<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-toradex.git/fs/proc/meminfo.c, branch v4.10</title>
<subtitle>Linux kernel for Apalis and Colibri modules</subtitle>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/'/>
<entry>
<title>meminfo: break apart a very long seq_printf with #ifdefs</title>
<updated>2016-10-08T01:46:30+00:00</updated>
<author>
<name>Joe Perches</name>
<email>joe@perches.com</email>
</author>
<published>2016-10-08T00:02:23+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=e16e2d8e14a14bd87df8482c637dde8f760a8d5f'/>
<id>e16e2d8e14a14bd87df8482c637dde8f760a8d5f</id>
<content type='text'>
Use a specific routine to emit most lines so that the code is easier to
read and maintain.

akpm:
   text    data     bss     dec     hex filename
   2976       8       0    2984     ba8 fs/proc/meminfo.o before
   2669       8       0    2677     a75 fs/proc/meminfo.o after

Link: http://lkml.kernel.org/r/8fce7fdef2ba081a4ef531594e97da8a9feebb58.1470810406.git.joe@perches.com
Signed-off-by: Joe Perches &lt;joe@perches.com&gt;
Cc: Andi Kleen &lt;andi@firstfloor.org&gt;
Cc: Alexey Dobriyan &lt;adobriyan@gmail.com&gt;
Cc: Al Viro &lt;viro@zeniv.linux.org.uk&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>
Use a specific routine to emit most lines so that the code is easier to
read and maintain.

akpm:
   text    data     bss     dec     hex filename
   2976       8       0    2984     ba8 fs/proc/meminfo.o before
   2669       8       0    2677     a75 fs/proc/meminfo.o after

Link: http://lkml.kernel.org/r/8fce7fdef2ba081a4ef531594e97da8a9feebb58.1470810406.git.joe@perches.com
Signed-off-by: Joe Perches &lt;joe@perches.com&gt;
Cc: Andi Kleen &lt;andi@firstfloor.org&gt;
Cc: Alexey Dobriyan &lt;adobriyan@gmail.com&gt;
Cc: Al Viro &lt;viro@zeniv.linux.org.uk&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>proc, meminfo: use correct helpers for calculating LRU sizes in meminfo</title>
<updated>2016-08-11T23:58:13+00:00</updated>
<author>
<name>Mel Gorman</name>
<email>mgorman@techsingularity.net</email>
</author>
<published>2016-08-11T22:32:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=2f95ff90b99600f53df4a0aa652322d349d67957'/>
<id>2f95ff90b99600f53df4a0aa652322d349d67957</id>
<content type='text'>
meminfo_proc_show() and si_mem_available() are using the wrong helpers
for calculating the size of the LRUs.  The user-visible impact is that
there appears to be an abnormally high number of unevictable pages.

Link: http://lkml.kernel.org/r/20160805105805.GR2799@techsingularity.net
Signed-off-by: Mel Gorman &lt;mgorman@techsingularity.net&gt;
Cc: Dave Chinner &lt;david@fromorbit.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>
meminfo_proc_show() and si_mem_available() are using the wrong helpers
for calculating the size of the LRUs.  The user-visible impact is that
there appears to be an abnormally high number of unevictable pages.

Link: http://lkml.kernel.org/r/20160805105805.GR2799@techsingularity.net
Signed-off-by: Mel Gorman &lt;mgorman@techsingularity.net&gt;
Cc: Dave Chinner &lt;david@fromorbit.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: track NR_KERNEL_STACK in KiB instead of number of stacks</title>
<updated>2016-07-28T23:07:41+00:00</updated>
<author>
<name>Andy Lutomirski</name>
<email>luto@kernel.org</email>
</author>
<published>2016-07-28T22:48:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=d30dd8be06a5ae640766b20ea9ae288832bd12ac'/>
<id>d30dd8be06a5ae640766b20ea9ae288832bd12ac</id>
<content type='text'>
Currently, NR_KERNEL_STACK tracks the number of kernel stacks in a zone.
This only makes sense if each kernel stack exists entirely in one zone,
and allowing vmapped stacks could break this assumption.

Since frv has THREAD_SIZE &lt; PAGE_SIZE, we need to track kernel stack
allocations in a unit that divides both THREAD_SIZE and PAGE_SIZE on all
architectures.  Keep it simple and use KiB.

Link: http://lkml.kernel.org/r/083c71e642c5fa5f1b6898902e1b2db7b48940d4.1468523549.git.luto@kernel.org
Signed-off-by: Andy Lutomirski &lt;luto@kernel.org&gt;
Cc: Vladimir Davydov &lt;vdavydov@virtuozzo.com&gt;
Acked-by: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Michal Hocko &lt;mhocko@kernel.org&gt;
Reviewed-by: Josh Poimboeuf &lt;jpoimboe@redhat.com&gt;
Reviewed-by: Vladimir Davydov &lt;vdavydov@virtuozzo.com&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.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>
Currently, NR_KERNEL_STACK tracks the number of kernel stacks in a zone.
This only makes sense if each kernel stack exists entirely in one zone,
and allowing vmapped stacks could break this assumption.

Since frv has THREAD_SIZE &lt; PAGE_SIZE, we need to track kernel stack
allocations in a unit that divides both THREAD_SIZE and PAGE_SIZE on all
architectures.  Keep it simple and use KiB.

Link: http://lkml.kernel.org/r/083c71e642c5fa5f1b6898902e1b2db7b48940d4.1468523549.git.luto@kernel.org
Signed-off-by: Andy Lutomirski &lt;luto@kernel.org&gt;
Cc: Vladimir Davydov &lt;vdavydov@virtuozzo.com&gt;
Acked-by: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Michal Hocko &lt;mhocko@kernel.org&gt;
Reviewed-by: Josh Poimboeuf &lt;jpoimboe@redhat.com&gt;
Reviewed-by: Vladimir Davydov &lt;vdavydov@virtuozzo.com&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.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: move most file-based accounting to the node</title>
<updated>2016-07-28T23:07:41+00:00</updated>
<author>
<name>Mel Gorman</name>
<email>mgorman@techsingularity.net</email>
</author>
<published>2016-07-28T22:46:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=11fb998986a72aa7e997d96d63d52582a01228c5'/>
<id>11fb998986a72aa7e997d96d63d52582a01228c5</id>
<content type='text'>
There are now a number of accounting oddities such as mapped file pages
being accounted for on the node while the total number of file pages are
accounted on the zone.  This can be coped with to some extent but it's
confusing so this patch moves the relevant file-based accounted.  Due to
throttling logic in the page allocator for reliable OOM detection, it is
still necessary to track dirty and writeback pages on a per-zone basis.

[mgorman@techsingularity.net: fix NR_ZONE_WRITE_PENDING accounting]
  Link: http://lkml.kernel.org/r/1468404004-5085-5-git-send-email-mgorman@techsingularity.net
Link: http://lkml.kernel.org/r/1467970510-21195-20-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman &lt;mgorman@techsingularity.net&gt;
Acked-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Hillf Danton &lt;hillf.zj@alibaba-inc.com&gt;
Acked-by: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Joonsoo Kim &lt;iamjoonsoo.kim@lge.com&gt;
Cc: Minchan Kim &lt;minchan@kernel.org&gt;
Cc: Rik van Riel &lt;riel@surriel.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 are now a number of accounting oddities such as mapped file pages
being accounted for on the node while the total number of file pages are
accounted on the zone.  This can be coped with to some extent but it's
confusing so this patch moves the relevant file-based accounted.  Due to
throttling logic in the page allocator for reliable OOM detection, it is
still necessary to track dirty and writeback pages on a per-zone basis.

[mgorman@techsingularity.net: fix NR_ZONE_WRITE_PENDING accounting]
  Link: http://lkml.kernel.org/r/1468404004-5085-5-git-send-email-mgorman@techsingularity.net
Link: http://lkml.kernel.org/r/1467970510-21195-20-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman &lt;mgorman@techsingularity.net&gt;
Acked-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Hillf Danton &lt;hillf.zj@alibaba-inc.com&gt;
Acked-by: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Joonsoo Kim &lt;iamjoonsoo.kim@lge.com&gt;
Cc: Minchan Kim &lt;minchan@kernel.org&gt;
Cc: Rik van Riel &lt;riel@surriel.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: rename NR_ANON_PAGES to NR_ANON_MAPPED</title>
<updated>2016-07-28T23:07:41+00:00</updated>
<author>
<name>Mel Gorman</name>
<email>mgorman@techsingularity.net</email>
</author>
<published>2016-07-28T22:46:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=4b9d0fab7166c9323f06d708518a35cf3a90426c'/>
<id>4b9d0fab7166c9323f06d708518a35cf3a90426c</id>
<content type='text'>
NR_FILE_PAGES  is the number of        file pages.
NR_FILE_MAPPED is the number of mapped file pages.
NR_ANON_PAGES  is the number of mapped anon pages.

This is unhelpful naming as it's easy to confuse NR_FILE_MAPPED and
NR_ANON_PAGES for mapped pages.  This patch renames NR_ANON_PAGES so we
have

NR_FILE_PAGES  is the number of        file pages.
NR_FILE_MAPPED is the number of mapped file pages.
NR_ANON_MAPPED is the number of mapped anon pages.

Link: http://lkml.kernel.org/r/1467970510-21195-19-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman &lt;mgorman@techsingularity.net&gt;
Acked-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: Hillf Danton &lt;hillf.zj@alibaba-inc.com&gt;
Cc: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Joonsoo Kim &lt;iamjoonsoo.kim@lge.com&gt;
Cc: Michal Hocko &lt;mhocko@kernel.org&gt;
Cc: Minchan Kim &lt;minchan@kernel.org&gt;
Cc: Rik van Riel &lt;riel@surriel.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>
NR_FILE_PAGES  is the number of        file pages.
NR_FILE_MAPPED is the number of mapped file pages.
NR_ANON_PAGES  is the number of mapped anon pages.

This is unhelpful naming as it's easy to confuse NR_FILE_MAPPED and
NR_ANON_PAGES for mapped pages.  This patch renames NR_ANON_PAGES so we
have

NR_FILE_PAGES  is the number of        file pages.
NR_FILE_MAPPED is the number of mapped file pages.
NR_ANON_MAPPED is the number of mapped anon pages.

Link: http://lkml.kernel.org/r/1467970510-21195-19-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman &lt;mgorman@techsingularity.net&gt;
Acked-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Cc: Hillf Danton &lt;hillf.zj@alibaba-inc.com&gt;
Cc: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Joonsoo Kim &lt;iamjoonsoo.kim@lge.com&gt;
Cc: Michal Hocko &lt;mhocko@kernel.org&gt;
Cc: Minchan Kim &lt;minchan@kernel.org&gt;
Cc: Rik van Riel &lt;riel@surriel.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: move page mapped accounting to the node</title>
<updated>2016-07-28T23:07:41+00:00</updated>
<author>
<name>Mel Gorman</name>
<email>mgorman@techsingularity.net</email>
</author>
<published>2016-07-28T22:46:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=50658e2e04c12d5cd628381c1b9cb69d0093a9c0'/>
<id>50658e2e04c12d5cd628381c1b9cb69d0093a9c0</id>
<content type='text'>
Reclaim makes decisions based on the number of pages that are mapped but
it's mixing node and zone information.  Account NR_FILE_MAPPED and
NR_ANON_PAGES pages on the node.

Link: http://lkml.kernel.org/r/1467970510-21195-18-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman &lt;mgorman@techsingularity.net&gt;
Acked-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Hillf Danton &lt;hillf.zj@alibaba-inc.com&gt;
Acked-by: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Joonsoo Kim &lt;iamjoonsoo.kim@lge.com&gt;
Cc: Minchan Kim &lt;minchan@kernel.org&gt;
Cc: Rik van Riel &lt;riel@surriel.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>
Reclaim makes decisions based on the number of pages that are mapped but
it's mixing node and zone information.  Account NR_FILE_MAPPED and
NR_ANON_PAGES pages on the node.

Link: http://lkml.kernel.org/r/1467970510-21195-18-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman &lt;mgorman@techsingularity.net&gt;
Acked-by: Vlastimil Babka &lt;vbabka@suse.cz&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: Hillf Danton &lt;hillf.zj@alibaba-inc.com&gt;
Acked-by: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Joonsoo Kim &lt;iamjoonsoo.kim@lge.com&gt;
Cc: Minchan Kim &lt;minchan@kernel.org&gt;
Cc: Rik van Riel &lt;riel@surriel.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, rmap: account shmem thp pages</title>
<updated>2016-07-26T23:19:19+00:00</updated>
<author>
<name>Kirill A. Shutemov</name>
<email>kirill.shutemov@linux.intel.com</email>
</author>
<published>2016-07-26T22:26:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=65c453778aea374a46597f4d9826274d1eaf7338'/>
<id>65c453778aea374a46597f4d9826274d1eaf7338</id>
<content type='text'>
Let's add ShmemHugePages and ShmemPmdMapped fields into meminfo and
smaps.  It indicates how many times we allocate and map shmem THP.

