<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/include/linux/hugetlb.h, branch v3.19-rc2</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>Merge tag 'powerpc-3.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux</title>
<updated>2014-12-12T01:48:14+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2014-12-12T01:48:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=140cd7fb04a4a2bc09a30980bc8104cc89e09330'/>
<id>140cd7fb04a4a2bc09a30980bc8104cc89e09330</id>
<content type='text'>
Pull powerpc updates from Michael Ellerman:
 "Some nice cleanups like removing bootmem, and removal of
  __get_cpu_var().

  There is one patch to mm/gup.c.  This is the generic GUP
  implementation, but is only used by us and arm(64).  We have an ack
  from Steve Capper, and although we didn't get an ack from Andrew he
  told us to take the patch through the powerpc tree.

  There's one cxl patch.  This is in drivers/misc, but Greg said he was
  happy for us to manage fixes for it.

  There is an infrastructure patch to support an IPMI driver for OPAL.

  There is also an RTC driver for OPAL.  We weren't able to get any
  response from the RTC maintainer, Alessandro Zummo, so in the end we
  just merged the driver.

  The usual batch of Freescale updates from Scott"

* tag 'powerpc-3.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux: (101 commits)
  powerpc/powernv: Return to cpu offline loop when finished in KVM guest
  powerpc/book3s: Fix partial invalidation of TLBs in MCE code.
  powerpc/mm: don't do tlbie for updatepp request with NO HPTE fault
  powerpc/xmon: Cleanup the breakpoint flags
  powerpc/xmon: Enable HW instruction breakpoint on POWER8
  powerpc/mm/thp: Use tlbiel if possible
  powerpc/mm/thp: Remove code duplication
  powerpc/mm/hugetlb: Sanity check gigantic hugepage count
  powerpc/oprofile: Disable pagefaults during user stack read
  powerpc/mm: Check for matching hpte without taking hpte lock
  powerpc: Drop useless warning in eeh_init()
  powerpc/powernv: Cleanup unused MCE definitions/declarations.
  powerpc/eeh: Dump PHB diag-data early
  powerpc/eeh: Recover EEH error on ownership change for BCM5719
  powerpc/eeh: Set EEH_PE_RESET on PE reset
  powerpc/eeh: Refactor eeh_reset_pe()
  powerpc: Remove more traces of bootmem
  powerpc/pseries: Initialise nvram_pstore_info's buf_lock
  cxl: Name interrupts in /proc/interrupt
  cxl: Return error to PSL if IRQ demultiplexing fails &amp; print clearer warning
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull powerpc updates from Michael Ellerman:
 "Some nice cleanups like removing bootmem, and removal of
  __get_cpu_var().

  There is one patch to mm/gup.c.  This is the generic GUP
  implementation, but is only used by us and arm(64).  We have an ack
  from Steve Capper, and although we didn't get an ack from Andrew he
  told us to take the patch through the powerpc tree.

  There's one cxl patch.  This is in drivers/misc, but Greg said he was
  happy for us to manage fixes for it.

  There is an infrastructure patch to support an IPMI driver for OPAL.

  There is also an RTC driver for OPAL.  We weren't able to get any
  response from the RTC maintainer, Alessandro Zummo, so in the end we
  just merged the driver.

  The usual batch of Freescale updates from Scott"

* tag 'powerpc-3.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux: (101 commits)
  powerpc/powernv: Return to cpu offline loop when finished in KVM guest
  powerpc/book3s: Fix partial invalidation of TLBs in MCE code.
  powerpc/mm: don't do tlbie for updatepp request with NO HPTE fault
  powerpc/xmon: Cleanup the breakpoint flags
  powerpc/xmon: Enable HW instruction breakpoint on POWER8
  powerpc/mm/thp: Use tlbiel if possible
  powerpc/mm/thp: Remove code duplication
  powerpc/mm/hugetlb: Sanity check gigantic hugepage count
  powerpc/oprofile: Disable pagefaults during user stack read
  powerpc/mm: Check for matching hpte without taking hpte lock
  powerpc: Drop useless warning in eeh_init()
  powerpc/powernv: Cleanup unused MCE definitions/declarations.
  powerpc/eeh: Dump PHB diag-data early
  powerpc/eeh: Recover EEH error on ownership change for BCM5719
  powerpc/eeh: Set EEH_PE_RESET on PE reset
  powerpc/eeh: Refactor eeh_reset_pe()
  powerpc: Remove more traces of bootmem
  powerpc/pseries: Initialise nvram_pstore_info's buf_lock
  cxl: Name interrupts in /proc/interrupt
  cxl: Return error to PSL if IRQ demultiplexing fails &amp; print clearer warning
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>mm, hugetlb: correct bit shift in hstate_sizelog()</title>
<updated>2014-12-11T01:41:07+00:00</updated>
<author>
<name>Sasha Levin</name>
<email>sasha.levin@oracle.com</email>
</author>
<published>2014-12-10T23:44:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=97ad2be1daf8e6f2d297aa349101b340e1327917'/>
<id>97ad2be1daf8e6f2d297aa349101b340e1327917</id>
<content type='text'>
hstate_sizelog() would shift left an int rather than long, triggering
undefined behaviour and passing an incorrect value when the requested
page size was more than 4GB, thus breaking &gt;4GB pages.

Signed-off-by: Sasha Levin &lt;sasha.levin@oracle.com&gt;
Cc: Andrea Arcangeli &lt;aarcange@redhat.com&gt;
Cc: Mel Gorman &lt;mgorman@suse.de&gt;
Cc: Andrey Ryabinin &lt;a.ryabinin@samsung.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>
hstate_sizelog() would shift left an int rather than long, triggering
undefined behaviour and passing an incorrect value when the requested
page size was more than 4GB, thus breaking &gt;4GB pages.

Signed-off-by: Sasha Levin &lt;sasha.levin@oracle.com&gt;
Cc: Andrea Arcangeli &lt;aarcange@redhat.com&gt;
Cc: Mel Gorman &lt;mgorman@suse.de&gt;
Cc: Andrey Ryabinin &lt;a.ryabinin@samsung.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: Update generic gup implementation to handle hugepage directory</title>
<updated>2014-11-14T06:24:21+00:00</updated>
<author>
<name>Aneesh Kumar K.V</name>
<email>aneesh.kumar@linux.vnet.ibm.com</email>
</author>
<published>2014-11-05T16:27:40+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=f30c59e921f12b209852e1ddc197dc6a8fb0142b'/>
<id>f30c59e921f12b209852e1ddc197dc6a8fb0142b</id>
<content type='text'>
Update generic gup implementation with powerpc specific details.
On powerpc at pmd level we can have hugepte, normal pmd pointer
or a pointer to the hugepage directory.

Tested-by: Steve Capper &lt;steve.capper@linaro.org&gt;
Acked-by: Steve Capper &lt;steve.capper@linaro.org&gt;
Signed-off-by: Aneesh Kumar K.V &lt;aneesh.kumar@linux.vnet.ibm.com&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Update generic gup implementation with powerpc specific details.
On powerpc at pmd level we can have hugepte, normal pmd pointer
or a pointer to the hugepage directory.

Tested-by: Steve Capper &lt;steve.capper@linaro.org&gt;
Acked-by: Steve Capper &lt;steve.capper@linaro.org&gt;
Signed-off-by: Aneesh Kumar K.V &lt;aneesh.kumar@linux.vnet.ibm.com&gt;
Signed-off-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm, hugetlb: remove hugetlb_zero and hugetlb_infinity</title>
<updated>2014-08-07T01:01:19+00:00</updated>
<author>
<name>David Rientjes</name>
<email>rientjes@google.com</email>
</author>
<published>2014-08-06T23:06:54+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=ed4d4902ebdd7ca8b5a51daaf6bebf4b172895cc'/>
<id>ed4d4902ebdd7ca8b5a51daaf6bebf4b172895cc</id>
<content type='text'>
They are unnecessary: "zero" can be used in place of "hugetlb_zero" and
passing extra2 == NULL is equivalent to infinity.

