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Just a trivial issue I stumbled on while doing something else...
Signed-off-by: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Since commit 2d11085e404f ("memcg: do not create memsw files if swap
accounting is disabled") memsw files are created only if memcg swap
accounting is enabled so it doesn't make any sense to check for it
explicitly in mem_cgroup_read(), mem_cgroup_write() and
mem_cgroup_reset().
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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mem_cgroup_iter basically does two things currently. It takes care of
the house keeping (reference counting, raclaim cookie) and it iterates
through a hierarchy tree (by using cgroup generic tree walk). The code
would be much more easier to follow if we move the iteration outside of
the function (to __mem_cgrou_iter_next) so the distinction is more
clear. This patch doesn't introduce any functional changes.
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Ying Han <yinghan@google.com>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Glauber Costa <glommer@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The current implementation of mem_cgroup_iter has to consider both css
and memcg to find out whether no group has been found (css==NULL - aka
the loop is completed) and that no memcg is associated with the found
node (!memcg - aka css_tryget failed because the group is no longer
alive). This leads to awkward tweaks like tests for css && !memcg to
skip the current node.
It will be much easier if we got rid off css variable altogether and
only rely on memcg. In order to do that the iteration part has to skip
dead nodes. This sounds natural to me and as a nice side effect we will
get a simple invariant that memcg is always alive when non-NULL and all
nodes have been visited otherwise.
We could get rid of the surrounding while loop but keep it in for now to
make review easier. It will go away in the following patch.
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Ying Han <yinghan@google.com>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Glauber Costa <glommer@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Now that the per-node-zone-priority iterator caches memory cgroups
rather than their css ids we have to be careful and remove them from the
iterator when they are on the way out otherwise they might live for
unbounded amount of time even though their group is already gone (until
the global/targeted reclaim triggers the zone under priority to find out
the group is dead and let it to find the final rest).
We can fix this issue by relaxing rules for the last_visited memcg.
Instead of taking a reference to the css before it is stored into
iter->last_visited we can just store its pointer and track the number of
removed groups from each memcg's subhierarchy.
This number would be stored into iterator everytime when a memcg is
cached. If the iter count doesn't match the curent walker root's one we
will start from the root again. The group counter is incremented
upwards the hierarchy every time a group is removed.
The iter_lock can be dropped because racing iterators cannot leak the
reference anymore as the reference count is not elevated for
last_visited when it is cached.
Locking rules got a bit complicated by this change though. The iterator
primarily relies on rcu read lock which makes sure that once we see a
valid last_visited pointer then it will be valid for the whole RCU walk.
smp_rmb makes sure that dead_count is read before last_visited and
last_dead_count while smp_wmb makes sure that last_visited is updated
before last_dead_count so the up-to-date last_dead_count cannot point to
an outdated last_visited. css_tryget then makes sure that the
last_visited is still alive in case the iteration races with the cached
group removal (css is invalidated before mem_cgroup_css_offline
increments dead_count).
In short:
mem_cgroup_iter
rcu_read_lock()
dead_count = atomic_read(parent->dead_count)
smp_rmb()
if (dead_count != iter->last_dead_count)
last_visited POSSIBLY INVALID -> last_visited = NULL
if (!css_tryget(iter->last_visited))
last_visited DEAD -> last_visited = NULL
next = find_next(last_visited)
css_tryget(next)
css_put(last_visited) // css would be invalidated and parent->dead_count
// incremented if this was the last reference
iter->last_visited = next
smp_wmb()
iter->last_dead_count = dead_count
rcu_read_unlock()
cgroup_rmdir
cgroup_destroy_locked
atomic_add(CSS_DEACT_BIAS, &css->refcnt) // subsequent css_tryget fail
mem_cgroup_css_offline
mem_cgroup_invalidate_reclaim_iterators
while(parent = parent_mem_cgroup)
atomic_inc(parent->dead_count)
css_put(css) // last reference held by cgroup core
Spotted by Ying Han.
Original idea from Johannes Weiner.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Ying Han <yinghan@google.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Glauber Costa <glommer@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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mem_cgroup_iter curently relies on css->id when walking down a group
hierarchy tree. This is really awkward because the tree walk depends on
the groups creation ordering. The only guarantee is that a parent node is
visited before its children.
Example:
1) mkdir -p a a/d a/b/c
2) mkdir -a a/b/c a/d
Will create the same trees but the tree walks will be different:
1) a, d, b, c
2) a, b, c, d
Commit 574bd9f7c7c1 ("cgroup: implement generic child / descendant walk
macros") has introduced generic cgroup tree walkers which provide either
pre-order or post-order tree walk. This patch converts css->id based
iteration to pre-order tree walk to keep the semantic with the original
iterator where parent is always visited before its subtree.
cgroup_for_each_descendant_pre suggests using post_create and
pre_destroy for proper synchronization with groups addidition resp.
removal. This implementation doesn't use those because a new memory
cgroup is initialized sufficiently for iteration in mem_cgroup_css_alloc
already and css reference counting enforces that the group is alive for
both the last seen cgroup and the found one resp. it signals that the
group is dead and it should be skipped.
If the reclaim cookie is used we need to store the last visited group
into the iterator so we have to be careful that it doesn't disappear in
the mean time. Elevated reference count on the css keeps it alive even
though the group have been removed (parked waiting for the last dput so
that it can be freed).
Per node-zone-prio iter_lock has been introduced to ensure that
css_tryget and iter->last_visited is set atomically. Otherwise two
racing walkers could both take a references and only one release it
leading to a css leak (which pins cgroup dentry).
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Ying Han <yinghan@google.com>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Glauber Costa <glommer@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The patchset tries to make mem_cgroup_iter saner in the way how it walks
hierarchies. css->id based traversal is far from being ideal as it is not
deterministic because it depends on the creation ordering. Additional to
that css_id is considered a burden for cgroup maintainers because it is
quite some code and memcg is the last user of it. After this series only
the swap accounting uses css_id but that one will follow up later.
Diffstat (if we exclude removed/added comments) looks quite
promising. We got rid of some code:
$ git diff mmotm... | grep -v "^[+-][[:space:]]*[/ ]\*" | diffstat
b/include/linux/cgroup.h | 3 ---
kernel/cgroup.c | 33 ---------------------------------
mm/memcontrol.c | 4 +++-
3 files changed, 3 insertions(+), 37 deletions(-)
The first patch is just preparatory and it changes when we release css of
the previously returned memcg. Nothing controlversial.
The second patch is the core of the patchset and it replaces css_get_next
based on css_id by the generic cgroup pre-order. This brings some
chalanges for the last visited group caching during the reclaim
(mem_cgroup_per_zone::reclaim_iter). We have to use memcg pointers
directly now which means that we have to keep a reference to those groups'
css to keep them alive.
I also folded iter_lock introduced by https://lkml.org/lkml/2013/1/3/295
in the previous version into this patch. Johannes felt the race I was
describing should be mostly harmless and I haven't been able to trigger it
so the lock doesn't deserve its own patch. It is still needed
temporarily, though, because the reference counting on iter->last_visited
depends on it. It will go away with the next patch.
The next patch fixups an unbounded cgroup removal holdoff caused by the
elevated css refcount. The issue has been observed by Ying Han. Johannes
wasn't impressed by the previous version of the fix
(https://lkml.org/lkml/2013/2/8/379) which cleaned up pending references
during mem_cgroup_css_offline when a group is removed. He has suggested a
different way when the iterator checks whether a cached memcg is still
valid or no. More on that in the patch but the basic idea is that every
memcg tracks the number removed subgroups and iterator records this number
when a group is cached. These numbers are checked before
iter->last_visited is about to be used and the iteration is restarted if
it is invalid.
The fourth and fifth patches are an attempt for simplification of the
mem_cgroup_iter. css juggling is removed and the iteration logic is moved
to a helper so that the reference counting and iteration are separated.
The last patch just removes css_get_next as there is no user for it any
longer.
My testing looked as follows:
A (use_hierarchy=1, limit_in_bytes=150M)
/|\
1 2 3
Children groups were created so that the number is never higher than 3 and
their limits were random between 50-100M. Each group hosts a kernel build
(starting with tar -xf so the tree is not shared and make -jNUM_CPUs/3)
and terminated after random time - up to 5 minutes) and then it is
removed.
This should exercise both leaf and hierarchical reclaim as well as races
with cgroup removals and debugging messages I added on top proved that.
100 groups were created during the test.
This patch:
css reference counting keeps the cgroup alive even though it has been
already removed. mem_cgroup_iter relies on this fact and takes a
reference to the returned group. The reference is then released on the
next iteration or mem_cgroup_iter_break. mem_cgroup_iter currently
releases the reference right after it gets the last css_id.
This is correct because neither prev's memcg nor cgroup are accessed after
then. This will change in the next patch so we need to hold the group
alive a bit longer so let's move the css_put at the end of the function.
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Ying Han <yinghan@google.com>
Cc: Tejun Heo <htejun@gmail.com>
Cc: Glauber Costa <glommer@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Fix a warning from lockdep caused by calling cancel_work_sync() for
uninitialized struct work. This path has been triggered by destructon
kmem-cache hierarchy via destroying its root kmem-cache.
cache ffff88003c072d80
obj ffff88003b410000 cache ffff88003c072d80
obj ffff88003b924000 cache ffff88003c20bd40
INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
Pid: 2825, comm: insmod Tainted: G O 3.9.0-rc1-next-20130307+ #611
Call Trace:
__lock_acquire+0x16a2/0x1cb0
lock_acquire+0x8a/0x120
flush_work+0x38/0x2a0
__cancel_work_timer+0x89/0xf0
cancel_work_sync+0xb/0x10
kmem_cache_destroy_memcg_children+0x81/0xb0
kmem_cache_destroy+0xf/0xe0
init_module+0xcb/0x1000 [kmem_test]
do_one_initcall+0x11a/0x170
load_module+0x19b0/0x2320
SyS_init_module+0xc6/0xf0
system_call_fastpath+0x16/0x1b
Example module to demonstrate:
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/workqueue.h>
int __init mod_init(void)
{
int size = 256;
struct kmem_cache *cache;
void *obj;
struct page *page;
cache = kmem_cache_create("kmem_cache_test", size, size, 0, NULL);
if (!cache)
return -ENOMEM;
printk("cache %p\n", cache);
obj = kmem_cache_alloc(cache, GFP_KERNEL);
if (obj) {
page = virt_to_head_page(obj);
printk("obj %p cache %p\n", obj, page->slab_cache);
kmem_cache_free(cache, obj);
}
flush_scheduled_work();
obj = kmem_cache_alloc(cache, GFP_KERNEL);
if (obj) {
page = virt_to_head_page(obj);
printk("obj %p cache %p\n", obj, page->slab_cache);
kmem_cache_free(cache, obj);
}
kmem_cache_destroy(cache);
return -EBUSY;
}
module_init(mod_init);
MODULE_LICENSE("GPL");
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Glauber Costa <glommer@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Whilst I run the risk of a flogging for disloyalty to the Lord of Sealand,
I do have CONFIG_MEMCG=y CONFIG_MEMCG_KMEM not set, and grow tired of the
"mm/memcontrol.c:4972:12: warning: `memcg_propagate_kmem' defined but not
used [-Wunused-function]" seen in 3.8-rc: move the #ifdef outwards.
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Glauber Costa <glommer@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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We should encourage all memcg controller initialization independent on a
specific mem_cgroup to be done here rather than exploit css_alloc
callback and assume that nothing happens before root cgroup is created.
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <htejun@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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memcg_stock are currently initialized during the root cgroup allocation
which is OK but it pointlessly pollutes memcg allocation code with
something that can be called when the memcg subsystem is initialized by
mem_cgroup_init along with other controller specific parts.
This patch wraps the current memcg_stock initialization code into a
helper calls it from the controller subsystem initialization code.
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <htejun@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Per-node-zone soft limit tree is currently initialized when the root
cgroup is created which is OK but it pointlessly pollutes memcg
allocation code with something that can be called when the memcg
subsystem is initialized by mem_cgroup_init along with other controller
specific parts.
While we are at it let's make mem_cgroup_soft_limit_tree_init void
because it doesn't make much sense to report memory failure because if
we fail to allocate memory that early during the boot then we are
screwed anyway (this saves some code).
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <htejun@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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An inactive file list is considered low when its active counterpart is
bigger, regardless of whether it is a global zone LRU list or a memcg
zone LRU list. The only difference is in how the LRU size is assessed.
get_lru_size() does the right thing for both global and memcg reclaim
situations.
Get rid of inactive_file_is_low_global() and
mem_cgroup_inactive_file_is_low() by using get_lru_size() and compare
the numbers in common code.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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When use_hierarchy is enabled, we acquire an extra reference count in
our parent during cgroup creation. We don't release it, though, if any
failure exist in the creation process.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Reported-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Tejun Heo <tj@kernel.org>
Cc: Hiroyuki Kamezawa <kamezawa.hiroyuki@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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We were deferring the kmemcg static branch increment to a later time,
due to a nasty dependency between the cpu_hotplug lock, taken by the
jump label update, and the cgroup_lock.
Now we no longer take the cgroup lock, and we can save ourselves the
trouble.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Tejun Heo <tj@kernel.org>
Cc: Hiroyuki Kamezawa <kamezawa.hiroyuki@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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After the preparation work done in earlier patches, the cgroup_lock can
be trivially replaced with a memcg-specific lock. This is an automatic
translation at every site where the values involved were queried.
The sites where values are written, however, used to be naturally called
under cgroup_lock. This is the case for instance in the css_online
callback. For those, we now need to explicitly add the memcg lock.
With this, all the calls to cgroup_lock outside cgroup core are gone.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Tejun Heo <tj@kernel.org>
Cc: Hiroyuki Kamezawa <kamezawa.hiroyuki@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Currently, we use cgroups' provided list of children to verify if it is
safe to proceed with any value change that is dependent on the cgroup
being empty.
This is less than ideal, because it enforces a dependency over cgroup
core that we would be better off without. The solution proposed here is
to iterate over the child cgroups and if any is found that is already
online, we bounce and return: we don't really care how many children we
have, only if we have any.
This is also made to be hierarchy aware. IOW, cgroups with hierarchy
disabled, while they still exist, will be considered for the purpose of
this interface as having no children.
[akpm@linux-foundation.org: tweak comments]
Signed-off-by: Glauber Costa <glommer@parallels.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Tejun Heo <tj@kernel.org>
Cc: Hiroyuki Kamezawa <kamezawa.hiroyuki@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This patch is a preparatory work for later locking rework to get rid of
big cgroup lock from memory controller code.
The memory controller uses some tunables to adjust its operation. Those
tunables are inherited from parent to children upon children
intialization. For most of them, the value cannot be changed after the
parent has a new children.
cgroup core splits initialization in two phases: css_alloc and css_online.
After css_alloc, the memory allocation and basic initialization are done.
But the new group is not yet visible anywhere, not even for cgroup core
code. It is only somewhere between css_alloc and css_online that it is
inserted into the internal children lists. Copying tunable values in
css_alloc will lead to inconsistent values: the children will copy the old
parent values, that can change between the copy and the moment in which
the groups is linked to any data structure that can indicate the presence
of children.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Tejun Heo <tj@kernel.org>
Cc: Hiroyuki Kamezawa <kamezawa.hiroyuki@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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In memcg, we use the cgroup_lock basically to synchronize against
attaching new children to a cgroup. We do this because we rely on
cgroup core to provide us with this information.
We need to guarantee that upon child creation, our tunables are
consistent. For those, the calls to cgroup_lock() all live in handlers
like mem_cgroup_hierarchy_write(), where we change a tunable in the
group that is hierarchy-related. For instance, the use_hierarchy flag
cannot be changed if the cgroup already have children.
Furthermore, those values are propagated from the parent to the child
when a new child is created. So if we don't lock like this, we can end
up with the following situation:
A B
memcg_css_alloc() mem_cgroup_hierarchy_write()
copy use hierarchy from parent change use hierarchy in parent
finish creation.
This is mainly because during create, we are still not fully connected
to the css tree. So all iterators and the such that we could use, will
fail to show that the group has children.
My observation is that all of creation can proceed in parallel with
those tasks, except value assignment. So what this patch series does is
to first move all value assignment that is dependent on parent values
from css_alloc to css_online, where the iterators all work, and then we
lock only the value assignment. This will guarantee that parent and
children always have consistent values. Together with an online test,
that can be derived from the observation that the refcount of an online
memcg can be made to be always positive, we should be able to
synchronize our side without the cgroup lock.
This patch:
Currently, we rely on the cgroup_lock() to prevent changes to
move_charge_at_immigrate during task migration. However, this is only
needed because the current strategy keeps checking this value throughout
the whole process. Since all we need is serialization, one needs only
to guarantee that whatever decision we made in the beginning of a
specific migration is respected throughout the process.
We can achieve this by just saving it in mc. By doing this, no kind of
locking is needed.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Tejun Heo <tj@kernel.org>
Cc: Hiroyuki Kamezawa <kamezawa.hiroyuki@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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In order to maintain all the memcg bookkeeping, we need per-node
descriptors, which will in turn contain a per-zone descriptor.
Because we want to statically allocate those, this array ends up being
very big. Part of the reason is that we allocate something large enough
to hold MAX_NUMNODES, the compile time constant that holds the maximum
number of nodes we would ever consider.
However, we can do better in some cases if the firmware help us. This
is true for modern x86 machines; coincidentally one of the architectures
in which MAX_NUMNODES tends to be very big.
By using the firmware-provided maximum number of nodes instead of
MAX_NUMNODES, we can reduce the memory footprint of struct memcg
considerably. In the extreme case in which we have only one node, this
reduces the size of the structure from ~ 64k to ~2k. This is
particularly important because it means that we will no longer resort to
the vmalloc area for the struct memcg on defconfigs. We also have
enough room for an extra node and still be outside vmalloc.
One also has to keep in mind that with the industry's ability to fit
more processors in a die as fast as the FED prints money, a nodes = 2
configuration is already respectably big.
[akpm@linux-foundation.org: add check for invalid nid, remove inline]
Signed-off-by: Glauber Costa <glommer@parallels.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Greg Thelen <gthelen@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ying Han <yinghan@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Memcg swap accounting is currently enabled by enable_swap_cgroup when
the root cgroup is created. mem_cgroup_init acts as a memcg subsystem
initializer which sounds like a much better place for enable_swap_cgroup
as well. We already register memsw files from there so it makes a lot
of sense to merge those two into a single enable_swap_cgroup function.
This patch doesn't introduce any semantic changes.
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Cc: Zhouping Liu <zliu@redhat.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: CAI Qian <caiqian@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Zhouping Liu has reported that memsw files are exported even though swap
accounting is runtime disabled if MEMCG_SWAP is enabled. This behavior
has been introduced by commit af36f906c0f4 ("memcg: always create memsw
files if CGROUP_MEM_RES_CTLR_SWAP") and it causes any attempt to open
the file to return EOPNOTSUPP. Although EOPNOTSUPP should say be clear
that memsw operations are not supported in the given configuration it is
fair to say that this behavior could be quite confusing.
Let's tear memsw files out of default cgroup files and add them only if
the swap accounting is really enabled (either by MEMCG_SWAP_ENABLED or
swapaccount=1 boot parameter). We can hook into mem_cgroup_init which
is called when the memcg subsystem is initialized and which happens
after boot command line is processed.
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Reported-by: Zhouping Liu <zliu@redhat.com>
Tested-by: Zhouping Liu <zliu@redhat.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: CAI Qian <caiqian@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
When I use several fast SSD to do swap, swapper_space.tree_lock is
heavily contended. This makes each swap partition have one
address_space to reduce the lock contention. There is an array of
address_space for swap. The swap entry type is the index to the array.
In my test with 3 SSD, this increases the swapout throughput 20%.
[akpm@linux-foundation.org: revert unneeded change to __add_to_swap_cache]
Signed-off-by: Shaohua Li <shli@fusionio.com>
Cc: Hugh Dickins <hughd@google.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Acked-by: Sha Zhengju <handai.szj@taobao.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Currently when a memcg oom is happening the oom dump messages is still
global state and provides few useful info for users. This patch prints
more pointed memcg page statistics for memcg-oom and take hierarchy into
consideration:
Based on Michal's advice, we take hierarchy into consideration: supppose
we trigger an OOM on A's limit
root_memcg
|
A (use_hierachy=1)
/ \
B C
|
D
then the printed info will be:
Memory cgroup stats for /A:...
Memory cgroup stats for /A/B:...
Memory cgroup stats for /A/C:...
Memory cgroup stats for /A/B/D:...
Following are samples of oom output:
(1) Before change:
mal-80 invoked oom-killer:gfp_mask=0xd0, order=0, oom_score_adj=0
mal-80 cpuset=/ mems_allowed=0
Pid: 2976, comm: mal-80 Not tainted 3.7.0+ #10
Call Trace:
[<ffffffff8167fbfb>] dump_header+0x83/0x1ca
..... (call trace)
[<ffffffff8168a818>] page_fault+0x28/0x30
<<<<<<<<<<<<<<<<<<<<< memcg specific information
Task in /A/B/D killed as a result of limit of /A
memory: usage 101376kB, limit 101376kB, failcnt 57
memory+swap: usage 101376kB, limit 101376kB, failcnt 0
kmem: usage 0kB, limit 9007199254740991kB, failcnt 0
<<<<<<<<<<<<<<<<<<<<< print per cpu pageset stat
Mem-Info:
Node 0 DMA per-cpu:
CPU 0: hi: 0, btch: 1 usd: 0
......
CPU 3: hi: 0, btch: 1 usd: 0
Node 0 DMA32 per-cpu:
CPU 0: hi: 186, btch: 31 usd: 173
......
CPU 3: hi: 186, btch: 31 usd: 130
<<<<<<<<<<<<<<<<<<<<< print global page state
active_anon:92963 inactive_anon:40777 isolated_anon:0
active_file:33027 inactive_file:51718 isolated_file:0
unevictable:0 dirty:3 writeback:0 unstable:0
free:729995 slab_reclaimable:6897 slab_unreclaimable:6263
mapped:20278 shmem:35971 pagetables:5885 bounce:0
free_cma:0
<<<<<<<<<<<<<<<<<<<<< print per zone page state
Node 0 DMA free:15836kB ... all_unreclaimable? no
lowmem_reserve[]: 0 3175 3899 3899
Node 0 DMA32 free:2888564kB ... all_unrelaimable? no
lowmem_reserve[]: 0 0 724 724
lowmem_reserve[]: 0 0 0 0
Node 0 DMA: 1*4kB (U) ... 3*4096kB (M) = 15836kB
Node 0 DMA32: 41*4kB (UM) ... 702*4096kB (MR) = 2888316kB
120710 total pagecache pages
0 pages in swap cache
<<<<<<<<<<<<<<<<<<<<< print global swap cache stat
Swap cache stats: add 0, delete 0, find 0/0
Free swap = 499708kB
Total swap = 499708kB
1040368 pages RAM
58678 pages reserved
169065 pages shared
173632 pages non-shared
[ pid ] uid tgid total_vm rss nr_ptes swapents oom_score_adj name
[ 2693] 0 2693 6005 1324 17 0 0 god
[ 2754] 0 2754 6003 1320 16 0 0 god
[ 2811] 0 2811 5992 1304 18 0 0 god
[ 2874] 0 2874 6005 1323 18 0 0 god
[ 2935] 0 2935 8720 7742 21 0 0 mal-30
[ 2976] 0 2976 21520 17577 42 0 0 mal-80
Memory cgroup out of memory: Kill process 2976 (mal-80) score 665 or sacrifice child
Killed process 2976 (mal-80) total-vm:86080kB, anon-rss:69964kB, file-rss:344kB
We can see that messages dumped by show_free_areas() are longsome and can
provide so limited info for memcg that just happen oom.
