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2009-02-20slab: introduce kzfree()Johannes Weiner
kzfree() is a wrapper for kfree() that additionally zeroes the underlying memory before releasing it to the slab allocator. Currently there is code which memset()s the memory region of an object before releasing it back to the slab allocator to make sure security-sensitive data are really zeroed out after use. These callsites can then just use kzfree() which saves some code, makes users greppable and allows for a stupid destructor that isn't necessarily aware of the actual object size. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Matt Mackall <mpm@selenic.com> Acked-by: Christoph Lameter <cl@linux-foundation.org> Cc: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-12-29Merge branches 'topic/fixes', 'topic/cleanups' and 'topic/documentation' ↵Pekka Enberg
into for-linus
2008-12-29slab: Fix comment on #endifPascal Terjan
This #endif in slab.h is described as closing the inner block while it's for the big CONFIG_NUMA one. That makes reading the code a bit harder. This trivial patch fixes the comment. Signed-off-by: Pascal Terjan <pterjan@mandriva.com> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
2008-11-26SLUB: Replace __builtin_return_address(0) with _RET_IP_.Eduard - Gabriel Munteanu
This patch replaces __builtin_return_address(0) with _RET_IP_, since a previous patch moved _RET_IP_ and _THIS_IP_ to include/linux/kernel.h and they're widely available now. This makes for shorter and easier to read code. [penberg@cs.helsinki.fi: remove _RET_IP_ casts to void pointer] Signed-off-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
2008-11-13slab: document SLAB_DESTROY_BY_RCUPeter Zijlstra
Explain this SLAB_DESTROY_BY_RCU thing... [hugh@veritas.com: add a pointer to comment in mm/slab.c] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Jens Axboe <jens.axboe@oracle.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Christoph Lameter <cl@linux-foundation.org> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
2008-10-23proc: move /proc/slabinfo boilerplate to mm/slub.c, mm/slab.cAlexey Dobriyan
Lose dummy ->write hook in case of SLUB, it's possible now. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
2008-07-26Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6Linus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: netns: fix ip_rt_frag_needed rt_is_expired netfilter: nf_conntrack_extend: avoid unnecessary "ct->ext" dereferences netfilter: fix double-free and use-after free netfilter: arptables in netns for real netfilter: ip{,6}tables_security: fix future section mismatch selinux: use nf_register_hooks() netfilter: ebtables: use nf_register_hooks() Revert "pkt_sched: sch_sfq: dump a real number of flows" qeth: use dev->ml_priv instead of dev->priv syncookies: Make sure ECN is disabled net: drop unused BUG_TRAP() net: convert BUG_TRAP to generic WARN_ON drivers/net: convert BUG_TRAP to generic WARN_ON
2008-07-26netfilter: fix double-free and use-after freePekka Enberg
As suggested by Patrick McHardy, introduce a __krealloc() that doesn't free the original buffer to fix a double-free and use-after-free bug introduced by me in netfilter that uses RCU. Reported-by: Patrick McHardy <kaber@trash.net> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi> Tested-by: Dieter Ries <clip2@gmx.de> Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2008-07-26SL*B: drop kmem cache argument from constructorAlexey Dobriyan
Kmem cache passed to constructor is only needed for constructors that are themselves multiplexeres. Nobody uses this "feature", nor does anybody uses passed kmem cache in non-trivial way, so pass only pointer to object. Non-trivial places are: arch/powerpc/mm/init_64.c arch/powerpc/mm/hugetlbpage.c This is flag day, yes. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Acked-by: Christoph Lameter <cl@linux-foundation.org> Cc: Jon Tollefson <kniht@linux.vnet.ibm.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Matt Mackall <mpm@selenic.com> [akpm@linux-foundation.org: fix arch/powerpc/mm/hugetlbpage.c] [akpm@linux-foundation.org: fix mm/slab.c] [akpm@linux-foundation.org: fix ubifs] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-24kcalloc: remove runtime divisionMilton Miller
While in all cases in the kernel we know the size of the elements to be created, we don't always know the count of elements. By commuting the size and count in the overflow check, the compiler can reduce the runtime division of size_t with a compare to a (unique) constant in these cases. Signed-off-by: Milton Miller <miltonm@bga.com> Cc: Takashi Iwai <tiwai@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-04Christoph has movedChristoph Lameter
Remove all clameter@sgi.com addresses from the kernel tree since they will become invalid on June 27th. Change my maintainer email address for the slab allocators to cl@linux-foundation.org (which will be the new email address for the future). Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Christoph Lameter <cl@linux-foundation.org> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Matt Mackall <mpm@selenic.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-06-06vm: add kzalloc_node() inlineJeff Layton
To get zeroed out memory from a particular NUMA node. To be used by sunrpc. Signed-off-by: Jeff Layton <jlayton@redhat.com> Cc: Christoph Lameter <clameter@sgi.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30Remove "#ifdef __KERNEL__" checks from unexported headersRobert P. J. Day
Remove the "#ifdef __KERNEL__" tests from unexported header files in linux/include whose entire contents are wrapped in that preprocessor test. Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30slab: add a flag to prevent debug_free checks on a kmem_cacheThomas Gleixner
This is a preperatory patch for the debugobjects infrastructure. The flag prevents debug_free checks on kmem_caches. This is necessary to avoid resursive calls into a debug mechanism which uses a kmem_cache itself. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-01-02Unify /proc/slabinfo configurationLinus Torvalds
Both SLUB and SLAB really did almost exactly the same thing for /proc/slabinfo setup, using duplicate code and per-allocator #ifdef's. This just creates a common CONFIG_SLABINFO that is enabled by both SLUB and SLAB, and shares all the setup code. Maybe SLOB will want this some day too. Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17Slab API: remove useless ctor parameter and reorder parametersChristoph Lameter
Slab constructors currently have a flags parameter that is never used. And the order of the arguments is opposite to other slab functions. The object pointer is placed before the kmem_cache pointer. Convert ctor(void *object, struct kmem_cache *s, unsigned long flags) to ctor(struct kmem_cache *s, void *object) throughout the kernel [akpm@linux-foundation.org: coupla fixes] Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16Group short-lived and reclaimable kernel allocationsMel Gorman
This patch marks a number of allocations that are either short-lived such as network buffers or are reclaimable such as inode allocations. When something like updatedb is called, long-lived and unmovable kernel allocations tend to be spread throughout the address space which increases fragmentation. This patch groups these allocations together as much as possible by adding a new MIGRATE_TYPE. The MIGRATE_RECLAIMABLE type is for allocations that can be reclaimed on demand, but not moved. i.e. they can be migrated by deleting them and re-reading the information from elsewhere. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Cc: Andy Whitcroft <apw@shadowen.org> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-20Fix ZERO_OR_NULL_PTR(ZERO_SIZE_PTR)Roland Dreier
The comparison with ZERO_SIZE_PTR in ZERO_OR_NULL_PTR() needs to be <= (not just <) so that ZERO_OR_NULL_PTR(ZERO_SIZE_PTR) is 1. Signed-off-by: Roland Dreier <rolandd@cisco.com> [ Duh! - Linus ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-20mm: Remove slab destructors from kmem_cache_create().Paul Mundt
Slab destructors were no longer supported after Christoph's c59def9f222d44bb7e2f0a559f2906191a0862d7 change. They've been BUGs for both slab and slub, and slob never supported them either. This rips out support for the dtor pointer from kmem_cache_create() completely and fixes up every single callsite in the kernel (there were about 224, not including the slab allocator definitions themselves, or the documentation references). Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2007-07-17Slab allocators: Cleanup zeroing allocationsChristoph Lameter
It becomes now easy to support the zeroing allocs with generic inline functions in slab.h. Provide inline definitions to allow the continued use of kzalloc, kmem_cache_zalloc etc but remove other definitions of zeroing functions from the slab allocators and util.c. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-17Slab allocators: consistent ZERO_SIZE_PTR support and NULL result semanticsChristoph Lameter
Define ZERO_OR_NULL_PTR macro to be able to remove the checks from the allocators. Move ZERO_SIZE_PTR related stuff into slab.h. Make ZERO_SIZE_PTR work for all slab allocators and get rid of the WARN_ON_ONCE(size == 0) that is still remaining in SLAB. Make slub return NULL like the other allocators if a too large memory segment is requested via __kmalloc. Signed-off-by: Christoph Lameter <clameter@sgi.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16slob: initial NUMA supportPaul Mundt
