From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755415AbcFGM7X (ORCPT ); Tue, 7 Jun 2016 08:59:23 -0400 Received: from szxga03-in.huawei.com ([119.145.14.66]:45771 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754983AbcFGM7U (ORCPT ); Tue, 7 Jun 2016 08:59:20 -0400 Subject: Re: [PATCH v4 11/14] arm64/numa: support HAVE_MEMORYLESS_NODES To: Ganapatrao Kulkarni References: <1465286898-13828-1-git-send-email-thunder.leizhen@huawei.com> <1465286898-13828-12-git-send-email-thunder.leizhen@huawei.com> CC: Catalin Marinas , Will Deacon , linux-arm-kernel , Ganapatrao Kulkarni , Robert Richter , "David Daney" , Rob Herring , "Frank Rowand" , Grant Likely , devicetree , linux-kernel , Xinwei Hu , Zefan Li , Hanjun Guo , Tianhong Ding From: "Leizhen (ThunderTown)" Message-ID: <5756C4C6.7060706@huawei.com> Date: Tue, 7 Jun 2016 20:57:42 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.23.164] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020201.5756C4E2.00B6,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-05-26 15:14:31, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: cf35000efffceefacd976447253071b7 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2016/6/7 16:31, Ganapatrao Kulkarni wrote: > On Tue, Jun 7, 2016 at 1:38 PM, Zhen Lei wrote: >> Some numa nodes may have no memory. For example: >> 1. cpu0 on node0 >> 2. cpu1 on node1 >> 3. device0 access the momory from node0 and node1 take the same time. > > i am wondering, if access to both nodes is same, then why you need numa. > the example you are quoting is against the basic principle of "numa" > what is device0 here? cpu? The device0 can also be a cpu. I drew a simple diagram: cpu0 cpu1 cpu2/device0 | | | | | | DDR0 DDR1 No DIMM slots or no DIMM plugged (node0) (node1) (node2) >> >> So, we can not simply classify device0 to node0 or node1, but we can >> define a node2 which distances to node0 and node1 are the same. >> >> Signed-off-by: Zhen Lei >> --- >> arch/arm64/Kconfig | 4 ++++ >> arch/arm64/kernel/smp.c | 1 + >> arch/arm64/mm/numa.c | 43 +++++++++++++++++++++++++++++++++++++++++-- >> 3 files changed, 46 insertions(+), 2 deletions(-) >> >> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig >> index 05c1bf1..5904a62 100644 >> --- a/arch/arm64/Kconfig >> +++ b/arch/arm64/Kconfig >> @@ -581,6 +581,10 @@ config NEED_PER_CPU_EMBED_FIRST_CHUNK >> def_bool y >> depends on NUMA >> >> +config HAVE_MEMORYLESS_NODES >> + def_bool y >> + depends on NUMA >> + >> source kernel/Kconfig.preempt >> source kernel/Kconfig.hz >> >> diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c >> index d099306..9e15297 100644 >> --- a/arch/arm64/kernel/smp.c >> +++ b/arch/arm64/kernel/smp.c >> @@ -620,6 +620,7 @@ static void __init of_parse_and_init_cpus(void) >> } >> >> bootcpu_valid = true; >> + early_map_cpu_to_node(0, of_node_to_nid(dn)); >> >> /* >> * cpu_logical_map has already been >> diff --git a/arch/arm64/mm/numa.c b/arch/arm64/mm/numa.c >> index df5c842..d73b0a0 100644 >> --- a/arch/arm64/mm/numa.c >> +++ b/arch/arm64/mm/numa.c >> @@ -128,6 +128,14 @@ void __init early_map_cpu_to_node(unsigned int cpu, int nid) >> nid = 0; >> >> cpu_to_node_map[cpu] = nid; >> + >> + /* >> + * We should set the numa node of cpu0 as soon as possible, because it >> + * has already been set up online before. cpu_to_node(0) will soon be >> + * called. >> + */ >> + if (!cpu) >> + set_cpu_numa_node(cpu, nid); >> } >> >> #ifdef CONFIG_HAVE_SETUP_PER_CPU_AREA >> @@ -215,6 +223,35 @@ int __init numa_add_memblk(int nid, u64 start, u64 end) >> return ret; >> } >> >> +static u64 __init alloc_node_data_from_nearest_node(int nid, const size_t size) >> +{ >> + int i, best_nid, distance; >> + u64 pa; >> + DECLARE_BITMAP(nodes_map, MAX_NUMNODES); >> + >> + bitmap_zero(nodes_map, MAX_NUMNODES); >> + bitmap_set(nodes_map, nid, 1); >> + >> +find_nearest_node: >> + best_nid = NUMA_NO_NODE; >> + distance = INT_MAX; >> + >> + for_each_clear_bit(i, nodes_map, MAX_NUMNODES) >> + if (numa_distance[nid][i] < distance) { >> + best_nid = i; >> + distance = numa_distance[nid][i]; >> + } >> + >> + pa = memblock_alloc_nid(size, SMP_CACHE_BYTES, best_nid); >> + if (!pa) { >> + BUG_ON(best_nid == NUMA_NO_NODE); >> + bitmap_set(nodes_map, best_nid, 1); >> + goto find_nearest_node; >> + } >> + >> + return pa; >> +} >> + >> /** >> * Initialize NODE_DATA for a node on the local memory >> */ >> @@ -228,7 +265,9 @@ static void __init setup_node_data(int nid, u64 start_pfn, u64 end_pfn) >> pr_info("Initmem setup node %d [mem %#010Lx-%#010Lx]\n", >> nid, start_pfn << PAGE_SHIFT, (end_pfn << PAGE_SHIFT) - 1); >> >> - nd_pa = memblock_alloc_try_nid(nd_size, SMP_CACHE_BYTES, nid); >> + nd_pa = memblock_alloc_nid(nd_size, SMP_CACHE_BYTES, nid); >> + if (!nd_pa) >> + nd_pa = alloc_node_data_from_nearest_node(nid, nd_size); >> nd = __va(nd_pa); >> >> /* report and initialize */ >> @@ -238,7 +277,7 @@ static void __init setup_node_data(int nid, u64 start_pfn, u64 end_pfn) >> if (tnid != nid) >> pr_info(" NODE_DATA(%d) on node %d\n", nid, tnid); >> >> - node_data[nid] = nd; >> + NODE_DATA(nid) = nd; >> memset(NODE_DATA(nid), 0, sizeof(pg_data_t)); >> NODE_DATA(nid)->node_id = nid; >> NODE_DATA(nid)->node_start_pfn = start_pfn; >> -- >> 2.5.0 >> >> > Ganapat >> >> _______________________________________________ >> linux-arm-kernel mailing list >> linux-arm-kernel@lists.infradead.org >> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > > . >