| Message ID | 1356350964-13437-3-git-send-email-tangchen@cn.fujitsu.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
(2012/12/24 21:09), Tang Chen wrote: > From: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> > > We remove the memory like this: > 1. lock memory hotplug > 2. offline a memory block > 3. unlock memory hotplug > 4. repeat 1-3 to offline all memory blocks > 5. lock memory hotplug > 6. remove memory(TODO) > 7. unlock memory hotplug > > All memory blocks must be offlined before removing memory. But we don't hold > the lock in the whole operation. So we should check whether all memory blocks > are offlined before step6. Otherwise, kernel maybe panicked. > > Signed-off-by: Wen Congyang <wency@cn.fujitsu.com> > Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> a nitpick below. > --- > drivers/base/memory.c | 6 +++++ > include/linux/memory_hotplug.h | 1 + > mm/memory_hotplug.c | 47 ++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 54 insertions(+), 0 deletions(-) > > diff --git a/drivers/base/memory.c b/drivers/base/memory.c > index 987604d..8300a18 100644 > --- a/drivers/base/memory.c > +++ b/drivers/base/memory.c > @@ -693,6 +693,12 @@ int offline_memory_block(struct memory_block *mem) > return ret; > } > > +/* return true if the memory block is offlined, otherwise, return false */ > +bool is_memblock_offlined(struct memory_block *mem) > +{ > + return mem->state == MEM_OFFLINE; > +} > + > /* > * Initialize the sysfs support for memory devices... > */ > diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h > index 4a45c4e..8dd0950 100644 > --- a/include/linux/memory_hotplug.h > +++ b/include/linux/memory_hotplug.h > @@ -247,6 +247,7 @@ extern int add_memory(int nid, u64 start, u64 size); > extern int arch_add_memory(int nid, u64 start, u64 size); > extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages); > extern int offline_memory_block(struct memory_block *mem); > +extern bool is_memblock_offlined(struct memory_block *mem); > extern int remove_memory(u64 start, u64 size); > extern int sparse_add_one_section(struct zone *zone, unsigned long start_pfn, > int nr_pages); > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c > index 62e04c9..d43d97b 100644 > --- a/mm/memory_hotplug.c > +++ b/mm/memory_hotplug.c > @@ -1430,6 +1430,53 @@ repeat: > goto repeat; > } > > + lock_memory_hotplug(); > + > + /* > + * we have offlined all memory blocks like this: > + * 1. lock memory hotplug > + * 2. offline a memory block > + * 3. unlock memory hotplug > + * > + * repeat step1-3 to offline the memory block. All memory blocks > + * must be offlined before removing memory. But we don't hold the > + * lock in the whole operation. So we should check whether all > + * memory blocks are offlined. > + */ > + > + for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { I prefer adding mem = NULL at the start of this for(). > + section_nr = pfn_to_section_nr(pfn); > + if (!present_section_nr(section_nr)) > + continue; > + > + section = __nr_to_section(section_nr); > + /* same memblock? */ > + if (mem) > + if ((section_nr >= mem->start_section_nr) && > + (section_nr <= mem->end_section_nr)) > + continue; > + Thanks, -Kame
On 12/26/2012 11:10 AM, Kamezawa Hiroyuki wrote: > (2012/12/24 21:09), Tang Chen wrote: >> From: Yasuaki Ishimatsu<isimatu.yasuaki@jp.fujitsu.com> >> >> We remove the memory like this: >> 1. lock memory hotplug >> 2. offline a memory block >> 3. unlock memory hotplug >> 4. repeat 1-3 to offline all memory blocks >> 5. lock memory hotplug >> 6. remove memory(TODO) >> 7. unlock memory hotplug >> >> All memory blocks must be offlined before removing memory. But we don't hold >> the lock in the whole operation. So we should check whether all memory blocks >> are offlined before step6. Otherwise, kernel maybe panicked. >> >> Signed-off-by: Wen Congyang<wency@cn.fujitsu.com> >> Signed-off-by: Yasuaki Ishimatsu<isimatu.yasuaki@jp.fujitsu.com> > > Acked-by: KAMEZAWA Hiroyuki<kamezawa.hiroyu@jp.fujitsu.com> > > a nitpick below. > >> + >> + for (pfn = start_pfn; pfn< end_pfn; pfn += PAGES_PER_SECTION) { > > I prefer adding mem = NULL at the start of this for(). Hi Kamezawa-san, Added, thanks. :) > >> + section_nr = pfn_to_section_nr(pfn); >> + if (!present_section_nr(section_nr)) >> + continue; >> + >> + section = __nr_to_section(section_nr); >> + /* same memblock? */ >> + if (mem) >> + if ((section_nr>= mem->start_section_nr)&& >> + (section_nr<= mem->end_section_nr)) >> + continue; >> + > > Thanks, > -Kame > > >
diff --git a/drivers/base/memory.c b/drivers/base/memory.c index 987604d..8300a18 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -693,6 +693,12 @@ int offline_memory_block(struct memory_block *mem) return ret; } +/* return true if the memory block is offlined, otherwise, return false */ +bool is_memblock_offlined(struct memory_block *mem) +{ + return mem->state == MEM_OFFLINE; +} + /* * Initialize the sysfs support for memory devices... */ diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h index 4a45c4e..8dd0950 100644 --- a/include/linux/memory_hotplug.h +++ b/include/linux/memory_hotplug.h @@ -247,6 +247,7 @@ extern int add_memory(int nid, u64 start, u64 size); extern int arch_add_memory(int nid, u64 start, u64 size); extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages); extern int offline_memory_block(struct memory_block *mem); +extern bool is_memblock_offlined(struct memory_block *mem); extern int remove_memory(u64 start, u64 size); extern int sparse_add_one_section(struct zone *zone, unsigned long start_pfn, int nr_pages); diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 62e04c9..d43d97b 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1430,6 +1430,53 @@ repeat: goto repeat; } + lock_memory_hotplug(); + + /* + * we have offlined all memory blocks like this: + * 1. lock memory hotplug + * 2. offline a memory block + * 3. unlock memory hotplug + * + * repeat step1-3 to offline the memory block. All memory blocks + * must be offlined before removing memory. But we don't hold the + * lock in the whole operation. So we should check whether all + * memory blocks are offlined. + */ + + for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) { + section_nr = pfn_to_section_nr(pfn); + if (!present_section_nr(section_nr)) + continue; + + section = __nr_to_section(section_nr); + /* same memblock? */ + if (mem) + if ((section_nr >= mem->start_section_nr) && + (section_nr <= mem->end_section_nr)) + continue; + + mem = find_memory_block_hinted(section, mem); + if (!mem) + continue; + + ret = is_memblock_offlined(mem); + if (!ret) { + pr_warn("removing memory fails, because memory " + "[%#010llx-%#010llx] is onlined\n", + PFN_PHYS(section_nr_to_pfn(mem->start_section_nr)), + PFN_PHYS(section_nr_to_pfn(mem->end_section_nr + 1)) - 1); + + kobject_put(&mem->dev.kobj); + unlock_memory_hotplug(); + return ret; + } + } + + if (mem) + kobject_put(&mem->dev.kobj); + unlock_memory_hotplug(); + return 0; } #else