Signed-off-by: David Rientjes &lt;rientjes@google.com&gt;
Cc: Joonsoo Kim &lt;iamjoonsoo.kim@lge.com&gt;
Reviewed-by: Naoya Horiguchi &lt;n-horiguchi@ah.jp.nec.com&gt;
Reviewed-by: Luiz Capitulino &lt;lcapitulino@redhat.com&gt;
Cc: "Kirill A. Shutemov" &lt;kirill.shutemov@linux.intel.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>
They are unnecessary: "zero" can be used in place of "hugetlb_zero" and
passing extra2 == NULL is equivalent to infinity.

Signed-off-by: David Rientjes &lt;rientjes@google.com&gt;
Cc: Joonsoo Kim &lt;iamjoonsoo.kim@lge.com&gt;
Reviewed-by: Naoya Horiguchi &lt;n-horiguchi@ah.jp.nec.com&gt;
Reviewed-by: Luiz Capitulino &lt;lcapitulino@redhat.com&gt;
Cc: "Kirill A. Shutemov" &lt;kirill.shutemov@linux.intel.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>kexec: export free_huge_page to VMCOREINFO</title>
<updated>2014-07-31T00:16:13+00:00</updated>
<author>
<name>Atsushi Kumagai</name>
<email>kumagai-atsushi@mxc.nes.nec.co.jp</email>
</author>
<published>2014-07-30T23:08:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=8f1d26d0e59b9676587c54578f976709b625d6e9'/>
<id>8f1d26d0e59b9676587c54578f976709b625d6e9</id>
<content type='text'>
PG_head_mask was added into VMCOREINFO to filter huge pages in b3acc56bfe1
("kexec: save PG_head_mask in VMCOREINFO"), but makedumpfile still need
another symbol to filter *hugetlbfs* pages.

If a user hope to filter user pages, makedumpfile tries to exclude them by
checking the condition whether the page is anonymous, but hugetlbfs pages
aren't anonymous while they also be user pages.

We know it's possible to detect them in the same way as PageHuge(),
so we need the start address of free_huge_page():

    int PageHuge(struct page *page)
    {
            if (!PageCompound(page))
                    return 0;

            page = compound_head(page);
            return get_compound_page_dtor(page) == free_huge_page;
    }

For that reason, this patch changes free_huge_page() into public
to export it to VMCOREINFO.

Signed-off-by: Atsushi Kumagai &lt;kumagai-atsushi@mxc.nes.nec.co.jp&gt;
Acked-by: Baoquan He &lt;bhe@redhat.com&gt;
Cc: Vivek Goyal &lt;vgoyal@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>
PG_head_mask was added into VMCOREINFO to filter huge pages in b3acc56bfe1
("kexec: save PG_head_mask in VMCOREINFO"), but makedumpfile still need
another symbol to filter *hugetlbfs* pages.

If a user hope to filter user pages, makedumpfile tries to exclude them by
checking the condition whether the page is anonymous, but hugetlbfs pages
aren't anonymous while they also be user pages.

We know it's possible to detect them in the same way as PageHuge(),
so we need the start address of free_huge_page():

    int PageHuge(struct page *page)
    {
            if (!PageCompound(page))
                    return 0;

            page = compound_head(page);
            return get_compound_page_dtor(page) == free_huge_page;
    }

For that reason, this patch changes free_huge_page() into public
to export it to VMCOREINFO.

Signed-off-by: Atsushi Kumagai &lt;kumagai-atsushi@mxc.nes.nec.co.jp&gt;
Acked-by: Baoquan He &lt;bhe@redhat.com&gt;
Cc: Vivek Goyal &lt;vgoyal@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>hugetlb: rename hugepage_migration_support() to ..._supported()</title>
<updated>2014-06-04T23:54:12+00:00</updated>
<author>
<name>Naoya Horiguchi</name>
<email>n-horiguchi@ah.jp.nec.com</email>
</author>
<published>2014-06-04T23:10:56+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=100873d7a777b67ad35197c5a998b5e778f8bf3f'/>
<id>100873d7a777b67ad35197c5a998b5e778f8bf3f</id>
<content type='text'>
We already have a function named hugepages_supported(), and the similar
name hugepage_migration_support() is a bit unconfortable, so let's rename
it hugepage_migration_supported().

