<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/mm/huge_memory.c, branch v3.19</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux</title>
<updated>2014-12-15T23:52:01+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2014-12-15T23:52:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=988adfdffdd43cfd841df734664727993076d7cb'/>
<id>988adfdffdd43cfd841df734664727993076d7cb</id>
<content type='text'>
Pull drm updates from Dave Airlie:
 "Highlights:

   - AMD KFD driver merge

     This is the AMD HSA interface for exposing a lowlevel interface for
     GPGPU use.  They have an open source userspace built on top of this
     interface, and the code looks as good as it was going to get out of
     tree.

   - Initial atomic modesetting work

     The need for an atomic modesetting interface to allow userspace to
     try and send a complete set of modesetting state to the driver has
     arisen, and been suffering from neglect this past year.  No more,
     the start of the common code and changes for msm driver to use it
     are in this tree.  Ongoing work to get the userspace ioctl finished
     and the code clean will probably wait until next kernel.

   - DisplayID 1.3 and tiled monitor exposed to userspace.

     Tiled monitor property is now exposed for userspace to make use of.

   - Rockchip drm driver merged.

   - imx gpu driver moved out of staging

  Other stuff:

   - core:
        panel - MIPI DSI + new panels.
        expose suggested x/y properties for virtual GPUs

   - i915:
        Initial Skylake (SKL) support
        gen3/4 reset work
        start of dri1/ums removal
        infoframe tracking
        fixes for lots of things.

   - nouveau:
        tegra k1 voltage support
        GM204 modesetting support
        GT21x memory reclocking work

   - radeon:
        CI dpm fixes
        GPUVM improvements
        Initial DPM fan control

   - rcar-du:
        HDMI support added
        removed some support for old boards
        slave encoder driver for Analog Devices adv7511

   - exynos:
        Exynos4415 SoC support

   - msm:
        a4xx gpu support
        atomic helper conversion

   - tegra:
        iommu support
        universal plane support
        ganged-mode DSI support

   - sti:
        HDMI i2c improvements

   - vmwgfx:
        some late fixes.

   - qxl:
        use suggested x/y properties"

* 'drm-next' of git://people.freedesktop.org/~airlied/linux: (969 commits)
  drm: sti: fix module compilation issue
  drm/i915: save/restore GMBUS freq across suspend/resume on gen4
  drm: sti: correctly cleanup CRTC and planes
  drm: sti: add HQVDP plane
  drm: sti: add cursor plane
  drm: sti: enable auxiliary CRTC
  drm: sti: fix delay in VTG programming
  drm: sti: prepare sti_tvout to support auxiliary crtc
  drm: sti: use drm_crtc_vblank_{on/off} instead of drm_vblank_{on/off}
  drm: sti: fix hdmi avi infoframe
  drm: sti: remove event lock while disabling vblank
  drm: sti: simplify gdp code
  drm: sti: clear all mixer control
  drm: sti: remove gpio for HDMI hot plug detection
  drm: sti: allow to change hdmi ddc i2c adapter
  drm/doc: Document drm_add_modes_noedid() usage
  drm/i915: Remove '&amp; 0xffff' from the mask given to WA_REG()
  drm/i915: Invert the mask and val arguments in wa_add() and WA_REG()
  drm: Zero out DRM object memory upon cleanup
  drm/i915/bdw: Fix the write setting up the WIZ hashing mode
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull drm updates from Dave Airlie:
 "Highlights:

   - AMD KFD driver merge

     This is the AMD HSA interface for exposing a lowlevel interface for
     GPGPU use.  They have an open source userspace built on top of this
     interface, and the code looks as good as it was going to get out of
     tree.

   - Initial atomic modesetting work

     The need for an atomic modesetting interface to allow userspace to
     try and send a complete set of modesetting state to the driver has
     arisen, and been suffering from neglect this past year.  No more,
     the start of the common code and changes for msm driver to use it
     are in this tree.  Ongoing work to get the userspace ioctl finished
     and the code clean will probably wait until next kernel.

   - DisplayID 1.3 and tiled monitor exposed to userspace.

     Tiled monitor property is now exposed for userspace to make use of.

   - Rockchip drm driver merged.

   - imx gpu driver moved out of staging

  Other stuff:

   - core:
        panel - MIPI DSI + new panels.
        expose suggested x/y properties for virtual GPUs

   - i915:
        Initial Skylake (SKL) support
        gen3/4 reset work
        start of dri1/ums removal
        infoframe tracking
        fixes for lots of things.

   - nouveau:
        tegra k1 voltage support
        GM204 modesetting support
        GT21x memory reclocking work

   - radeon:
        CI dpm fixes
        GPUVM improvements
        Initial DPM fan control

   - rcar-du:
        HDMI support added
        removed some support for old boards
        slave encoder driver for Analog Devices adv7511

   - exynos:
        Exynos4415 SoC support

   - msm:
        a4xx gpu support
        atomic helper conversion

   - tegra:
        iommu support
        universal plane support
        ganged-mode DSI support

   - sti:
        HDMI i2c improvements

   - vmwgfx:
        some late fixes.

   - qxl:
        use suggested x/y properties"

* 'drm-next' of git://people.freedesktop.org/~airlied/linux: (969 commits)
  drm: sti: fix module compilation issue
  drm/i915: save/restore GMBUS freq across suspend/resume on gen4
  drm: sti: correctly cleanup CRTC and planes
  drm: sti: add HQVDP plane
  drm: sti: add cursor plane
  drm: sti: enable auxiliary CRTC
  drm: sti: fix delay in VTG programming
  drm: sti: prepare sti_tvout to support auxiliary crtc
  drm: sti: use drm_crtc_vblank_{on/off} instead of drm_vblank_{on/off}
  drm: sti: fix hdmi avi infoframe
  drm: sti: remove event lock while disabling vblank
  drm: sti: simplify gdp code
  drm: sti: clear all mixer control
  drm: sti: remove gpio for HDMI hot plug detection
  drm: sti: allow to change hdmi ddc i2c adapter
  drm/doc: Document drm_add_modes_noedid() usage
  drm/i915: Remove '&amp; 0xffff' from the mask given to WA_REG()
  drm/i915: Invert the mask and val arguments in wa_add() and WA_REG()
  drm: Zero out DRM object memory upon cleanup
  drm/i915/bdw: Fix the write setting up the WIZ hashing mode
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux</title>
<updated>2014-12-12T01:30:55+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2014-12-12T01:30:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=27afc5dbda52ee3dbcd0bda7375c917c6936b470'/>
<id>27afc5dbda52ee3dbcd0bda7375c917c6936b470</id>
<content type='text'>
Pull s390 updates from Martin Schwidefsky:
 "The most notable change for this pull request is the ftrace rework
  from Heiko.  It brings a small performance improvement and the ground
  work to support a new gcc option to replace the mcount blocks with a
  single nop.

  Two new s390 specific system calls are added to emulate user space
  mmio for PCI, an artifact of the how PCI memory is accessed.

  Two patches for the memory management with changes to common code.
  For KVM mm_forbids_zeropage is added which disables the empty zero
  page for an mm that is used by a KVM process.  And an optimization,
  pmdp_get_and_clear_full is added analog to ptep_get_and_clear_full.

  Some micro optimization for the cmpxchg and the spinlock code.

  And as usual bug fixes and cleanups"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (46 commits)
  s390/cputime: fix 31-bit compile
  s390/scm_block: make the number of reqs per HW req configurable
  s390/scm_block: handle multiple requests in one HW request
  s390/scm_block: allocate aidaw pages only when necessary
  s390/scm_block: use mempool to manage aidaw requests
  s390/eadm: change timeout value
  s390/mm: fix memory leak of ptlock in pmd_free_tlb
  s390: use local symbol names in entry[64].S
  s390/ptrace: always include vector registers in core files
  s390/simd: clear vector register pointer on fork/clone
  s390: translate cputime magic constants to macros
  s390/idle: convert open coded idle time seqcount
  s390/idle: add missing irq off lockdep annotation
  s390/debug: avoid function call for debug_sprintf_*
  s390/kprobes: fix instruction copy for out of line execution
  s390: remove diag 44 calls from cpu_relax()
  s390/dasd: retry partition detection
  s390/dasd: fix list corruption for sleep_on requests
  s390/dasd: fix infinite term I/O loop
  s390/dasd: remove unused code
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull s390 updates from Martin Schwidefsky:
 "The most notable change for this pull request is the ftrace rework
  from Heiko.  It brings a small performance improvement and the ground
  work to support a new gcc option to replace the mcount blocks with a
  single nop.

