From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:45114 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725931AbgHAKy4 (ORCPT ); Sat, 1 Aug 2020 06:54:56 -0400 Subject: Re: [PATCH 06/15] powerpc: fadamp: simplify fadump_reserve_crash_area() References: <20200728051153.1590-1-rppt@kernel.org> <20200728051153.1590-7-rppt@kernel.org> <87d04d5hda.fsf@mpe.ellerman.id.au> <20200801101854.GD534153@kernel.org> From: Hari Bathini Message-ID: Date: Sat, 1 Aug 2020 16:23:15 +0530 MIME-Version: 1.0 In-Reply-To: <20200801101854.GD534153@kernel.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-s390-owner@vger.kernel.org List-ID: To: Mike Rapoport , Michael Ellerman Cc: linux-sh@vger.kernel.org, Peter Zijlstra , Dave Hansen , Hari Bathini , linux-mips@vger.kernel.org, Max Filippov , Paul Mackerras , sparclinux@vger.kernel.org, linux-riscv@lists.infradead.org, Will Deacon , Stafford Horne , Marek Szyprowski , linux-s390@vger.kernel.org, linux-c6x-dev@linux-c6x.org, Yoshinori Sato , x86@kernel.org, Russell King , Mike Rapoport , clang-built-linux@googlegroups.com, Ingo Molnar , Catalin Marinas , uclinux-h8-devel@lists.sourceforge.jp, linux-xtensa@linux-xtensa.org, openrisc@lists.librecores.org, Borislav Petkov , Andy Lutomirski , Paul Walmsley , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, Michal Simek , linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Palmer Dabbelt , Andrew Morton , Christoph Hellwig On 01/08/20 3:48 pm, Mike Rapoport wrote: > On Thu, Jul 30, 2020 at 10:15:13PM +1000, Michael Ellerman wrote: >> Mike Rapoport writes: >>> From: Mike Rapoport >>> >>> fadump_reserve_crash_area() reserves memory from a specified base address >>> till the end of the RAM. >>> >>> Replace iteration through the memblock.memory with a single call to >>> memblock_reserve() with appropriate that will take care of proper memory >> ^ >> parameters? >>> reservation. >>> >>> Signed-off-by: Mike Rapoport >>> --- >>> arch/powerpc/kernel/fadump.c | 20 +------------------- >>> 1 file changed, 1 insertion(+), 19 deletions(-) >> >> I think this looks OK to me, but I don't have a setup to test it easily. >> I've added Hari to Cc who might be able to. >> >> But I'll give you an ack in the hope that it works :) > > Actually, I did some digging in the git log and the traversal was added > there on purpose by the commit b71a693d3db3 ("powerpc/fadump: exclude > memory holes while reserving memory in second kernel") I was about to comment on the same :) memblock_reserve() was being used until we ran into the issue talked about in the above commit... > Presuming this is still reqruired I'm going to drop this patch and will Yeah, it is still required.. > simply replace for_each_memblock() with for_each_mem_range() in v2. Sounds right. > >> Acked-by: Michael Ellerman >> >> >>> diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c >>> index 78ab9a6ee6ac..2446a61e3c25 100644 >>> --- a/arch/powerpc/kernel/fadump.c >>> +++ b/arch/powerpc/kernel/fadump.c >>> @@ -1658,25 +1658,7 @@ int __init fadump_reserve_mem(void) >>> /* Preserve everything above the base address */ >>> static void __init fadump_reserve_crash_area(u64 base) >>> { >>> - struct memblock_region *reg; >>> - u64 mstart, msize; >>> - >>> - for_each_memblock(memory, reg) { >>> - mstart = reg->base; >>> - msize = reg->size; >>> - >>> - if ((mstart + msize) < base) >>> - continue; >>> - >>> - if (mstart < base) { >>> - msize -= (base - mstart); >>> - mstart = base; >>> - } >>> - >>> - pr_info("Reserving %lluMB of memory at %#016llx for preserving crash data", >>> - (msize >> 20), mstart); >>> - memblock_reserve(mstart, msize); >>> - } >>> + memblock_reserve(base, memblock_end_of_DRAM() - base); >>> } >>> >>> unsigned long __init arch_reserved_kernel_pages(void) >>> -- >>> 2.26.2 > Thanks Hari