Commit Graph

386 Commits

Author SHA1 Message Date
Andrew Morton
22905f775d identify multipage ->writepages() calls
NFS needs to be able to distinguish between single-page ->writepage() calls and
 multipage ->writepages() calls.

 For the single-page writepage calls NFS can kick off the I/O within the
 context of ->writepage().

 For multipage ->writepages calls, nfs_writepage() will leave the I/O pending
 and nfs_writepages() will kick off the I/O when it all has been queued up
 within NFS.

 Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
 Signed-off-by: Andrew Morton <akpm@osdl.org>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2006-01-06 14:58:38 -05:00
Rafael J. Wysocki
3a291a20bd [PATCH] mm: add a new function (needed for swap suspend)
This adds the function get_swap_page_of_type() allowing us to specify an index
in swap_info[] and select a swap_info_struct structure to be used for
allocating a swap page.

This function (or another one of similar functionality) will be necessary for
implementing the image-writing part of swsusp in the user space.   It can also
be used for simplifying the current in-kernel implementation of the
image-writing part of swsusp.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:43 -08:00
Anton Blanchard
c898ec16e8 [PATCH] allow flatmem to be disabled when only sparsemem is implemented
On architectures that implement sparsemem but not discontigmem we want to
be able to hide the flatmem option in some cases.  On ppc64 for example,
when we select NUMA we must not select flatmem.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:37 -08:00
David Howells
b0e15190ea [PATCH] NOMMU: Make SYSV IPC SHM use ramfs facilities on NOMMU
The attached patch makes the SYSV IPC shared memory facilities use the new
ramfs facilities on a no-MMU kernel.

The following changes are made:

 (1) There are now shmem_mmap() and shmem_get_unmapped_area() functions to
     allow the IPC SHM facilities to commune with the tiny-shmem and shmem
     code.

 (2) ramfs files now need resizing using do_truncate() rather than by modifying
     the inode size directly (see shmem_file_setup()). This causes ramfs to
     attempt to bind a block of pages of sufficient size to the inode.

 (3) CONFIG_SYSVIPC is no longer contingent on CONFIG_MMU.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:32 -08:00
Nick Piggin
a74609fafa [PATCH] mm: page_state opt
Optimise page_state manipulations by introducing interrupt unsafe accessors
to page_state fields.  Callers must provide their own locking (either
disable interrupts or not update from interrupt context).

Switch over the hot callsites that can easily be moved under interrupts off
sections.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:29 -08:00
Christoph Lameter
070f80326a [PATCH] build_zonelists_node(): rename args
Give j and r meaningful names.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:28 -08:00
Christoph Lameter
02a68a5ebc [PATCH] Fix zone policy determination
The use k in the inner loop means that the highest zone nr is always used
if any zone of a node is populated.  This means that the policy zone is not
correctly determined on arches that do no use HIGHMEM like ia64.

Change the loop to decrement k which also simplifies the BUG_ON.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:28 -08:00
Christoph Lameter
4be38e351c [PATCH] mm: move determination of policy_zone into page allocator
Currently the function to build a zonelist for a BIND policy has the side
effect to set the policy_zone.  This seems to be a bit strange.  policy
zone seems to not be initialized elsewhere and therefore 0.  Do we police
ZONE_DMA if no bind policy has been used yet?

This patch moves the determination of the zone to apply policies to into
the page allocator.  We determine the zone while building the zonelist for
nodes.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:28 -08:00
Christoph Lameter
1a93205bdf [PATCH] mm: simplify build_zonelists_node by removing the case statement.
Simplify build_zonelists_node by removing the case statement.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:28 -08:00
Con Kolivas
f3fe65122d [PATCH] mm: add populated_zone() helper
There are numerous places we check whether a zone is populated or not.

Provide a helper function to check for populated zones and convert all
checks for zone->present_pages.

Signed-off-by: Con Kolivas <kernel@kolivas.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:28 -08:00
Andrew Morton
80bfed904c [PATCH] consolidate lru_add_drain() and lru_drain_cache()
Cc: Christoph Lameter <clameter@engr.sgi.com>
Cc: Rajesh Shah <rajesh.shah@intel.com>
Cc: Li Shaohua <shaohua.li@intel.com>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:28 -08:00
Andrew Morton
210fe53030 [PATCH] vmscan: balancing fix
Revert a patch which went into 2.6.8-rc1.  The changelog for that patch was:

  The shrink_zone() logic can, under some circumstances, cause far too many
  pages to be reclaimed.  Say, we're scanning at high priority and suddenly
  hit a large number of reclaimable pages on the LRU.

  Change things so we bale out when SWAP_CLUSTER_MAX pages have been
  reclaimed.

Problem is, this change caused significant imbalance in inter-zone scan
balancing by truncating scans of larger zones.

Suppose, for example, ZONE_HIGHMEM is 10x the size of ZONE_NORMAL.  The zone
balancing algorithm would require that if we're scanning 100 pages of
ZONE_HIGHMEM, we should scan 10 pages of ZONE_NORMAL.  But this logic will
cause the scanning of ZONE_HIGHMEM to bale out after only 32 pages are
reclaimed.  Thus effectively causing smaller zones to be scanned relatively
harder than large ones.

Now I need to remember what the workload was which caused me to write this
patch originally, then fix it up in a different way...

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:27 -08:00
Nick Piggin
41e9b63b35 [PATCH] mm: pfault optimisation
This atomic operation is superfluous: the pte will be added with the
referenced bit set, and the page will be referenced through this mapping after
the page fault handler returns anyway.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:27 -08:00
Nick Piggin
9617d95e6e [PATCH] mm: rmap optimisation
Optimise rmap functions by minimising atomic operations when we know there
will be no concurrent modifications.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:27 -08:00
Nick Piggin
224abf92b2 [PATCH] mm: bad_page optimisation
Cut down size slightly by not passing bad_page the function name (it should be
able to be determined by dump_stack()).  And cut down the number of printks in
bad_page.

Also, cut down some branching in the destroy_compound_page path.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:26 -08:00
Nick Piggin
9328b8faae [PATCH] mm: dma32 zone statistics
Add dma32 to zone statistics.  Also attempt to arrange struct page_state a
bit better (visually).

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:26 -08:00
Andrew Morton
7756b9e4e3 [PATCH] kill last zone_reclaim() bits
Remove the last bits of Martin's ill-fated sys_set_zone_reclaim().

Cc: Martin Hicks <mort@wildopensource.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:26 -08:00
Nikita Danilov
bbfbb7cec9 [PATCH] find_lock_page(): call __lock_page() directly.
As find_lock_page() already checks with TestSetPageLocked() that page is
locked, there is no need to call lock_page() that will try-lock page again
(chances of page being unlocked in between are small).  Call __lock_page()
directly, this saves one atomic operation.

Also, mark truncate-while-slept path as unlikely while we are here.

(akpm: ug.  But this is actually a common path for normal old read()s against
a page which is under readahead I/O so ho-hum.)

Signed-off-by: Nikita Danilov <danilov@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:26 -08:00
David Howells
a226f6c899 [PATCH] FRV: Clean up bootmem allocator's page freeing algorithm
The attached patch cleans up the way the bootmem allocator frees pages.

A new function, __free_pages_bootmem(), is provided in mm/page_alloc.c that is
called from mm/bootmem.c to turn pages over to the main allocator.  All the
bits of code to initialise pages (clearing PG_reserved and setting the page
count) are moved to here.  The checks on page validity are removed, on the
assumption that the struct page arrays will have been prepared correctly.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:26 -08:00
Ravikiran G Thirumalai
008857c1a4 [PATCH] Cleanup bootmem allocator and fix alloc_bootmem_low
Patch cleans up the alloc_bootmem fix for swiotlb.  Patch removes
alloc_bootmem_*_limit api and fixes alloc_boot_*low api to do the right
thing -- allocate from low32 memory.

Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:26 -08:00
Nick Piggin
085cc7d5de [PATCH] mm: page_alloc cleanups
Small cleanups that does not change generated code with the gcc's I've tested
with.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:25 -08:00
Nick Piggin
a86b1f5316 [PATCH] mm: page_state fixes
read_page_state and __get_page_state only traverse online CPUs, which will
cause results to fluctuate when CPUs are plugged in or out.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:25 -08:00
Nick Piggin
2d92c5c915 [PATCH] mm: remove pcp low
struct per_cpu_pages.low is useless.  Remove it.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:25 -08:00
Nick Piggin
13e7444b0e [PATCH] mm: remove bad_range
bad_range is supposed to be a temporary check.  It would be a pity to throw it
out.  Make it depend on CONFIG_DEBUG_VM instead.