This adds preliminary NUMA support to SLOB, primarily aimed at systems with small nodes (tested all the way down to a 128kB SRAM block), whether asymmetric or otherwise. We follow the same conventions as SLAB/SLUB, preferring current node placement for new pages, or with explicit placement, if a node has been specified. Presently on UP NUMA this has the side-effect of preferring node#0 allocations (since numa_node_id() == 0, though this could be reworked if we could hand off a pfn to determine node placement), so single-CPU NUMA systems will want to place smaller nodes further out in terms of node id. Once a page has been bound to a node (via explicit node id typing), we only do block allocations from partial free pages that have a matching node id in the page flags. The current implementation does have some scalability problems, in that all partial free pages are tracked in the global freelist (with contention due to the single spinlock). However, these are things that are being reworked for SMP scalability first, while things like per-node freelists can easily be built on top of this sort of functionality once it's been added. More background can be found in: http://marc.info/?l=linux-mm&m=118117916022379&w=2 http://marc.info/?l=linux-mm&m=118170446306199&w=2 http://marc.info/?l=linux-mm&m=118187859420048&w=2 and subsequent threads. Acked-by: Christoph Lameter <clameter@sgi.com> Acked-by: Matt Mackall <mpm@selenic.com> Signed-off-by: Paul Mundt <lethal@linux-sh.org> Acked-by: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16Remove the deprecated "kmem_cache_t" typedef from slab.h.Robert P. J. Day
Given that there is no remaining usage of the deprecated kmem_cache_t typedef anywhere in the tree, remove that typedef. Signed-off-by: Robert P. J. Day <rpjday@mindspring.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-06-24slab allocators: MAX_ORDER one off fixChristoph Lameter
MAX_ORDER is the first order that is not possible. Use MAX_ORDER - 1 to calculate the larges possible object size in slab.h Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-17Slab allocators: define common size limitationsChristoph Lameter
Currently we have a maze of configuration variables that determine the maximum slab size. Worst of all it seems to vary between SLAB and SLUB. So define a common maximum size for kmalloc. For conveniences sake we use the maximum size ever supported which is 32 MB. We limit the maximum size to a lower limit if MAX_ORDER does not allow such large allocations. For many architectures this patch will have the effect of adding large kmalloc sizes. x86_64 adds 5 new kmalloc sizes. So a small amount of memory will be needed for these caches (contemporary SLAB has dynamically sizeable node and cpu structure so the waste is less than in the past) Most architectures will then be able to allocate object with sizes up to MAX_ORDER. We have had repeated breakage (in fact whenever we doubled the number of supported processors) on IA64 because one or the other struct grew beyond what the slab allocators supported. This will avoid future issues and f.e. avoid fixes for 2k and 4k cpu support. CONFIG_LARGE_ALLOCS is no longer necessary so drop it. It fixes sparc64 with SLAB. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-17Remove SLAB_CTOR_CONSTRUCTORChristoph Lameter
SLAB_CTOR_CONSTRUCTOR is always specified. No point in checking it. Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: David Howells <dhowells@redhat.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Steven French <sfrench@us.ibm.com> Cc: Michael Halcrow <mhalcrow@us.ibm.com> Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Dave Kleikamp <shaggy@austin.ibm.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: "J. Bruce Fields" <bfields@fieldses.org> Cc: Anton Altaparmakov <aia21@cantab.net> Cc: Mark Fasheh <mark.fasheh@oracle.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Jan Kara <jack@ucw.cz> Cc: David Chinner <dgc@sgi.com> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-17SLAB: Move two remaining SLAB specific definitions to slab_def.hChristoph Lameter
Two definitions remained in slab.h that are particular to the SLAB allocator. Move to slab_def.h Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07slab allocators: Remove SLAB_CTOR_ATOMICChristoph Lameter
