From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ob0-f174.google.com (mail-ob0-f174.google.com [209.85.214.174]) by kanga.kvack.org (Postfix) with ESMTP id 535F96B0099 for ; Mon, 3 Nov 2014 20:53:53 -0500 (EST) Received: by mail-ob0-f174.google.com with SMTP id uz6so10105105obc.33 for ; Mon, 03 Nov 2014 17:53:52 -0800 (PST) Received: from szxga02-in.huawei.com (szxga02-in.huawei.com. [119.145.14.65]) by mx.google.com with ESMTPS id ok7si19901573obc.96.2014.11.03.17.53.45 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Mon, 03 Nov 2014 17:53:51 -0800 (PST) Message-ID: <545830E3.1020907@huawei.com> Date: Tue, 4 Nov 2014 09:50:27 +0800 From: Xishi Qiu MIME-Version: 1.0 Subject: Re: [PATCH 1/2] mem-hotplug: Reset node managed pages when hot-adding a new pgdat. References: <1414748812-22610-1-git-send-email-tangchen@cn.fujitsu.com> <1414748812-22610-2-git-send-email-tangchen@cn.fujitsu.com> In-Reply-To: <1414748812-22610-2-git-send-email-tangchen@cn.fujitsu.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Tang Chen Cc: akpm@linux-foundation.org, santosh.shilimkar@ti.com, grygorii.strashko@ti.com, yinghai@kernel.org, isimatu.yasuaki@jp.fujitsu.co, fabf@skynet.be, nzimmer@sgi.com, wangnan0@huawei.com, vdavydov@parallels.com, toshi.kani@hp.com, phacht@linux.vnet.ibm.com, tj@kernel.org, kirill.shutemov@linux.intel.com, riel@redhat.com, luto@amacapital.net, hpa@linux.intel.com, aarcange@redhat.com, mgorman@suse.de, rientjes@google.com, hannes@cmpxchg.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Yasuaki Ishimatsu On 2014/10/31 17:46, Tang Chen wrote: > In free_area_init_core(), zone->managed_pages is set to an approximate > value for lowmem, and will be adjusted when the bootmem allocator frees > pages into the buddy system. But free_area_init_core() is also called > by hotadd_new_pgdat() when hot-adding memory. As a result, zone->managed_pages > of the newly added node's pgdat is set to an approximate value in the > very beginning. Even if the memory on that node has node been onlined, > /sys/device/system/node/nodeXXX/meminfo has wrong value. > > hot-add node2 (memory not onlined) > cat /sys/device/system/node/node2/meminfo > Node 2 MemTotal: 33554432 kB > Node 2 MemFree: 0 kB > Node 2 MemUsed: 33554432 kB > Node 2 Active: 0 kB > > This patch fixes this problem by reset node managed pages to 0 after hot-adding > a new node. > > 1. Move reset_managed_pages_done from reset_node_managed_pages() to reset_all_zones_managed_pages() > 2. Make reset_node_managed_pages() non-static > 3. Call reset_node_managed_pages() in hotadd_new_pgdat() after pgdat is initialized > > Signed-off-by: Tang Chen > Signed-off-by: Yasuaki Ishimatsu > --- > include/linux/bootmem.h | 1 + > mm/bootmem.c | 9 +++++---- > mm/memory_hotplug.c | 9 +++++++++ > mm/nobootmem.c | 8 +++++--- > 4 files changed, 20 insertions(+), 7 deletions(-) > > diff --git a/include/linux/bootmem.h b/include/linux/bootmem.h > index 4e2bd4c..0995c2d 100644 > --- a/include/linux/bootmem.h > +++ b/include/linux/bootmem.h > @@ -46,6 +46,7 @@ extern unsigned long init_bootmem_node(pg_data_t *pgdat, > extern unsigned long init_bootmem(unsigned long addr, unsigned long memend); > > extern unsigned long free_all_bootmem(void); > +extern void reset_node_managed_pages(pg_data_t *pgdat); > extern void reset_all_zones_managed_pages(void); > > extern void free_bootmem_node(pg_data_t *pgdat, > diff --git a/mm/bootmem.c b/mm/bootmem.c > index 8a000ce..477be69 100644 > --- a/mm/bootmem.c > +++ b/mm/bootmem.c > @@ -243,13 +243,10 @@ static unsigned long __init free_all_bootmem_core(bootmem_data_t *bdata) > > static int reset_managed_pages_done __initdata; > > -static inline void __init reset_node_managed_pages(pg_data_t *pgdat) > +void reset_node_managed_pages(pg_data_t *pgdat) > { > struct zone *z; > > - if (reset_managed_pages_done) > - return; > - > for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++) > z->managed_pages = 0; > } > @@ -258,8 +255,12 @@ void __init reset_all_zones_managed_pages(void) > { > struct pglist_data *pgdat; > > + if (reset_managed_pages_done) > + return; > + > for_each_online_pgdat(pgdat) > reset_node_managed_pages(pgdat); > + > reset_managed_pages_done = 1; > } > > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > index 29d8693..3ab01b2 100644 > --- a/mm/memory_hotplug.c > +++ b/mm/memory_hotplug.c > @@ -31,6 +31,7 @@ > #include > #include > #include > +#include > > #include > > @@ -1096,6 +1097,14 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start) > build_all_zonelists(pgdat, NULL); > mutex_unlock(&zonelists_mutex); > > + /* > + * zone->managed_pages is set to an approximate value in > + * free_area_init_core(), which will cause > + * /sys/device/system/node/nodeX/meminfo has wrong data. > + * So reset it to 0 before any memory is onlined. > + */ > + reset_node_managed_pages(pgdat); > + I aggree with you, we should reset it before online pages. Thanks, Xishi Qiu > return pgdat; > } > > diff --git a/mm/nobootmem.c b/mm/nobootmem.c > index 7c7ab32..90b5046 100644 > --- a/mm/nobootmem.c > +++ b/mm/nobootmem.c > @@ -145,12 +145,10 @@ static unsigned long __init free_low_memory_core_early(void) > > static int reset_managed_pages_done __initdata; > > -static inline void __init reset_node_managed_pages(pg_data_t *pgdat) > +void reset_node_managed_pages(pg_data_t *pgdat) > { > struct zone *z; > > - if (reset_managed_pages_done) > - return; > for (z = pgdat->node_zones; z < pgdat->node_zones + MAX_NR_ZONES; z++) > z->managed_pages = 0; > } > @@ -159,8 +157,12 @@ void __init reset_all_zones_managed_pages(void) > { > struct pglist_data *pgdat; > > + if (reset_managed_pages_done) > + return; > + > for_each_online_pgdat(pgdat) > reset_node_managed_pages(pgdat); > + > reset_managed_pages_done = 1; > } > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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