Messages in this thread Patch in this message | | | Date | Tue, 26 Jul 2011 20:43:42 +0200 | From | Michal Hocko <> | Subject | Re: [PATCH v2] cgroup/kmemcheck: Annotate alloc_page() for cgroup allocations |
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On Tue 26-07-11 14:17:29, Steven Rostedt wrote: > When the cgroup base was allocated with kmalloc, it was necessary to > annotate the variable with kmemcheck_not_leak(). But because it has > recently been changed to be allocated with alloc_page() (which skips > kmemleak checks) causes a warning on boot up. > > I was triggering this output: > > allocated 8388608 bytes of page_cgroup > please try 'cgroup_disable=memory' option if you don't want memory > cgroups > kmemleak: Trying to color unknown object at 0xf5840000 as Grey > Pid: 0, comm: swapper Not tainted 3.0.0-test #12 > Call Trace: > [<c17e34e6>] ? printk+0x1d/0x1f^M > [<c10e2941>] paint_ptr+0x4f/0x78 > [<c178ab57>] kmemleak_not_leak+0x58/0x7d > [<c108ae9f>] ? __rcu_read_unlock+0x9/0x7d > [<c1cdb462>] kmemleak_init+0x19d/0x1e9 > [<c1cbf771>] start_kernel+0x346/0x3ec > [<c1cbf1b4>] ? loglevel+0x18/0x18 > [<c1cbf0aa>] i386_start_kernel+0xaa/0xb0 > > After a bit of debugging I tracked the object 0xf840000 (and others) > down to the cgroup code. The change from allocating base with kmalloc to > alloc_page() has the base not calling kmemleak_alloc() which adds the > pointer to the object_tree_root, but kmemleak_not_leak() adds it to the > crt_early_log[] table. On kmemleak_init(), the entry is found in the > early_log[] but not the object_tree_root, and this error message is > displayed. > > If alloc_page() fails then it defaults back to vmalloc() which still > uses the kmemleak_alloc() which makes us still need the > kmemleak_not_leak() call. The solution is to call the kmemleak_alloc() > directly if the alloc_page() succeeds.
OK, so you are making the allocation [kv]malloc like wrt. kmemleak. I can see that kmalloc_order does the exactly same thing and there are couple of oders that do it as well so I guess this should be correct.
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Maybe just a nit. What about making gfp_t flags = GFP_KERNEL | __GFP_NOWARN; and use it at both places?
Anyway feel free to add my: Reviewed-by: Michal Hocko <mhocko@suse.cz>
> > diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c > index 53bffc6..79c0e00 100644 > --- a/mm/page_cgroup.c > +++ b/mm/page_cgroup.c > @@ -135,8 +135,10 @@ static void *__meminit alloc_page_cgroup(size_t size, int nid) > void *addr = NULL; > > addr = alloc_pages_exact_nid(nid, size, GFP_KERNEL | __GFP_NOWARN); > - if (addr) > + if (addr) { > + kmemleak_alloc(addr, size, 1, GFP_KERNEL | __GFP_NOWARN); > return addr; > + } > > if (node_state(nid, N_HIGH_MEMORY)) > addr = vmalloc_node(size, nid); > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
-- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic
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