From: Tang Chen <tangchen@cn.fujitsu.com>
To: Wen Congyang <wency@cn.fujitsu.com>
Cc: linux-s390@vger.kernel.org, linux-ia64@vger.kernel.org,
Len Brown <len.brown@intel.com>,
linux-acpi@vger.kernel.org, linux-sh@vger.kernel.org,
x86@kernel.org, linux-kernel@vger.kernel.org,
cmetcalf@tilera.com, Jianguo Wu <wujianguo@huawei.com>,
linux-mm@kvack.org,
Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>,
paulus@samba.org, Minchan Kim <minchan.kim@gmail.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
David Rientjes <rientjes@google.com>,
sparclinux@vger.kernel.org, Christoph Lameter <cl@linux.com>,
linuxppc-dev@lists.ozlabs.org,
Andrew Morton <akpm@linux-foundation.org>,
Jiang Liu <liuj97@gmail.com>
Subject: Re: [Patch v4 01/12] memory-hotplug: try to offline the memory twice to avoid dependence
Date: Tue, 04 Dec 2012 17:17:30 +0800 [thread overview]
Message-ID: <50BDBFAA.7040008@cn.fujitsu.com> (raw)
In-Reply-To: <1354010422-19648-2-git-send-email-wency@cn.fujitsu.com>
On 11/27/2012 06:00 PM, Wen Congyang wrote:
> memory can't be offlined when CONFIG_MEMCG is selected.
> For example: there is a memory device on node 1. The address range
> is [1G, 1.5G). You will find 4 new directories memory8, memory9, memory10,
> and memory11 under the directory /sys/devices/system/memory/.
>
> If CONFIG_MEMCG is selected, we will allocate memory to store page cgroup
> when we online pages. When we online memory8, the memory stored page cgroup
> is not provided by this memory device. But when we online memory9, the memory
> stored page cgroup may be provided by memory8. So we can't offline memory8
> now. We should offline the memory in the reversed order.
>
> When the memory device is hotremoved, we will auto offline memory provided
> by this memory device. But we don't know which memory is onlined first, so
> offlining memory may fail. In such case, iterate twice to offline the memory.
> 1st iterate: offline every non primary memory block.
> 2nd iterate: offline primary (i.e. first added) memory block.
>
> This idea is suggested by KOSAKI Motohiro.
>
> CC: David Rientjes<rientjes@google.com>
> CC: Jiang Liu<liuj97@gmail.com>
> CC: Len Brown<len.brown@intel.com>
> CC: Christoph Lameter<cl@linux.com>
> Cc: Minchan Kim<minchan.kim@gmail.com>
> CC: Andrew Morton<akpm@linux-foundation.org>
> CC: KOSAKI Motohiro<kosaki.motohiro@jp.fujitsu.com>
> CC: Yasuaki Ishimatsu<isimatu.yasuaki@jp.fujitsu.com>
> Signed-off-by: Wen Congyang<wency@cn.fujitsu.com>
Reviewed-by: Tang Chen <tangchen@cn.fujitsu.com>
> ---
> mm/memory_hotplug.c | 16 ++++++++++++++--
> 1 file changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index e4eeaca..b825dbc 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1012,10 +1012,13 @@ int remove_memory(u64 start, u64 size)
> unsigned long start_pfn, end_pfn;
> unsigned long pfn, section_nr;
> int ret;
> + int return_on_error = 0;
> + int retry = 0;
>
> start_pfn = PFN_DOWN(start);
> end_pfn = start_pfn + PFN_DOWN(size);
>
> +repeat:
> for (pfn = start_pfn; pfn< end_pfn; pfn += PAGES_PER_SECTION) {
> section_nr = pfn_to_section_nr(pfn);
> if (!present_section_nr(section_nr))
> @@ -1034,14 +1037,23 @@ int remove_memory(u64 start, u64 size)
>
> ret = offline_memory_block(mem);
> if (ret) {
> - kobject_put(&mem->dev.kobj);
> - return ret;
> + if (return_on_error) {
> + kobject_put(&mem->dev.kobj);
> + return ret;
> + } else {
> + retry = 1;
> + }
> }
> }
>
> if (mem)
> kobject_put(&mem->dev.kobj);
>
> + if (retry) {
> + return_on_error = 1;
> + goto repeat;
> + }
> +
> return 0;
> }
> #else
next prev parent reply other threads:[~2012-12-04 9:18 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-27 10:00 [Patch v4 00/12] memory-hotplug: hot-remove physical memory Wen Congyang
2012-11-27 10:00 ` [Patch v4 01/12] memory-hotplug: try to offline the memory twice to avoid dependence Wen Congyang
2012-12-04 9:17 ` Tang Chen [this message]
2012-11-27 10:00 ` [Patch v4 02/12] memory-hotplug: check whether all memory blocks are offlined or not when removing memory Wen Congyang
2012-12-04 9:22 ` Tang Chen
2012-11-27 10:00 ` [Patch v4 03/12] memory-hotplug: remove redundant codes Wen Congyang
2012-12-04 9:22 ` Tang Chen
2012-12-04 10:31 ` Tang Chen
2012-11-27 10:00 ` [Patch v4 04/12] memory-hotplug: remove /sys/firmware/memmap/X sysfs Wen Congyang
2012-11-27 10:00 ` [Patch v4 05/12] memory-hotplug: introduce new function arch_remove_memory() for removing page table depends on architecture Wen Congyang
2012-12-04 9:30 ` Tang Chen
2012-11-27 10:00 ` [Patch v4 06/12] memory-hotplug: unregister memory section on SPARSEMEM_VMEMMAP Wen Congyang
2012-12-04 9:34 ` Tang Chen
2012-11-27 10:00 ` [Patch v4 07/12] memory-hotplug: implement register_page_bootmem_info_section of sparse-vmemmap Wen Congyang
2012-11-27 10:00 ` [Patch v4 08/12] memory-hotplug: remove memmap " Wen Congyang
2012-11-28 9:40 ` Jianguo Wu
2012-11-30 1:45 ` Wen Congyang
2012-11-30 2:47 ` Jianguo Wu
2012-11-30 2:55 ` Yasuaki Ishimatsu
2012-12-03 2:23 ` Jianguo Wu
2012-12-04 9:13 ` Tang Chen
2012-12-04 12:20 ` Jianguo Wu
2012-12-05 2:07 ` Tang Chen
2012-12-05 3:23 ` Jianguo Wu
2012-12-07 1:42 ` Tang Chen
2012-12-07 2:20 ` Jianguo Wu
2012-12-04 9:47 ` Tang Chen
2012-11-27 10:00 ` [Patch v4 09/12] memory-hotplug: remove page table of x86_64 architecture Wen Congyang
2012-12-07 6:43 ` Tang Chen
2012-12-07 7:06 ` Jianguo Wu
2012-11-27 10:00 ` [Patch v4 10/12] memory-hotplug: memory_hotplug: clear zone when removing the memory Wen Congyang
2012-12-04 10:09 ` Tang Chen
2012-11-27 10:00 ` [Patch v4 11/12] memory-hotplug: remove sysfs file of node Wen Congyang
2012-12-04 10:10 ` Tang Chen
2012-11-27 10:00 ` [Patch v4 12/12] memory-hotplug: free node_data when a node is offlined Wen Congyang
2012-12-04 10:10 ` Tang Chen
2012-11-27 19:27 ` [Patch v4 00/12] memory-hotplug: hot-remove physical memory Andrew Morton
2012-11-27 19:38 ` Rafael J. Wysocki
2012-11-28 0:43 ` Yasuaki Ishimatsu
2012-11-30 6:37 ` Tang Chen
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