1. 02 2月, 2008 1 次提交
  2. 20 10月, 2007 1 次提交
  3. 17 5月, 2007 1 次提交
    • C
      Slab allocators: define common size limitations · 0aa817f0
      Christoph Lameter 提交于
      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: NChristoph Lameter <clameter@sgi.com>
      Signed-off-by: N"David S. Miller" <davem@davemloft.net>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      0aa817f0
  4. 10 5月, 2007 1 次提交
  5. 08 5月, 2007 1 次提交
    • C
      SLUB core · 81819f0f
      Christoph Lameter 提交于
      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: NChristoph Lameter <clameter@sgi.com>
      Signed-off-by: NHugh Dickins <hugh@veritas.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      81819f0f
  6. 12 2月, 2007 1 次提交
    • C
      [PATCH] optional ZONE_DMA: introduce CONFIG_ZONE_DMA · 66701b14
      Christoph Lameter 提交于
      This patch simply defines CONFIG_ZONE_DMA for all arches.  We later do special
      things with CONFIG_ZONE_DMA after the VM and an arch are prepared to work
      without ZONE_DMA.
      
      CONFIG_ZONE_DMA can be defined in two ways depending on how an architecture
      handles ISA DMA.
      
      First if CONFIG_GENERIC_ISA_DMA is set by the arch then we know that the arch
      needs ZONE_DMA because ISA DMA devices are supported.  We can catch this in
      mm/Kconfig and do not need to modify arch code.
      
      Second, arches may use ZONE_DMA in an unknown way.  We set CONFIG_ZONE_DMA for
      all arches that do not set CONFIG_GENERIC_ISA_DMA in order to insure backwards
      compatibility.  The arches may later undefine ZONE_DMA if their arch code has
      been verified to not depend on ZONE_DMA.
      Signed-off-by: NChristoph Lameter <clameter@sgi.com>
      Cc: Andi Kleen <ak@suse.de>
      Cc: "Luck, Tony" <tony.luck@intel.com>
      Cc: Kyle McMartin <kyle@mcmartin.ca>
      Cc: Matthew Wilcox <willy@debian.org>
      Cc: James Bottomley <James.Bottomley@steeleye.com>
      Cc: Paul Mundt <lethal@linux-sh.org>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      66701b14
  7. 09 12月, 2006 1 次提交
    • D
      [PATCH] LOG2: Implement a general integer log2 facility in the kernel · f0d1b0b3
      David Howells 提交于
      This facility provides three entry points:
      
      	ilog2()		Log base 2 of unsigned long
      	ilog2_u32()	Log base 2 of u32
      	ilog2_u64()	Log base 2 of u64
      
      These facilities can either be used inside functions on dynamic data:
      
      	int do_something(long q)
      	{
      		...;
      		y = ilog2(x)
      		...;
      	}
      
      Or can be used to statically initialise global variables with constant values:
      
      	unsigned n = ilog2(27);
      
      When performing static initialisation, the compiler will report "error:
      initializer element is not constant" if asked to take a log of zero or of
      something not reducible to a constant.  They treat negative numbers as
      unsigned.
      
      When not dealing with a constant, they fall back to using fls() which permits
      them to use arch-specific log calculation instructions - such as BSR on
      x86/x86_64 or SCAN on FRV - if available.
      
      [akpm@osdl.org: MMC fix]
      Signed-off-by: NDavid Howells <dhowells@redhat.com>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Herbert Xu <herbert@gondor.apana.org.au>
      Cc: David Howells <dhowells@redhat.com>
      Cc: Wojtek Kaniewski <wojtekka@toxygen.net>
      Signed-off-by: NAndrew Morton <akpm@osdl.org>
      Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      f0d1b0b3
  8. 03 10月, 2006 1 次提交
  9. 26 9月, 2006 2 次提交
  10. 07 9月, 2006 1 次提交
  11. 27 3月, 2006 1 次提交
  12. 15 2月, 2006 1 次提交
  13. 11 1月, 2006 1 次提交
    • A
      [PATCH] "tiny-make-id16-support-optional" fixes · 2308acca
      Adrian Bunk 提交于
      It seems the "make UID16 support optional" patch was checked when it
      edited the -tiny tree some time ago, but it wasn't checked whether it
      still matches the current situation when it was submitted for inclusion
      in -mm. This patch fixes the following bugs:
      - ARCH_S390X does no longer exist, nowadays this has to be expressed
        through (S390 && 64BIT)
      - in five architecture specific Kconfig files the UID16 options
        weren't removed
      
      Additionally, it changes the fragile negative dependencies of UID16 to
      positive dependencies (new architectures are more likely to not require
      UID16 support).
      Signed-off-by: NAdrian Bunk <bunk@stusta.de>
      Acked-by: NMatt Mackall <mpm@selenic.com>
      Signed-off-by: NAndrew Morton <akpm@osdl.org>
      Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      2308acca
  14. 09 1月, 2006 2 次提交
  15. 12 7月, 2005 1 次提交
    • S
      [NET]: add a top-level Networking menu to *config · d5950b43
      Sam Ravnborg 提交于
      Create a new top-level menu named "Networking" thus moving
      net related options and protocol selection way from the drivers
      menu and up on the top-level where they belong.
      
      To implement this all architectures has to source "net/Kconfig" before
      drivers/*/Kconfig in their Kconfig file. This change has been
      implemented for all architectures.
      
      Device drivers for ordinary NIC's are still to be found
      in the Device Drivers section, but Bluetooth, IrDA and ax25
      are located with their corresponding menu entries under the new
      networking menu item.
      Signed-off-by: NSam Ravnborg <sam@ravnborg.org>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      d5950b43
  16. 24 6月, 2005 1 次提交
  17. 17 4月, 2005 1 次提交
    • L
      Linux-2.6.12-rc2 · 1da177e4
      Linus Torvalds 提交于
      Initial git repository build. I'm not bothering with the full history,
      even though we have it. We can create a separate "historical" git
      archive of that later if we want to, and in the meantime it's about
      3.2GB when imported into git - space that would just make the early
      git days unnecessarily complicated, when we don't have a lot of good
      infrastructure for it.
      
      Let it rip!
      1da177e4