From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Thu, 12 Jul 2018 11:50:02 +0200 From: Oscar Salvador To: Michael Ellerman Cc: Oscar Salvador , Pavel Tatashin , Andrew Morton , broonie@kernel.org, mhocko@suse.cz, Stephen Rothwell , linux-next@vger.kernel.org, linux-fsdevel@vger.kernel.org, Linux Memory Management List , LKML , mm-commits@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, bhe@redhat.com, aneesh.kumar@linux.ibm.com, khandual@linux.vnet.ibm.com Subject: Re: Boot failures with "mm/sparse: Remove CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER" on powerpc (was Re: mmotm 2018-07-10-16-50 uploaded) Message-ID: <20180712095002.GA5342@techadventures.net> References: <20180710235044.vjlRV%akpm@linux-foundation.org> <87lgai9bt5.fsf@concordia.ellerman.id.au> <20180711133737.GA29573@techadventures.net> <87efg981rd.fsf@concordia.ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87efg981rd.fsf@concordia.ellerman.id.au> Sender: owner-linux-mm@kvack.org List-ID: > > I just roughly check, but if I checked the right place, > > vmemmap_populated() checks for the section to contain the flags we are > > setting in sparse_init_one_section(). > > Yes. > > > But with this patch, we populate first everything, and then we call > > sparse_init_one_section() in sparse_init(). > > As I said I could be mistaken because I just checked the surface. > > Yeah I think that's correct. > > This might just be a bug in our code, let me look at it a bit. I wonder if something like this could make the trick: diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c index 51ce091914f9..e281651f50cd 100644 --- a/arch/powerpc/mm/init_64.c +++ b/arch/powerpc/mm/init_64.c @@ -177,6 +177,8 @@ static __meminit void vmemmap_list_populate(unsigned long phys, vmemmap_list = vmem_back; } +static unsigned long last_addr_populated = 0; + int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, struct vmem_altmap *altmap) { @@ -191,7 +193,7 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, void *p; int rc; - if (vmemmap_populated(start, page_size)) + if (start + page_size <= last_addr_populated) continue; if (altmap) @@ -212,6 +214,7 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node, __func__, rc); return -EFAULT; } + last_addr_populated = start + page_size; } I know it looks hacky, and chances are that are wrong, but could you give it a try? I will try to grab a ppc server and try it out too. Thanks -- Oscar Salvador SUSE L3