SLAB_CTOR atomic is never used which is no surprise since I cannot imagine that one would want to do something serious in a constructor or destructor. In particular given that the slab allocators run with interrupts disabled. Actions in constructors and destructors are by their nature very limited and usually do not go beyond initializing variables and list operations. (The i386 pgd ctor and dtors do take a spinlock in constructor and destructor..... I think that is the furthest we go at this point.) There is no flag passed to the destructor so removing SLAB_CTOR_ATOMIC also establishes a certain symmetry. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07slab allocators: Remove SLAB_DEBUG_INITIAL flagChristoph Lameter
I have never seen a use of SLAB_DEBUG_INITIAL. It is only supported by SLAB. I think its purpose was to have a callback after an object has been freed to verify that the state is the constructor state again? The callback is performed before each freeing of an object. I would think that it is much easier to check the object state manually before the free. That also places the check near the code object manipulation of the object. Also the SLAB_DEBUG_INITIAL callback is only performed if the kernel was compiled with SLAB debugging on. If there would be code in a constructor handling SLAB_DEBUG_INITIAL then it would have to be conditional on SLAB_DEBUG otherwise it would just be dead code. But there is no such code in the kernel. I think SLUB_DEBUG_INITIAL is too problematic to make real use of, difficult to understand and there are easier ways to accomplish the same effect (i.e. add debug code before kfree). There is a related flag SLAB_CTOR_VERIFY that is frequently checked to be clear in fs inode caches. Remove the pointless checks (they would even be pointless without removeal of SLAB_DEBUG_INITIAL) from the fs constructors. This is the last slab flag that SLUB did not support. Remove the check for unimplemented flags from SLUB. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07KMEM_CACHE(): simplify slab cache creationChristoph Lameter
This patch provides a new macro KMEM_CACHE(<struct>, <flags>) to simplify slab creation. KMEM_CACHE creates a slab with the name of the struct, with the size of the struct and with the alignment of the struct. Additional slab flags may be specified if necessary. Example struct test_slab { int a,b,c; struct list_head; } __cacheline_aligned_in_smp; test_slab_cache = KMEM_CACHE(test_slab, SLAB_PANIC) will create a new slab named "test_slab" of the size sizeof(struct test_slab) and aligned to the alignment of test slab. If it fails then we panic. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07slab allocators: Remove obsolete SLAB_MUST_HWCACHE_ALIGNChristoph Lameter
This patch was recently posted to lkml and acked by Pekka. The flag SLAB_MUST_HWCACHE_ALIGN is 1. Never checked by SLAB at all. 2. A duplicate of SLAB_HWCACHE_ALIGN for SLUB 3. Fulfills the role of SLAB_HWCACHE_ALIGN for SLOB. The only remaining use is in sparc64 and ppc64 and their use there reflects some earlier role that the slab flag once may have had. If its specified then SLAB_HWCACHE_ALIGN is also specified. The flag is confusing, inconsistent and has no purpose. Remove it. Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07SLUB coreChristoph Lameter
This is a new slab allocator which was motivated by the complexity of the existing code in mm/slab.c. It attempts to address a variety of concerns with the existing implementation. A. Management of object queues A particular concern was the complex management of the numerous object queues in SLAB. SLUB has no such queues. Instead we dedicate a slab for each allocating CPU and use objects from a slab directly instead of queueing them up. B. Storage overhead of object queues SLAB Object queues exist per node, per CPU. The alien cache queue even has a queue array that contain a queue for each processor on each node. For very large systems the number of queues and the number of objects that may be caught in those queues grows exponentially. On our systems with 1k nodes / processors we have several gigabytes just tied up for storing references to objects for those queues This does not include the objects that could be on those queues. One fears that the whole memory of the machine could one day be consumed by those queues. C. SLAB meta data overhead SLAB has overhead at the beginning of each slab. This means that data cannot be naturally aligned at the beginning of a slab block. SLUB keeps all meta data in the corresponding page_struct. Objects can be naturally aligned in the slab. F.e. a 128 byte object will be aligned at 128 byte boundaries and can fit tightly into a 4k page with no bytes left over. SLAB cannot do this. D. SLAB has a complex cache reaper SLUB does not need a cache reaper for UP systems. On SMP systems the per CPU slab may be pushed back into partial list but that operation is simple and does not require an iteration over a list of objects. SLAB