NR_ANON_TRANSPARENT_HUGEPAGES is renamed to NR_ANON_THPS.

Link: http://lkml.kernel.org/r/1466021202-61880-27-git-send-email-kirill.shutemov@linux.intel.com
Signed-off-by: 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>
Let's add ShmemHugePages and ShmemPmdMapped fields into meminfo and
smaps.  It indicates how many times we allocate and map shmem THP.

NR_ANON_TRANSPARENT_HUGEPAGES is renamed to NR_ANON_THPS.

Link: http://lkml.kernel.org/r/1466021202-61880-27-git-send-email-kirill.shutemov@linux.intel.com
Signed-off-by: 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>mm/page_alloc.c: calculate 'available' memory in a separate function</title>
<updated>2016-03-17T22:09:34+00:00</updated>
<author>
<name>Igor Redko</name>
<email>redkoi@virtuozzo.com</email>
</author>
<published>2016-03-17T21:19:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=d02bd27bd33dd7e8d22594cd568b81be0cb584cd'/>
<id>d02bd27bd33dd7e8d22594cd568b81be0cb584cd</id>
<content type='text'>
Add a new field, VIRTIO_BALLOON_S_AVAIL, to virtio_balloon memory
statistics protocol, corresponding to 'Available' in /proc/meminfo.

It indicates to the hypervisor how big the balloon can be inflated
without pushing the guest system to swap.  This metric would be very
useful in VM orchestration software to improve memory management of
different VMs under overcommit.

This patch (of 2):

Factor out calculation of the available memory counter into a separate
exportable function, in order to be able to use it in other parts of the
kernel.

In particular, it appears a relevant metric to report to the hypervisor
via virtio-balloon statistics interface (in a followup patch).

Signed-off-by: Igor Redko &lt;redkoi@virtuozzo.com&gt;
Signed-off-by: Denis V. Lunev &lt;den@openvz.org&gt;
Reviewed-by: Roman Kagan &lt;rkagan@virtuozzo.com&gt;
Cc: Michael S. Tsirkin &lt;mst@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>
Add a new field, VIRTIO_BALLOON_S_AVAIL, to virtio_balloon memory
statistics protocol, corresponding to 'Available' in /proc/meminfo.

It indicates to the hypervisor how big the balloon can be inflated
without pushing the guest system to swap.  This metric would be very
useful in VM orchestration software to improve memory management of
different VMs under overcommit.

This patch (of 2):

Factor out calculation of the available memory counter into a separate
exportable function, in order to be able to use it in other parts of the
kernel.

In particular, it appears a relevant metric to report to the hypervisor
via virtio-balloon statistics interface (in a followup patch).

Signed-off-by: Igor Redko &lt;redkoi@virtuozzo.com&gt;
Signed-off-by: Denis V. Lunev &lt;den@openvz.org&gt;
Reviewed-by: Roman Kagan &lt;rkagan@virtuozzo.com&gt;
Cc: Michael S. Tsirkin &lt;mst@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>proc: meminfo: estimate available memory more conservatively</title>
<updated>2016-01-15T00:00:49+00:00</updated>
<author>
<name>Johannes Weiner</name>
<email>hannes@cmpxchg.org</email>
</author>
<published>2016-01-14T23:20:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=84ad5802a33a4964a49b8f7d24d80a214a096b19'/>
<id>84ad5802a33a4964a49b8f7d24d80a214a096b19</id>
<content type='text'>
The MemAvailable item in /proc/meminfo is to give users a hint of how
much memory is allocatable without causing swapping, so it excludes the
zones' low watermarks as unavailable to userspace.

However, for a userspace allocation, kswapd will actually reclaim until
the free pages hit a combination of the high watermark and the page
allocator's lowmem protection that keeps a certain amount of DMA and
DMA32 memory from userspace as well.

Subtract the full amount we know to be unavailable to userspace from the
number of free pages when calculating MemAvailable.

Signed-off-by: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Rik van Riel &lt;riel@redhat.com&gt;
Cc: Mel Gorman &lt;mgorman@suse.de&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.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>
The MemAvailable item in /proc/meminfo is to give users a hint of how
much memory is allocatable without causing swapping, so it excludes the
zones' low watermarks as unavailable to userspace.

However, for a userspace allocation, kswapd will actually reclaim until
the free pages hit a combination of the high watermark and the page
allocator's lowmem protection that keeps a certain amount of DMA and
DMA32 memory from userspace as well.

Subtract the full amount we know to be unavailable to userspace from the
number of free pages when calculating MemAvailable.

Signed-off-by: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Cc: Rik van Riel &lt;riel@redhat.com&gt;
Cc: Mel Gorman &lt;mgorman@suse.de&gt;
Acked-by: Michal Hocko &lt;mhocko@suse.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: get rid of 'vmalloc_info' from /proc/meminfo</title>
<updated>2015-11-02T01:09:15+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2015-11-02T01:09:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.toradex.cn/cgit/linux-toradex.git/commit/?id=a5ad88ce8c7fae7ddc72ee49a11a75aa837788e0'/>
<id>a5ad88ce8c7fae7ddc72ee49a11a75aa837788e0</id>
<content type='text'>
It turns out that at least some versions of glibc end up reading
/proc/meminfo at every single startup, because glibc wants to know the
amount of memory the machine has.  And while that's arguably insane,
it's just how things are.

And it turns out that it's not all that expensive most of the time, but
the vmalloc information statistics (amount of virtual memory used in the
vmalloc space, and the biggest remaining chunk) can be rather expensive
to compute.

The 'get_vmalloc_info()' function actually showed up on my profiles as
4% of the CPU usage of "make test" in the git source repository, because
the git tests are lots of very short-lived shell-scripts etc.

It turns out that apparently this same silly vmalloc info gathering
shows up on the facebook servers too, according to Dave Jones.  So it's
not just "make test" for git.

We had two patches to just cache the information (one by me, one by
Ingo) to mitigate this issue, but the whole vmalloc information of of
rather dubious value to begin with, and people who *actually* want to
know what the situation is wrt the vmalloc area should just look at the
much more complete /proc/vmallocinfo instead.

In fact, according to my testing - and perhaps more importantly,
according to that big search engine in the sky: Google - there is
nothing out there that actually cares about those two expensive fields:
VmallocUsed and VmallocChunk.

So let's try to just remove them entirely.  Actually, this just removes
the computation and reports the numbers as zero for now, just to try to
be minimally intrusive.

If this breaks anything, we'll obviously have to re-introduce the code
to compute this all and add the caching patches on top.  But if given
the option, I'd really prefer to just remove this bad idea entirely
rather than add even more code to work around our historical mistake
that likely nobody really cares about.

Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
It turns out that at least some versions of glibc end up reading
/proc/meminfo at every single startup, because glibc wants to know the
amount of memory the machine has.  And while that's arguably insane,
it's just how things are.

And it turns out that it's not all that expensive most of the time, but
the vmalloc information statistics (amount of virtual memory used in the
vmalloc space, and the biggest remaining chunk) can be rather expensive
to compute.

The 'get_vmalloc_info()' function actually showed up on my profiles as
4% of the CPU usage of "make test" in the git source repository, because
the git tests are lots of very short-lived shell-scripts etc.

It turns out that apparently this same silly vmalloc info gathering
shows up on the facebook servers too, according to Dave Jones.  So it's
not just "make test" for git.

We had two patches to just cache the information (one by me, one by
Ingo) to mitigate this issue, but the whole vmalloc information of of
rather dubious value to begin with, and people who *actually* want to
know what the situation is wrt the vmalloc area should just look at the
much more complete /proc/vmallocinfo instead.

In fact, according to my testing - and perhaps more importantly,
according to that big search engine in the sky: Google - there is
nothing out there that actually cares about those two expensive fields:
VmallocUsed and VmallocChunk.

So let's try to just remove them entirely.  Actually, this just removes
the computation and reports the numbers as zero for now, just to try to
be minimally intrusive.

If this breaks anything, we'll obviously have to re-introduce the code
to compute this all and add the caching patches on top.  But if given
the option, I'd really prefer to just remove this bad idea entirely
rather than add even more code to work around our historical mistake
that likely nobody really cares about.

Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
