linux.git/Documentation/vm, branch v3.14-rc2

mm: documentation: remove hopelessly out-of-date locking doc

2014-01-24T00:36:50+00:00

Documentation/vm/locking is a blast from the past.  In the entire git
history, it has had precisely Three modifications.  Two of those look to
be pure renames, and the third was from 2005.

The doc contains such gems as:

> The page_table_lock is grabbed while holding the
> kernel_lock spinning monitor.

> Page stealers hold kernel_lock to protect against a bunch of
> races.

Or this which talks about mmap_sem:

> 4. The exception to this rule is expand_stack, which just
>    takes the read lock and the page_table_lock, this is ok
>    because it doesn't really modify fields anybody relies on.

expand_stack() doesn't take any locks any more directly, and the
mmap_sem acquisition was long ago moved up in to the page fault code
itself.

It could be argued that we need to rewrite this, but it is dangerous to
leave it as-is.  It will confuse more people than it helps.

Signed-off-by: Dave Hansen 
Cc: Hugh Dickins 
Acked-by: Vlastimil Babka 
Cc: Wanpeng Li 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: add overcommit_kbytes sysctl variable

2014-01-22T00:19:44+00:00

Some applications that run on HPC clusters are designed around the
availability of RAM and the overcommit ratio is fine tuned to get the
maximum usage of memory without swapping.  With growing memory, the
1%-of-all-RAM grain provided by overcommit_ratio has become too coarse
for these workload (on a 2TB machine it represents no less than 20GB).

This patch adds the new overcommit_kbytes sysctl variable that allow a
much finer grain.

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix nommu build]
Signed-off-by: Jerome Marchand 
Cc: Dave Hansen 
Cc: Alan Cox 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

x86, mm: do not leak page->ptl for pmd page tables

2013-11-22T00:42:28+00:00

There are two code paths how page with pmd page table can be freed:
pmd_free() and pmd_free_tlb().

I've missed the second one and didn't add page table destructor call
there.  It leads to leak of page->ptl for pmd page tables, if
dynamically allocated page->ptl is in use.

The patch adds the missed destructor and modifies documentation
accordingly.

Signed-off-by: Kirill A. Shutemov 
Reported-by: Andrey Vagin 
Tested-by: Andrey Vagin 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial

2013-11-16T00:47:22+00:00

Pull trivial tree updates from Jiri Kosina:
 "Usual earth-shaking, news-breaking, rocket science pile from
  trivial.git"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (23 commits)
  doc: usb: Fix typo in Documentation/usb/gadget_configs.txt
  doc: add missing files to timers/00-INDEX
  timekeeping: Fix some trivial typos in comments
  mm: Fix some trivial typos in comments
  irq: Fix some trivial typos in comments
  NUMA: fix typos in Kconfig help text
  mm: update 00-INDEX
  doc: Documentation/DMA-attributes.txt fix typo
  DRM: comment: `halve' -> `half'
  Docs: Kconfig: `devlopers' -> `developers'
  doc: typo on word accounting in kprobes.c in mutliple architectures
  treewide: fix "usefull" typo
  treewide: fix "distingush" typo
  mm/Kconfig: Grammar s/an/a/
  kexec: Typo s/the/then/
  Documentation/kvm: Update cpuid documentation for steal time and pv eoi
  treewide: Fix common typo in "identify"
  __page_to_pfn: Fix typo in comment
  Correct some typos for word frequency
  clk: fixed-factor: Fix a trivial typo
  ...

mm: dynamically allocate page->ptl if it cannot be embedded to struct page

2013-11-15T00:32:20+00:00

If split page table lock is in use, we embed the lock into struct page
of table's page.  We have to disable split lock, if spinlock_t is too
big be to be embedded, like when DEBUG_SPINLOCK or DEBUG_LOCK_ALLOC
enabled.

This patch add support for dynamic allocation of split page table lock
if we can't embed it to struct page.

page->ptl is unsigned long now and we use it as spinlock_t if
sizeof(spinlock_t) <= sizeof(long), otherwise it's pointer to spinlock_t.

The spinlock_t allocated in pgtable_page_ctor() for PTE table and in
pgtable_pmd_page_ctor() for PMD table.  All other helpers converted to
support dynamically allocated page->ptl.

Signed-off-by: Kirill A. Shutemov 
Reviewed-by: Peter Zijlstra 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Documentation/vm/zswap.txt: fix typos

2013-11-13T03:09:05+00:00

Signed-off-by: Christian Hesse 
Acked-by: Seth Jennings 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: update 00-INDEX

2013-10-14T13:52:20+00:00

The following files moved files out of Documentation/vm/
c6dd897f ("mm: move page-types.c from Documentation to tools/vm")
f0f57b2b ("move hugepage test examples to tools/testing/selftests/vm)

Remove these files from vm/00-INDEX.

The following commits added new files do Documentation/vm/
4fe4746a ("mm/fs: cleancache documentation") added vm/cleancache.txt
d65bfacb ("mm: highmem documentation") added vm/highmem.txt
1c9bf22c ("thp: transparent hugepage support documentation") added
           vm/transhuge.txt
0f8975ec ("mm: soft-dirty bits for user memory changes tracking")
61b0d760 ("zswap: add documentation")
27c6aec2 ("mm: frontswap: config and doc files")

Add the missing documentation-files with a short description to 00-INDEX

Signed-off-by: Henrik Austad 
Signed-off-by: Jiri Kosina

mm: track vma changes with VM_SOFTDIRTY bit

2013-09-11T22:57:56+00:00

Pavel reported that in case if vma area get unmapped and then mapped (or
expanded) in-place, the soft dirty tracker won't be able to recognize this
situation since it works on pte level and ptes are get zapped on unmap,
loosing soft dirty bit of course.

So to resolve this situation we need to track actions on vma level, there
VM_SOFTDIRTY flag comes in.  When new vma area created (or old expanded)
we set this bit, and keep it here until application calls for clearing
soft dirty bit.

Thus when user space application track memory changes now it can detect if
vma area is renewed.

Reported-by: Pavel Emelyanov 
Signed-off-by: Cyrill Gorcunov 
Cc: Andy Lutomirski 
Cc: Matt Mackall 
Cc: Xiao Guangrong 
Cc: Marcelo Tosatti 
Cc: KOSAKI Motohiro 
Cc: Stephen Rothwell 
Cc: Peter Zijlstra 
Cc: "Aneesh Kumar K.V" 
Cc: Rob Landley 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

hugepage: mention libhugetlbfs in doc

2013-09-11T22:57:39+00:00

Explicitly mention/recommend using the libhugetlbfs test cases when
changing related kernel code.  Developers that are unaware of the project
can easily miss this and introduce potential regressions that may or may
not be caught by community review.

Also do some cleanups that make the document visually easier to view at a
first glance.

Signed-off-by: Davidlohr Bueso 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

zswap: add documentation

2013-07-11T01:11:34+00:00

Add the documentation file for the zswap functionality

Signed-off-by: Seth Jennings 
Acked-by: Rik van Riel 
Cc: Greg Kroah-Hartman 
Cc: Nitin Gupta 
Cc: Minchan Kim 
Cc: Konrad Rzeszutek Wilk 
Cc: Dan Magenheimer 
Cc: Robert Jennings 
Cc: Jenifer Hopper 
Cc: Mel Gorman 
Cc: Johannes Weiner 
Cc: Larry Woodman 
Cc: Benjamin Herrenschmidt 
Cc: Dave Hansen 
Cc: Joe Perches 
Cc: Joonsoo Kim 
Cc: Cody P Schafer 
Cc: Hugh Dickens 
Cc: Paul Mackerras 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds