Messages in this thread | | | Date | Mon, 17 Mar 2008 17:59:03 +0530 | From | Balbir Singh <> | Subject | Re: [RFC][2/3] Account and control virtual address space allocations |
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Pavel Emelyanov wrote: > [snip] > >> +int mem_cgroup_update_as(struct mm_struct *mm, long nr_pages) >> +{ >> + int ret = 0; >> + struct mem_cgroup *mem; >> + if (mem_cgroup_subsys.disabled) >> + return ret; >> + >> + rcu_read_lock(); >> + mem = rcu_dereference(mm->mem_cgroup); >> + css_get(&mem->css); >> + rcu_read_unlock(); >> + >> + if (nr_pages > 0) { >> + if (res_counter_charge(&mem->as_res, (nr_pages * PAGE_SIZE))) >> + ret = 1; >> + } else >> + res_counter_uncharge(&mem->as_res, (-nr_pages * PAGE_SIZE)); > > No, please, no. Let's make two calls - mem_cgroup_charge_as and mem_cgroup_uncharge_as. > > [snip] >
Yes, sure :)
>> @@ -1117,6 +1117,9 @@ munmap_back: >> } >> } >> >> + if (mem_cgroup_update_as(mm, len >> PAGE_SHIFT)) >> + return -ENOMEM; >> + > > Why not use existintg cap_vm_enough_memory and co? >
I thought about it and almost used may_expand_vm(), but there is a slight catch there. With cap_vm_enough_memory() or security_vm_enough_memory(), they are called after total_vm has been calculated. In our case we need to keep the cgroups equivalent of total_vm up to date, and we do this in mem_cgorup_update_as.
-- Warm Regards, Balbir Singh Linux Technology Center IBM, ISTL
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