Messages in this thread | | | Date | Thu, 27 Mar 2008 10:19:26 +0300 | From | Pavel Emelyanov <> | Subject | Re: [RFC][2/3] Account and control virtual address space allocations (v2) |
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Balbir Singh wrote: > Changelog v2 > ------------ > Change the accounting to what is already present in the kernel. Split > the address space accounting into mem_cgroup_charge_as and > mem_cgroup_uncharge_as. At the time of VM expansion, call > mem_cgroup_cannot_expand_as to check if the new allocation will push > us over the limit > > This patch implements accounting and control of virtual address space. > Accounting is done when the virtual address space of any task/mm_struct > belonging to the cgroup is incremented or decremented. This patch > fails the expansion if the cgroup goes over its limit. > > TODOs > > 1. Only when CONFIG_MMU is enabled, is the virtual address space control > enabled. Should we do this for nommu cases as well? My suspicion is > that we don't have to. > > Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> > --- > > arch/ia64/kernel/perfmon.c | 2 + > arch/x86/kernel/ptrace.c | 7 +++ > fs/exec.c | 2 + > include/linux/memcontrol.h | 26 +++++++++++++ > include/linux/res_counter.h | 19 ++++++++-- > init/Kconfig | 2 - > kernel/fork.c | 17 +++++++-- > mm/memcontrol.c | 83 ++++++++++++++++++++++++++++++++++++++++++++ > mm/mmap.c | 11 +++++ > mm/mremap.c | 2 + > 10 files changed, 163 insertions(+), 8 deletions(-) > > diff -puN mm/memcontrol.c~memory-controller-virtual-address-space-accounting-and-control mm/memcontrol.c > --- linux-2.6.25-rc5/mm/memcontrol.c~memory-controller-virtual-address-space-accounting-and-control 2008-03-26 16:27:59.000000000 +0530 > +++ linux-2.6.25-rc5-balbir/mm/memcontrol.c 2008-03-27 00:18:16.000000000 +0530 > @@ -526,6 +526,76 @@ unsigned long mem_cgroup_isolate_pages(u > return nr_taken; > } > > +#ifdef CONFIG_CGROUP_MEM_RES_CTLR_AS > +/* > + * Charge the address space usage for cgroup. This routine is most > + * likely to be called from places that expand the total_vm of a mm_struct. > + */ > +void mem_cgroup_charge_as(struct mm_struct *mm, long nr_pages) > +{ > + struct mem_cgroup *mem; > + > + if (mem_cgroup_subsys.disabled) > + return; > + > + rcu_read_lock(); > + mem = rcu_dereference(mm->mem_cgroup); > + css_get(&mem->css); > + rcu_read_unlock(); > + > + res_counter_charge(&mem->as_res, (nr_pages * PAGE_SIZE)); > + css_put(&mem->css);
Why don't you check whether the counter is charged? This is bad for two reasons: 1. you allow for some growth above the limit (e.g. in expand_stack) 2. you will undercharge it in the future when uncharging the vme, whose charge was failed and thus unaccounted.
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