Signed-off-by: Naoya Horiguchi &lt;n-horiguchi@ah.jp.nec.com&gt;
Acked-by: Hugh Dickins &lt;hughd@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>
We already have a function named hugepages_supported(), and the similar
name hugepage_migration_support() is a bit unconfortable, so let's rename
it hugepage_migration_supported().

Signed-off-by: Naoya Horiguchi &lt;n-horiguchi@ah.jp.nec.com&gt;
Acked-by: Hugh Dickins &lt;hughd@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>
<entry>
<title>hugetlb: add hstate_is_gigantic()</title>
<updated>2014-06-04T23:53:59+00:00</updated>
<author>
<name>Luiz Capitulino</name>
<email>lcapitulino@redhat.com</email>
</author>
<published>2014-06-04T23:07:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=bae7f4ae14d47008a11b4358b167cb0ae186c06a'/>
<id>bae7f4ae14d47008a11b4358b167cb0ae186c06a</id>
<content type='text'>
Signed-off-by: Luiz Capitulino &lt;lcapitulino@redhat.com&gt;
Reviewed-by: Andrea Arcangeli &lt;aarcange@redhat.com&gt;
Reviewed-by: Naoya Horiguchi &lt;n-horiguchi@ah.jp.nec.com&gt;
Reviewed-by: Yasuaki Ishimatsu &lt;isimatu.yasuaki@jp.fujitsu.com&gt;
Reviewed-by: Davidlohr Bueso &lt;davidlohr@hp.com&gt;
Acked-by: Kirill A. Shutemov &lt;kirill.shutemov@linux.intel.com&gt;
Reviewed-by: Zhang Yanfei &lt;zhangyanfei@cn.fujitsu.com&gt;
Cc: David Rientjes &lt;rientjes@google.com&gt;
Cc: Marcelo Tosatti &lt;mtosatti@redhat.com&gt;
Cc: Rik van Riel &lt;riel@redhat.com&gt;
Cc: Yinghai Lu &lt;yinghai@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>
Signed-off-by: Luiz Capitulino &lt;lcapitulino@redhat.com&gt;
Reviewed-by: Andrea Arcangeli &lt;aarcange@redhat.com&gt;
Reviewed-by: Naoya Horiguchi &lt;n-horiguchi@ah.jp.nec.com&gt;
Reviewed-by: Yasuaki Ishimatsu &lt;isimatu.yasuaki@jp.fujitsu.com&gt;
Reviewed-by: Davidlohr Bueso &lt;davidlohr@hp.com&gt;
Acked-by: Kirill A. Shutemov &lt;kirill.shutemov@linux.intel.com&gt;
Reviewed-by: Zhang Yanfei &lt;zhangyanfei@cn.fujitsu.com&gt;
Cc: David Rientjes &lt;rientjes@google.com&gt;
Cc: Marcelo Tosatti &lt;mtosatti@redhat.com&gt;
Cc: Rik van Riel &lt;riel@redhat.com&gt;
Cc: Yinghai Lu &lt;yinghai@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>hugetlb: restrict hugepage_migration_support() to x86_64</title>
<updated>2014-06-04T23:53:51+00:00</updated>
<author>
<name>Naoya Horiguchi</name>
<email>n-horiguchi@ah.jp.nec.com</email>
</author>
<published>2014-06-04T23:05:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=c177c81e09e517bbf75b67762cdab1b83aba6976'/>
<id>c177c81e09e517bbf75b67762cdab1b83aba6976</id>
<content type='text'>
Currently hugepage migration is available for all archs which support
pmd-level hugepage, but testing is done only for x86_64 and there're
bugs for other archs.  So to avoid breaking such archs, this patch
limits the availability strictly to x86_64 until developers of other
archs get interested in enabling this feature.

Simply disabling hugepage migration on non-x86_64 archs is not enough to
fix the reported problem where sys_move_pages() hits the BUG_ON() in
follow_page(FOLL_GET), so let's fix this by checking if hugepage
migration is supported in vma_migratable().