  Two new s390 specific system calls are added to emulate user space
  mmio for PCI, an artifact of the how PCI memory is accessed.

  Two patches for the memory management with changes to common code.
  For KVM mm_forbids_zeropage is added which disables the empty zero
  page for an mm that is used by a KVM process.  And an optimization,
  pmdp_get_and_clear_full is added analog to ptep_get_and_clear_full.

  Some micro optimization for the cmpxchg and the spinlock code.

  And as usual bug fixes and cleanups"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (46 commits)
  s390/cputime: fix 31-bit compile
  s390/scm_block: make the number of reqs per HW req configurable
  s390/scm_block: handle multiple requests in one HW request
  s390/scm_block: allocate aidaw pages only when necessary
  s390/scm_block: use mempool to manage aidaw requests
  s390/eadm: change timeout value
  s390/mm: fix memory leak of ptlock in pmd_free_tlb
  s390: use local symbol names in entry[64].S
  s390/ptrace: always include vector registers in core files
  s390/simd: clear vector register pointer on fork/clone
  s390: translate cputime magic constants to macros
  s390/idle: convert open coded idle time seqcount
  s390/idle: add missing irq off lockdep annotation
  s390/debug: avoid function call for debug_sprintf_*
  s390/kprobes: fix instruction copy for out of line execution
  s390: remove diag 44 calls from cpu_relax()
  s390/dasd: retry partition detection
  s390/dasd: fix list corruption for sleep_on requests
  s390/dasd: fix infinite term I/O loop
  s390/dasd: remove unused code
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>thp: do not mark zero-page pmd write-protected explicitly</title>
<updated>2014-12-11T01:41:08+00:00</updated>
<author>
<name>Kirill A. Shutemov</name>
<email>kirill@shutemov.name</email>
</author>
<published>2014-12-10T23:44:22+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=e544a4e74e02108035de69f97fde7bdf19dba978'/>
<id>e544a4e74e02108035de69f97fde7bdf19dba978</id>
<content type='text'>
Zero pages can be used only in anonymous mappings, which never have
writable vma-&gt;vm_page_prot: see protection_map in mm/mmap.c and __PX1X
definitions.

Let's drop redundant pmd_wrprotect() in set_huge_zero_page().

Signed-off-by: "Kirill A. Shutemov" &lt;kirill@shutemov.name&gt;
Cc: Andrea Arcangeli &lt;aarcange@redhat.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Zero pages can be used only in anonymous mappings, which never have
writable vma-&gt;vm_page_prot: see protection_map in mm/mmap.c and __PX1X
definitions.

Let's drop redundant pmd_wrprotect() in set_huge_zero_page().

Signed-off-by: "Kirill A. Shutemov" &lt;kirill@shutemov.name&gt;
Cc: Andrea Arcangeli &lt;aarcange@redhat.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm, thp: fix collapsing of hugepages on madvise</title>
<updated>2014-10-29T23:33:14+00:00</updated>
<author>
<name>David Rientjes</name>
<email>rientjes@google.com</email>
</author>
<published>2014-10-29T21:50:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=6d50e60cd2edb5a57154db5a6f64eef5aa59b751'/>
<id>6d50e60cd2edb5a57154db5a6f64eef5aa59b751</id>
<content type='text'>
If an anonymous mapping is not allowed to fault thp memory and then
madvise(MADV_HUGEPAGE) is used after fault, khugepaged will never
collapse this memory into thp memory.

This occurs because the madvise(2) handler for thp, hugepage_madvise(),
clears VM_NOHUGEPAGE on the stack and it isn't stored in vma-&gt;vm_flags
until the final action of madvise_behavior().  This causes the
khugepaged_enter_vma_merge() to be a no-op in hugepage_madvise() when
the vma had previously had VM_NOHUGEPAGE set.

Fix this by passing the correct vma flags to the khugepaged mm slot
handler.  There's no chance khugepaged can run on this vma until after
madvise_behavior() returns since we hold mm-&gt;mmap_sem.

It would be possible to clear VM_NOHUGEPAGE directly from vma-&gt;vm_flags
in hugepage_advise(), but I didn't want to introduce special case
behavior into madvise_behavior().  I think it's best to just let it
always set vma-&gt;vm_flags itself.

