UP __alloc_percpu() triggered WARN_ON_ONCE() if the requested
alignment is larger than that of unsigned long long, which is too
small for all the cacheline aligned allocations.  Bump it up to
SMP_CACHE_BYTES which kmalloc allocations generally guarantee.
Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-by: NIngo Molnar <mingo@elte.hu>

Impact: build fix

the !SMP branch had a 'gfp' leftover:

 include/linux/percpu.h: In function '__alloc_percpu':
 include/linux/percpu.h:160: error: 'gfp' undeclared (first use in this function)
 include/linux/percpu.h:160: error: (Each undeclared identifier is reported only once
 include/linux/percpu.h:160: error: for each function it appears in.)

Use GFP_KERNEL like the SMP version does.

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: more latitude for first percpu chunk allocation

The first percpu chunk serves the kernel static percpu area and may or
may not contain extra room for further dynamic allocation.
Initialization of the first chunk needs to be done before normal
memory allocation service is up, so it has its own init path -
pcpu_setup_static().

It seems archs need more latitude while initializing the first chunk
for example to take advantage of large page mapping.  This patch makes
the following changes to allow this.

* Define PERCPU_DYNAMIC_RESERVE to give arch hint about how much space
  to reserve in the first chunk for further dynamic allocation.

* Rename pcpu_setup_static() to pcpu_setup_first_chunk().

* Make pcpu_setup_first_chunk() much more flexible by fetching page
  pointer by callback and adding optional @unit_size, @free_size and
  @base_addr arguments which allow archs to selectively part of chunk
  initialization to their likings.
Signed-off-by: NTejun Heo <tj@kernel.org>

Impact: new scalable dynamic percpu allocator which allows dynamic
        percpu areas to be accessed the same way as static ones

Implement scalable dynamic percpu allocator which can be used for both
static and dynamic percpu areas.  This will allow static and dynamic
areas to share faster direct access methods.  This feature is optional
and enabled only when CONFIG_HAVE_DYNAMIC_PER_CPU_AREA is defined by
arch.  Please read comment on top of mm/percpu.c for details.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>

Impact: kill unused functions

percpu_alloc() and its friends never saw much action.  It was supposed
to replace the cpu-mask unaware __alloc_percpu() but it never happened
and in fact __percpu_alloc_mask() itself never really grew proper
up/down handling interface either (no exported interface for
populate/depopulate).

percpu allocation is about to go through major reimplementation and
there's no reason to carry this unused interface around.  Replace it
with __alloc_percpu() and free_percpu().
Signed-off-by: NTejun Heo <tj@kernel.org>

This prepares for a real __alloc_percpu, by adding an alignment argument.
Only one place uses __alloc_percpu directly, and that's for a string.

tj: af_inet also uses __alloc_percpu(), update it.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Jens Axboe <axboe@kernel.dk>

Impact: cleanup

There are two allocated per-cpu accessor macros with almost identical
spelling.  The original and far more popular is per_cpu_ptr (44
files), so change over the other 4 files.

tj: kill percpu_ptr() and update UP too
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: mingo@redhat.com
Cc: lenb@kernel.org
Cc: cpufreq@vger.kernel.org
Signed-off-by: NTejun Heo <tj@kernel.org>

Impact: bug fix

IA-64 needs to put percpu data in the seperate section even on UP.
Fixes regression caused by "percpu: refactor percpu.h"
Signed-off-by: NBrian Gerst <brgerst@gmail.com>
Acked-by: NTony Luck <tony.luck@intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Impact: cleanup

Refactor the DEFINE_PER_CPU_* macros and add .data.percpu.first
section.
Signed-off-by: NBrian Gerst <brgerst@gmail.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

This patch makes the following needlessly global functions static:
 - percpu_depopulate()
 - __percpu_depopulate_mask()
 - percpu_populate()
 - __percpu_populate_mask()
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Acked-by: NChristoph Lameter <cl@linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

While examining holes in percpu section I found this :

c05f5000 D per_cpu__current_task
c05f5000 D __per_cpu_start
c05f5004 D per_cpu__cpu_number
c05f5008 D per_cpu__irq_regs
c05f500c d per_cpu__cpu_devices
c05f5040 D per_cpu__cyc2ns

<Big Hole of about 4000 bytes>

c05f6000 d per_cpu__cpuid4_info
c05f6004 d per_cpu__cache_kobject
c05f6008 d per_cpu__index_kobject

<Big Hole of about 4000 bytes>

c05f7000 D per_cpu__gdt_page

This is because gdt_page is a percpu variable, defined with
a page alignement, and linker is doing its job, two times because of .o
nesting in the build process.

I introduced a new macro DEFINE_PER_CPU_PAGE_ALIGNED() to avoid
wasting this space. All page aligned variables (only one at this time)
are put in a separate
subsection .data.percpu.page_aligned, at the very begining of percpu zone.

Before patch , on a x86_32 machine :

.data.percpu                30232   3227471872
.data.percpu                22168   3227471872

Thats 8064 bytes saved for each CPU.
Signed-off-by: NEric Dumazet <dada1@cosmosbay.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Current module loader lookups ".data.percpu" ELF section to perform
per_cpu relocation.  But DEFINE_PER_CPU_SHARED_ALIGNED() uses another
section (".data.percpu.shared_aligned"), currently only handled in
vmlinux.lds, not by module loader.

To correct this problem, instead of adding logic into module loader, or
using at build time a module.lds file for all arches to group
".data.percpu.shared_aligned" into ".data.percpu", just use ".data.percpu"
for modules.

Alignment requirements are correctly handled by ld and module loader.
Signed-off-by: NEric Dumazet <dada1@cosmosbay.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There's nothing in percpu.h that requires an explicit inclusion of
string.h.
Signed-off-by: NRobert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Instead of allocating a fix sized array of NR_CPUS pointers for percpu_data,
we can use nr_cpu_ids, which is generally < NR_CPUS.
Signed-off-by: NEric Dumazet <dada1@cosmosbay.com>
Cc: Christoph Lameter <clameter@sgi.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

ia64 has a special processor specific mapping that can be used to locate the
offset for the current per cpu area.

Cc: linux-ia64@vger.kernel.org
Signed-off-by: NMike Travis <travis@sgi.com>
Acked-by: NTony Luck <tony.luck@intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

- Special consideration for IA64: Add the ability to specify
  arch specific per cpu flags

- remove .data.percpu attribute from DEFINE_PER_CPU for non-smp case.

The arch definitions are all the same. So move them into linux/percpu.h.

We cannot move DECLARE_PER_CPU since some include files just include
asm/percpu.h to avoid include recursion problems.

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NMike Travis <travis@sgi.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Remove the obviously unnecessary includes of <linux/spinlock.h> under the
include/linux/ directory, and fix the couple errors that are introduced as
a result of that.
Signed-off-by: NRobert P. J. Day <rpjday@mindspring.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Rather than using a single constant PERCPU_ENOUGH_ROOM, compute it as
the sum of kernel_percpu + PERCPU_MODULE_RESERVE.  This is now common
to all architectures; if an architecture wants to set
PERCPU_ENOUGH_ROOM to something special, then it may do so (ia64 is
the only one which does).
Signed-off-by: NJeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: NAndi Kleen <ak@suse.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Andi Kleen <ak@suse.de>

Trivial typo fix in the "syntax error if percpu macros are incorrectly
used" patch.  I misspelled "identifier" in all places.  D'Oh!

Thanks to Dirk Mueller to point this out.
Signed-off-by: NJan Blunck <jblunck@suse.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

...  or we'll end up with cpu_online_map being evaluated on UP.  In
modules.  cpumask.h is very careful to avoid that, and for a very good
reason.  So should we...

PS: yes, it really triggers (on alpha).
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch splits alloc_percpu() up into two phases.  Likewise for
free_percpu().  This allows clients to limit initial allocations to online
cpu's, and to populate or depopulate per-cpu data at run time as needed:

  struct my_struct *obj;

  /* initial allocation for online cpu's */
  obj = percpu_alloc(sizeof(struct my_struct), GFP_KERNEL);

  ...

  /* populate per-cpu data for cpu coming online */
  ptr = percpu_populate(obj, sizeof(struct my_struct), GFP_KERNEL, cpu);

  ...

  /* access per-cpu object */
  ptr = percpu_ptr(obj, smp_processor_id());

  ...

  /* depopulate per-cpu data for cpu going offline */
  percpu_depopulate(obj, cpu);

  ...

  /* final removal */
  percpu_free(obj);
Signed-off-by: NMartin Peschke <mp3@de.ibm.com>
Cc: Paul Jackson <pj@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

get_cpu_var()/per_cpu()/__get_cpu_var() arguments must be simple
identifiers.  Otherwise the arch dependent implementations might break.

This patch enforces the correct usage of the macros by producing a syntax
error if the variable is not a simple identifier.
Signed-off-by: NJan Blunck <jblunck@suse.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

I found that blkp field was not used in kernel tree.

As most of the times NR_CPUS is a power of two and kmalloc() memory blocks
too, this extra field basically doubles the memory space allocated in
__alloc_percpu() to store the 'struct percpu_data'

(for example, if NR_CPUS=8 on i386, kmalloc(4*8+4) returns a 64 bytes block
instead of a 32 bytes block after this patch)
Signed-off-by: NEric Dumazet <dada1@cosmosbay.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

__alloc_percpu and alloc_percpu both take an 'align' argument which is
completely ignored.  snmp6_mib_init() in net/ipv6/af_inet6.c attempts to use
it, but it will be ignored.  Therefore, remove the 'align' argument and fixup
the lone caller.
Signed-off-by: NMatthew Dobson <colpatch@us.ibm.com>
Acked-by: NManfred Spraul <manfred@colorfullife.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Currently per_cpu_ptr() doesn't really do anything with 'cpu' in the UP
case.  This is problematic in the cases where this is the only place the
variable is referenced:

  CC      kernel/workqueue.o
  kernel/workqueue.c: In function `current_is_keventd':
  kernel/workqueue.c:460: warning: unused variable `cpu'
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

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!