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path: root/include/linux/mmzone.h
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* memcg: allocate all page_cgroup at bootKAMEZAWA Hiroyuki2008-10-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Allocate all page_cgroup at boot and remove page_cgroup poitner from struct page. This patch adds an interface as struct page_cgroup *lookup_page_cgroup(struct page*) All FLATMEM/DISCONTIGMEM/SPARSEMEM and MEMORY_HOTPLUG is supported. Remove page_cgroup pointer reduces the amount of memory by - 4 bytes per PAGE_SIZE. - 8 bytes per PAGE_SIZE if memory controller is disabled. (even if configured.) On usual 8GB x86-32 server, this saves 8MB of NORMAL_ZONE memory. On my x86-64 server with 48GB of memory, this saves 96MB of memory. I think this reduction makes sense. By pre-allocation, kmalloc/kfree in charge/uncharge are removed. This means - we're not necessary to be afraid of kmalloc faiulre. (this can happen because of gfp_mask type.) - we can avoid calling kmalloc/kfree. - we can avoid allocating tons of small objects which can be fragmented. - we can know what amount of memory will be used for this extra-lru handling. I added printk message as "allocated %ld bytes of page_cgroup" "please try cgroup_disable=memory option if you don't want" maybe enough informative for users. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* vmstat: mlocked pages statisticsNick Piggin2008-10-20
| | | | | | | | | | | | | | | | | Add NR_MLOCK zone page state, which provides a (conservative) count of mlocked pages (actually, the number of mlocked pages moved off the LRU). Reworked by lts to fit in with the modified mlock page support in the Reclaim Scalability series. [kosaki.motohiro@jp.fujitsu.com: fix incorrect Mlocked field of /proc/meminfo] [lee.schermerhorn@hp.com: mlocked-pages: add event counting with statistics] Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Unevictable LRU InfrastructureLee Schermerhorn2008-10-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When the system contains lots of mlocked or otherwise unevictable pages, the pageout code (kswapd) can spend lots of time scanning over these pages. Worse still, the presence of lots of unevictable pages can confuse kswapd into thinking that more aggressive pageout modes are required, resulting in all kinds of bad behaviour. Infrastructure to manage pages excluded from reclaim--i.e., hidden from vmscan. Based on a patch by Larry Woodman of Red Hat. Reworked to maintain "unevictable" pages on a separate per-zone LRU list, to "hide" them from vmscan. Kosaki Motohiro added the support for the memory controller unevictable lru list. Pages on the unevictable list have both PG_unevictable and PG_lru set. Thus, PG_unevictable is analogous to and mutually exclusive with PG_active--it specifies which LRU list the page is on. The unevictable infrastructure is enabled by a new mm Kconfig option [CONFIG_]UNEVICTABLE_LRU. A new function 'page_evictable(page, vma)' in vmscan.c tests whether or not a page may be evictable. Subsequent patches will add the various !evictable tests. We'll want to keep these tests light-weight for use in shrink_active_list() and, possibly, the fault path. To avoid races between tasks putting pages [back] onto an LRU list and tasks that might be moving the page from non-evictable to evictable state, the new function 'putback_lru_page()' -- inverse to 'isolate_lru_page()' -- tests the "evictability" of a page after placing it on the LRU, before dropping the reference. If the page has become unevictable, putback_lru_page() will redo the 'putback', thus moving the page to the unevictable list. This way, we avoid "stranding" evictable pages on the unevictable list. [akpm@linux-foundation.org: fix fallout from out-of-order merge] [riel@redhat.com: fix UNEVICTABLE_LRU and !PROC_PAGE_MONITOR build] [nishimura@mxp.nes.nec.co.jp: remove redundant mapping check] [kosaki.motohiro@jp.fujitsu.com: unevictable-lru-infrastructure: putback_lru_page()/unevictable page handling rework] [kosaki.motohiro@jp.fujitsu.com: kill unnecessary lock_page() in vmscan.c] [kosaki.motohiro@jp.fujitsu.com: revert migration change of unevictable lru infrastructure] [kosaki.motohiro@jp.fujitsu.com: revert to unevictable-lru-infrastructure-kconfig-fix.patch] [kosaki.motohiro@jp.fujitsu.com: restore patch failure of vmstat-unevictable-and-mlocked-pages-vm-events.patch] Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Debugged-by: Benjamin Kidwell <benjkidwell@yahoo.com> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* vmscan: second chance replacement for anonymous pagesRik van Riel2008-10-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We avoid evicting and scanning anonymous pages for the most part, but under some workloads we can end up with most of memory filled with anonymous pages. At that point, we suddenly need to clear the referenced bits on all of memory, which can take ages on very large memory systems. We can reduce the maximum number of pages that need to be scanned by not taking the referenced state into account when deactivating an anonymous page. After all, every anonymous page starts out referenced, so why check? If an anonymous page gets referenced again before it reaches the end of the inactive list, we move it back to the active list. To keep the maximum amount of necessary work reasonable, we scale the active to inactive ratio with the size of memory, using the formula active:inactive ratio = sqrt(memory in GB * 10). Kswapd CPU use now seems to scale by the amount of pageout bandwidth, instead of by the amount of memory present in the system. [kamezawa.hiroyu@jp.fujitsu.com: fix OOM with memcg] [kamezawa.hiroyu@jp.fujitsu.com: memcg: lru scan fix] Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* vmscan: split LRU lists into anon & file setsRik van Riel2008-10-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Split the LRU lists in two, one set for pages that are backed by real file systems ("file") and one for pages that are backed by memory and swap ("anon"). The latter includes tmpfs. The advantage of doing this is that the VM will not have to scan over lots of anonymous pages (which we generally do not want to swap out), just to find the page cache pages that it should evict. This patch has the infrastructure and a basic policy to balance how much we scan the anon lists and how much we scan the file lists. The big policy changes are in separate patches. [lee.schermerhorn@hp.com: collect lru meminfo statistics from correct offset] [kosaki.motohiro@jp.fujitsu.com: prevent incorrect oom under split_lru] [kosaki.motohiro@jp.fujitsu.com: fix pagevec_move_tail() doesn't treat unevictable page] [hugh@veritas.com: memcg swapbacked pages active] [hugh@veritas.com: splitlru: BDI_CAP_SWAP_BACKED] [akpm@linux-foundation.org: fix /proc/vmstat units] [nishimura@mxp.nes.nec.co.jp: memcg: fix handling of shmem migration] [kosaki.motohiro@jp.fujitsu.com: adjust Quicklists field of /proc/meminfo] [kosaki.motohiro@jp.fujitsu.com: fix style issue of get_scan_ratio()] Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* vmscan: Use an indexed array for LRU variablesChristoph Lameter2008-10-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently we are defining explicit variables for the inactive and active list. An indexed array can be more generic and avoid repeating similar code in several places in the reclaim code. We are saving a few bytes in terms of code size: Before: text data bss dec hex filename 4097753 573120 4092484 8763357 85b7dd vmlinux After: text data bss dec hex filename 4097729 573120 4092484 8763333 85b7c5 vmlinux Having an easy way to add new lru lists may ease future work on the reclaim code. Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Christoph Lameter <cl@linux-foundation.org> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: mark the correct zone as full when scanning zonelistsMel Gorman2008-09-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The iterator for_each_zone_zonelist() uses a struct zoneref *z cursor when scanning zonelists to keep track of where in the zonelist it is. The zoneref that is returned corresponds to the the next zone that is to be scanned, not the current one. It was intended to be treated as an opaque list. When the page allocator is scanning a zonelist, it marks elements in the zonelist corresponding to zones that are temporarily full. As the zonelist is being updated, it uses the cursor here; if (NUMA_BUILD) zlc_mark_zone_full(zonelist, z); This is intended to prevent rescanning in the near future but the zoneref cursor does not correspond to the zone that has been found to be full. This is an easy misunderstanding to make so this patch corrects the problem by changing zoneref cursor to be the current zone being scanned instead of the next one. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Cc: Andy Whitcroft <apw@shadowen.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: <stable@kernel.org> [2.6.26.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* for_each_online_pgdat(): kerneldoc fixFernando Luis Vazquez Cao2008-05-24
| | | | | | | | | for_each_pgdat() was renamed to for_each_online_pgdat() and kerneldoc comments should be updated accordingly. Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Remove "#ifdef __KERNEL__" checks from unexported headersRobert P. J. Day2008-04-30
| | | | | | | | | | | | Remove the "#ifdef __KERNEL__" tests from unexported header files in linux/include whose entire contents are wrapped in that preprocessor test. Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: Add NR_WRITEBACK_TEMP counterMiklos Szeredi2008-04-30
| | | | | | | | | | | | | | | | | | | | Fuse will use temporary buffers to write back dirty data from memory mappings (normal writes are done synchronously). This is needed, because there cannot be any guarantee about the time in which a write will complete. By using temporary buffers, from the MM's point if view the page is written back immediately. If the writeout was due to memory pressure, this effectively migrates data from a full zone to a less full zone. This patch adds a new counter (NR_WRITEBACK_TEMP) for the number of pages used as temporary buffers. [Lee.Schermerhorn@hp.com: add vmstat_text for NR_WRITEBACK_TEMP] Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memory hotplug: register section/node id to freeYasunori Goto2008-04-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <y-goto@jp.fujitsu.com> Cc: Badari Pulavarty <pbadari@us.ibm.com> Cc: Yinghai Lu <yhlu.kernel@gmail.com> Cc: Yasunori Goto <y-goto@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: Get rid of __ZONE_COUNTChristoph Lameter2008-04-28
| | | | | | | | | | It was used to compensate because MAX_NR_ZONES was not available to the #ifdefs. Export MAX_NR_ZONES via the new mechanism and get rid of __ZONE_COUNT. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pageflags: get rid of FLAGS_RESERVEDChristoph Lameter2008-04-28
| | | | | | | | | | | | | | | | | | | | | | NR_PAGEFLAGS specifies the number of page flags we are using. From that we can calculate the number of bits leftover that can be used for zone, node (and maybe the sections id). There is no need anymore for FLAGS_RESERVED if we use NR_PAGEFLAGS. Use the new methods to make NR_PAGEFLAGS available via the preprocessor. NR_PAGEFLAGS is used to calculate field boundaries in the page flags fields. These field widths have to be available to the preprocessor. Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: David Miller <davem@davemloft.net> Cc: Andy Whitcroft <apw@shadowen.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: make early_pfn_to_nid() a C functionAndrew Morton2008-04-28
| | | | | | | | | | | | | | | | | | | | | Fix this (sparc64) mm/sparse-vmemmap.c: In function `vmemmap_verify': mm/sparse-vmemmap.c:64: warning: unused variable `pfn' by switching to a C function which touches its arg. (reason 3,555 why macros are bad) Also, the `nid' arg was misnamed. Reviewed-by: Christoph Lameter <clameter@sgi.com> Acked-by: Andy Whitcroft <apw@shadowen.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Andi Kleen <ak@suse.de> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: filter based on a nodemask as well as a gfp_maskMel Gorman2008-04-28
| | | | | | | | | | | | | | | | | | | | | | | | | | The MPOL_BIND policy creates a zonelist that is used for allocations controlled by that mempolicy. As the per-node zonelist is already being filtered based on a zone id, this patch adds a version of __alloc_pages() that takes a nodemask for further filtering. This eliminates the need for MPOL_BIND to create a custom zonelist. A positive benefit of this is that allocations using MPOL_BIND now use the local node's distance-ordered zonelist instead of a custom node-id-ordered zonelist. I.e., pages will be allocated from the closest allowed node with available memory. [Lee.Schermerhorn@hp.com: Mempolicy: update stale documentation and comments] [Lee.Schermerhorn@hp.com: Mempolicy: make dequeue_huge_page_vma() obey MPOL_BIND nodemask] [Lee.Schermerhorn@hp.com: Mempolicy: make dequeue_huge_page_vma() obey MPOL_BIND nodemask rework] Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Hugh Dickins <hugh@veritas.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: have zonelist contains structs with both a zone pointer and zone_idxMel Gorman2008-04-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Filtering zonelists requires very frequent use of zone_idx(). This is costly as it involves a lookup of another structure and a substraction operation. As the zone_idx is often required, it should be quickly accessible. The node idx could also be stored here if it was found that accessing zone->node is significant which may be the case on workloads where nodemasks are heavily used. This patch introduces a struct zoneref to store a zone pointer and a zone index. The zonelist then consists of an array of these struct zonerefs which are looked up as necessary. Helpers are given for accessing the zone index as well as the node index. [kamezawa.hiroyu@jp.fujitsu.com: Suggested struct zoneref instead of embedding information in pointers] [hugh@veritas.com: mm-have-zonelist: fix memcg ooms] [hugh@veritas.com: just return do_try_to_free_pages] [hugh@veritas.com: do_try_to_free_pages gfp_mask redundant] Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Christoph Lameter <clameter@sgi.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Christoph Lameter <clameter@sgi.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: use two zonelist that are filtered by GFP maskMel Gorman2008-04-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | Currently a node has two sets of zonelists, one for each zone type in the system and a second set for GFP_THISNODE allocations. Based on the zones allowed by a gfp mask, one of these zonelists is selected. All of these zonelists consume memory and occupy cache lines. This patch replaces the multiple zonelists per-node with two zonelists. The first contains all populated zones in the system, ordered by distance, for fallback allocations when the target/preferred node has no free pages. The second contains all populated zones in the node suitable for GFP_THISNODE allocations. An iterator macro is introduced called for_each_zone_zonelist() that interates through each zone allowed by the GFP flags in the selected zonelist. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Christoph Lameter <clameter@sgi.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* remove sparse warning for mmzone.hHarvey Harrison2008-04-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | include/linux/mmzone.h:640:22: warning: potentially expensive pointer subtraction Calculate the offset into the node_zones array rather than the index using casts to (char *) and comparing against the index * sizeof(struct zone). On X86_32 this saves a sar, but code size increases by one byte per is_highmem() use due to 32-bit cmps rather than 16 bit cmps. Before: 207: 2b 80 8c 07 00 00 sub 0x78c(%eax),%eax 20d: c1 f8 0b sar $0xb,%eax 210: 83 f8 02 cmp $0x2,%eax 213: 74 16 je 22b <kmap_atomic_prot+0x144> 215: 83 f8 03 cmp $0x3,%eax 218: 0f 85 8f 00 00 00 jne 2ad <kmap_atomic_prot+0x1c6> 21e: 83 3d 00 00 00 00 02 cmpl $0x2,0x0 225: 0f 85 82 00 00 00 jne 2ad <kmap_atomic_prot+0x1c6> 22b: 64 a1 00 00 00 00 mov %fs:0x0,%eax After: 207: 2b 80 8c 07 00 00 sub 0x78c(%eax),%eax 20d: 3d 00 10 00 00 cmp $0x1000,%eax 212: 74 18 je 22c <kmap_atomic_prot+0x145> 214: 3d 00 18 00 00 cmp $0x1800,%eax 219: 0f 85 8f 00 00 00 jne 2ae <kmap_atomic_prot+0x1c7> 21f: 83 3d 00 00 00 00 02 cmpl $0x2,0x0 226: 0f 85 82 00 00 00 jne 2ae <kmap_atomic_prot+0x1c7> 22c: 64 a1 00 00 00 00 mov %fs:0x0,%eax [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Remove unused MAX_NODES_SHIFTJohannes Weiner2008-04-21
| | | | | | | MAX_NODES_SHIFT is not referenced anywhere in the tree, so dump it. Signed-off-by: Johannes Weiner <hannes@saeurebad.de> Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
* Page allocator: get rid of the list of cold pagesChristoph Lameter2008-02-05
| | | | | | | | | | | | | | | | | We have repeatedly discussed if the cold pages still have a point. There is one way to join the two lists: Use a single list and put the cold pages at the end and the hot pages at the beginning. That way a single list can serve for both types of allocations. The discussion of the RFC for this and Mel's measurements indicate that there may not be too much of a point left to having separate lists for hot and cold pages (see http://marc.info/?t=119492914200001&r=1&w=2). Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Martin Bligh <mbligh@mbligh.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: test and set zone reclaim lock before starting reclaimDavid Rientjes2007-10-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | Introduces new zone flag interface for testing and setting flags: int zone_test_and_set_flag(struct zone *zone, zone_flags_t flag) Instead of setting and clearing ZONE_RECLAIM_LOCKED each time shrink_zone() is called, this flag is test and set before starting zone reclaim. Zone reclaim starts in __alloc_pages() when a zone's watermark fails and the system is in zone_reclaim_mode. If it's already in reclaim, there's no need to start again so it is simply considered full for that allocation attempt. There is a change of behavior with regard to concurrent zone shrinking. It is now possible for try_to_free_pages() or kswapd to already be shrinking a particular zone when __alloc_pages() starts zone reclaim. In this case, it is possible for two concurrent threads to invoke shrink_zone() for a single zone. This change forbids a zone to be in zone reclaim twice, which was always the behavior, but allows for concurrent try_to_free_pages() or kswapd shrinking when starting zone reclaim. Cc: Andrea Arcangeli <andrea@suse.de> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* oom: add per-zone lockingDavid Rientjes2007-10-17
| | | | | | | | | | | | | | | | | | | | | | | | OOM killer synchronization should be done with zone granularity so that memory policy and cpuset allocations may have their corresponding zones locked and allow parallel kills for other OOM conditions that may exist elsewhere in the system. DMA allocations can be targeted at the zone level, which would not be possible if locking was done in nodes or globally. Synchronization shall be done with a variation of "trylocks." The goal is to put the current task to sleep and restart the failed allocation attempt later if the trylock fails. Otherwise, the OOM killer is invoked. Each zone in the zonelist that __alloc_pages() was called with is checked for the newly-introduced ZONE_OOM_LOCKED flag. If any zone has this flag present, the "trylock" to serialize the OOM killer fails and returns zero. Otherwise, all the zones have ZONE_OOM_LOCKED set and the try_set_zone_oom() function returns non-zero. Cc: Andrea Arcangeli <andrea@suse.de> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* oom: change all_unreclaimable zone member to flagsDavid Rientjes2007-10-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Convert the int all_unreclaimable member of struct zone to unsigned long flags. This can now be used to specify several different zone flags such as all_unreclaimable and reclaim_in_progress, which can now be removed and converted to a per-zone flag. Flags are set and cleared as follows: zone_set_flag(struct zone *zone, zone_flags_t flag) zone_clear_flag(struct zone *zone, zone_flags_t flag) Defines the first zone flags, ZONE_ALL_UNRECLAIMABLE and ZONE_RECLAIM_LOCKED, which have the same semantics as the old zone->all_unreclaimable and zone->reclaim_in_progress, respectively. Also converts all current users that set or clear either flag to use the new interface. Helper functions are defined to test the flags: int zone_is_all_unreclaimable(const struct zone *zone) int zone_is_reclaim_locked(const struct zone *zone) All flag operators are of the atomic variety because there are currently readers that are implemented that do not take zone->lock. [akpm@linux-foundation.org: add needed include] Cc: Andrea Arcangeli <andrea@suse.de> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memory unplug: page isolationKAMEZAWA Hiroyuki2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Implement generic chunk-of-pages isolation method by using page grouping ops. This patch add MIGRATE_ISOLATE to MIGRATE_TYPES. By this - MIGRATE_TYPES increases. - bitmap for migratetype is enlarged. pages of MIGRATE_ISOLATE migratetype will not be allocated even if it is free. By this, you can isolated *freed* pages from users. How-to-free pages is not a purpose of this patch. You may use reclaim and migrate codes to free pages. If start_isolate_page_range(start,end) is called, - migratetype of the range turns to be MIGRATE_ISOLATE if its type is MIGRATE_MOVABLE. (*) this check can be updated if other memory reclaiming works make progress. - MIGRATE_ISOLATE is not on migratetype fallback list. - All free pages and will-be-freed pages are isolated. To check all pages in the range are isolated or not, use test_pages_isolated(), To cancel isolation, use undo_isolate_page_range(). Changes V6 -> V7 - removed unnecessary #ifdef There are HOLES_IN_ZONE handling codes...I'm glad if we can remove them.. Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Print out statistics in relation to fragmentation avoidance to ↵Mel Gorman2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | /proc/pagetypeinfo This patch provides fragmentation avoidance statistics via /proc/pagetypeinfo. The information is collected only on request so there is no runtime overhead. The statistics are in three parts: The first part prints information on the size of blocks that pages are being grouped on and looks like Page block order: 10 Pages per block: 1024 The second part is a more detailed version of /proc/buddyinfo and looks like Free pages count per migrate type at order 0 1 2 3 4 5 6 7 8 9 10 Node 0, zone DMA, type Unmovable 0 0 0 0 0 0 0 0 0 0 0 Node 0, zone DMA, type Reclaimable 1 0 0 0 0 0 0 0 0 0 0 Node 0, zone DMA, type Movable 0 0 0 0 0 0 0 0 0 0 0 Node 0, zone DMA, type Reserve 0 4 4 0 0 0 0 1 0 1 0 Node 0, zone Normal, type Unmovable 111 8 4 4 2 3 1 0 0 0 0 Node 0, zone Normal, type Reclaimable 293 89 8 0 0 0 0 0 0 0 0 Node 0, zone Normal, type Movable 1 6 13 9 7 6 3 0 0 0 0 Node 0, zone Normal, type Reserve 0 0 0 0 0 0 0 0 0 0 4 The third part looks like Number of blocks type Unmovable Reclaimable Movable Reserve Node 0, zone DMA 0 1 2 1 Node 0, zone Normal 3 17 94 4 To walk the zones within a node with interrupts disabled, walk_zones_in_node() is introduced and shared between /proc/buddyinfo, /proc/zoneinfo and /proc/pagetypeinfo to reduce code duplication. It seems specific to what vmstat.c requires but could be broken out as a general utility function in mmzone.c if there were other other potential users. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Andy Whitcroft <apw@shadowen.org> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Do not depend on MAX_ORDER when grouping pages by mobilityMel Gorman2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently mobility grouping works at the MAX_ORDER_NR_PAGES level. This makes sense for the majority of users where this is also the huge page size. However, on platforms like ia64 where the huge page size is runtime configurable it is desirable to group at a lower order. On x86_64 and occasionally on x86, the hugepage size may not always be MAX_ORDER_NR_PAGES. This patch groups pages together based on the value of HUGETLB_PAGE_ORDER. It uses a compile-time constant if possible and a variable where the huge page size is runtime configurable. It is assumed that grouping should be done at the lowest sensible order and that the user would not want to override this. If this is not true, page_block order could be forced to a variable initialised via a boot-time kernel parameter. One potential issue with this patch is that IA64 now parses hugepagesz with early_param() instead of __setup(). __setup() is called after the memory allocator has been initialised and the pageblock bitmaps already setup. In tests on one IA64 there did not seem to be any problem with using early_param() and in fact may be more correct as it guarantees the parameter is handled before the parsing of hugepages=. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Andy Whitcroft <apw@shadowen.org> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* don't group high order atomic allocationsMel Gorman2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Grouping high-order atomic allocations together was intended to allow bursty users of atomic allocations to work such as e1000 in situations where their preallocated buffers were depleted. This did not work in at least one case with a wireless network adapter needing order-1 allocations frequently. To resolve that, the free pages used for min_free_kbytes were moved to separate contiguous blocks with the patch bias-the-location-of-pages-freed-for-min_free_kbytes-in-the-same-max_order_nr_pages-blocks. It is felt that keeping the free pages in the same contiguous blocks should be sufficient for bursty short-lived high-order atomic allocations to succeed, maybe even with the e1000. Even if there is a failure, increasing the value of min_free_kbytes will free pages as contiguous bloks in contrast to the standard buddy allocator which makes no attempt to keep the minimum number of free pages contiguous. This patch backs out grouping high order atomic allocations together to determine if it is really needed or not. If a new report comes in about high-order atomic allocations failing, the feature can be reintroduced to determine if it fixes the problem or not. As a side-effect, this patch reduces by 1 the number of bits required to track the mobility type of pages within a MAX_ORDER_NR_PAGES block. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* remove PAGE_GROUP_BY_MOBILITYMel Gorman2007-10-16
| | | | | | | | | | | | Grouping pages by mobility can be disabled at compile-time. This was considered undesirable by a number of people. However, in the current stack of patches, it is not a simple case of just dropping the configurable patch as it would cause merge conflicts. This patch backs out the configuration option. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Bias the location of pages freed for min_free_kbytes in the same ↵Mel Gorman2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | MAX_ORDER_NR_PAGES blocks The standard buddy allocator always favours the smallest block of pages. The effect of this is that the pages free to satisfy min_free_kbytes tends to be preserved since boot time at the same location of memory ffor a very long time and as a contiguous block. When an administrator sets the reserve at 16384 at boot time, it tends to be the same MAX_ORDER blocks that remain free. This allows the occasional high atomic allocation to succeed up until the point the blocks are split. In practice, it is difficult to split these blocks but when they do split, the benefit of having min_free_kbytes for contiguous blocks disappears. Additionally, increasing min_free_kbytes once the system has been running for some time has no guarantee of creating contiguous blocks. On the other hand, CONFIG_PAGE_GROUP_BY_MOBILITY favours splitting large blocks when there are no free pages of the appropriate type available. A side-effect of this is that all blocks in memory tends to be used up and the contiguous free blocks from boot time are not preserved like in the vanilla allocator. This can cause a problem if a new caller is unwilling to reclaim or does not reclaim for long enough. A failure scenario was found for a wireless network device allocating order-1 atomic allocations but the allocations were not intense or frequent enough for a whole block of pages to be preserved for MIGRATE_HIGHALLOC. This was reproduced on a desktop by booting with mem=256mb, forcing the driver to allocate at order-1, running a bittorrent client (downloading a debian ISO) and building a kernel with -j2. This patch addresses the problem on the desktop machine booted with mem=256mb. It works by setting aside a reserve of MAX_ORDER_NR_PAGES blocks, the number of which depends on the value of min_free_kbytes. These blocks are only fallen back to when there is no other free pages. Then the smallest possible page is used just like the normal buddy allocator instead of the largest possible page to preserve contiguous pages The pages in free lists in the reserve blocks are never taken for another migrate type. The results is that even if min_free_kbytes is set to a low value, contiguous blocks will be preserved in the MIGRATE_RESERVE blocks. This works better than the vanilla allocator because if min_free_kbytes is increased, a new reserve block will be chosen based on the location of reclaimable pages and the block will free up as contiguous pages. In the vanilla allocator, no effort is made to target a block of pages to free as contiguous pages and min_free_kbytes pages are scattered randomly. This effect has been observed on the test machine. min_free_kbytes was set initially low but it was kept as a contiguous free block within MIGRATE_RESERVE. min_free_kbytes was then set to a higher value and over a period of time, the free blocks were within the reserve and coalescing. How long it takes to free up depends on how quickly LRU is rotating. Amusingly, this means that more activity will free the blocks faster. This mechanism potentially replaces MIGRATE_HIGHALLOC as it may be more effective than grouping contiguous free pages together. It all depends on whether the number of active atomic high allocations exceeds min_free_kbytes or not. If the number of active allocations exceeds min_free_kbytes, it's worth it but maybe in that situation, min_free_kbytes should be set higher. Once there are no more reports of allocation failures, a patch will be submitted that backs out MIGRATE_HIGHALLOC and see if the reports stay missing. Credit to Mariusz Kozlowski for discovering the problem, describing the failure scenario and testing patches and scenarios. [akpm@linux-foundation.org: cleanups] Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Fix corruption of memmap on IA64 SPARSEMEM when mem_section is not a power of 2Mel Gorman2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are problems in the use of SPARSEMEM and pageblock flags that causes problems on ia64. The first part of the problem is that units are incorrect in SECTION_BLOCKFLAGS_BITS computation. This results in a map_section's section_mem_map being treated as part of a bitmap which isn't good. This was evident with an invalid virtual address when mem_init attempted to free bootmem pages while relinquishing control from the bootmem allocator. The second part of the problem occurs because the pageblock flags bitmap is be located with the mem_section. The SECTIONS_PER_ROOT computation using sizeof (mem_section) may not be a power of 2 depending on the size of the bitmap. This renders masks and other such things not power of 2 base. This issue was seen with SPARSEMEM_EXTREME on ia64. This patch moves the bitmap outside of mem_section and uses a pointer instead in the mem_section. The bitmaps are allocated when the section is being initialised. Note that sparse_early_usemap_alloc() does not use alloc_remap() like sparse_early_mem_map_alloc(). The allocation required for the bitmap on x86, the only architecture that uses alloc_remap is typically smaller than a cache line. alloc_remap() pads out allocations to the cache size which would be a needless waste. Credit to Bob Picco for identifying the original problem and effecting a fix for the SECTION_BLOCKFLAGS_BITS calculation. Credit to Andy Whitcroft for devising the best way of allocating the bitmaps only when required for the section. [wli@holomorphy.com: warning fix] Signed-off-by: Bob Picco <bob.picco@hp.com> Signed-off-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Mel Gorman <mel@csn.ul.ie> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: William Irwin <bill.irwin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Group high-order atomic allocationsMel Gorman2007-10-16
| | | | | | | | | | | | | | | | In rare cases, the kernel needs to allocate a high-order block of pages without sleeping. For example, this is the case with e1000 cards configured to use jumbo frames. Migrating or reclaiming pages in this situation is not an option. This patch groups these allocations together as much as possible by adding a new MIGRATE_TYPE. The MIGRATE_HIGHATOMIC type are exactly what they sound like. Care is taken that pages of other migrate types do not use the same blocks as high-order atomic allocations. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Group short-lived and reclaimable kernel allocationsMel Gorman2007-10-16
| | | | | | | | | | | | | | | | | | This patch marks a number of allocations that are either short-lived such as network buffers or are reclaimable such as inode allocations. When something like updatedb is called, long-lived and unmovable kernel allocations tend to be spread throughout the address space which increases fragmentation. This patch groups these allocations together as much as possible by adding a new MIGRATE_TYPE. The MIGRATE_RECLAIMABLE type is for allocations that can be reclaimed on demand, but not moved. i.e. they can be migrated by deleting them and re-reading the information from elsewhere. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Cc: Andy Whitcroft <apw@shadowen.org> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Add a configure option to group pages by mobilityMel Gorman2007-10-16