CONFIG_HOLES_IN_ZONE systems were relying on this to check pfn_valid in the
page allocator.  Add that to page_is_buddy instead.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:25 -08:00
Nick Piggin
92be2e33b1 [PATCH] mm: microopt conditions
Micro optimise some conditionals where we don't need lazy evaluation.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:25 -08:00
Nick Piggin
77a8a78834 [PATCH] mm: set_page_refs opt
Inline set_page_refs.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:25 -08:00
Nick Piggin
c54ad30c78 [PATCH] mm: pagealloc opt
Slightly optimise some page allocation and freeing functions by taking
advantage of knowing whether or not interrupts are disabled.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:25 -08:00
Hugh Dickins
c484d41042 [PATCH] mm: free_pages_and_swap_cache opt
Minor optimization (though it doesn't help in the PREEMPT case, severely
constrained by small ZAP_BLOCK_SIZE).  free_pages_and_swap_cache works in
chunks of 16, calling release_pages which works in chunks of PAGEVEC_SIZE.
But PAGEVEC_SIZE was dropped from 16 to 14 in 2.6.10, so we're now doing more
spin_lock_irq'ing than necessary: use PAGEVEC_SIZE throughout.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:24 -08:00
Mike Kravetz
a94b3ab7ea [PATCH] mm: remove arch independent NODES_SPAN_OTHER_NODES
The NODES_SPAN_OTHER_NODES config option was created so that DISCONTIGMEM
could handle pSeries numa layouts.  However, support for DISCONTIGMEM has
been replaced by SPARSEMEM on powerpc.  As a result, this config option and
supporting code is no longer needed.

I have already sent a patch to Paul that removes the option from powerpc
specific code.  This removes the arch independent piece.  Doesn't really
matter which is applied first.

Signed-off-by: Mike Kravetz <kravetz@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:24 -08:00
Christoph Lameter
6bda666a03 [PATCH] hugepages: fold find_or_alloc_pages into huge_no_page()
The number of parameters for find_or_alloc_page increases significantly after
policy support is added to huge pages.  Simplify the code by folding
find_or_alloc_huge_page() into hugetlb_no_page().

Adam Litke objected to this piece in an earlier patch but I think this is a
good simplification.  Diffstat shows that we can get rid of almost half of the
lines of find_or_alloc_page().  If we can find no consensus then lets simply
drop this patch.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@muc.de>
Acked-by: William Lee Irwin III <wli@holomorphy.com>
Cc: Adam Litke <agl@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:23 -08:00
Christoph Lameter
21abb1478a [PATCH] Remove old node based policy interface from mempolicy.c
mempolicy.c contains provisional interface for huge page allocation based on
node numbers.  This is in use in SLES9 but was never used (AFAIK) in upstream
versions of Linux.

Huge page allocations now use zonelists to figure out where to allocate pages.
 The use of zonelists allows us to find the closest hugepage which was the
consideration of the NUMA distance for huge page allocations.

Remove the obsolete functions.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@muc.de>
Acked-by: William Lee Irwin III <wli@holomorphy.com>
Cc: Adam Litke <agl@us.ibm.com>
Acked-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:23 -08:00
Christoph Lameter
5da7ca8607 [PATCH] Add NUMA policy support for huge pages.
The huge_zonelist() function in the memory policy layer provides an list of
zones ordered by NUMA distance.  The hugetlb layer will walk that list looking
for a zone that has available huge pages but is also in the nodeset of the
current cpuset.

This patch does not contain the folding of find_or_alloc_huge_page() that was
controversial in the earlier discussion.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@muc.de>
Acked-by: William Lee Irwin III <wli@holomorphy.com>
Cc: Adam Litke <agl@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:23 -08:00
Christoph Lameter
96df9333c9 [PATCH] mm: dequeue a huge page near to this node
This was discussed at
http://marc.theaimsgroup.com/?l=linux-kernel&m=113166526217117&w=2

This patch changes the dequeueing to select a huge page near the node
executing instead of always beginning to check for free nodes from node 0.
This will result in a placement of the huge pages near the executing
processor improving performance.

The existing implementation can place the huge pages far away from the
executing processor causing significant degradation of performance.  The
search starting from zero also means that the lower zones quickly run out
of memory.  Selecting a huge page near the process distributed the huge
pages better.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: Adam Litke <agl@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:23 -08:00
David Gibson
1e8f889b10 [PATCH] Hugetlb: Copy on Write support
Implement copy-on-write support for hugetlb mappings so MAP_PRIVATE can be
supported.  This helps us to safely use hugetlb pages in many more
applications.  The patch makes the following changes.  If needed, I also have
it broken out according to the following paragraphs.