expires per CPU, shared and alien object queues during cache reaping which may cause strange hold offs. E. SLAB has complex NUMA policy layer support SLUB pushes NUMA policy handling into the page allocator. This means that allocation is coarser (SLUB does interleave on a page level) but that situation was also present before 2.6.13. SLABs application of policies to individual slab objects allocated in SLAB is certainly a performance concern due to the frequent references to memory policies which may lead a sequence of objects to come from one node after another. SLUB will get a slab full of objects from one node and then will switch to the next. F. Reduction of the size of partial slab lists SLAB has per node partial lists. This means that over time a large number of partial slabs may accumulate on those lists. These can only be reused if allocator occur on specific nodes. SLUB has a global pool of partial slabs and will consume slabs from that pool to decrease fragmentation. G. Tunables SLAB has sophisticated tuning abilities for each slab cache. One can manipulate the queue sizes in detail. However, filling the queues still requires the uses of the spin lock to check out slabs. SLUB has a global parameter (min_slab_order) for tuning. Increasing the minimum slab order can decrease the locking overhead. The bigger the slab order the less motions of pages between per CPU and partial lists occur and the better SLUB will be scaling. G. Slab merging We often have slab caches with similar parameters. SLUB detects those on boot up and merges them into the corresponding general caches. This leads to more effective memory use. About 50% of all caches can be eliminated through slab merging. This will also decrease slab fragmentation because partial allocated slabs can be filled up again. Slab merging can be switched off by specifying slub_nomerge on boot up. Note that merging can expose heretofore unknown bugs in the kernel because corrupted objects may now be placed differently and corrupt differing neighboring objects. Enable sanity checks to find those. H. Diagnostics The current slab diagnostics are difficult to use and require a recompilation of the kernel. SLUB contains debugging code that is always available (but is kept out of the hot code paths). SLUB diagnostics can be enabled via the "slab_debug" option. Parameters can be specified to select a single or a group of slab caches for diagnostics. This means that the system is running with the usual performance and it is much more likely that race conditions can be reproduced. I. Resiliency If basic sanity checks are on then SLUB is capable of detecting common error conditions and recover as best as possible to allow the system to continue. J. Tracing Tracing can be enabled via the slab_debug=T,<slabcache> option during boot. SLUB will then protocol all actions on that slabcache and dump the object contents on free. K. On demand DMA cache creation. Generally DMA caches are not needed. If a kmalloc is used with __GFP_DMA then just create this single slabcache that is needed. For systems that have no ZONE_DMA requirement the support is completely eliminated. L. Performance increase Some benchmarks have shown speed improvements on kernbench in the range of 5-10%. The locking overhead of slub is based on the underlying base allocation size. If we can reliably allocate larger order pages then it is possible to increase slub performance much further. The anti-fragmentation patches may enable further performance increases. Tested on: i386 UP + SMP, x86_64 UP + SMP + NUMA emulation, IA64 NUMA + Simulator SLUB Boot options slub_nomerge Disable merging of slabs slub_min_order=x Require a minimum order for slab caches. This increases the managed chunk size and therefore reduces meta data and locking overhead. slub_min_objects=x Mininum objects per slab. Default is 8. slub_max_order=x Avoid generating slabs larger than order specified. slub_debug Enable all diagnostics for all caches slub_debug=<options> Enable selective options for all caches slub_debug=<o>,<cache> Enable selective options for a certain set of caches Available Debug options F Double Free checking, sanity and resiliency R Red zoning P Object / padding poisoning U Track last free / alloc T Trace all allocs / frees (only use for individual slabs). To use SLUB: Apply this patch and then select SLUB as the default slab allocator. [hugh@veritas.com: fix an oops-causing locking error] [akpm@linux-foundation.org: various stupid cleanups and small fixes] Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07mm/slab.c: proper prototypesAdrian Bunk
Add proper prototypes in include/linux/slab.h. Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07slab: introduce kreallocPekka Enberg
