linux-toradex.git/Documentation/cgroups/memory.txt, branch v3.4.69

memcg: oom: fix totalpages calculation for memory.swappiness==0

2012-11-26T19:37:45+00:00

commit 9a5a8f19b43430752067ecaee62fc59e11e88fa6 upstream.

oom_badness() takes a totalpages argument which says how many pages are
available and it uses it as a base for the score calculation.  The value
is calculated by mem_cgroup_get_limit which considers both limit and
total_swap_pages (resp.  memsw portion of it).

This is usually correct but since fe35004fbf9e ("mm: avoid swapping out
with swappiness==0") we do not swap when swappiness is 0 which means
that we cannot really use up all the totalpages pages.  This in turn
confuses oom score calculation if the memcg limit is much smaller than
the available swap because the used memory (capped by the limit) is
negligible comparing to totalpages so the resulting score is too small
if adj!=0 (typically task with CAP_SYS_ADMIN or non zero oom_score_adj).
A wrong process might be selected as result.

The problem can be worked around by checking mem_cgroup_swappiness==0
and not considering swap at all in such a case.

Signed-off-by: Michal Hocko 
Acked-by: David Rientjes 
Acked-by: Johannes Weiner 
Acked-by: KOSAKI Motohiro 
Acked-by: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

memcg: fix up documentation on global LRU

2012-04-12T20:12:11+00:00

In v3.3-rc1, the global LRU was removed in commit 925b7673cce3 ("mm:
make per-memcg LRU lists exclusive").  The patch fixes up the memcg
docs.

I left the swap session to someone who has better understanding of
'memory+swap'.

Signed-off-by: Ying Han 
Acked-by: Michal Hocko 
Acked-by: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: fix pgpgin/pgpgout documentation

2012-01-13T04:13:06+00:00

The two memcg stats pgpgin/pgpgout have different meaning than the ones
in vmstat, which indicates that we picked a bad naming for them.

It might be late to change the stat name, but better documentation is
always helpful.

Signed-off-by: Ying Han 
Acked-by: KAMEZAWA Hiroyuki 
Acked-by: Johannes Weiner 
Acked-by: Michal Hocko 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Documentation/cgroups/memory.txt: fix typo

2012-01-13T04:13:06+00:00

It should be memsw.max_usage_in_bytes. This typo has been there for
a really long time.

Signed-off-by: Zhu Yanhai 
Acked-by: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Partial revert "Basic kernel memory functionality for the Memory Controller"

2011-12-23T03:37:18+00:00

This reverts commit e5671dfae59b165e2adfd4dfbdeab11ac8db5bda.

After a follow up discussion with Michal, it was agreed it would
be better to leave the kmem controller with just the tcp files,
deferring the behavior of the other general memory.kmem.* files
for a later time, when more caches are controlled. This is because
generic kmem files are not used by tcp accounting and it is
not clear how other slab caches would fit into the scheme.

We are reverting the original commit so we can track the reference.
Part of the patch is kept, because it was used by the later tcp
code. Conflicts are shown in the bottom. init/Kconfig is removed from
the revert entirely.

Signed-off-by: Glauber Costa 
Acked-by: Michal Hocko 
CC: Kirill A. Shutemov 
CC: Paul Menage 
CC: Greg Thelen 
CC: Johannes Weiner 
CC: David S. Miller 

Conflicts:

	Documentation/cgroups/memory.txt
	mm/memcontrol.c
Signed-off-by: David S. Miller

Display current tcp memory allocation in kmem cgroup

2011-12-13T00:04:11+00:00

This patch introduces kmem.tcp.usage_in_bytes file, living in the
kmem_cgroup filesystem. It is a simple read-only file that displays the
amount of kernel memory currently consumed by the cgroup.

Signed-off-by: Glauber Costa 
Reviewed-by: Hiroyouki Kamezawa 
CC: David S. Miller 
CC: Eric W. Biederman 
Signed-off-by: David S. Miller

tcp buffer limitation: per-cgroup limit

2011-12-13T00:04:11+00:00

This patch uses the "tcp.limit_in_bytes" field of the kmem_cgroup to
effectively control the amount of kernel memory pinned by a cgroup.

This value is ignored in the root cgroup, and in all others,
caps the value specified by the admin in the net namespaces'
view of tcp_sysctl_mem.

If namespaces are being used, the admin is allowed to set a
value bigger than cgroup's maximum, the same way it is allowed
to set pretty much unlimited values in a real box.

Signed-off-by: Glauber Costa 
Reviewed-by: Hiroyouki Kamezawa 
CC: David S. Miller 
CC: Eric W. Biederman 
Signed-off-by: David S. Miller

tcp memory pressure controls

2011-12-13T00:04:10+00:00

This patch introduces memory pressure controls for the tcp
protocol. It uses the generic socket memory pressure code
introduced in earlier patches, and fills in the
necessary data in cg_proto struct.

Signed-off-by: Glauber Costa 
Reviewed-by: KAMEZAWA Hiroyuki 
CC: Eric W. Biederman 
Signed-off-by: David S. Miller

socket: initial cgroup code.

2011-12-13T00:04:10+00:00

The goal of this work is to move the memory pressure tcp
controls to a cgroup, instead of just relying on global
conditions.

To avoid excessive overhead in the network fast paths,
the code that accounts allocated memory to a cgroup is
hidden inside a static_branch(). This branch is patched out
until the first non-root cgroup is created. So when nobody
is using cgroups, even if it is mounted, no significant performance
penalty should be seen.

This patch handles the generic part of the code, and has nothing
tcp-specific.

Signed-off-by: Glauber Costa 
Reviewed-by: KAMEZAWA Hiroyuki 
CC: Kirill A. Shutemov 
CC: David S. Miller 
CC: Eric W. Biederman 
CC: Eric Dumazet 
Signed-off-by: David S. Miller

Basic kernel memory functionality for the Memory Controller

2011-12-13T00:03:55+00:00

This patch lays down the foundation for the kernel memory component
of the Memory Controller.

As of today, I am only laying down the following files:

 * memory.independent_kmem_limit
 * memory.kmem.limit_in_bytes (currently ignored)
 * memory.kmem.usage_in_bytes (always zero)

Signed-off-by: Glauber Costa 
CC: Kirill A. Shutemov 
CC: Paul Menage 
CC: Greg Thelen 
CC: Johannes Weiner 
CC: Michal Hocko 
Signed-off-by: David S. Miller