1. Add a pair of functions to set/clear write access on huge ptes.  The
   writable check in make_huge_pte is moved out to the caller for use by COW
   later.

2. Hugetlb copy-on-write requires special case handling in the following
   situations:

   - copy_hugetlb_page_range() - Copied pages must be write protected so
     a COW fault will be triggered (if necessary) if those pages are written
     to.

   - find_or_alloc_huge_page() - Only MAP_SHARED pages are added to the
     page cache.  MAP_PRIVATE pages still need to be locked however.

3. Provide hugetlb_cow() and calls from hugetlb_fault() and
   hugetlb_no_page() which handles the COW fault by making the actual copy.

4. Remove the check in hugetlbfs_file_map() so that MAP_PRIVATE mmaps
   will be allowed.  Make MAP_HUGETLB exempt from the depricated VM_RESERVED
   mapping check.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Adam Litke <agl@us.ibm.com>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: "Seth, Rohit" <rohit.seth@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:23 -08:00
Adam Litke
86e5216f8d [PATCH] Hugetlb: Reorganize hugetlb_fault to prepare for COW
This patch splits the "no_page()" type activity into its own function,
hugetlb_no_page().  hugetlb_fault() becomes the entry point for hugetlb faults
and delegates to the appropriate handler depending on the type of fault.
Right now we still have only hugetlb_no_page() but a later patch introduces a
COW fault.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Adam Litke <agl@us.ibm.com>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: "Seth, Rohit" <rohit.seth@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:22 -08:00
Adam Litke
85ef47f74a [PATCH] Hugetlb: Rename find_lock_page to find_or_alloc_huge_page
find_lock_huge_page() isn't a great name, since it does extra things not
analagous to find_lock_page().  Rename it find_or_alloc_huge_page() which is
closer to the mark.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Adam Litke <agl@us.ibm.com>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: "Seth, Rohit" <rohit.seth@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:22 -08:00
Adam Litke
f0916794f0 [PATCH] Hugetlb: Remove duplicate i_size check
cleanup

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Adam Litke <agl@us.ibm.com>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: "Seth, Rohit" <rohit.seth@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:22 -08:00
Badari Pulavarty
f6b3ec238d [PATCH] madvise(MADV_REMOVE): remove pages from tmpfs shm backing store
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 <pbadari@us.ibm.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Andrea Arcangeli <andrea@suse.de>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Cc: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:22 -08:00
Hans Reiser
d7339071f6 [PATCH] reiser4: vfs: add truncate_inode_pages_range()
This patch makes truncate_inode_pages_range from truncate_inode_pages.
truncate_inode_pages became a one-liner call to truncate_inode_pages_range.

Reiser4 needs truncate_inode_pages_ranges because it tries to keep
correspondence between existences of metadata pointing to data pages and pages
to which those metadata point to.  So, when metadata of certain part of file
is removed from filesystem tree, only pages of corresponding range are to be
truncated.

(Needed by the madvise(MADV_REMOVE) patch)

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:22 -08:00
Andy Whitcroft
5ac24eefd1 [PATCH] memhotplug: __add_section remove unused pgdat definition
__add_section defines an unused pointer to the zones pgdat.  Remove this
definition.  This fixes a compile warning.

Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:21 -08:00
Paul Jackson
47f3a867f6 [PATCH] mm: fix __alloc_pages cpuset ALLOC_* flags
Two changes to the setting of the ALLOC_CPUSET flag in
mm/page_alloc.c:__alloc_pages()

- A bug fix - the "ignoring mins" case should not be honoring ALLOC_CPUSET.
  This case of all cases, since it is handling a request that will free up
  more memory than is asked for (exiting tasks, e.g.) should be allowed to
  escape cpuset constraints when memory is tight.

- A logic change to make it simpler.  Honor cpusets even on GFP_ATOMIC
  (!wait) requests.  With this, cpuset confinement applies to all requests
  except ALLOC_NO_WATERMARKS, so that in a subsequent cleanup patch, I can
  remove the ALLOC_CPUSET flag entirely.  Since I don't know any real reason
  this logic has to be either way, I am choosing the path of the simplest
  code.

Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 08:33:21 -08:00
Zach Brown
994fc28c7b [PATCH] add AOP_TRUNCATED_PAGE, prepend AOP_ to WRITEPAGE_ACTIVATE
readpage(), prepare_write(), and commit_write() callers are updated to
understand the special return code AOP_TRUNCATED_PAGE in the style of
writepage() and WRITEPAGE_ACTIVATE.  AOP_TRUNCATED_PAGE tells the caller that
the callee has unlocked the page and that the operation should be tried again
with a new page.  OCFS2 uses this to detect and work around a lock inversion in
its aop methods.  There should be no change in behaviour for methods that don't
return AOP_TRUNCATED_PAGE.

WRITEPAGE_ACTIVATE is also prepended with AOP_ for consistency and they are
made enums so that kerneldoc can be used to document their semantics.

Signed-off-by: Zach Brown <zach.brown@oracle.com>
2006-01-03 11:45:42 -08:00
Andi Kleen
8f493d797b [PATCH] Make sure interleave masks have at least one node set
Otherwise a bad mem policy system call can confuse the interleaving
code into referencing undefined nodes.

Originally reported by Doug Chapman

I was told it's CVE-2005-3358
(one has to love these security people - they make everything sound important)

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-02 17:01:42 -08:00
Linus Torvalds
4d7672b462 Make sure we copy pages inserted with "vm_insert_page()" on fork
The logic that decides that a fork() might be able to avoid copying a VM
area when it can be re-created by page faults didn't know about the new
vm_insert_page() case.

Also make some things a bit more anal wrt VM_PFNMAP.

Pointed out by Hugh Dickins <hugh@veritas.com>

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-12-16 10:21:23 -08:00
Al Viro
78d9955bb0 [PATCH] missing prototype (mm/page_alloc.c)
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-12-15 10:04:30 -08:00
Yasunori Goto
118c71bcac [PATCH] Fix calculation of grow_pgdat_span() in mm/memory_hotplug.c
The calculation for node_spanned_pages at grow_pgdat_span() is clearly
wrong.  This is patch for it.

(Please see grow_zone_span() to compare. It is correct.)

Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Acked-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-12-13 21:18:16 -08:00
Linus Torvalds
1ff8038988 get_user_pages: don't try to follow PFNMAP pages
Nick Piggin points out that a few drivers play games with VM_IO (why?
who knows..) and thus a pfn-remapped area may not have that bit set even
if remap_pfn_range() set it originally.

So make it explicit in get_user_pages() that we don't follow VM_PFNMAP
pages, since pretty much by definition they do not have a "struct page"
associated with them.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-12-12 16:24:33 -08:00
Haren Myneni
66d43e98ea [PATCH] fix in __alloc_bootmem_core() when there is no free page in first node's memory
Hitting BUG_ON() in __alloc_bootmem_core() when there is no free page
available in the first node's memory.  For the case of kdump on PPC64
(Power 4 machine), the captured kernel is used two memory regions - memory
for TCE tables (tce-base and tce-size at top of RAM and reserved) and
captured kernel memory region (crashk_base and crashk_size).  Since we
reserve the memory for the first node, we should be returning from
__alloc_bootmem_core() to search for the next node (pg_dat).

Currently, find_next_zero_bit() is returning the n^th bit (eidx) when there
is no free page.  Then, test_bit() is failed since we set 0xff only for the
actual size initially (init_bootmem_core()) even though rounded up to one
page for bdata->node_bootmem_map.  We are hitting the BUG_ON after failing
to enter second "for" loop.

Signed-off-by: Haren Myneni <haren@us.ibm.com>
Cc: Andy Whitcroft <apw@shadowen.org>
Cc: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-12-12 08:57:45 -08:00
Linus Torvalds
67121172f9 Allow arbitrary read-only shared pfn-remapping too
The VM layer (for historical reasons) turns a read-only shared mmap into
a private-like mapping with the VM_MAYWRITE bit clear.  Thus checking
just VM_SHARED isn't actually sufficient.

So use a trivial helper function for the cases where we wanted to inquire
if a mapping was COW-like or not.

Moo!

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-12-11 20:38:17 -08:00
Linus Torvalds
7fc7e2eeec Remove (at least temporarily) the "incomplete PFN mapping" support
With the previous commit, we can handle arbitrary shared re-mappings
even without this complexity, and since the only known private mappings
are for strange users of /dev/mem (which never create an incomplete one),
there seems to be no reason to support it.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-12-11 19:57:52 -08:00