linux-toradex.git/include/linux/mm.h, branch v2.6.18-rc7

[PATCH] fuse: fix error case in fuse_readpages

2006-08-14T19:54:29+00:00

Don't let fuse_readpages leave the @pages list not empty when exiting
on error.

[akpm@osdl.org: kernel-doc fixes]
Signed-off-by: Alexander Zarochentsev 
Signed-off-by: Miklos Szeredi 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

[PATCH] lockdep: better lock debugging

2006-07-03T22:27:01+00:00

Generic lock debugging:

 - generalized lock debugging framework. For example, a bug in one lock
   subsystem turns off debugging in all lock subsystems.

 - got rid of the caller address passing (__IP__/__IP_DECL__/etc.) from
   the mutex/rtmutex debugging code: it caused way too much prototype
   hackery, and lockdep will give the same information anyway.

 - ability to do silent tests

 - check lock freeing in vfree too.

 - more finegrained debugging options, to allow distributions to
   turn off more expensive debugging features.

There's no separate 'held mutexes' list anymore - but there's a 'held locks'
stack within lockdep, which unifies deadlock detection across all lock
classes.  (this is independent of the lockdep validation stuff - lockdep first
checks whether we are holding a lock already)

Here are the current debugging options:

CONFIG_DEBUG_MUTEXES=y
CONFIG_DEBUG_LOCK_ALLOC=y

which do:

 config DEBUG_MUTEXES
          bool "Mutex debugging, basic checks"

 config DEBUG_LOCK_ALLOC
         bool "Detect incorrect freeing of live mutexes"

Signed-off-by: Ingo Molnar 
Signed-off-by: Arjan van de Ven 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] zoned vm counters: create vmstat.c/.h from page_alloc.c/.h

2006-06-30T18:25:34+00:00

NOTE: ZVC are *not* the lightweight event counters.  ZVCs are reliable whereas
event counters do not need to be.

Zone based VM statistics are necessary to be able to determine what the state
of memory in one zone is.  In a NUMA system this can be helpful for local
reclaim and other memory optimizations that may be able to shift VM load in
order to get more balanced memory use.

It is also useful to know how the computing load affects the memory
allocations on various zones.  This patchset allows the retrieval of that data
from userspace.

The patchset introduces a framework for counters that is a cross between the
existing page_stats --which are simply global counters split per cpu-- and the
approach of deferred incremental updates implemented for nr_pagecache.

Small per cpu 8 bit counters are added to struct zone.  If the counter exceeds
certain thresholds then the counters are accumulated in an array of
atomic_long in the zone and in a global array that sums up all zone values.
The small 8 bit counters are next to the per cpu page pointers and so they
will be in high in the cpu cache when pages are allocated and freed.

Access to VM counter information for a zone and for the whole machine is then
possible by simply indexing an array (Thanks to Nick Piggin for pointing out
that approach).  The access to the total number of pages of various types does
no longer require the summing up of all per cpu counters.

Benefits of this patchset right now:

- Ability for UP and SMP configuration to determine how memory
  is balanced between the DMA, NORMAL and HIGHMEM zones.

- loops over all processors are avoided in writeback and
  reclaim paths. We can avoid caching the writeback information
  because the needed information is directly accessible.

- Special handling for nr_pagecache removed.

- zone_reclaim_interval vanishes since VM stats can now determine
  when it is worth to do local reclaim.

- Fast inline per node page state determination.

- Accurate counters in /sys/devices/system/node/node*/meminfo. Current
  counters are counting simply which processor allocated a page somewhere
  and guestimate based on that. So the counters were not useful to show
  the actual distribution of page use on a specific zone.

- The swap_prefetch patch requires per node statistics in order to
  figure out when processors of a node can prefetch. This patch provides
  some of the needed numbers.

- Detailed VM counters available in more /proc and /sys status files.

