lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Message-ID: <50DA68A8.4060001@jp.fujitsu.com> Date: Wed, 26 Dec 2012 12:02:00 +0900 From: Kamezawa Hiroyuki <kamezawa.hiroyu@...fujitsu.com> To: Tang Chen <tangchen@...fujitsu.com> CC: akpm@...ux-foundation.org, rientjes@...gle.com, liuj97@...il.com, len.brown@...el.com, benh@...nel.crashing.org, paulus@...ba.org, cl@...ux.com, minchan.kim@...il.com, kosaki.motohiro@...fujitsu.com, isimatu.yasuaki@...fujitsu.com, wujianguo@...wei.com, wency@...fujitsu.com, hpa@...or.com, linfeng@...fujitsu.com, laijs@...fujitsu.com, mgorman@...e.de, yinghai@...nel.org, x86@...nel.org, linux-mm@...ck.org, linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org, linux-acpi@...r.kernel.org, linux-s390@...r.kernel.org, linux-sh@...r.kernel.org, linux-ia64@...r.kernel.org, cmetcalf@...era.com, sparclinux@...r.kernel.org Subject: Re: [PATCH v5 01/14] memory-hotplug: try to offline the memory twice to avoid dependence (2012/12/24 21:09), Tang Chen wrote: > From: Wen Congyang <wency@...fujitsu.com> > > 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. > If memory8 is onlined as NORMAL memory ...right ? IIUC, vmalloc() uses __GFP_HIGHMEM but doesn't use __GFP_MOVABLE. > 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. > > Signed-off-by: Wen Congyang <wency@...fujitsu.com> I'm not sure but the whole DIMM should be onlined as MOVABLE mem ? Anyway, I agree this kind of retry is required if memory is onlined as NORMAL mem. But retry-once is ok ? Thanks, -Kame > --- > mm/memory_hotplug.c | 16 ++++++++++++++-- > 1 files changed, 14 insertions(+), 2 deletions(-) > > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > index d04ed87..62e04c9 100644 > --- a/mm/memory_hotplug.c > +++ b/mm/memory_hotplug.c > @@ -1388,10 +1388,13 @@ 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)) > @@ -1410,14 +1413,23 @@ 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 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists