From: Konstantin Khlebnikov <koct9i@gmail.com>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Armin Rigo <arigo@tunes.org>,
Andrew Morton <akpm@linux-foundation.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCHv2 0/2] remap_file_pages() decommission
Date: Mon, 12 May 2014 18:59:15 +0400 [thread overview]
Message-ID: <CALYGNiMY=f0M2gAJWgUSxa5z61PS3H8nXvJsiXp3XPbsJE+jyQ@mail.gmail.com> (raw)
In-Reply-To: <20140512124344.GA26865@node.dhcp.inet.fi>
On Mon, May 12, 2014 at 4:43 PM, Kirill A. Shutemov
<kirill@shutemov.name> wrote:
> On Fri, May 09, 2014 at 08:14:08AM -0700, Linus Torvalds wrote:
>> On Fri, May 9, 2014 at 7:05 AM, Kirill A. Shutemov
>> <kirill.shutemov@linux.intel.com> wrote:
>> >
>> > Hm. I'm confused here. Do we have any limit forced per-user?
>>
>> Sure we do. See "struct user_struct". We limit max number of
>> processes, open files, signals etc.
>>
>> > I only see things like rlimits which are copied from parrent.
>> > Is it what you want?
>>
>> No, rlimits are per process (although in some cases what they limit
>> are counted per user despite the _limits_ of those resources then
>> being settable per thread).
>>
>> So I was just thinking that if we raise the per-mm default limits,
>> maybe we should add a global per-user limit to make it harder for a
>> user to use tons and toms of vma's.
>
> Here's the first attempt.
>
> I'm not completely happy about current_user(). It means we rely on that
> user of mm owner task is always equal to user of current. Not sure if it's
> always the case.
>
> Other option is to make MM_OWNER is always on and lookup proper user
> through task_cred_xxx(rcu_dereference(mm->owner), user).
>
> From 5ee6f6dd721ada8eb66c84a91003ac1e3eb2970a Mon Sep 17 00:00:00 2001
> From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
> Date: Mon, 12 May 2014 15:13:12 +0300
> Subject: [PATCH] mm: add per-user limit on mapping count
>
> We're going to increase per-mm map_count. To avoid non-obvious memory
> abuse by creating a lot of VMA's, let's introduce per-user limit.
>
> The limit is implemented as sysctl. For now value of limit is pretty
> arbitrary -- 2^20.
>
> sizeof(vm_area_struct) with my kernel config (DEBUG_KERNEL=n) is 184
> bytes. It means with the limit user can use up to 184 MiB of RAM in
> VMAs.
>
> The limit is not applicable for root (INIT_USER).
I don't like this.
Maybe we could just account VMAs into OOM-badness points and let
OOM-killer do its job?
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -170,7 +170,9 @@ unsigned long oom_badness(struct task_struct *p,
struct mem_cgroup *memcg,
* task's rss, pagetable and swap space use.
*/
points = get_mm_rss(p->mm) + atomic_long_read(&p->mm->nr_ptes) +
- get_mm_counter(p->mm, MM_SWAPENTS);
+ get_mm_counter(p->mm, MM_SWAPENTS) +
+ (long)p->mm->map_count *
+ sizeof(struct vm_area_struct) / PAGE_SIZE;
task_unlock(p);
/*
next prev parent reply other threads:[~2014-05-12 14:59 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-08 12:41 [PATCHv2 0/2] remap_file_pages() decommission Kirill A. Shutemov
2014-05-08 12:41 ` [PATCH 1/2] mm: mark remap_file_pages() syscall as deprecated Kirill A. Shutemov
2014-06-12 5:48 ` Michael Kerrisk
2014-06-12 9:40 ` Kirill A. Shutemov
2014-06-12 9:44 ` Michael Kerrisk (man-pages)
2014-05-08 12:41 ` [PATCH 2/2] mm: replace remap_file_pages() syscall with emulation Kirill A. Shutemov
2014-05-08 21:57 ` Andrew Morton
2014-05-12 15:11 ` Sasha Levin
2014-05-12 17:05 ` Kirill A. Shutemov
2014-05-14 20:52 ` Sasha Levin
2014-05-14 21:17 ` Kirill A. Shutemov
2014-05-14 21:40 ` Andrew Morton
2014-05-13 7:32 ` Armin Rigo
2014-05-13 12:57 ` Sasha Levin
2014-05-08 15:35 ` [PATCHv2 0/2] remap_file_pages() decommission Linus Torvalds
2014-05-08 15:44 ` Armin Rigo
2014-05-08 16:02 ` Kirill A. Shutemov
2014-05-08 16:08 ` Linus Torvalds
2014-05-09 14:05 ` Kirill A. Shutemov
2014-05-09 15:14 ` Linus Torvalds
2014-05-09 18:19 ` Kirill A. Shutemov
2014-05-12 12:43 ` Kirill A. Shutemov
2014-05-12 14:59 ` Konstantin Khlebnikov [this message]
2014-05-12 3:36 ` Andi Kleen
2014-05-12 5:16 ` Konstantin Khlebnikov
2014-05-12 7:50 ` Armin Rigo
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