmalloc-xx cannot work because in the
>> create_kmalloc_caches() the s->name is created after the
>> create_kmalloc_cache() is called. The name is NULL in the
>> create_kmalloc_cache() so the kmem_cache_flags() would not set the
>> slub_debug flags to the s->flags. The fix here set up a temporary
>> kmalloc_names string array for the initialization purpose. After the
>> kmalloc_caches are already it can be used to create s->name in the
>> kasprintf.
>
> Ok if you do that then the dynamic creation of the kmalloc hostname can
> also be removed. This patch should do that as well.

Thanks for your reply. I put the kmalloc_names in the __initdata
section. And it will be cleaned. Do you think the kmalloc_names should
be put in the global data section to avoid the dynamic creation of the
kmalloc hostname again?

Gavin

Subject: Re: [PATCH] mm/slab_common: Support the slub_debug boot option on specific object size

On Tue, 21 Apr 2015, Gavin Guo wrote:

> Thanks for your reply. I put the kmalloc_names in the __initdata
> section. And it will be cleaned. Do you think the kmalloc_names should
> be put in the global data section to avoid the dynamic creation of the
> kmalloc hostname again?

Yes.