Messages in this thread | | | Date | Tue, 26 Jun 2012 16:48:08 +0400 | From | Glauber Costa <> | Subject | Re: [PATCH 11/11] protect architectures where THREAD_SIZE >= PAGE_SIZE against fork bombs |
| |
On 06/25/2012 10:38 PM, Tejun Heo wrote: > On Mon, Jun 25, 2012 at 06:55:35PM +0200, Frederic Weisbecker wrote: >> On 06/25/2012 04:15 PM, Glauber Costa wrote: >> >>> Because those architectures will draw their stacks directly from >>> the page allocator, rather than the slab cache, we can directly >>> pass __GFP_KMEMCG flag, and issue the corresponding free_pages. >>> >>> This code path is taken when the architecture doesn't define >>> CONFIG_ARCH_THREAD_INFO_ALLOCATOR (only ia64 seems to), and has >>> THREAD_SIZE >= PAGE_SIZE. Luckily, most - if not all - of the >>> remaining architectures fall in this category. >>> >>> This will guarantee that every stack page is accounted to the memcg >>> the process currently lives on, and will have the allocations to fail >>> if they go over limit. >>> >>> For the time being, I am defining a new variant of THREADINFO_GFP, not >>> to mess with the other path. Once the slab is also tracked by memcg, >>> we can get rid of that flag. >>> >>> Tested to successfully protect against :(){ :|:& };: >>> >>> Signed-off-by: Glauber Costa <glommer@parallels.com> >>> CC: Christoph Lameter <cl@linux.com> >>> CC: Pekka Enberg <penberg@cs.helsinki.fi> >>> CC: Michal Hocko <mhocko@suse.cz> >>> CC: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> >>> CC: Johannes Weiner <hannes@cmpxchg.org> >>> CC: Suleiman Souhlal <suleiman@google.com> >> >> >> Acked-by: Frederic Weisbecker <fweisbec@redhat.com> > > Frederic, does this (with proper slab accounting added later) achieve > what you wanted with the task counter? >
A note: Frederic may confirm, but I think he doesn't even need the slab accounting to follow to achieve that goal.
| |