linux/mm/memory_hotplug.c, branch v2.6.34

mm: introduce dump_page() and print symbolic flag names

2010-03-12T23:52:28Z

- introduce dump_page() to print the page info for debugging some error condition. - convert three mm users: bad_page(), print_bad_pte() and memory offline failure. - print an extra field: the symbolic names of page->flags Example dump_page() output: [ 157.521694] page:ffffea0000a7cba8 count:2 mapcount:1 mapping:ffff88001c901791 index:0x147 [ 157.525570] page flags: 0x100000000100068(uptodate|lru|active|swapbacked) Signed-off-by: Wu Fengguang Cc: Ingo Molnar Cc: Alex Chiang Cc: Rik van Riel Cc: Andi Kleen Cc: Mel Gorman Cc: Christoph Lameter Cc: KOSAKI Motohiro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

memory-hotplug: create /sys/firmware/memmap entry for new memory

2010-03-06T19:26:25Z

A memmap is a directory in sysfs which includes 3 text files: start, end and type. For example: start: 0x100000 end: 0x7e7b1cff type: System RAM Interface firmware_map_add was not called explicitly. Remove it and add function firmware_map_add_hotplug as hotplug interface of memmap. Each memory entry has a memmap in sysfs, When we hot-add new memory, sysfs does not export memmap entry for it. We add a call in function add_memory to function firmware_map_add_hotplug. Add a new function add_sysfs_fw_map_entry() to create memmap entry, it will be called when initialize memmap and hot-add memory. [akpm@linux-foundation.org: un-kernedoc a no longer kerneldoc comment] Signed-off-by: Shaohui Zheng Acked-by: Andi Kleen Acked-by: Yasunori Goto Reviewed-by: Wu Fengguang Cc: Dave Hansen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: fix section mismatch in memory_hotplug.c

2009-12-15T16:53:20Z

__free_pages_bootmem() is a __meminit function - which has been called from put_pages_bootmem thus causes a section mismatch warning. We were warned by the following warning: LD mm/built-in.o WARNING: mm/built-in.o(.text+0x26b22): Section mismatch in reference from the function put_page_bootmem() to the function .meminit.text:__free_pages_bootmem() The function put_page_bootmem() references the function __meminit __free_pages_bootmem(). This is often because put_page_bootmem lacks a __meminit annotation or the annotation of __free_pages_bootmem is wrong. Signed-off-by: Rakib Mullick Cc: Yasunori Goto Cc: Badari Pulavarty Cc: Johannes Weiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: memory_hotplug: make offline_pages() static

2009-12-15T16:53:20Z

It has no references outside memory_hotplug.c. Cc: "Rafael J. Wysocki" Cc: Andi Kleen Cc: Gerald Schaefer Cc: KOSAKI Motohiro Cc: Yasunori Goto Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

ksm: memory hotremove migration only

2009-12-15T16:53:20Z

The previous patch enables page migration of ksm pages, but that soon gets into trouble: not surprising, since we're using the ksm page lock to lock operations on its stable_node, but page migration switches the page whose lock is to be used for that. Another layer of locking would fix it, but do we need that yet? Do we actually need page migration of ksm pages? Yes, memory hotremove needs to offline sections of memory: and since we stopped allocating ksm pages with GFP_HIGHUSER, they will tend to be GFP_HIGHUSER_MOVABLE candidates for migration. But KSM is currently unconscious of NUMA issues, happily merging pages from different NUMA nodes: at present the rule must be, not to use MADV_MERGEABLE where you care about NUMA. So no, NUMA page migration of ksm pages does not make sense yet. So, to complete support for ksm swapping we need to make hotremove safe. ksm_memory_callback() take ksm_thread_mutex when MEM_GOING_OFFLINE and release it when MEM_OFFLINE or MEM_CANCEL_OFFLINE. But if mapped pages are freed before migration reaches them, stable_nodes may be left still pointing to struct pages which have been removed from the system: the stable_node needs to identify a page by pfn rather than page pointer, then it can safely prune them when MEM_OFFLINE. And make NUMA migration skip PageKsm pages where it skips PageReserved. But it's only when we reach unmap_and_move() that the page lock is taken and we can be sure that raised pagecount has prevented a PageAnon from being upgraded: so add offlining arg to migrate_pages(), to migrate ksm page when offlining (has sufficient locking) but reject it otherwise. Signed-off-by: Hugh Dickins Cc: Izik Eidus Cc: Andrea Arcangeli Cc: Chris Wright Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: clear node in N_HIGH_MEMORY and stop kswapd when all memory is offlined

2009-12-15T16:53:13Z

When memory is hot-removed, its node must be cleared in N_HIGH_MEMORY if there are no present pages left. In such a situation, kswapd must also be stopped since it has nothing left to do. Signed-off-by: David Rientjes Signed-off-by: Lee Schermerhorn Cc: Christoph Lameter Cc: Yasunori Goto Cc: Mel Gorman Cc: Rafael J. Wysocki Cc: Rik van Riel Cc: KAMEZAWA Hiroyuki Cc: Lee Schermerhorn Cc: Mel Gorman Cc: Randy Dunlap Cc: Nishanth Aravamudan Cc: Andi Kleen Cc: David Rientjes Cc: Adam Litke Cc: Andy Whitcroft Cc: Eric Whitney Cc: Christoph Lameter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: move inc_zone_page_state(NR_ISOLATED) to just isolated place

2009-12-15T16:53:12Z

Christoph pointed out inc_zone_page_state(NR_ISOLATED) should be placed in right after isolate_page(). This patch does it. Reviewed-by: Christoph Lameter Signed-off-by: KOSAKI Motohiro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: allow memory hotplug and hibernation in the same kernel

2009-11-18T01:40:33Z

Allow memory hotplug and hibernation in the same kernel Memory hotplug and hibernation were exclusive in Kconfig. This is obviously a problem for distribution kernels who want to support both in the same image. After some discussions with Rafael and others the only problem is with parallel memory hotadd or removal while a hibernation operation is in process. It was also working for s390 before. This patch removes the Kconfig level exclusion, and simply makes the memory add / remove functions grab the pm_mutex to exclude against hibernation. Fixes a regression - old kernels didn't exclude memory hotadd and hibernation. Signed-off-by: Andi Kleen Cc: Gerald Schaefer Cc: KOSAKI Motohiro Cc: Yasunori Goto Acked-by: Rafael J. Wysocki Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/memory_hotplug: fix section mismatch

2009-11-18T01:40:33Z

With CONFIG_MEMORY_HOTPLUG I got following warning: WARNING: vmlinux.o(.text+0x1276b0): Section mismatch in reference from the function hotadd_new_pgdat() to the function .meminit.text:free_area_init_node() The function hotadd_new_pgdat() references the function __meminit free_area_init_node(). This is often because hotadd_new_pgdat lacks a __meminit annotation or the annotation of free_area_init_node is wrong. Use __ref to fix this. Signed-off-by: Hidetoshi Seto Cc: Minchan Kim Cc: Mel Gorman Cc: Yasunori Goto Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

walk system ram range

2009-09-23T14:39:41Z

Originally, walk_memory_resource() was introduced to traverse all memory of "System RAM" for detecting memory hotplug/unplug range. For doing so, flags of IORESOUCE_MEM|IORESOURCE_BUSY was used and this was enough for memory hotplug. But for using other purpose, /proc/kcore, this may includes some firmware area marked as IORESOURCE_BUSY | IORESOUCE_MEM. This patch makes the check strict to find out busy "System RAM". Note: PPC64 keeps their own walk_memory_resouce(), which walk through ppc64's lmb informaton. Because old kclist_add() is called per lmb, this patch makes no difference in behavior, finally. And this patch removes CONFIG_MEMORY_HOTPLUG check from this function. Because pfn_valid() just show "there is memmap or not* and cannot be used for "there is physical memory or not", this function is useful in generic to scan physical memory range. Signed-off-by: KAMEZAWA Hiroyuki Cc: Ralf Baechle Cc: Benjamin Herrenschmidt Cc: WANG Cong Cc: Américo Wang Cc: David Rientjes Cc: Roland Dreier Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds