Re: [PATCH v3] mm/hugetlb: split hugetlb_cma in nodes with memory

[Will Deacon <will@kernel.org>]

On Fri, Jul 17, 2020 at 10:32:53AM +0530, Anshuman Khandual wrote:
> 
> 
> On 07/16/2020 11:55 PM, Mike Kravetz wrote:
> >>From 17c8f37afbf42fe7412e6eebb3619c6e0b7e1c3c Mon Sep 17 00:00:00 2001
> > From: Mike Kravetz <mike.kravetz@oracle.com>
> > Date: Tue, 14 Jul 2020 15:54:46 -0700
> > Subject: [PATCH] hugetlb: move cma reservation to code setting up gigantic
> >  hstate
> > 
> > Instead of calling hugetlb_cma_reserve() directly from arch specific
> > code, call from hugetlb_add_hstate when adding a gigantic hstate.
> > hugetlb_add_hstate is either called from arch specific huge page setup,
> > or as the result of hugetlb command line processing.  In either case,
> > this is late enough in the init process that all numa memory information
> > should be initialized.  And, it is early enough to still use early
> > memory allocator.
> 
> This assumes that hugetlb_add_hstate() is called from the arch code at
> the right point in time for the generic HugeTLB to do the required CMA
> reservation which is not ideal. I guess it must have been a reason why
> CMA reservation should always called by the platform code which knows
> the boot sequence timing better.

Ha, except we've moved it around two or three times already in the last
month or so, so I'd say we don't have a clue when to call it in the arch
code.

Will