Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751087AbbGBPC2 (ORCPT ); Thu, 2 Jul 2015 11:02:28 -0400 Received: from mail-qk0-f171.google.com ([209.85.220.171]:33137 "EHLO mail-qk0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751170AbbGBPCT (ORCPT ); Thu, 2 Jul 2015 11:02:19 -0400 Message-ID: <5595527a.0b32370a.6c7e.01ee@mx.google.com> Date: Thu, 02 Jul 2015 08:02:18 -0700 (PDT) From: Yasuaki Ishimatsu To: Tang Chen Cc: Xishi Qiu , , , , , , , , , , , , , , , , , Subject: Re: [PATCH 1/1] mem-hotplug: Handle node hole when initializing numa_meminfo. In-Reply-To: <55939CF2.6080108@cn.fujitsu.com> References: <1435720614-16480-1-git-send-email-tangchen@cn.fujitsu.com> <559387EF.5050701@huawei.com> <55939CF2.6080108@cn.fujitsu.com> X-Mailer: Sylpheed 3.4.2 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5977 Lines: 158 Hi Tang, > On my box, if I run lscpu, the output looks like this: > > NUMA node0 CPU(s): 0-14,128-142 > NUMA node1 CPU(s): 15-29,143-157 > NUMA node2 CPU(s): > NUMA node3 CPU(s): > NUMA node4 CPU(s): 62-76,190-204 > NUMA node5 CPU(s): 78-92,206-220 > > Node 2 and 3 are not exist, but they are online. According your description of patch, node 4 and 5 are mistakenly set to online. Why does lscpu show the above result? Thanks, Yasuaki Ishimatsu On Wed, 1 Jul 2015 15:55:30 +0800 Tang Chen wrote: > > On 07/01/2015 02:25 PM, Xishi Qiu wrote: > > On 2015/7/1 11:16, Tang Chen wrote: > > > >> When parsing SRAT, all memory ranges are added into numa_meminfo. > >> In numa_init(), before entering numa_cleanup_meminfo(), all possible > >> memory ranges are in numa_meminfo. And numa_cleanup_meminfo() removes > >> all ranges over max_pfn or empty. > >> > >> But, this only works if the nodes are continuous. Let's have a look > >> at the following example: > >> > >> We have an SRAT like this: > >> SRAT: Node 0 PXM 0 [mem 0x00000000-0x5fffffff] > >> SRAT: Node 0 PXM 0 [mem 0x100000000-0x1ffffffffff] > >> SRAT: Node 1 PXM 1 [mem 0x20000000000-0x3ffffffffff] > >> SRAT: Node 4 PXM 2 [mem 0x40000000000-0x5ffffffffff] hotplug > >> SRAT: Node 5 PXM 3 [mem 0x60000000000-0x7ffffffffff] hotplug > >> SRAT: Node 2 PXM 4 [mem 0x80000000000-0x9ffffffffff] hotplug > >> SRAT: Node 3 PXM 5 [mem 0xa0000000000-0xbffffffffff] hotplug > >> SRAT: Node 6 PXM 6 [mem 0xc0000000000-0xdffffffffff] hotplug > >> SRAT: Node 7 PXM 7 [mem 0xe0000000000-0xfffffffffff] hotplug > >> > >> On boot, only node 0,1,2,3 exist. > >> > >> And the numa_meminfo will look like this: > >> numa_meminfo.nr_blks = 9 > >> 1. on node 0: [0, 60000000] > >> 2. on node 0: [100000000, 20000000000] > >> 3. on node 1: [20000000000, 40000000000] > >> 4. on node 4: [40000000000, 60000000000] > >> 5. on node 5: [60000000000, 80000000000] > >> 6. on node 2: [80000000000, a0000000000] > >> 7. on node 3: [a0000000000, a0800000000] > >> 8. on node 6: [c0000000000, a0800000000] > >> 9. on node 7: [e0000000000, a0800000000] > >> > >> And numa_cleanup_meminfo() will merge 1 and 2, and remove 8,9 because > >> the end address is over max_pfn, which is a0800000000. But 4 and 5 > >> are not removed because their end addresses are less then max_pfn. > >> But in fact, node 4 and 5 don't exist. > >> > >> In a word, numa_cleanup_meminfo() is not able to handle holes between nodes. > >> > >> Since memory ranges in node 4 and 5 are in numa_meminfo, in numa_register_memblks(), > >> node 4 and 5 will be mistakenly set to online. > >> > >> In this patch, we use memblock_overlaps_region() to check if ranges in > >> numa_meminfo overlap with ranges in memory_block. Since memory_block contains > >> all available memory at boot time, if they overlap, it means the ranges > >> exist. If not, then remove them from numa_meminfo. > >> > > Hi Tang Chen, > > > > What's the impact of this problem? > > > > Command "numactl --hard" will show an empty node(no cpu and no memory, > > but pgdat is created), right? > > On my box, if I run lscpu, the output looks like this: > > NUMA node0 CPU(s): 0-14,128-142 > NUMA node1 CPU(s): 15-29,143-157 > NUMA node2 CPU(s): > NUMA node3 CPU(s): > NUMA node4 CPU(s): 62-76,190-204 > NUMA node5 CPU(s): 78-92,206-220 > > Node 2 and 3 are not exist, but they are online. > > Thanks. > > > > > Thanks, > > Xishi Qiu > > > >> Signed-off-by: Tang Chen > >> --- > >> arch/x86/mm/numa.c | 6 ++++-- > >> include/linux/memblock.h | 2 ++ > >> mm/memblock.c | 2 +- > >> 3 files changed, 7 insertions(+), 3 deletions(-) > >> > >> diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c > >> index 4053bb5..0c55cc5 100644 > >> --- a/arch/x86/mm/numa.c > >> +++ b/arch/x86/mm/numa.c > >> @@ -246,8 +246,10 @@ int __init numa_cleanup_meminfo(struct numa_meminfo *mi) > >> bi->start = max(bi->start, low); > >> bi->end = min(bi->end, high); > >> > >> - /* and there's no empty block */ > >> - if (bi->start >= bi->end) > >> + /* and there's no empty or non-exist block */ > >> + if (bi->start >= bi->end || > >> + memblock_overlaps_region(&memblock.memory, > >> + bi->start, bi->end - bi->start) == -1) > >> numa_remove_memblk_from(i--, mi); > >> } > >> > >> diff --git a/include/linux/memblock.h b/include/linux/memblock.h > >> index 0215ffd..3bf6cc1 100644 > >> --- a/include/linux/memblock.h > >> +++ b/include/linux/memblock.h > >> @@ -77,6 +77,8 @@ int memblock_remove(phys_addr_t base, phys_addr_t size); > >> int memblock_free(phys_addr_t base, phys_addr_t size); > >> int memblock_reserve(phys_addr_t base, phys_addr_t size); > >> void memblock_trim_memory(phys_addr_t align); > >> +long memblock_overlaps_region(struct memblock_type *type, > >> + phys_addr_t base, phys_addr_t size); > >> int memblock_mark_hotplug(phys_addr_t base, phys_addr_t size); > >> int memblock_clear_hotplug(phys_addr_t base, phys_addr_t size); > >> int memblock_mark_mirror(phys_addr_t base, phys_addr_t size); > >> diff --git a/mm/memblock.c b/mm/memblock.c > >> index 1b444c7..55b5f9f 100644 > >> --- a/mm/memblock.c > >> +++ b/mm/memblock.c > >> @@ -91,7 +91,7 @@ static unsigned long __init_memblock memblock_addrs_overlap(phys_addr_t base1, p > >> return ((base1 < (base2 + size2)) && (base2 < (base1 + size1))); > >> } > >> > >> -static long __init_memblock memblock_overlaps_region(struct memblock_type *type, > >> +long __init_memblock memblock_overlaps_region(struct memblock_type *type, > >> phys_addr_t base, phys_addr_t size) > >> { > >> unsigned long i; > > > > > > . > > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/