This introduce krealloc() that reallocates memory while keeping the contents unchanged. The allocator avoids reallocation if the new size fits the currently used cache. I also added a simple non-optimized version for mm/slob.c for compatibility. [akpm@linux-foundation.org: fix warnings] Acked-by: Josef Sipek <jsipek@fsl.cs.sunysb.edu> Acked-by: Matt Mackall <mpm@selenic.com> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2006-12-13[PATCH] More slab.h cleanupsChristoph Lameter
More cleanups for slab.h 1. Remove tabs from weird locations as suggested by Pekka 2. Drop the check for NUMA and SLAB_DEBUG from the fallback section as suggested by Pekka. 3. Uses static inline for the fallback defs as also suggested by Pekka. 4. Make kmem_ptr_valid take a const * argument. 5. Separate the NUMA fallback definitions from the kmalloc_track fallback definitions. Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-13[PATCH] Cleanup slab headers / API to allow easy addition of new slab allocatorsChristoph Lameter
This is a response to an earlier discussion on linux-mm about splitting slab.h components per allocator. Patch is against 2.6.19-git11. See http://marc.theaimsgroup.com/?l=linux-mm&m=116469577431008&w=2 This patch cleans up the slab header definitions. We define the common functions of slob and slab in slab.h and put the extra definitions needed for slab's kmalloc implementations in <linux/slab_def.h>. In order to get a greater set of common functions we add several empty functions to slob.c and also rename slob's kmalloc to __kmalloc. Slob does not need any special definitions since we introduce a fallback case. If there is no need for a slab implementation to provide its own kmalloc mess^H^H^Hacros then we simply fall back to __kmalloc functions. That is sufficient for SLOB. Sort the function in slab.h according to their functionality. First the functions operating on struct kmem_cache * then the kmalloc related functions followed by special debug and fallback definitions. Also redo a lot of comments. Signed-off-by: Christoph Lameter <clameter@sgi.com>? Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07[PATCH] slab: deprecate kmem_cache_tAndrew Morton
Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07[PATCH] slab: remove SLAB_DMAChristoph Lameter
SLAB_DMA is an alias of GFP_DMA. This is the last one so we remove the leftover comment too. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07[PATCH] slab: remove SLAB_KERNELChristoph Lameter
SLAB_KERNEL is an alias of GFP_KERNEL. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07[PATCH] slab: remove SLAB_ATOMICChristoph Lameter
SLAB_ATOMIC is an alias of GFP_ATOMIC Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07[PATCH] slab: remove SLAB_USERChristoph Lameter
SLAB_USER is an alias of GFP_USER Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07[PATCH] slab: remove SLAB_NOFSChristoph Lameter
SLAB_NOFS is an alias of GFP_NOFS. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07[PATCH] slab: remove SLAB_NOIOChristoph Lameter
SLAB_NOIO is an alias of GFP_NOIO with a single instance of use. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07[PATCH] slab: remove SLAB_LEVEL_MASKChristoph Lameter
SLAB_LEVEL_MASK is only used internally to the slab and is and alias of GFP_LEVEL_MASK. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07[PATCH] slab: remove SLAB_NO_GROWChristoph Lameter
It is only used internally in the slab. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07[PATCH] Remove uses of kmem_cache_t from mm/* and include/linux/slab.hChristoph Lameter
Remove all uses of kmem_cache_t (the most were left in slab.h). The typedef for kmem_cache_t is then only necessary for other kernel subsystems. Add a comment to that effect. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07[PATCH] Move names_cachep to linux/fs.hChristoph Lameter
The names_cachep is used for getname() and putname(). So lets put it into fs.h near those two definitions. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07[PATCH] Move fs_cachep to linux/fs_struct.hChristoph Lameter
fs_cachep is only used in kernel/exit.c and in kernel/fork.c. It is used to store fs_struct items so it should be placed in linux/fs_struct.h Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07[PATCH] Move filep_cachep to include/file.hChristoph Lameter
filp_cachep is only used in fs/file_table.c and in fs/dcache.c where it is defined. Move it to related definitions in linux/file.h. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07[PATCH] Move files_cachep to include/file.hChristoph Lameter
Proper place is in file.h since files_cachep uses are rated to file I/O. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>