(2) After change
mal-80 invoked oom-killer: gfp_mask=0xd0, order=0, oom_score_adj=0
mal-80 cpuset=/ mems_allowed=0
Pid: 2704, comm: mal-80 Not tainted 3.7.0+ #10
Call Trace:
[<ffffffff8167fd0b>] dump_header+0x83/0x1d1
.......(call trace)
[<ffffffff8168a918>] page_fault+0x28/0x30
Task in /A/B/D killed as a result of limit of /A
<<<<<<<<<<<<<<<<<<<<< memcg specific information
memory: usage 102400kB, limit 102400kB, failcnt 140
memory+swap: usage 102400kB, limit 102400kB, failcnt 0
kmem: usage 0kB, limit 9007199254740991kB, failcnt 0
Memory cgroup stats for /A: cache:32KB rss:30984KB mapped_file:0KB swap:0KB inactive_anon:6912KB active_anon:24072KB inactive_file:32KB active_file:0KB unevictable:0KB
Memory cgroup stats for /A/B: cache:0KB rss:0KB mapped_file:0KB swap:0KB inactive_anon:0KB active_anon:0KB inactive_file:0KB active_file:0KB unevictable:0KB
Memory cgroup stats for /A/C: cache:0KB rss:0KB mapped_file:0KB swap:0KB inactive_anon:0KB active_anon:0KB inactive_file:0KB active_file:0KB unevictable:0KB
Memory cgroup stats for /A/B/D: cache:32KB rss:71352KB mapped_file:0KB swap:0KB inactive_anon:6656KB active_anon:64696KB inactive_file:16KB active_file:16KB unevictable:0KB
[ pid ] uid tgid total_vm rss nr_ptes swapents oom_score_adj name
[ 2260] 0 2260 6006 1325 18 0 0 god
[ 2383] 0 2383 6003 1319 17 0 0 god
[ 2503] 0 2503 6004 1321 18 0 0 god
[ 2622] 0 2622 6004 1321 16 0 0 god
[ 2695] 0 2695 8720 7741 22 0 0 mal-30
[ 2704] 0 2704 21520 17839 43 0 0 mal-80
Memory cgroup out of memory: Kill process 2704 (mal-80) score 669 or sacrifice child
Killed process 2704 (mal-80) total-vm:86080kB, anon-rss:71016kB, file-rss:340kB
This version provides more pointed info for memcg in "Memory cgroup stats
for XXX" section.
Signed-off-by: Sha Zhengju <handai.szj@taobao.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
The designed workflow for the caches in kmemcg is: register it with
memcg_register_cache() if kmemcg is already available or later on when a
new kmemcg appears at memcg_update_cache_sizes() which will handle all
caches in the system. The caches created at boot time will be handled
by the later, and the memcg-caches as well as any system caches that are
registered later on by the former.
There is a bug, however, in memcg_register_cache: we correctly set up
the array size, but do not mark the cache as a root cache.
This means that allocations for any cache appearing late in the game
will see memcg->memcg_params->is_root_cache == false, and in particular,
trigger VM_BUG_ON(!cachep->memcg_params->is_root_cache) in
__memcg_kmem_cache_get.
The obvious fix is to include the missing assignment.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Commit 648bb56d076b ("cgroup: lock cgroup_mutex in cgroup_init_subsys()")
made cgroup_init_subsys() grab cgroup_mutex before invoking
->css_alloc() for the root css. Because memcg registers hotcpu notifier
from ->css_alloc() for the root css, this introduced circular locking
dependency between cgroup_mutex and cpu hotplug.
Fix it by moving hotcpu notifier registration to a subsys initcall.
======================================================
[ INFO: possible circular locking dependency detected ]
3.7.0-rc4-work+ #42 Not tainted
-------------------------------------------------------
bash/645 is trying to acquire lock:
(cgroup_mutex){+.+.+.}, at: [<ffffffff8110c5b7>] cgroup_lock+0x17/0x20
but task is already holding lock:
(cpu_hotplug.lock){+.+.+.}, at: [<ffffffff8109300f>] cpu_hotplug_begin+0x2f/0x60
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (cpu_hotplug.lock){+.+.+.}:
lock_acquire+0x97/0x1e0
mutex_lock_nested+0x61/0x3b0
get_online_cpus+0x3c/0x60
rebuild_sched_domains_locked+0x1b/0x70
cpuset_write_resmask+0x298/0x2c0
cgroup_file_write+0x1ef/0x300
vfs_write+0xa8/0x160
sys_write+0x52/0xa0
system_call_fastpath+0x16/0x1b
-> #0 (cgroup_mutex){+.+.+.}:
__lock_acquire+0x14ce/0x1d20
lock_acquire+0x97/0x1e0
mutex_lock_nested+0x61/0x3b0
cgroup_lock+0x17/0x20
cpuset_handle_hotplug+0x1b/0x560
cpuset_update_active_cpus+0xe/0x10
cpuset_cpu_inactive+0x47/0x50
notifier_call_chain+0x66/0x150
__raw_notifier_call_chain+0xe/0x10
__cpu_notify+0x20/0x40
_cpu_down+0x7e/0x2f0
cpu_down+0x36/0x50
store_online+0x5d/0xe0
dev_attr_store+0x18/0x30
sysfs_write_file+0xe0/0x150
vfs_write+0xa8/0x160
sys_write+0x52/0xa0
system_call_fastpath+0x16/0x1b
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(cpu_hotplug.lock);
lock(cgroup_mutex);
lock(cpu_hotplug.lock);
lock(cgroup_mutex);
*** DEADLOCK ***
5 locks held by bash/645:
#0: (&buffer->mutex){+.+.+.}, at: [<ffffffff8123bab8>] sysfs_write_file+0x48/0x150
#1: (s_active#42){.+.+.+}, at: [<ffffffff8123bb38>] sysfs_write_file+0xc8/0x150
#2: (x86_cpu_hotplug_driver_mutex){+.+...}, at: [<ffffffff81079277>] cpu_hotplug_driver_lock+0x1
+7/0x20
#3: (cpu_add_remove_lock){+.+.+.}, at: [<ffffffff81093157>] cpu_maps_update_begin+0x17/0x20
#4: (cpu_hotplug.lock){+.+.+.}, at: [<ffffffff8109300f>] cpu_hotplug_begin+0x2f/0x60
stack backtrace:
Pid: 645, comm: bash Not tainted 3.7.0-rc4-work+ #42
Call Trace:
print_circular_bug+0x28e/0x29f
__lock_acquire+0x14ce/0x1d20
lock_acquire+0x97/0x1e0
mutex_lock_nested+0x61/0x3b0
cgroup_lock+0x17/0x20
cpuset_handle_hotplug+0x1b/0x560
cpuset_update_active_cpus+0xe/0x10
cpuset_cpu_inactive+0x47/0x50
notifier_call_chain+0x66/0x150
__raw_notifier_call_chain+0xe/0x10
__cpu_notify+0x20/0x40
_cpu_down+0x7e/0x2f0
cpu_down+0x36/0x50
store_online+0x5d/0xe0
dev_attr_store+0x18/0x30
sysfs_write_file+0xe0/0x150
vfs_write+0xa8/0x160
sys_write+0x52/0xa0
system_call_fastpath+0x16/0x1b
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
SLAB allows us to tune a particular cache behavior with tunables. When
creating a new memcg cache copy, we'd like to preserve any tunables the
parent cache already had.
This could be done by an explicit call to do_tune_cpucache() after the
cache is created. But this is not very convenient now that the caches are
created from common code, since this function is SLAB-specific.
Another method of doing that is taking advantage of the fact that
do_tune_cpucache() is always called from enable_cpucache(), which is
called at cache initialization. We can just preset the values, and then
things work as expected.
It can also happen that a root cache has its tunables updated during
normal system operation. In this case, we will propagate the change to
all caches that are already active.
This change will require us to move the assignment of root_cache in
memcg_params a bit earlier. We need this to be already set - which
memcg_kmem_register_cache will do - when we reach __kmem_cache_create()
Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
When we create caches in memcgs, we need to display their usage
information somewhere. We'll adopt a scheme similar to /proc/meminfo,
with aggregate totals shown in the global file, and per-group information
stored in the group itself.
For the time being, only reads are allowed in the per-group cache.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
This means that when we destroy a memcg cache that happened to be empty,
those caches may take a lot of time to go away: removing the memcg
reference won't destroy them - because there are pending references, and
the empty pages will stay there, until a shrinker is called upon for any
reason.
In this patch, we will call kmem_cache_shrink() for all dead caches that
cannot be destroyed because of remaining pages. After shrinking, it is
possible that it could be freed. If this is not the case, we'll schedule
a lazy worker to keep trying.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
This enables us to remove all the children of a kmem_cache being
destroyed, if for example the kernel module it's being used in gets
unloaded. Otherwise, the children will still point to the destroyed
parent.
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Implement destruction of memcg caches. Right now, only caches where our
reference counter is the last remaining are deleted. If there are any
other reference counters around, we just leave the caches lying around
until they go away.
When that happens, a destruction function is called from the cache code.
Caches are only destroyed in process context, so we queue them up for
later processing in the general case.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
We are able to match a cache allocation to a particular memcg. If the
task doesn't change groups during the allocation itself - a rare event,
this will give us a good picture about who is the first group to touch a
cache page.
This patch uses the now available infrastructure by calling
memcg_kmem_get_cache() before all the cache allocations.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Create a mechanism that skip memcg allocations during certain pieces of
our core code. It basically works in the same way as
preempt_disable()/preempt_enable(): By marking a region under which all
allocations will be accounted to the root memcg.
We need this to prevent races in early cache creation, when we
allocate data using caches that are not necessarily created already.
Signed-off-by: Glauber Costa <glommer@parallels.com>
yCc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
The page allocator is able to bind a page to a memcg when it is
allocated. But for the caches, we'd like to have as many objects as
possible in a page belonging to the same cache.
This is done in this patch by calling memcg_kmem_get_cache in the
beginning of every allocation function. This function is patched out by
static branches when kernel memory controller is not being used.
It assumes that the task allocating, which determines the memcg in the
page allocator, belongs to the same cgroup throughout the whole process.
Misaccounting can happen if the task calls memcg_kmem_get_cache() while
belonging to a cgroup, and later on changes. This is considered
acceptable, and should only happen upon task migration.
Before the cache is created by the memcg core, there is also a possible
imbalance: the task belongs to a memcg, but the cache being allocated from
is the global cache, since the child cache is not yet guaranteed to be
ready. This case is also fine, since in this case the GFP_KMEMCG will not
be passed and the page allocator will not attempt any cgroup accounting.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Every cache that is considered a root cache (basically the "original"
caches, tied to the root memcg/no-memcg) will have an array that should be
large enough to store a cache pointer per each memcg in the system.
Theoreticaly, this is as high as 1 << sizeof(css_id), which is currently
in the 64k pointers range. Most of the time, we won't be using that much.
What goes in this patch, is a simple scheme to dynamically allocate such
an array, in order to minimize memory usage for memcg caches. Because we
would also like to avoid allocations all the time, at least for now, the
array will only grow. It will tend to be big enough to hold the maximum
number of kmem-limited memcgs ever achieved.
We'll allocate it to be a minimum of 64 kmem-limited memcgs. When we have
more than that, we'll start doubling the size of this array every time the
limit is reached.
Because we are only considering kmem limited memcgs, a natural point for
this to happen is when we write to the limit. At that point, we already
have set_limit_mutex held, so that will become our natural synchronization
mechanism.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Allow a memcg parameter to be passed during cache creation. When the slub
allocator is being used, it will only merge caches that belong to the same
memcg. We'll do this by scanning the global list, and then translating
the cache to a memcg-specific cache
Default function is created as a wrapper, passing NULL to the memcg
version. We only merge caches that belong to the same memcg.
A helper is provided, memcg_css_id: because slub needs a unique cache name
for sysfs. Since this is visible, but not the canonical location for slab
data, the cache name is not used, the css_id should suffice.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
A lot of the initialization we do in mem_cgroup_create() is done with
softirqs enabled. This include grabbing a css id, which holds
&ss->id_lock->rlock, and the per-zone trees, which holds
rtpz->lock->rlock. All of those signal to the lockdep mechanism that
those locks can be used in SOFTIRQ-ON-W context.
This means that the freeing of memcg structure must happen in a
compatible context, otherwise we'll get a deadlock, like the one below,
caught by lockdep:
free_accounted_pages+0x47/0x4c
free_task+0x31/0x5c
__put_task_struct+0xc2/0xdb
put_task_struct+0x1e/0x22
delayed_put_task_struct+0x7a/0x98
__rcu_process_callbacks+0x269/0x3df
rcu_process_callbacks+0x31/0x5b
__do_softirq+0x122/0x277
This usage pattern could not be triggered before kmem came into play.
With the introduction of kmem stack handling, it is possible that we call
the last mem_cgroup_put() from the task destructor, which is run in an rcu
callback. Such callbacks are run with softirqs disabled, leading to the
offensive usage pattern.
In general, we have little, if any, means to guarantee in which context
the last memcg_put will happen. The best we can do is test it and try to
make sure no invalid context releases are happening. But as we add more
code to memcg, the possible interactions grow in number and expose more
ways to get context conflicts. One thing to keep in mind, is that part of
the freeing process is already deferred to a worker, such as vfree(), that
can only be called from process context.
For the moment, the only two functions we really need moved away are:
* free_css_id(), and
* mem_cgroup_remove_from_trees().
But because the later accesses per-zone info,
free_mem_cgroup_per_zone_info() needs to be moved as well. With that, we
are left with the per_cpu stats only. Better move it all.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Tested-by: Greg Thelen <gthelen@google.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Because the ultimate goal of the kmem tracking in memcg is to track slab
pages as well, we can't guarantee that we'll always be able to point a
page to a particular process, and migrate the charges along with it -
since in the common case, a page will contain data belonging to multiple
processes.
Because of that, when we destroy a memcg, we only make sure the
destruction will succeed by discounting the kmem charges from the user
charges when we try to empty the cgroup.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Acked-by: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
We can use static branches to patch the code in or out when not used.
Because the _ACTIVE bit on kmem_accounted is only set after the increment
is done, we guarantee that the root memcg will always be selected for kmem
charges until all call sites are patched (see memcg_kmem_enabled). This
guarantees that no mischarges are applied.
Static branch decrement happens when the last reference count from the
kmem accounting in memcg dies. This will only happen when the charges
drop down to 0.
When that happens, we need to disable the static branch only on those
memcgs that enabled it. To achieve this, we would be forced to complicate
the code by keeping track of which memcgs were the ones that actually
enabled limits, and which ones got it from its parents.
It is a lot simpler just to do static_key_slow_inc() on every child
that is accounted.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Because kmem charges can outlive the cgroup, we need to make sure that we
won't free the memcg structure while charges are still in flight. For
reviewing simplicity, the charge functions will issue mem_cgroup_get() at
every charge, and mem_cgroup_put() at every uncharge.
This can get expensive, however, and we can do better. mem_cgroup_get()
only really needs to be issued once: when the first limit is set. In the
same spirit, we only need to issue mem_cgroup_put() when the last charge
is gone.
We'll need an extra bit in kmem_account_flags for that:
KMEM_ACCOUNTED_DEAD. it will be set when the cgroup dies, if there are
charges in the group. If there aren't, we can proceed right away.
Our uncharge function will have to test that bit every time the charges
drop to 0. Because that is not the likely output of res_counter_uncharge,
this should not impose a big hit on us: it is certainly much better than a
reference count decrease at every operation.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Introduce infrastructure for tracking kernel memory pages to a given
memcg. This will happen whenever the caller includes the flag
__GFP_KMEMCG flag, and the task belong to a memcg other than the root.
In memcontrol.h those functions are wrapped in inline acessors. The idea
is to later on, patch those with static branches, so we don't incur any
overhead when no mem cgroups with limited kmem are being used.
Users of this functionality shall interact with the memcg core code
through the following functions:
memcg_kmem_newpage_charge: will return true if the group can handle the
allocation. At this point, struct page is not
yet allocated.
memcg_kmem_commit_charge: will either revert the charge, if struct page
allocation failed, or embed memcg information
into page_cgroup.
memcg_kmem_uncharge_page: called at free time, will revert the charge.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Add the basic infrastructure for the accounting of kernel memory. To
control that, the following files are created:
* memory.kmem.usage_in_bytes
* memory.kmem.limit_in_bytes
* memory.kmem.failcnt
* memory.kmem.max_usage_in_bytes
They have the same meaning of their user memory counterparts. They
reflect the state of the "kmem" res_counter.
Per cgroup kmem memory accounting is not enabled until a limit is set for
the group. Once the limit is set the accounting cannot be disabled for
that group. This means that after the patch is applied, no behavioral
changes exists for whoever is still using memcg to control their memory
usage, until memory.kmem.limit_in_bytes is set for the first time.
We always account to both user and kernel resource_counters. This
effectively means that an independent kernel limit is in place when the
limit is set to a lower value than the user memory. A equal or higher
value means that the user limit will always hit first, meaning that kmem
is effectively unlimited.
People who want to track kernel memory but not limit it, can set this
limit to a very high number (like RESOURCE_MAX - 1page - that no one will
ever hit, or equal to the user memory)
[akpm@linux-foundation.org: MEMCG_MMEM only works with slab and slub]
Signed-off-by: Glauber Costa <glommer@parallels.com>
Acked-by: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
This is just a cleanup patch for clarity of expression. In earlier
submissions, people asked it to be in a separate patch, so here it is.