Signed-off-by: David Rientjes &lt;rientjes@google.com&gt;
Reported-by: Suleiman Souhlal &lt;suleiman@google.com&gt;
Cc: "Kirill A. Shutemov" &lt;kirill.shutemov@linux.intel.com&gt;
Cc: Andrea Arcangeli &lt;aarcange@redhat.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
If an anonymous mapping is not allowed to fault thp memory and then
madvise(MADV_HUGEPAGE) is used after fault, khugepaged will never
collapse this memory into thp memory.

This occurs because the madvise(2) handler for thp, hugepage_madvise(),
clears VM_NOHUGEPAGE on the stack and it isn't stored in vma-&gt;vm_flags
until the final action of madvise_behavior().  This causes the
khugepaged_enter_vma_merge() to be a no-op in hugepage_madvise() when
the vma had previously had VM_NOHUGEPAGE set.

Fix this by passing the correct vma flags to the khugepaged mm slot
handler.  There's no chance khugepaged can run on this vma until after
madvise_behavior() returns since we hold mm-&gt;mmap_sem.

It would be possible to clear VM_NOHUGEPAGE directly from vma-&gt;vm_flags
in hugepage_advise(), but I didn't want to introduce special case
behavior into madvise_behavior().  I think it's best to just let it
always set vma-&gt;vm_flags itself.

Signed-off-by: David Rientjes &lt;rientjes@google.com&gt;
Reported-by: Suleiman Souhlal &lt;suleiman@google.com&gt;
Cc: "Kirill A. Shutemov" &lt;kirill.shutemov@linux.intel.com&gt;
Cc: Andrea Arcangeli &lt;aarcange@redhat.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm: free compound page with correct order</title>
<updated>2014-10-29T23:33:14+00:00</updated>
<author>
<name>Yu Zhao</name>
<email>yuzhao@google.com</email>
</author>
<published>2014-10-29T21:50:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=5ddacbe92b806cd5b4f8f154e8e46ac267fff55c'/>
<id>5ddacbe92b806cd5b4f8f154e8e46ac267fff55c</id>
<content type='text'>
Compound page should be freed by put_page() or free_pages() with correct
order.  Not doing so will cause tail pages leaked.

The compound order can be obtained by compound_order() or use
HPAGE_PMD_ORDER in our case.  Some people would argue the latter is
faster but I prefer the former which is more general.

This bug was observed not just on our servers (the worst case we saw is
11G leaked on a 48G machine) but also on our workstations running Ubuntu
based distro.

  $ cat /proc/vmstat  | grep thp_zero_page_alloc
  thp_zero_page_alloc 55
  thp_zero_page_alloc_failed 0

This means there is (thp_zero_page_alloc - 1) * (2M - 4K) memory leaked.

Fixes: 97ae17497e99 ("thp: implement refcounting for huge zero page")
Signed-off-by: Yu Zhao &lt;yuzhao@google.com&gt;
Acked-by: Kirill A. Shutemov &lt;kirill.shutemov@linux.intel.com&gt;
Cc: Andrea Arcangeli &lt;aarcange@redhat.com&gt;
Cc: Mel Gorman &lt;mel@csn.ul.ie&gt;
Cc: David Rientjes &lt;rientjes@google.com&gt;
Cc: Bob Liu &lt;lliubbo@gmail.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;	[3.8+]
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Compound page should be freed by put_page() or free_pages() with correct
order.  Not doing so will cause tail pages leaked.

The compound order can be obtained by compound_order() or use
HPAGE_PMD_ORDER in our case.  Some people would argue the latter is
faster but I prefer the former which is more general.

This bug was observed not just on our servers (the worst case we saw is
11G leaked on a 48G machine) but also on our workstations running Ubuntu
based distro.

  $ cat /proc/vmstat  | grep thp_zero_page_alloc
  thp_zero_page_alloc 55
  thp_zero_page_alloc_failed 0

This means there is (thp_zero_page_alloc - 1) * (2M - 4K) memory leaked.

