From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Daney Subject: Re: [PATCH v6 13/14] arm64, acpi, numa: NUMA support based on SRAT and SLIT Date: Thu, 12 May 2016 13:40:24 -0700 Message-ID: <5734EA38.2040206@caviumnetworks.com> References: <1461780436-27182-1-git-send-email-ddaney.cavm@gmail.com> <1461780436-27182-14-git-send-email-ddaney.cavm@gmail.com> <20160511103929.GC3051@e104818-lin.cambridge.arm.com> <5733C8F5.6090206@caviumnetworks.com> <20160512094915.GD11226@e104818-lin.cambridge.arm.com> <5734A0CC.8010600@caviumnetworks.com> <20160512162449.GK11226@e104818-lin.cambridge.arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20160512162449.GK11226@e104818-lin.cambridge.arm.com> Sender: linux-ia64-owner@vger.kernel.org To: Catalin Marinas Cc: "Rafael J. Wysocki" , Will Deacon , Mark Rutland , linux-ia64@vger.kernel.org, David Daney , Robert Moore , Lv Zheng , "H. Peter Anvin" , Frank Rowand , x86@kernel.org, linux-acpi@vger.kernel.org, Ingo Molnar , Grant Likely , Len Brown , Fenghua Yu , Marc Zyngier , Jon Masters , Robert Richter , Rob Herring , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, devel@acpica.org, Tony Luck , linux-kernel@vger.kernel.org, Hanjun Guo , Ganapatrao Kulkarni List-Id: linux-acpi@vger.kernel.org On 05/12/2016 09:24 AM, Catalin Marinas wrote: > On Thu, May 12, 2016 at 08:27:08AM -0700, David Daney wrote: >> On 05/12/2016 02:49 AM, Catalin Marinas wrote: >>> On Wed, May 11, 2016 at 05:06:13PM -0700, David Daney wrote: >>>> On 05/11/2016 03:39 AM, Catalin Marinas wrote: >> [...] >>>>> >>>>> I wonder whether you could replace the get_mpidr_in_madt() function with >>>>> something like acpi_get_phys_id(). It looks like get_mpidr_in_madt() >>>>> duplicates functionality already available elsewhere. >>>> >>>> I just tried that, and it doesn't work. >>>> >>>> The problem is that this code is being run very early in the boot, and >>>> kmalloc cannot be used. acpi_get_phys_id() and its ilk can only be used >>>> once we have working kmalloc. We need to extract the NUMA information early >>>> like this precisely because it is needed to initializing the slab system >>>> >>>> Notice that we are using early_acpi_os_unmap_memory() et al. in >>>> get_mpidr_in_madt() explicitly for this reason. >>>> >>>> In summary: I don't think we need another revision of this patch, it is like >>>> this for a good reason. >>> >>> Slightly confusing, in another reply you said you are going to address >>> my comment. So, is it doable? >> >> I don't think so. >> >> My previous reply, to the thread in 0/14, was prematurely made with the >> incorrect assumption that it was a simple change. Now, after really digging >> in to the code, and attempting to do as you suggested, I have changed my >> mind. > > Would the snippet below help with avoiding any kmalloc calls? At a quick > look, it seems that it's only map_mat_entry() that ends up using > kmalloc() calls. Alternatively, exporting map_madt_entry() may work as > well. I think making a non-static version of map_madt_entry() is the cleanest solution. That works, so I will send a new version of the patch set that does that instead. David. > > diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c > index 33a38d604630..77af0a7df914 100644 > --- a/drivers/acpi/processor_core.c > +++ b/drivers/acpi/processor_core.c > @@ -152,6 +152,9 @@ static phys_cpuid_t map_mat_entry(acpi_handle handle, int type, u32 acpi_id) > struct acpi_subtable_header *header; > phys_cpuid_t phys_id = PHYS_CPUID_INVALID; > > + if (!acpi_gbl_permanent_mmap) > + return phys_id; > + > if (ACPI_FAILURE(acpi_evaluate_object(handle, "_MAT", NULL, &buffer))) > goto exit; > >