References to earlier discussions:
V1 http://marc.theaimsgroup.com/?l=linux-kernel&m=113511649910826&w=2
V2 http://marc.theaimsgroup.com/?l=linux-kernel&m=114980851924230&w=2
V3 http://marc.theaimsgroup.com/?l=linux-kernel&m=115014697910351&w=2
V4 http://marc.theaimsgroup.com/?l=linux-kernel&m=115024767318740&w=2

Performance tests with AIM7 did not show any regressions.  Seems to be a tad
faster even.  Tested on ia64/NUMA.  Builds fine on i386, SMP / UP.  Includes
fixes for s390/arm/uml arch code.

This patch:

Move counter code from page_alloc.c/page-flags.h to vmstat.c/h.

Create vmstat.c/vmstat.h by separating the counter code and the proc
functions.

Move the vm_stat_text array before zoneinfo_show.

[akpm@osdl.org: s390 build fix]
[akpm@osdl.org: HOTPLUG_CPU build fix]
Signed-off-by: Christoph Lameter 
Cc: Heiko Carstens 
Cc: Martin Schwidefsky 
Cc: Trond Myklebust 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] pi-futex: rt mutex debug

2006-06-28T00:32:47+00:00

Runtime debugging functionality for rt-mutexes.

Signed-off-by: Ingo Molnar 
Signed-off-by: Thomas Gleixner 
Signed-off-by: Arjan van de Ven 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] pi-futex: introduce debug_check_no_locks_freed()

2006-06-28T00:32:46+00:00

Add debug_check_no_locks_freed(), as a central inline to add
bad-lock-free-debugging functionality to.

Signed-off-by: Ingo Molnar 
Signed-off-by: Thomas Gleixner 
Signed-off-by: Arjan van de Ven 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] vdso: randomize the i386 vDSO by moving it into a vma

2006-06-28T00:32:38+00:00

Move the i386 VDSO down into a vma and thus randomize it.

Besides the security implications, this feature also helps debuggers, which
can COW a vma-backed VDSO just like a normal DSO and can thus do
single-stepping and other debugging features.

It's good for hypervisors (Xen, VMWare) too, which typically live in the same
high-mapped address space as the VDSO, hence whenever the VDSO is used, they
get lots of guest pagefaults and have to fix such guest accesses up - which
slows things down instead of speeding things up (the primary purpose of the
VDSO).

There's a new CONFIG_COMPAT_VDSO (default=y) option, which provides support
for older glibcs that still rely on a prelinked high-mapped VDSO.  Newer
distributions (using glibc 2.3.3 or later) can turn this option off.  Turning
it off is also recommended for security reasons: attackers cannot use the
predictable high-mapped VDSO page as syscall trampoline anymore.

There is a new vdso=[0|1] boot option as well, and a runtime
/proc/sys/vm/vdso_enabled sysctl switch, that allows the VDSO to be turned
on/off.

(This version of the VDSO-randomization patch also has working ELF
coredumping, the previous patch crashed in the coredumping code.)

This code is a combined work of the exec-shield VDSO randomization
code and Gerd Hoffmann's hypervisor-centric VDSO patch. Rusty Russell
started this patch and i completed it.

[akpm@osdl.org: cleanups]
[akpm@osdl.org: compile fix]
[akpm@osdl.org: compile fix 2]
[akpm@osdl.org: compile fix 3]
[akpm@osdl.org: revernt MAXMEM change]
Signed-off-by: Ingo Molnar 
Signed-off-by: Arjan van de Ven 
Cc: Gerd Hoffmann 
Cc: Rusty Russell 
Cc: Zachary Amsden 
Cc: Andi Kleen 
Cc: Jan Beulich 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] page migration: Support a vma migration function

2006-06-25T17:00:55+00:00

Hooks for calling vma specific migration functions

With this patch a vma may define a vma->vm_ops->migrate function.  That
function may perform page migration on its own (some vmas may not contain page
structs and therefore cannot be handled by regular page migration.  Pages in a
vma may require special preparatory treatment before migration is possible
etc) .  Only mmap_sem is held when the migration function is called.  The
migrate() function gets passed two sets of nodemasks describing the source and
the target of the migration.  The flags parameter either contains

MPOL_MF_MOVE	which means that only pages used exclusively by
		the specified mm should be moved

or

MPOL_MF_MOVE_ALL which means that pages shared with other processes
		should also be moved.

The migration function returns 0 on success or an error condition.  An error
condition will prevent regular page migration from occurring.

On its own this patch cannot be included since there are no users for this
functionality.  But it seems that the uncached allocator will need this
functionality at some point.

Signed-off-by: Christoph Lameter 
Cc: Hugh Dickins 
Cc: Andi Kleen 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] mm: remove VM_LOCKED before remap_pfn_range and drop VM_SHM

2006-06-25T17:00:55+00:00

Remove VM_LOCKED before remap_pfn range from device drivers and get rid of
VM_SHM.

remap_pfn_range() already sets VM_IO.  There is no need to set VM_SHM since
it does nothing.  VM_LOCKED is of no use since the remap_pfn_range does not
place pages on the LRU.  The pages are therefore never subject to swap
anyways.  Remove all the vm_flags settings before calling remap_pfn_range.

After removing all the vm_flag settings no use of VM_SHM is left.  Drop it.

Signed-off-by: Christoph Lameter 
Acked-by: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] add page_mkwrite() vm_operations method

2006-06-23T14:42:51+00:00

Add a new VMA operation to notify a filesystem or other driver about the
MMU generating a fault because userspace attempted to write to a page
mapped through a read-only PTE.

This facility permits the filesystem or driver to:

 (*) Implement storage allocation/reservation on attempted write, and so to
     deal with problems such as ENOSPC more gracefully (perhaps by generating
     SIGBUS).

 (*) Delay making the page writable until the contents have been written to a
     backing cache. This is useful for NFS/AFS when using FS-Cache/CacheFS.
     It permits the filesystem to have some guarantee about the state of the
     cache.

 (*) Account and limit number of dirty pages. This is one piece of the puzzle
     needed to make shared writable mapping work safely in FUSE.

Needed by cachefs (Or is it cachefiles?  Or fscache? ).

At least four other groups have stated an interest in it or a desire to use
the functionality it provides: FUSE, OCFS2, NTFS and JFFS2.  Also, things like
EXT3 really ought to use it to deal with the case of shared-writable mmap
encountering ENOSPC before we permit the page to be dirtied.

From: Peter Zijlstra 

  get_user_pages(.write=1, .force=1) can generate COW hits on read-only
  shared mappings, this patch traps those as mkpage_write candidates and fails
  to handle them the old way.

Signed-off-by: David Howells 
Cc: Miklos Szeredi 
Cc: Joel Becker 
Cc: Mark Fasheh 
Cc: Anton Altaparmakov 
Cc: David Woodhouse 
Cc: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

[PATCH] zone handle unaligned zone boundaries

2006-06-23T14:42:45+00:00

The buddy allocator has a requirement that boundaries between contigious
zones occur aligned with the the MAX_ORDER ranges.  Where they do not we
will incorrectly merge pages cross zone boundaries.  This can lead to pages
from the wrong zone being handed out.

Originally the buddy allocator would check that buddies were in the same
zone by referencing the zone start and end page frame numbers.  This was
removed as it became very expensive and the buddy allocator already made
the assumption that zones boundaries were aligned.

It is clear that not all configurations and architectures are honouring
this alignment requirement.  Therefore it seems safest to reintroduce
support for non-aligned zone boundaries.  This patch introduces a new check
when considering a page a buddy it compares the zone_table index for the
two pages and refuses to merge the pages where they do not match.  The
zone_table index is unique for each node/zone combination when
FLATMEM/DISCONTIGMEM is enabled and for each section/zone combination when
SPARSEMEM is enabled (a SPARSEMEM section is at least a MAX_ORDER size).

Signed-off-by: Andy Whitcroft 
Cc: Dave Hansen 
Cc: Mel Gorman 
Cc: Yasunori Goto 
Cc: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds