C12 [00/19] Sl[auo]b: Common code rework V12

C12 [00/19] Sl[auo]b: Common code rework V12

[Christoph Lameter]

V11->V12
- Rediff against current slab/next from Pekka
- Drop label name change patch

V10->V11
- Fix issues pointed out by Joonsoo and Glauber
- Simplify Slab bootstrap further

V9->V10
- Memory leak was a false alarm
- Resequence patches to make it easier
  to apply.
- Do more boot sequence consolidation in slab/slub.
  [We could still do much more like common kmalloc
  handling]
- Fixes suggested by David and Glauber

V8->V9:
- Fix numerous things pointed out by Glauber.
- Cleanup the way error handling works in the
  common kmem_cache_create() function.
- General cleanup by breaking things up
  into multiple patches were necessary.

V7->V8:
- Do not use kfree for kmem_cache in slub.
- Add more patches up to a common
  scheme for object alignment.

V6->V7:
- Omit pieces that were merged for 3.6
- Fix issues pointed out by Glauber.
- Include the patches up to the point at which
  the slab name handling is unified

V5->V6:
- Patches against Pekka's for-next tree.
- Go slow and cut down to just patches that are safe
  (there will likely be some churn already due to the
  mutex unification between slabs)
- More to come next week when I have more time (
  took me almost the whole week to catch up after
  being gone for awhile).

V4->V5
- Rediff against current upstream + Pekka's cleanup branch.

V3->V4:
- Do not use the COMMON macro anymore.
- Fixup various issues
- No general sysfs support yet due to lockdep issues with
  keys in kmalloc'ed memory.

V2->V3:
- Incorporate more feedback from Joonsoo Kim and Glauber Costa
- And a couple more patches to deal with slab duping and move
  more code to slab_common.c

V1->V2:
- Incorporate glommers feedback.
- Add 2 more patches dealing with common code in kmem_cache_destroy

This is a series of patches that extracts common functionality from
slab allocators into a common code base. The intend is to standardize
as much as possible of the allocator behavior while keeping the
distinctive features of each allocator which are mostly due to their
storage format and serialization approaches.

This patchset makes a beginning by extracting common functionality in
kmem_cache_create() and kmem_cache_destroy(). However, there are
numerous other areas where such work could be beneficial:

1. Extract the sysfs support from SLUB and make it common. That way
   all allocators have a common sysfs API and are handleable in the same
   way regardless of the allocator chose.

2. Extract the error reporting and checking from SLUB and make
   it available for all allocators. This means that all allocators
   will gain the resiliency and error handling capabilties.

3. Extract the memory hotplug and cpu hotplug handling. It seems that
   SLAB may be more sophisticated here. Having common code here will
   make it easier to maintain the special code.

4. Extract the aliasing capability of SLUB. This will enable fast
   slab creation without creating too many additional slab caches.
   The arrays of caches of varying sizes in numerous subsystems
   do not cause the creation of numerous slab caches. Storage
   density is increased and the cache footprint is reduced.

Ultimately it is to be hoped that the special code for each allocator
shrinks to a mininum. This will also make it easier to make modification
to allocators.

In the far future one could envision that the current allocators will
just become storage algorithms that can be chosen based on the need of
the subsystem. F.e.

Cpu cache dependend performance		= Bonwick allocator (SLAB)
Minimal cycle count and cache footprint	= SLUB
Maximum storage density			= K&R allocator (SLOB)


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Re: C12 [00/19] Sl[auo]b: Common code rework V12

[Christoph Lameter]

Sorry guys "quit mail" seems to have the hiccups today. It creates
content-disposition headers which are not liked too much by my email
provider.

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Re: C12 [00/19] Sl[auo]b: Common code rework V12

[Glauber Costa]

[-- Attachment #1: Type: text/plain, Size: 4959 bytes --]

On 08/21/2012 12:03 AM, Christoph Lameter wrote:
> V11->V12
> - Rediff against current slab/next from Pekka
> - Drop label name change patch
> 
> V10->V11
> - Fix issues pointed out by Joonsoo and Glauber
> - Simplify Slab bootstrap further
> 
> V9->V10
> - Memory leak was a false alarm
> - Resequence patches to make it easier
>   to apply.
> - Do more boot sequence consolidation in slab/slub.
>   [We could still do much more like common kmalloc
>   handling]
> - Fixes suggested by David and Glauber
> 
> V8->V9:
> - Fix numerous things pointed out by Glauber.
> - Cleanup the way error handling works in the
>   common kmem_cache_create() function.
> - General cleanup by breaking things up
>   into multiple patches were necessary.
> 
> V7->V8:
> - Do not use kfree for kmem_cache in slub.
> - Add more patches up to a common
>   scheme for object alignment.
> 
> V6->V7:
> - Omit pieces that were merged for 3.6
> - Fix issues pointed out by Glauber.
> - Include the patches up to the point at which
>   the slab name handling is unified
> 
> V5->V6:
> - Patches against Pekka's for-next tree.
> - Go slow and cut down to just patches that are safe
>   (there will likely be some churn already due to the
>   mutex unification between slabs)
> - More to come next week when I have more time (
>   took me almost the whole week to catch up after
>   being gone for awhile).
> 
> V4->V5
> - Rediff against current upstream + Pekka's cleanup branch.
> 
> V3->V4:
> - Do not use the COMMON macro anymore.
> - Fixup various issues
> - No general sysfs support yet due to lockdep issues with
>   keys in kmalloc'ed memory.
> 
> V2->V3:
> - Incorporate more feedback from Joonsoo Kim and Glauber Costa
> - And a couple more patches to deal with slab duping and move
>   more code to slab_common.c
> 
> V1->V2:
> - Incorporate glommers feedback.
> - Add 2 more patches dealing with common code in kmem_cache_destroy
> 
> This is a series of patches that extracts common functionality from
> slab allocators into a common code base. The intend is to standardize
> as much as possible of the allocator behavior while keeping the
> distinctive features of each allocator which are mostly due to their
> storage format and serialization approaches.
> 
> This patchset makes a beginning by extracting common functionality in
> kmem_cache_create() and kmem_cache_destroy(). However, there are
> numerous other areas where such work could be beneficial:
> 
> 1. Extract the sysfs support from SLUB and make it common. That way
>    all allocators have a common sysfs API and are handleable in the same
>    way regardless of the allocator chose.
> 
> 2. Extract the error reporting and checking from SLUB and make
>    it available for all allocators. This means that all allocators
>    will gain the resiliency and error handling capabilties.
> 
> 3. Extract the memory hotplug and cpu hotplug handling. It seems that
>    SLAB may be more sophisticated here. Having common code here will
>    make it easier to maintain the special code.
> 
> 4. Extract the aliasing capability of SLUB. This will enable fast
>    slab creation without creating too many additional slab caches.
>    The arrays of caches of varying sizes in numerous subsystems
>    do not cause the creation of numerous slab caches. Storage
>    density is increased and the cache footprint is reduced.
> 
> Ultimately it is to be hoped that the special code for each allocator
> shrinks to a mininum. This will also make it easier to make modification
> to allocators.
> 
> In the far future one could envision that the current allocators will
> just become storage algorithms that can be chosen based on the need of
> the subsystem. F.e.
> 
> Cpu cache dependend performance		= Bonwick allocator (SLAB)
> Minimal cycle count and cache footprint	= SLUB
> Maximum storage density			= K&R allocator (SLOB)
> 
> 
With the whole series applied, I get a bug (dmesg attached). Allocator
is SLUB, with all the debugging options ontop.

Triggered by executing the test routine "mybug()" after the kernel is
fully functional, and then issuing "cat /proc/slabinfo".

This is the test case I was using before, but this time it all works
immediately after the caches are destructed and recreated - so it's
better. But transversing the list triggers it.

Code I used is below:

void mybug(void)
{
        struct kmem_cache *c1;

        c1 = KMEM_CACHE(st1,
                SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|SLAB_MEM_SPREAD);

        printk("c1: %p\n", c1);
        kmem_cache_destroy(c1);

        c1 = KMEM_CACHE(st1,
                SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|SLAB_MEM_SPREAD);
        printk("c1 again: %p\n", c1);

        kmem_cache_destroy(c1);
}

I tried to bisect it to the precise point, but I couldn't. The series is
not runtime bisectable. Since it is such a fragile code, having all
patches to at least boot would be of great help. (I'll post the output
in reply to the relevant patch)






[-- Attachment #2: newbug --]
[-- Type: text/plain, Size: 2315 bytes --]

[   61.334165] general protection fault: 0000 [#1] SMP 
[   61.335015] Modules linked in:
[   61.335015] CPU 0 
[   61.335015] Pid: 1152, comm: cat Not tainted 3.6.0-rc1+ #452 Bochs Bochs
[   61.335015] RIP: 0010:[<ffffffff81134a9c>]  [<ffffffff81134a9c>] s_show+0x42/0x111
[   61.335015] RSP: 0018:ffff88003a49bde8  EFLAGS: 00010286
[   61.335015] RAX: 0000000000000000 RBX: ffff880037972000 RCX: 0000000000000000
[   61.335015] RDX: 0000000000000000 RSI: 0000000000000200 RDI: 840f04f883078b41
[   61.335015] RBP: ffff88003a49be38 R08: ffffffff81b8a948 R09: 00000000fffffffd
[   61.335015] R10: 0000000038320000 R11: 0000000000000000 R12: 0000000000000000
[   61.335015] R13: ffffffff81b8a948 R14: 0000000000000000 R15: 0000000000000000
[   61.335015] FS:  00007f2af63d5720(0000) GS:ffff88003ea00000(0000) knlGS:0000000000000000
[   61.335015] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[   61.335015] CR2: 00000000025ee000 CR3: 000000003b443000 CR4: 00000000000006f0
[   61.335015] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   61.335015] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[   61.335015] Process cat (pid: 1152, threadinfo ffff88003a49a000, task ffff88003a27c220)
[   61.335015] Stack:
[   61.335015]  0000000000000013 ffffffff00000002 ffff880037972000 ffff880000000000
[   61.335015]  ffff88003a49be38 0000000000000000 0000000000008000 ffff88003a49bf60
[   61.335015]  ffff880037972000 ffff880037b2a500 ffff88003a49bea8 ffffffff81162fbb
[   61.335015] Call Trace:
[   61.335015]  [<ffffffff81162fbb>] seq_read+0x28e/0x371
[   61.335015]  [<ffffffff81162d2d>] ? seq_lseek+0xd2/0xd2
[   61.335015]  [<ffffffff81199c8e>] proc_reg_read+0x8d/0xac
[   61.335015]  [<ffffffff81146e88>] vfs_read+0x9d/0xff
[   61.335015]  [<ffffffff811480ff>] ? fget_light+0x38/0x99
[   61.335015]  [<ffffffff81146f2d>] sys_read+0x43/0x70
[   61.335015]  [<ffffffff8152dd69>] system_call_fastpath+0x16/0x1b
[   61.335015] Code: 31 ff 45 31 f6 45 31 e4 48 89 fb 48 c7 c7 10 d2 ae 81 49 89 f5 e8 79 e7 ff ff 89 c2 eb 40 48 63 c2 49 8b 7c c5 58 48 85 ff 74 23 <48> 8b 47 50 48 c7 c6 84 30 13 81 49 01 c4 48 8b 47 58 89 55 c8 
[   61.335015] RIP  [<ffffffff81134a9c>] s_show+0x42/0x111
[   61.335015]  RSP <ffff88003a49bde8>
[   61.376508] ---[ end trace 9afcc456cc5b11e1 ]---

C12 [00/19] Sl[auo]b: Common code rework V12

[Christoph Lameter]

V11->V12
- Rediff against current slab/next from Pekka
- Drop the label renaming patch
- Also available via git at git://gentwo.org/christoph common

V10->V11
- Fix issues pointed out by Joonsoo and Glauber
- Simplify Slab bootstrap further

V9->V10
- Memory leak was a false alarm
- Resequence patches to make it easier
  to apply.
- Do more boot sequence consolidation in slab/slub.
  [We could still do much more like common kmalloc
  handling]
- Fixes suggested by David and Glauber

V8->V9:
- Fix numerous things pointed out by Glauber.
- Cleanup the way error handling works in the
  common kmem_cache_create() function.
- General cleanup by breaking things up
  into multiple patches were necessary.

V7->V8:
- Do not use kfree for kmem_cache in slub.
- Add more patches up to a common
  scheme for object alignment.

V6->V7:
- Omit pieces that were merged for 3.6
- Fix issues pointed out by Glauber.
- Include the patches up to the point at which
  the slab name handling is unified

V5->V6:
- Patches against Pekka's for-next tree.
- Go slow and cut down to just patches that are safe
  (there will likely be some churn already due to the
  mutex unification between slabs)
- More to come next week when I have more time (
  took me almost the whole week to catch up after
  being gone for awhile).

V4->V5
- Rediff against current upstream + Pekka's cleanup branch.

V3->V4:
- Do not use the COMMON macro anymore.
- Fixup various issues
- No general sysfs support yet due to lockdep issues with
  keys in kmalloc'ed memory.

V2->V3:
- Incorporate more feedback from Joonsoo Kim and Glauber Costa
- And a couple more patches to deal with slab duping and move
  more code to slab_common.c

V1->V2:
- Incorporate glommers feedback.
- Add 2 more patches dealing with common code in kmem_cache_destroy

This is a series of patches that extracts common functionality from
slab allocators into a common code base. The intend is to standardize
as much as possible of the allocator behavior while keeping the
distinctive features of each allocator which are mostly due to their
storage format and serialization approaches.

This patchset makes a beginning by extracting common functionality in
kmem_cache_create() and kmem_cache_destroy(). However, there are
numerous other areas where such work could be beneficial:

1. Extract the sysfs support from SLUB and make it common. That way
   all allocators have a common sysfs API and are handleable in the same
   way regardless of the allocator chose.

2. Extract the error reporting and checking from SLUB and make
   it available for all allocators. This means that all allocators
   will gain the resiliency and error handling capabilties.

3. Extract the memory hotplug and cpu hotplug handling. It seems that
   SLAB may be more sophisticated here. Having common code here will
   make it easier to maintain the special code.

4. Extract the aliasing capability of SLUB. This will enable fast
   slab creation without creating too many additional slab caches.
   The arrays of caches of varying sizes in numerous subsystems
   do not cause the creation of numerous slab caches. Storage
   density is increased and the cache footprint is reduced.

Ultimately it is to be hoped that the special code for each allocator
shrinks to a mininum. This will also make it easier to make modification
to allocators.

In the far future one could envision that the current allocators will
just become storage algorithms that can be chosen based on the need of
the subsystem. F.e.

Cpu cache dependend performance		= Bonwick allocator (SLAB)
Minimal cycle count and cache footprint	= SLUB
Maximum storage density			= K&R allocator (SLOB)


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