On Tue, Oct 14, 2014 at 07:08:43PM -0400, Sasha Levin wrote: > On 10/14/2014 04:29 PM, David Cohen wrote: > >> + VM_BUG_ON(PageTail(page)); > >> > + VM_BUG_ON(PageHead(page) && compound_order(page) != order); > > It may be too severe. AFAIU we're not talking about a fatal error. > > How about VM_WARN_ON()? > > VM_BUG_ON() should catch anything which is not "supposed" to happen, > and not just the severe stuff. Unlike BUG_ON, VM_BUG_ON only gets > hit with mm debugging enabled.
Thanks for pointing that out :) VM_WARN_ON*() is recent, so there isn't much examples when to use it. I considered the below case similar to this patch. But your point does make sense anyway. commit 82f71ae4a2b829a25971bdf54b4d0d3d69d3c8b7 Author: Konstantin Khlebnikov <[email protected]> Date: Wed Aug 6 16:06:36 2014 -0700 mm: catch memory commitment underflow Print a warning (if CONFIG_DEBUG_VM=y) when memory commitment becomes too negative. This shouldn't happen any more - the previous two patches fixed the committed_as underflow issues. [[email protected]: use VM_WARN_ONCE, per Dave] Br, David > > > Thanks, > Sasha > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
