On Fri, 17 Nov 2017 13:19:56 -0500 Pavel Tatashin <pasha.tatas...@oracle.com> wrote:
> On Thu, Nov 16, 2017 at 5:06 AM, Mel Gorman <mgor...@techsingularity.net> > wrote: > > 4. Put a check into the page allocator slowpath that triggers serialised > > init if the system is booting and an allocation is about to fail. It > > would be such a cold path that it would never be noticable although it > > would leave dead code in the kernel image once boot had completed > > Hi Mel, > > The forth approach is the best as it is seamless for admins and > engineers, it will also work on any system configuration with any > parameters without any special involvement. Apart from what-mel-said, I'd be concerned that this failsafe would almost never get tested. We should find some way to ensure that this code gets exercised in some people's kernels on a permanent basis and I'm not sure how to do that. One option might be to ask Fengguang to add the occasional test_pavels_stuff=1 to the kernel boot commandline. That's better than nothing but 0-day only runs on a small number of machine types.