Fixes: 97ae17497e99 ("thp: implement refcounting for huge zero page")
Signed-off-by: Yu Zhao &lt;yuzhao@google.com&gt;
Acked-by: Kirill A. Shutemov &lt;kirill.shutemov@linux.intel.com&gt;
Cc: Andrea Arcangeli &lt;aarcange@redhat.com&gt;
Cc: Mel Gorman &lt;mel@csn.ul.ie&gt;
Cc: David Rientjes &lt;rientjes@google.com&gt;
Cc: Bob Liu &lt;lliubbo@gmail.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;	[3.8+]
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>s390/mm: pmdp_get_and_clear_full optimization</title>
<updated>2014-10-27T12:27:30+00:00</updated>
<author>
<name>Martin Schwidefsky</name>
<email>schwidefsky@de.ibm.com</email>
</author>
<published>2014-10-24T08:52:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=fcbe08d66f57c368e77ca729dd01e6b539ffb3ff'/>
<id>fcbe08d66f57c368e77ca729dd01e6b539ffb3ff</id>
<content type='text'>
Analog to ptep_get_and_clear_full define a variant of the
pmpd_get_and_clear primitive which gets the full hint from the
mmu_gather struct. This allows s390 to avoid a costly instruction
when destroying an address space.

Signed-off-by: Martin Schwidefsky &lt;schwidefsky@de.ibm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Analog to ptep_get_and_clear_full define a variant of the
pmpd_get_and_clear primitive which gets the full hint from the
mmu_gather struct. This allows s390 to avoid a costly instruction
when destroying an address space.

Signed-off-by: Martin Schwidefsky &lt;schwidefsky@de.ibm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm: introduce mm_forbids_zeropage function</title>
<updated>2014-10-27T12:27:24+00:00</updated>
<author>
<name>Dominik Dingel</name>
<email>dingel@linux.vnet.ibm.com</email>
</author>
<published>2014-10-23T10:07:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=593befa6ab74a805e4f503c8c737c3cffa8066b6'/>
<id>593befa6ab74a805e4f503c8c737c3cffa8066b6</id>
<content type='text'>
Add a new function stub to allow architectures to disable for
an mm_structthe backing of non-present, anonymous pages with
read-only empty zero pages.

Signed-off-by: Dominik Dingel &lt;dingel@linux.vnet.ibm.com&gt;
Reviewed-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Signed-off-by: Martin Schwidefsky &lt;schwidefsky@de.ibm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Add a new function stub to allow architectures to disable for
an mm_structthe backing of non-present, anonymous pages with
read-only empty zero pages.

Signed-off-by: Dominik Dingel &lt;dingel@linux.vnet.ibm.com&gt;
Reviewed-by: Paolo Bonzini &lt;pbonzini@redhat.com&gt;
Signed-off-by: Martin Schwidefsky &lt;schwidefsky@de.ibm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm: use VM_BUG_ON_MM where possible</title>
<updated>2014-10-10T02:25:58+00:00</updated>
<author>
<name>Sasha Levin</name>
<email>sasha.levin@oracle.com</email>
</author>
<published>2014-10-09T22:28:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=96dad67ff244e797c4bc3e4f7f0fdaa0cfdf0a7d'/>
<id>96dad67ff244e797c4bc3e4f7f0fdaa0cfdf0a7d</id>
<content type='text'>
Dump the contents of the relevant struct_mm when we hit the bug condition.

Signed-off-by: Sasha Levin &lt;sasha.levin@oracle.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Dump the contents of the relevant struct_mm when we hit the bug condition.

Signed-off-by: Sasha Levin &lt;sasha.levin@oracle.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm: convert a few VM_BUG_ON callers to VM_BUG_ON_VMA</title>
<updated>2014-10-10T02:25:57+00:00</updated>
<author>
<name>Sasha Levin</name>
<email>sasha.levin@oracle.com</email>
</author>
<published>2014-10-09T22:28:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=81d1b09c6be66afac7d41ee52279d9bccbce56d8'/>
<id>81d1b09c6be66afac7d41ee52279d9bccbce56d8</id>
<content type='text'>
Trivially convert a few VM_BUG_ON calls to VM_BUG_ON_VMA to extract
more information when they trigger.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Sasha Levin &lt;sasha.levin@oracle.com&gt;
Reviewed-by: Naoya Horiguchi &lt;n-horiguchi@ah.jp.nec.com&gt;
Cc: Kirill A. Shutemov &lt;kirill.shutemov@linux.intel.com&gt;
Cc: Konstantin Khlebnikov &lt;khlebnikov@openvz.org&gt;
Cc: Rik van Riel &lt;riel@redhat.com&gt;
Cc: Mel Gorman &lt;mgorman@suse.de&gt;
Cc: Michal Hocko &lt;mhocko@suse.cz&gt;
Cc: Hugh Dickins &lt;hughd@google.com&gt;
Cc: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: Michel Lespinasse &lt;walken@google.com&gt;
Cc: Minchan Kim &lt;minchan@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Trivially convert a few VM_BUG_ON calls to VM_BUG_ON_VMA to extract
more information when they trigger.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Sasha Levin &lt;sasha.levin@oracle.com&gt;
Reviewed-by: Naoya Horiguchi &lt;n-horiguchi@ah.jp.nec.com&gt;
Cc: Kirill A. Shutemov &lt;kirill.shutemov@linux.intel.com&gt;
Cc: Konstantin Khlebnikov &lt;khlebnikov@openvz.org&gt;
Cc: Rik van Riel &lt;riel@redhat.com&gt;
Cc: Mel Gorman &lt;mgorman@suse.de&gt;
Cc: Michal Hocko &lt;mhocko@suse.cz&gt;
Cc: Hugh Dickins &lt;hughd@google.com&gt;
Cc: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: Michel Lespinasse &lt;walken@google.com&gt;
Cc: Minchan Kim &lt;minchan@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm, THP: don't hold mmap_sem in khugepaged when allocating THP</title>
<updated>2014-10-10T02:25:53+00:00</updated>
<author>
<name>Vlastimil Babka</name>
<email>vbabka@suse.cz</email>
</author>
<published>2014-10-09T22:27:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=8b1645685acf3c7e0b93611fb4b328ef45c47e92'/>
<id>8b1645685acf3c7e0b93611fb4b328ef45c47e92</id>
<content type='text'>
When allocating huge page for collapsing, khugepaged currently holds
mmap_sem for reading on the mm where collapsing occurs.  Afterwards the
read lock is dropped before write lock is taken on the same mmap_sem.

Holding mmap_sem during whole huge page allocation is therefore useless,
the vma needs to be rechecked after taking the write lock anyway.
Furthemore, huge page allocation might involve a rather long sync
compaction, and thus block any mmap_sem writers and i.e.  affect workloads
that perform frequent m(un)map or mprotect oterations.

This patch simply releases the read lock before allocating a huge page.
It also deletes an outdated comment that assumed vma must be stable, as it
was using alloc_hugepage_vma().  This is no longer true since commit
9f1b868a13ac ("mm: thp: khugepaged: add policy for finding target node").

Signed-off-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: Minchan Kim &lt;minchan@kernel.org&gt;
Acked-by: Mel Gorman &lt;mgorman@suse.de&gt;
Cc: Joonsoo Kim &lt;iamjoonsoo.kim@lge.com&gt;
Cc: Michal Nazarewicz &lt;mina86@mina86.com&gt;
Cc: Naoya Horiguchi &lt;n-horiguchi@ah.jp.nec.com&gt;
Cc: Christoph Lameter &lt;cl@linux.com&gt;
Cc: Rik van Riel &lt;riel@redhat.com&gt;
Acked-by: David Rientjes &lt;rientjes@google.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When allocating huge page for collapsing, khugepaged currently holds
mmap_sem for reading on the mm where collapsing occurs.  Afterwards the
read lock is dropped before write lock is taken on the same mmap_sem.

Holding mmap_sem during whole huge page allocation is therefore useless,
the vma needs to be rechecked after taking the write lock anyway.
Furthemore, huge page allocation might involve a rather long sync
compaction, and thus block any mmap_sem writers and i.e.  affect workloads
that perform frequent m(un)map or mprotect oterations.

This patch simply releases the read lock before allocating a huge page.
It also deletes an outdated comment that assumed vma must be stable, as it
was using alloc_hugepage_vma().  This is no longer true since commit
9f1b868a13ac ("mm: thp: khugepaged: add policy for finding target node").

Signed-off-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: Minchan Kim &lt;minchan@kernel.org&gt;
Acked-by: Mel Gorman &lt;mgorman@suse.de&gt;
Cc: Joonsoo Kim &lt;iamjoonsoo.kim@lge.com&gt;
Cc: Michal Nazarewicz &lt;mina86@mina86.com&gt;
Cc: Naoya Horiguchi &lt;n-horiguchi@ah.jp.nec.com&gt;
Cc: Christoph Lameter &lt;cl@linux.com&gt;
Cc: Rik van Riel &lt;riel@redhat.com&gt;
Acked-by: David Rientjes &lt;rientjes@google.com&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
