kernel/linux.git/include/linux/memory_hotplug.h, branch v2.6.28

memory-hotplug: add sysfs removable attribute for hotplug memory remove

2008-07-24T17:47:21+00:00

Memory may be hot-removed on a per-memory-block basis, particularly on POWER where the SPARSEMEM section size often matches the memory-block size. A user-level agent must be able to identify which sections of memory are likely to be removable before attempting the potentially expensive operation. This patch adds a file called "removable" to the memory directory in sysfs to help such an agent. In this patch, a memory block is considered removable if; o It contains only MOVABLE pageblocks o It contains only pageblocks with free pages regardless of pageblock type On the other hand, a memory block starting with a PageReserved() page will never be considered removable. Without this patch, the user-agent is forced to choose a memory block to remove randomly. Sample output of the sysfs files: ./memory/memory0/removable: 0 ./memory/memory1/removable: 0 ./memory/memory2/removable: 0 ./memory/memory3/removable: 0 ./memory/memory4/removable: 0 ./memory/memory5/removable: 0 ./memory/memory6/removable: 0 ./memory/memory7/removable: 1 ./memory/memory8/removable: 0 ./memory/memory9/removable: 0 ./memory/memory10/removable: 0 ./memory/memory11/removable: 0 ./memory/memory12/removable: 0 ./memory/memory13/removable: 0 ./memory/memory14/removable: 0 ./memory/memory15/removable: 0 ./memory/memory16/removable: 0 ./memory/memory17/removable: 1 ./memory/memory18/removable: 1 ./memory/memory19/removable: 1 ./memory/memory20/removable: 1 ./memory/memory21/removable: 1 ./memory/memory22/removable: 1 Signed-off-by: Badari Pulavarty Signed-off-by: Mel Gorman Acked-by: KAMEZAWA Hiroyuki Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

memory hotplug: small fixes to bootmem freeing for memory hotremove

2008-07-24T17:47:21+00:00

- Change some naming * Magic -> types * MIX_INFO -> MIX_SECTION_INFO * Change definition of bootmem type from direct hex value - __free_pages_bootmem() becomes __meminit. Signed-off-by: Yasunori Goto Cc: Andy Whitcroft Cc: Badari Pulavarty Cc: Yinghai Lu Cc: Johannes Weiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[POWERPC] Make walk_memory_resource available with MEMORY_HOTPLUG=n

2008-06-09T01:32:41+00:00

The ehea driver was recently changed[1] to use walk_memory_resource() to detect the system's memory layout. However, walk_memory_resource() is available only when memory hotplug is enabled. So CONFIG_EHEA was made to depend on MEMORY_HOTPLUG [2], but it is inappropriate for a network driver to have such a dependency. Make the declaration of walk_memory_resource() and its powerpc implementation (ehea is powerpc-specific) unconditionally available. [1] 48cfb14f8b89d4d5b3df6c16f08b258686fb12ad "ehea: Add DLPAR memory remove support" [2] fb7b6ca2b6b7c23b52be143bdd5f55a23b9780c8 "ehea: Add dependency to Kconfig" Signed-off-by: Nathan Lynch Acked-by: Badari Pulavarty Signed-off-by: Paul Mackerras