Signed-off-by: Glauber Costa <glommer@parallels.com>
Acked-by: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
mem_cgroup_do_charge() was written before kmem accounting, and expects
three cases: being called for 1 page, being called for a stock of 32
pages, or being called for a hugepage. If we call for 2 or 3 pages (and
both the stack and several slabs used in process creation are such, at
least with the debug options I had), it assumed it's being called for
stock and just retried without reclaiming.
Fix that by passing down a minsize argument in addition to the csize.
And what to do about that (csize == PAGE_SIZE && ret) retry? If it's
needed at all (and presumably is since it's there, perhaps to handle
races), then it should be extended to more than PAGE_SIZE, yet how far?
And should there be a retry count limit, of what? For now retry up to
COSTLY_ORDER (as page_alloc.c does) and make sure not to do it if
__GFP_NORETRY.
v4: fixed nr pages calculation pointed out by Christoph Lameter.
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Glauber Costa <glommer@parallels.com>
Acked-by: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
We currently have a percpu stock cache scheme that charges one page at a
time from memcg->res, the user counter. When the kernel memory controller
comes into play, we'll need to charge more than that.
This is because kernel memory allocations will also draw from the user
counter, and can be bigger than a single page, as it is the case with the
stack (usually 2 pages) or some higher order slabs.
[glommer@parallels.com: added a changelog ]
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Glauber Costa <glommer@parallels.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/mel/linux-balancenuma
Pull Automatic NUMA Balancing bare-bones from Mel Gorman:
"There are three implementations for NUMA balancing, this tree
(balancenuma), numacore which has been developed in tip/master and
autonuma which is in aa.git.
In almost all respects balancenuma is the dumbest of the three because
its main impact is on the VM side with no attempt to be smart about
scheduling. In the interest of getting the ball rolling, it would be
desirable to see this much merged for 3.8 with the view to building
scheduler smarts on top and adapting the VM where required for 3.9.
The most recent set of comparisons available from different people are
mel: https://lkml.org/lkml/2012/12/9/108
mingo: https://lkml.org/lkml/2012/12/7/331
tglx: https://lkml.org/lkml/2012/12/10/437
srikar: https://lkml.org/lkml/2012/12/10/397
The results are a mixed bag. In my own tests, balancenuma does
reasonably well. It's dumb as rocks and does not regress against
mainline. On the other hand, Ingo's tests shows that balancenuma is
incapable of converging for this workloads driven by perf which is bad
but is potentially explained by the lack of scheduler smarts. Thomas'
results show balancenuma improves on mainline but falls far short of
numacore or autonuma. Srikar's results indicate we all suffer on a
large machine with imbalanced node sizes.
My own testing showed that recent numacore results have improved
dramatically, particularly in the last week but not universally.
We've butted heads heavily on system CPU usage and high levels of
migration even when it shows that overall performance is better.
There are also cases where it regresses. Of interest is that for
specjbb in some configurations it will regress for lower numbers of
warehouses and show gains for higher numbers which is not reported by
the tool by default and sometimes missed in treports. Recently I
reported for numacore that the JVM was crashing with
NullPointerExceptions but currently it's unclear what the source of
this problem is. Initially I thought it was in how numacore batch
handles PTEs but I'm no longer think this is the case. It's possible
numacore is just able to trigger it due to higher rates of migration.
These reports were quite late in the cycle so I/we would like to start
with this tree as it contains much of the code we can agree on and has
not changed significantly over the last 2-3 weeks."
* tag 'balancenuma-v11' of git://git.kernel.org/pub/scm/linux/kernel/git/mel/linux-balancenuma: (50 commits)
mm/rmap, migration: Make rmap_walk_anon() and try_to_unmap_anon() more scalable
mm/rmap: Convert the struct anon_vma::mutex to an rwsem
mm: migrate: Account a transhuge page properly when rate limiting
mm: numa: Account for failed allocations and isolations as migration failures
mm: numa: Add THP migration for the NUMA working set scanning fault case build fix
mm: numa: Add THP migration for the NUMA working set scanning fault case.
mm: sched: numa: Delay PTE scanning until a task is scheduled on a new node
mm: sched: numa: Control enabling and disabling of NUMA balancing if !SCHED_DEBUG
mm: sched: numa: Control enabling and disabling of NUMA balancing
mm: sched: Adapt the scanning rate if a NUMA hinting fault does not migrate
mm: numa: Use a two-stage filter to restrict pages being migrated for unlikely task<->node relationships
mm: numa: migrate: Set last_nid on newly allocated page
mm: numa: split_huge_page: Transfer last_nid on tail page
mm: numa: Introduce last_nid to the page frame
sched: numa: Slowly increase the scanning period as NUMA faults are handled
mm: numa: Rate limit setting of pte_numa if node is saturated
mm: numa: Rate limit the amount of memory that is migrated between nodes
mm: numa: Structures for Migrate On Fault per NUMA migration rate limiting
mm: numa: Migrate pages handled during a pmd_numa hinting fault
mm: numa: Migrate on reference policy
...
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The mm given to __mem_cgroup_count_vm_event() cannot be NULL because the
function is either called from the page fault path or vma->vm_mm is used.
So the check can be dropped.
The check was introduced by commit 456f998ec817 ("memcg: add the
pagefault count into memcg stats") because the originally proposed patch
used current->mm for shmem but this has been changed to vma->vm_mm later
on without the check being removed (thanks to Hugh for this
recollection).
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ying Han <yinghan@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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While profiling numa/core v16 with cgroup_disable=memory on the command
line, I noticed mem_cgroup_count_vm_event() still showed up as high as
0.60% in perftop.
This occurs because the function is called extremely often even when memcg
is disabled.
To fix this, inline the check for mem_cgroup_disabled() so we avoid the
unnecessary function call if memcg is disabled.
Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Glauber Costa <glommer@parallels.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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N_HIGH_MEMORY stands for the nodes that has normal or high memory.
N_MEMORY stands for the nodes that has any memory.
The code here need to handle with the nodes which have memory, we should
use N_MEMORY instead.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Lin Feng <linfeng@cn.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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