linux.git/include/asm-powerpc/mman.h, branch master

powerpc: Move include files to arch/powerpc/include/asm

2008-08-04T02:02:00+00:00

from include/asm-powerpc.  This is the result of a

mkdir arch/powerpc/include/asm
git mv include/asm-powerpc/* arch/powerpc/include/asm

Followed by a few documentation/comment fixups and a couple of places
where  was being used explicitly.  Of the latter only
one was outside the arch code and it is a driver only built for powerpc.

Signed-off-by: Stephen Rothwell 
Signed-off-by: Paul Mackerras

powerpc: mman.h export fixups

2008-07-15T02:24:53+00:00

Commit ef3d3246a0d06be622867d21af25f997aeeb105f ("powerpc/mm: Add Strong
Access Ordering support") in the powerpc/{next,master} tree caused the
following in a powerpc allmodconfig build:

usr/include/asm/mman.h requires linux/mm.h, which does not exist in exported headers

We should not use CONFIG_PPC64 in an unprotected (by __KERNEL__)
section of an exported include file and linux/mm.h is not exported.  So
protect the whole section that is CONFIG_PPC64 with __KERNEL__ and put
the two introduced includes in there as well.

Signed-off-by: Stephen Rothwell 
Acked-by: Dave Kleikamp 
Signed-off-by: Benjamin Herrenschmidt

powerpc/mm: Add Strong Access Ordering support

2008-07-09T06:30:45+00:00

Allow an application to enable Strong Access Ordering on specific pages of
memory on Power 7 hardware. Currently, power has a weaker memory model than
x86. Implementing a stronger memory model allows an emulator to more
efficiently translate x86 code into power code, resulting in faster code
execution.

On Power 7 hardware, storing 0b1110 in the WIMG bits of the hpte enables
strong access ordering mode for the memory page.  This patchset allows a
user to specify which pages are thus enabled by passing a new protection
bit through mmap() and mprotect().  I have defined PROT_SAO to be 0x10.

Signed-off-by: Dave Kleikamp 
Signed-off-by: Benjamin Herrenschmidt

powerpc/mm: Define flags for Strong Access Ordering

2008-07-09T06:30:45+00:00

This patch defines:

- PROT_SAO, which is passed into mmap() and mprotect() in the prot field
- VM_SAO in vma->vm_flags, and
- _PAGE_SAO, the combination of WIMG bits in the pte that enables strong
access ordering for the page.

Signed-off-by: Dave Kleikamp 
Signed-off-by: Benjamin Herrenschmidt

[PATCH] add asm-generic/mman.h

2006-02-15T23:32:22+00:00

Make new MADV_REMOVE, MADV_DONTFORK, MADV_DOFORK consistent across all
arches.  The idea is to make it possible to use them portably even before
distros include them in libc headers.

Move common flags to asm-generic/mman.h

Signed-off-by: Michael S. Tsirkin 
Cc: Roland Dreier 
Cc: Badari Pulavarty 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] madvise MADV_DONTFORK/MADV_DOFORK

2006-02-15T00:09:34+00:00

Currently, copy-on-write may change the physical address of a page even if the
user requested that the page is pinned in memory (either by mlock or by
get_user_pages).  This happens if the process forks meanwhile, and the parent
writes to that page.  As a result, the page is orphaned: in case of
get_user_pages, the application will never see any data hardware DMA's into
this page after the COW.  In case of mlock'd memory, the parent is not getting
the realtime/security benefits of mlock.

In particular, this affects the Infiniband modules which do DMA from and into
user pages all the time.

This patch adds madvise options to control whether memory range is inherited
across fork.  Useful e.g.  for when hardware is doing DMA from/into these
pages.  Could also be useful to an application wanting to speed up its forks
by cutting large areas out of consideration.

Signed-off-by: Michael S. Tsirkin 
Acked-by: Hugh Dickins 
Cc: Michael Kerrisk 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] madvise(MADV_REMOVE): remove pages from tmpfs shm backing store

2006-01-06T16:33:22+00:00

Here is the patch to implement madvise(MADV_REMOVE) - which frees up a
given range of pages & its associated backing store.  Current
implementation supports only shmfs/tmpfs and other filesystems return
-ENOSYS.

"Some app allocates large tmpfs files, then when some task quits and some
client disconnect, some memory can be released.  However the only way to
release tmpfs-swap is to MADV_REMOVE". - Andrea Arcangeli

Databases want to use this feature to drop a section of their bufferpool
(shared memory segments) - without writing back to disk/swap space.

This feature is also useful for supporting hot-plug memory on UML.

Concerns raised by Andrew Morton:

- "We have no plan for holepunching!  If we _do_ have such a plan (or
  might in the future) then what would the API look like?  I think
  sys_holepunch(fd, start, len), so we should start out with that."

- Using madvise is very weird, because people will ask "why do I need to
  mmap my file before I can stick a hole in it?"

- None of the other madvise operations call into the filesystem in this
  manner.  A broad question is: is this capability an MM operation or a
  filesytem operation?  truncate, for example, is a filesystem operation
  which sometimes has MM side-effects.  madvise is an mm operation and with
  this patch, it gains FS side-effects, only they're really, really
  significant ones."

Comments:

- Andrea suggested the fs operation too but then it's more efficient to
  have it as a mm operation with fs side effects, because they don't
  immediatly know fd and physical offset of the range.  It's possible to
  fixup in userland and to use the fs operation but it's more expensive,
  the vmas are already in the kernel and we can use them.

Short term plan &  Future Direction:

- We seem to need this interface only for shmfs/tmpfs files in the short
  term.  We have to add hooks into the filesystem for correctness and
  completeness.  This is what this patch does.

- In the future, plan is to support both fs and mmap apis also.  This
  also involves (other) filesystem specific functions to be implemented.

- Current patch doesn't support VM_NONLINEAR - which can be addressed in
  the future.

Signed-off-by: Badari Pulavarty 
Cc: Hugh Dickins 
Cc: Andrea Arcangeli 
Cc: Michael Kerrisk 
Cc: Ulrich Drepper 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] powerpc: Standardize on _ASM_POWERPC header symbol prefix

2005-09-09T12:11:34+00:00

Standardize on _ASM_POWERPC_... prefix for all #include
exclusion symbols.  Fixup all the non-compilers.

Signed-off-by: Jon Loeliger 
Signed-off-by: Kumar Gala 
Signed-off-by: Paul Mackerras

[PATCH] Move 3 more headers to asm-powerpc

2005-09-06T06:07:53+00:00

Merged several nearly-identical header files from asm-ppc and asm-ppc64
into asm-powerpc.

Signed-off-by: Kumar Gala 
Signed-off-by: Becky Bruce 
Signed-off-by: Paul Mackerras