Messages in this thread | | | Date | Thu, 13 Oct 2011 12:19:37 +0400 | From | Glauber Costa <> | Subject | Re: [PATCH v6 1/8] Basic kernel memory functionality for the Memory Controller |
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On 10/13/2011 11:18 AM, Greg Thelen wrote: > On Mon, Oct 10, 2011 at 3:24 AM, Glauber Costa<glommer@parallels.com> wrote: >> diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt >> index 06eb6d9..bf00cd2 100644 >> --- a/Documentation/cgroups/memory.txt >> +++ b/Documentation/cgroups/memory.txt > ... >> @@ -255,6 +262,31 @@ When oom event notifier is registered, event will be delivered. >> per-zone-per-cgroup LRU (cgroup's private LRU) is just guarded by >> zone->lru_lock, it has no lock of its own. >> >> +2.7 Kernel Memory Extension (CONFIG_CGROUP_MEM_RES_CTLR_KMEM) >> + >> + With the Kernel memory extension, the Memory Controller is able to limit > > Extra leading space before 'With'. > >> +the amount of kernel memory used by the system. Kernel memory is fundamentally >> +different than user memory, since it can't be swapped out, which makes it >> +possible to DoS the system by consuming too much of this precious resource. >> +Kernel memory limits are not imposed for the root cgroup. >> + >> +Memory limits as specified by the standard Memory Controller may or may not >> +take kernel memory into consideration. This is achieved through the file >> +memory.independent_kmem_limit. A Value different than 0 will allow for kernel > > s/Value/value/ > >> diff --git a/mm/memcontrol.c b/mm/memcontrol.c >> index 3508777..d25c5cb 100644 >> --- a/mm/memcontrol.c >> +++ b/mm/memcontrol.c > ... >> +static int kmem_limit_independent_write(struct cgroup *cont, struct cftype *cft, >> + u64 val) >> +{ >> + cgroup_lock(); >> + mem_cgroup_from_cont(cont)->kmem_independent_accounting = !!val; >> + cgroup_unlock(); > > I do not think cgroup_lock,unlock are needed here. The cont and > associated cgroup should be guaranteed by the caller to be valid. > Does this lock provide some other synchronization? Yeah, I think I was being overcautious.
With the following comments addressed, can I add your Reviewed-by to this one ?
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