Messages in this thread | | | From | KOSAKI Motohiro <> | Date | Fri, 12 Oct 2012 15:28:23 -0400 | Subject | Re: [PATCH 5/10] memory-hotplug : memory-hotplug: check page type in get_page_bootmem |
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On Thu, Oct 4, 2012 at 10:32 PM, Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> wrote: > The function get_page_bootmem() may be called more than one time to the same > page. There is no need to set page's type, private if the function is not > the first time called to the page. > > Note: the patch is just optimization and does not fix any problem. > > 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: Wen Congyang <wency@cn.fujitsu.com> > Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> > --- > mm/memory_hotplug.c | 15 +++++++++++---- > 1 file changed, 11 insertions(+), 4 deletions(-) > > Index: linux-3.6/mm/memory_hotplug.c > =================================================================== > --- linux-3.6.orig/mm/memory_hotplug.c 2012-10-04 18:29:58.284676075 +0900 > +++ linux-3.6/mm/memory_hotplug.c 2012-10-04 18:30:03.454680542 +0900 > @@ -95,10 +95,17 @@ static void release_memory_resource(stru > static void get_page_bootmem(unsigned long info, struct page *page, > unsigned long type) > { > - page->lru.next = (struct list_head *) type; > - SetPagePrivate(page); > - set_page_private(page, info); > - atomic_inc(&page->_count); > + unsigned long page_type; > + > + page_type = (unsigned long)page->lru.next;
If I understand correctly, page->lru.next might be uninitialized yet.
Moreover, I have no seen any good effect in this patch. I don't understand why we need to increase code complexity.
> + if (page_type < MEMORY_HOTPLUG_MIN_BOOTMEM_TYPE || > + page_type > MEMORY_HOTPLUG_MAX_BOOTMEM_TYPE){ > + page->lru.next = (struct list_head *)type; > + SetPagePrivate(page); > + set_page_private(page, info); > + atomic_inc(&page->_count); > + } else > + atomic_inc(&page->_count); > } > > /* reference to __meminit __free_pages_bootmem is valid > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
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