memory hotplug: register section/node id to free

2008-04-28T15:58:25+00:00

This patch set is to free pages which is allocated by bootmem for memory-hotremove. Some structures of memory management are allocated by bootmem. ex) memmap, etc. To remove memory physically, some of them must be freed according to circumstance. This patch set makes basis to free those pages, and free memmaps. Basic my idea is using remain members of struct page to remember information of users of bootmem (section number or node id). When the section is removing, kernel can confirm it. By this information, some issues can be solved. 1) When the memmap of removing section is allocated on other section by bootmem, it should/can be free. 2) When the memmap of removing section is allocated on the same section, it shouldn't be freed. Because the section has to be logical memory offlined already and all pages must be isolated against page allocater. If it is freed, page allocator may use it which will be removed physically soon. 3) When removing section has other section's memmap, kernel will be able to show easily which section should be removed before it for user. (Not implemented yet) 4) When the above case 2), the page isolation will be able to check and skip memmap's page when logical memory offline (offline_pages()). Current page isolation code fails in this case because this page is just reserved page and it can't distinguish this pages can be removed or not. But, it will be able to do by this patch. (Not implemented yet.) 5) The node information like pgdat has similar issues. But, this will be able to be solved too by this. (Not implemented yet, but, remembering node id in the pages.) Fortunately, current bootmem allocator just keeps PageReserved flags, and doesn't use any other members of page struct. The users of bootmem doesn't use them too. This patch: This is to register information which is node or section's id. Kernel can distinguish which node/section uses the pages allcated by bootmem. This is basis for hot-remove sections or nodes. Signed-off-by: Yasunori Goto Cc: Badari Pulavarty Cc: Yinghai Lu Cc: Yasunori Goto Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

hotplug memory remove: generic __remove_pages() support

2008-04-28T15:58:17+00:00

Generic helper function to remove section mappings and sysfs entries for the section of the memory we are removing. offline_pages() correctly adjusted zone and marked the pages reserved. TODO: Yasunori Goto is working on patches to free up allocations from bootmem. Signed-off-by: Badari Pulavarty Acked-by: Yasunori Goto Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

fix memory hot remove not configured case.

2007-10-16T16:43:02+00:00

Now, arch dependent code around CONFIG_MEMORY_HOTREMOVE is a mess. This patch cleans up them. This is against 2.6.23-rc6-mm1. - fix compile failure on ia64/ CONFIG_MEMORY_HOTPLUG && !CONFIG_MEMORY_HOTREMOVE case. - For !CONFIG_MEMORY_HOTREMOVE, add generic no-op remove_memory(), which returns -EINVAL. - removed remove_pages() only used in powerpc. - removed no-op remove_memory() in i386, sh, sparc64, x86_64. - only powerpc returns -ENOSYS at memory hot remove(no-op). changes it to return -EINVAL. Note: Currently, only ia64 supports CONFIG_MEMORY_HOTREMOVE. I welcome other archs if there are requirements and testers. Signed-off-by: KAMEZAWA Hiroyuki Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

memory unplug: page offline

2007-10-16T16:43:02+00:00

Logic. - set all pages in [start,end) as isolated migration-type. by this, all free pages in the range will be not-for-use. - Migrate all LRU pages in the range. - Test all pages in the range's refcnt is zero or not. Todo: - allocate migration destination page from better area. - confirm page_count(page)== 0 && PageReserved(page) page is safe to be freed.. (I don't like this kind of page but.. - Find out pages which cannot be migrated. - more running tests. - Use reclaim for unplugging other memory type area. Signed-off-by: KAMEZAWA Hiroyuki Signed-off-by: Yasunori Goto Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

memory unplug: memory hotplug cleanup

2007-10-16T16:43:01+00:00

A clean up patch for "scanning memory resource [start, end)" operation. Now, find_next_system_ram() function is used in memory hotplug, but this interface is not easy to use and codes are complicated. This patch adds walk_memory_resouce(start,len,arg,func) function. The function 'func' is called per valid memory resouce range in [start,pfn). [pbadari@us.ibm.com: Error handling in walk_memory_resource()] Signed-off-by: KAMEZAWA Hiroyuki Signed-off-by: Badari Pulavarty Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Clean up duplicate includes in include/linux/memory_hotplug.h

2007-10-16T16:42:52+00:00

This patch cleans up duplicate includes in include/linux/memory_hotplug.h Signed-off-by: Jesper Juhl Acked-by: Yasunori Goto Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] hot-add-mem x86_64: fixup externs

2006-10-01T07:39:18+00:00

Fix up externs in memory_hotplug.c. Cleanup. Signed-off-by: Keith Mannthey Cc: KAMEZAWA Hiroyuki Cc: Andi Kleen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds