From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Rapoport Date: Wed, 02 Jun 2021 10:53:41 +0000 Subject: [PATCH 2/9] arc: update comment about HIGHMEM implementation Message-Id: <20210602105348.13387-3-rppt@kernel.org> List-Id: References: <20210602105348.13387-1-rppt@kernel.org> In-Reply-To: <20210602105348.13387-1-rppt@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Andrew Morton Cc: Arnd Bergmann , Geert Uytterhoeven , Ivan Kokshaysky , Jonathan Corbet , Matt Turner , Mike Rapoport , Mike Rapoport , Richard Henderson , Vineet Gupta , kexec@lists.infradead.org, linux-alpha@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-mm@kvack.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-xtensa@linux-xtensa.org, linuxppc-dev@lists.ozlabs.org, sparclinux@vger.kernel.org From: Mike Rapoport Arc does not use DISCONTIGMEM to implement high memory, update the comment describing how high memory works to reflect this. Signed-off-by: Mike Rapoport --- arch/arc/mm/init.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) diff --git a/arch/arc/mm/init.c b/arch/arc/mm/init.c index e2ed355438c9..397a201adfe3 100644 --- a/arch/arc/mm/init.c +++ b/arch/arc/mm/init.c @@ -139,16 +139,13 @@ void __init setup_arch_memory(void) #ifdef CONFIG_HIGHMEM /* - * Populate a new node with highmem - * * On ARC (w/o PAE) HIGHMEM addresses are actually smaller (0 based) - * than addresses in normal ala low memory (0x8000_0000 based). + * than addresses in normal aka low memory (0x8000_0000 based). * Even with PAE, the huge peripheral space hole would waste a lot of - * mem with single mem_map[]. This warrants a mem_map per region design. - * Thus HIGHMEM on ARC is imlemented with DISCONTIGMEM. - * - * DISCONTIGMEM in turns requires multiple nodes. node 0 above is - * populated with normal memory zone while node 1 only has highmem + * mem with single contiguous mem_map[]. + * Thus when HIGHMEM on ARC is enabled the memory map corresponding + * to the hole is freed and ARC specific version of pfn_valid() + * handles the hole in the memory map. */ #ifdef CONFIG_DISCONTIGMEM node_set_online(1); -- 2.28.0