Signed-off-by: Naoya Horiguchi &lt;n-horiguchi@ah.jp.nec.com&gt;
Reported-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Tested-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Acked-by: Hugh Dickins &lt;hughd@google.com&gt;
Cc: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Cc: Russell King &lt;rmk@arm.linux.org.uk&gt;
Cc: Martin Schwidefsky &lt;schwidefsky@de.ibm.com&gt;
Cc: James Hogan &lt;james.hogan@imgtec.com&gt;
Cc: Ralf Baechle &lt;ralf@linux-mips.org&gt;
Cc: David Miller &lt;davem@davemloft.net&gt;
Cc: &lt;stable@vger.kernel.org&gt;	[3.12+]
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>
Currently hugepage migration is available for all archs which support
pmd-level hugepage, but testing is done only for x86_64 and there're
bugs for other archs.  So to avoid breaking such archs, this patch
limits the availability strictly to x86_64 until developers of other
archs get interested in enabling this feature.

Simply disabling hugepage migration on non-x86_64 archs is not enough to
fix the reported problem where sys_move_pages() hits the BUG_ON() in
follow_page(FOLL_GET), so let's fix this by checking if hugepage
migration is supported in vma_migratable().

Signed-off-by: Naoya Horiguchi &lt;n-horiguchi@ah.jp.nec.com&gt;
Reported-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Tested-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Acked-by: Hugh Dickins &lt;hughd@google.com&gt;
Cc: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Cc: Russell King &lt;rmk@arm.linux.org.uk&gt;
Cc: Martin Schwidefsky &lt;schwidefsky@de.ibm.com&gt;
Cc: James Hogan &lt;james.hogan@imgtec.com&gt;
Cc: Ralf Baechle &lt;ralf@linux-mips.org&gt;
Cc: David Miller &lt;davem@davemloft.net&gt;
Cc: &lt;stable@vger.kernel.org&gt;	[3.12+]
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>hugetlb: ensure hugepage access is denied if hugepages are not supported</title>
<updated>2014-05-06T20:04:58+00:00</updated>
<author>
<name>Nishanth Aravamudan</name>
<email>nacc@linux.vnet.ibm.com</email>
</author>
<published>2014-05-06T19:50:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=457c1b27ed56ec472d202731b12417bff023594a'/>
<id>457c1b27ed56ec472d202731b12417bff023594a</id>
<content type='text'>
Currently, I am seeing the following when I `mount -t hugetlbfs /none
/dev/hugetlbfs`, and then simply do a `ls /dev/hugetlbfs`.  I think it's
related to the fact that hugetlbfs is properly not correctly setting
itself up in this state?:

  Unable to handle kernel paging request for data at address 0x00000031
  Faulting instruction address: 0xc000000000245710
  Oops: Kernel access of bad area, sig: 11 [#1]
  SMP NR_CPUS=2048 NUMA pSeries
  ....

In KVM guests on Power, in a guest not backed by hugepages, we see the
following:

  AnonHugePages:         0 kB
  HugePages_Total:       0
  HugePages_Free:        0
  HugePages_Rsvd:        0
  HugePages_Surp:        0
  Hugepagesize:         64 kB

HPAGE_SHIFT == 0 in this configuration, which indicates that hugepages
are not supported at boot-time, but this is only checked in
hugetlb_init().  Extract the check to a helper function, and use it in a
few relevant places.

This does make hugetlbfs not supported (not registered at all) in this
environment.  I believe this is fine, as there are no valid hugepages
and that won't change at runtime.

[akpm@linux-foundation.org: use pr_info(), per Mel]
[akpm@linux-foundation.org: fix build when HPAGE_SHIFT is undefined]
Signed-off-by: Nishanth Aravamudan &lt;nacc@linux.vnet.ibm.com&gt;
Reviewed-by: Aneesh Kumar K.V &lt;aneesh.kumar@linux.vnet.ibm.com&gt;
Acked-by: Mel Gorman &lt;mgorman@suse.de&gt;
Cc: Randy Dunlap &lt;rdunlap@infradead.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>
Currently, I am seeing the following when I `mount -t hugetlbfs /none
/dev/hugetlbfs`, and then simply do a `ls /dev/hugetlbfs`.  I think it's
related to the fact that hugetlbfs is properly not correctly setting
itself up in this state?:

  Unable to handle kernel paging request for data at address 0x00000031
  Faulting instruction address: 0xc000000000245710
  Oops: Kernel access of bad area, sig: 11 [#1]
  SMP NR_CPUS=2048 NUMA pSeries
  ....

In KVM guests on Power, in a guest not backed by hugepages, we see the
following:

  AnonHugePages:         0 kB
  HugePages_Total:       0
  HugePages_Free:        0
  HugePages_Rsvd:        0
  HugePages_Surp:        0
  Hugepagesize:         64 kB

HPAGE_SHIFT == 0 in this configuration, which indicates that hugepages
are not supported at boot-time, but this is only checked in
hugetlb_init().  Extract the check to a helper function, and use it in a
few relevant places.

This does make hugetlbfs not supported (not registered at all) in this
environment.  I believe this is fine, as there are no valid hugepages
and that won't change at runtime.

[akpm@linux-foundation.org: use pr_info(), per Mel]
[akpm@linux-foundation.org: fix build when HPAGE_SHIFT is undefined]
Signed-off-by: Nishanth Aravamudan &lt;nacc@linux.vnet.ibm.com&gt;
Reviewed-by: Aneesh Kumar K.V &lt;aneesh.kumar@linux.vnet.ibm.com&gt;
Acked-by: Mel Gorman &lt;mgorman@suse.de&gt;
Cc: Randy Dunlap &lt;rdunlap@infradead.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, hugetlb: fix race in region tracking</title>
<updated>2014-04-03T23:20:59+00:00</updated>
<author>
<name>Davidlohr Bueso</name>
<email>davidlohr@hp.com</email>
</author>
<published>2014-04-03T21:47:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=7b24d8616be33616efd41ff67d3c76362c60ca84'/>
<id>7b24d8616be33616efd41ff67d3c76362c60ca84</id>
<content type='text'>
There is a race condition if we map a same file on different processes.
Region tracking is protected by mmap_sem and hugetlb_instantiation_mutex.
When we do mmap, we don't grab a hugetlb_instantiation_mutex, but only
mmap_sem (exclusively).  This doesn't prevent other tasks from modifying
the region structure, so it can be modified by two processes
concurrently.

To solve this, introduce a spinlock to resv_map and make region
manipulation function grab it before they do actual work.

[davidlohr@hp.com: updated changelog]
Signed-off-by: Davidlohr Bueso &lt;davidlohr@hp.com&gt;
Signed-off-by: Joonsoo Kim &lt;iamjoonsoo.kim@lge.com&gt;
Suggested-by: Joonsoo Kim &lt;iamjoonsoo.kim@lge.com&gt;
Acked-by: David Gibson &lt;david@gibson.dropbear.id.au&gt;
Cc: David Gibson &lt;david@gibson.dropbear.id.au&gt;
Cc: Naoya Horiguchi &lt;n-horiguchi@ah.jp.nec.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>
There is a race condition if we map a same file on different processes.
Region tracking is protected by mmap_sem and hugetlb_instantiation_mutex.
When we do mmap, we don't grab a hugetlb_instantiation_mutex, but only
mmap_sem (exclusively).  This doesn't prevent other tasks from modifying
the region structure, so it can be modified by two processes
concurrently.

To solve this, introduce a spinlock to resv_map and make region
manipulation function grab it before they do actual work.

[davidlohr@hp.com: updated changelog]
Signed-off-by: Davidlohr Bueso &lt;davidlohr@hp.com&gt;
Signed-off-by: Joonsoo Kim &lt;iamjoonsoo.kim@lge.com&gt;
Suggested-by: Joonsoo Kim &lt;iamjoonsoo.kim@lge.com&gt;
Acked-by: David Gibson &lt;david@gibson.dropbear.id.au&gt;
Cc: David Gibson &lt;david@gibson.dropbear.id.au&gt;
Cc: Naoya Horiguchi &lt;n-horiguchi@ah.jp.nec.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>
