On Thu, Jun 26, 2014 at 2:03 AM, Andrew Morton <a...@linux-foundation.org> wrote: > On Wed, 25 Jun 2014 00:16:14 +0400 Konstantin Khlebnikov <koc...@gmail.com> > wrote: > >> This patch prints warning (if CONFIG_DEBUG_VM=y) when >> memory commitment becomes too negative. >> >> ... >> >> --- a/mm/mmap.c >> +++ b/mm/mmap.c >> @@ -134,6 +134,12 @@ int __vm_enough_memory(struct mm_struct *mm, long >> pages, int cap_sys_admin) >> { >> unsigned long free, allowed, reserve; >> >> +#ifdef CONFIG_DEBUG_VM >> + WARN_ONCE(percpu_counter_read(&vm_committed_as) < >> + -(s64)vm_committed_as_batch * num_online_cpus(), >> + "memory commitment underflow"); >> +#endif >> + >> vm_acct_memory(pages); > > The changelog doesn't describe the reasons for making the change. > > I assume this warning will detect the situation which the previous two > patches just fixed?
Yep. Otherwise there is no way to validate these bugs, /proc/meminfo hides negative values. > Why not use VM_WARN_ON_ONCE()? This patch is older than this macro. Previously I've sent it in the last september and it was ignored. Now I've found it again in my backlog. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/