On Thu, Apr 09, 2020 at 03:08:07PM -0700, Mike Kravetz wrote: > On 4/9/20 2:58 PM, Peter Xu wrote: > > The hugepage options are not documented clearly. > > > > Firstly, default_hugepagesz= should always be specified after the > > declaration of the same type of huge page using hugepagesz=. For > > example, if we boot a x86_64 system with kernel cmdline > > "default_hugepagesz=2M", we'll get a very funny error message: > > > > "HugeTLB: unsupported default_hugepagesz 2097152. Reverting to 2097152" > > > > It's understandable from code-wise because when hugetlb_init() we > > didn't have the 2M page hstate registered, so it's unsupported. > > However 2M is actually the default huge page size on x86_64, so we'll > > register it right after the error message. However it's very > > confusing if without these knowledges. > > > > Secondly, hugepages= option must be used _after_ another hugepagesz=. > > The word "interleave" is fine but it didn't declare the fact that > > each of the hugepages= option will be applied to the previous parsed > > hugepagesz= option. > > > > State all these clear. > > > > Signed-off-by: Peter Xu <peterx@xxxxxxxxxx> > > Hi Peter, > > Did you happen to see this patch series? > > https://lore.kernel.org/linux-mm/20200401183819.20647-1-mike.kravetz@xxxxxxxxxx/ > > That should address the documentation issue and more. Great! I missed that, but I'll definitely read it (probably tomorrow). Let's ignore this patch then. Thanks, -- Peter Xu