| | | | | | | | | | | | | | The grouping mechanism has some memory overhead and a more complex allocation path. This patch allows the strategy to be disabled for small memory systems or if it is known the workload is suffering because of the strategy. It also acts to show where the page groupings strategy interacts with the standard buddy allocator. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Joel Schopp <jschopp@austin.ibm.com> Cc: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Split the free lists for movable and unmovable allocationsMel Gorman2007-10-16
| | | | | | | | | | | This patch adds the core of the fragmentation reduction strategy. It works by grouping pages together based on their ability to migrate or be reclaimed. Basically, it works by breaking the list in zone->free_area list into MIGRATE_TYPES number of lists. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Add a bitmap that is used to track flags affecting a block of pagesMel Gorman2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Here is the latest revision of the anti-fragmentation patches. Of particular note in this version is special treatment of high-order atomic allocations. Care is taken to group them together and avoid grouping pages of other types near them. Artifical tests imply that it works. I'm trying to get the hardware together that would allow setting up of a "real" test. If anyone already has a setup and test that can trigger the atomic-allocation problem, I'd appreciate a test of these patches and a report. The second major change is that these patches will apply cleanly with patches that implement anti-fragmentation through zones. kernbench shows effectively no performance difference varying between -0.2% and +2% on a variety of test machines. Success rates for huge page allocation are dramatically increased. For example, on a ppc64 machine, the vanilla kernel was only able to allocate 1% of memory as a hugepage and this was due to a single hugepage reserved as min_free_kbytes. With these patches applied, 17% was allocatable as superpages. With reclaim-related fixes from Andy Whitcroft, it was 40% and further reclaim-related improvements should increase this further. Changelog Since V28 o Group high-order atomic allocations together o It is no longer required to set min_free_kbytes to 10% of memory. A value of 16384 in most cases will be sufficient o Now applied with zone-based anti-fragmentation o Fix incorrect VM_BUG_ON within buffered_rmqueue() o Reorder the stack so later patches do not back out work from earlier patches o Fix bug were journal pages were being treated as movable o Bias placement of non-movable pages to lower PFNs o More agressive clustering of reclaimable pages in reactions to workloads like updatedb that flood the size of inode caches Changelog Since V27 o Renamed anti-fragmentation to Page Clustering. Anti-fragmentation was giving the mistaken impression that it was the 100% solution for high order allocations. Instead, it greatly increases the chances high-order allocations will succeed and lays the foundation for defragmentation and memory hot-remove to work properly o Redefine page groupings based on ability to migrate or reclaim instead of basing on reclaimability alone o Get rid of spurious inits o Per-cpu lists are no longer split up per-type. Instead the per-cpu list is searched for a page of the appropriate type o Added more explanation commentary o Fix up bug in pageblock code where bitmap was used before being initalised Changelog Since V26 o Fix double init of lists in setup_pageset Changelog Since V25 o Fix loop order of for_each_rclmtype_order so that order of loop matches args o gfpflags_to_rclmtype uses gfp_t instead of unsigned long o Rename get_pageblock_type() to get_page_rclmtype() o Fix alignment problem in move_freepages() o Add mechanism for assigning flags to blocks of pages instead of page->flags o On fallback, do not examine the preferred list of free pages a second time The purpose of these patches is to reduce external fragmentation by grouping pages of related types together. When pages are migrated (or reclaimed under memory pressure), large contiguous pages will be freed. This patch works by categorising allocations by their ability to migrate; Movable - The pages may be moved with the page migration mechanism. These are generally userspace pages. Reclaimable - These are allocations for some kernel caches that are reclaimable or allocations that are known to be very short-lived. Unmovable - These are pages that are allocated by the kernel that are not trivially reclaimed. For example, the memory allocated for a loaded module would be in this category. By default, allocations are considered to be of this type HighAtomic - These are high-order allocations belonging to callers that cannot sleep or perform any IO. In practice, this is restricted to jumbo frame allocation for network receive. It is assumed that the allocations are short-lived Instead of having one MAX_ORDER-sized array of free lists in struct free_area, there is one for each type of reclaimability. Once a 2^MAX_ORDER block of pages is split for a type of allocation, it is added to the free-lists for that type, in effect reserving it. Hence, over time, pages of the different types can be clustered together. When the preferred freelists are expired, the largest possible block is taken from an alternative list. Buddies that are split from that large block are placed on the preferred allocation-type freelists to mitigate fragmentation. This implementation gives best-effort for low fragmentation in all zones. Ideally, min_free_kbytes needs to be set to a value equal to 4 * (1 << (MAX_ORDER-1)) pages in most cases. This would be 16384 on x86 and x86_64 for example. Our tests show that about 60-70% of physical memory can be allocated on a desktop after a few days uptime. In benchmarks and stress tests, we are finding that 80% of memory is available as contiguous blocks at the end of the test. To compare, a standard kernel was getting < 1% of memory as large pages on a desktop and about 8-12% of memory as large pages at the end of stress tests. Following this email are 12 patches that implement thie page grouping feature. The first patch introduces a mechanism for storing flags related to a whole block of pages. Then allocations are split between movable and all other allocations. Following that are patches to deal with per-cpu pages and make the mechanism configurable. The next patch moves free pages between lists when partially allocated blocks are used for pages of another migrate type. The second last patch groups reclaimable kernel allocations such as inode caches together. The final patch related to groupings keeps high-order atomic allocations. The last two patches are more concerned with control of fragmentation. The second last patch biases placement of non-movable allocations towards the start of memory. This is with a view of supporting memory hot-remove of DIMMs with higher PFNs in the future. The biasing could be enforced a lot heavier but it would cost. The last patch agressively clusters reclaimable pages like inode caches together. The fragmentation reduction strategy needs to track if pages within a block can be moved or reclaimed so that pages are freed to the appropriate list. This patch adds a bitmap for flags affecting a whole a MAX_ORDER block of pages. In non-SPARSEMEM configurations, the bitmap is stored in the struct zone and allocated during initialisation. SPARSEMEM statically allocates the bitmap in a struct mem_section so that bitmaps do not have to be resized during memory hotadd. This wastes a small amount of memory per unused section (usually sizeof(unsigned long)) but the complexity of dynamically allocating the memory is quite high. Additional credit to Andy Whitcroft who reviewed up an earlier implementation of the mechanism an suggested how to make it a *lot* cleaner. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Cc: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Memoryless nodes: Fix GFP_THISNODE behaviorChristoph Lameter2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | GFP_THISNODE checks that the zone selected is within the pgdat (node) of the first zone of a nodelist. That only works if the node has memory. A memoryless node will have its first node on another pgdat (node). GFP_THISNODE currently will return simply memory on the first pgdat. Thus it is returning memory on other nodes. GFP_THISNODE should fail if there is no local memory on a node. Add a new set of zonelists for each node that only contain the nodes that belong to the zones itself so that no fallback is possible. Then modify gfp_type to pickup the right zone based on the presence of __GFP_THISNODE. Drop the existing GFP_THISNODE checks from the page_allocators hot path. Signed-off-by: Christoph Lameter <clameter@sgi.com> Acked-by: Nishanth Aravamudan <nacc@us.ibm.com> Tested-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Acked-by: Bob Picco <bob.picco@hp.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@skynet.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sparsemem: record when a section has a valid mem_mapAndy Whitcroft2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | We have flags to indicate whether a section actually has a valid mem_map associated with it. This is never set and we rely solely on the present bit to indicate a section is valid. By definition a section is not valid if it has no mem_map and there is a window during init where the present bit is set but there is no mem_map, during which pfn_valid() will return true incorrectly. Use the existing SECTION_HAS_MEM_MAP flag to indicate the presence of a valid mem_map. Switch valid_section{,_nr} and pfn_valid() to this bit. Add a new present_section{,_nr} and pfn_present() interfaces for those users who care to know that a section is going to be valid. [akpm@linux-foundation.org: coding-syle fixes] Signed-off-by: Andy Whitcroft <apw@shadowen.org> Acked-by: Mel Gorman <mel@csn.ul.ie> Cc: Christoph Lameter <clameter@sgi.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Andi Kleen <ak@suse.de> Cc: "David S. Miller" <davem@davemloft.net> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Apply memory policies to top two highest zones when highest zone is ZONE_MOVABLEMel Gorman2007-08-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The NUMA layer only supports NUMA policies for the highest zone. When ZONE_MOVABLE is configured with kernelcore=, the the highest zone becomes ZONE_MOVABLE. The result is that policies are only applied to allocations like anonymous pages and page cache allocated from ZONE_MOVABLE when the zone is used. This patch applies policies to the two highest zones when the highest zone is ZONE_MOVABLE. As ZONE_MOVABLE consists of pages from the highest "real" zone, it's always functionally equivalent. The patch has been tested on a variety of machines both NUMA and non-NUMA covering x86, x86_64 and ppc64. No abnormal results were seen in kernbench, tbench, dbench or hackbench. It passes regression tests from the numactl package with and without kernelcore= once numactl tests are patched to wait for vmstat counters to update. akpm: this is the nasty hack to fix NUMA mempolicies in the presence of ZONE_MOVABLE and kernelcore= in 2.6.23. Christoph says "For .24 either merge the mobility or get the other solution that Mel is working on. That solution would only use a single zonelist per node and filter on the fly. That may help performance and also help to make memory policies work better." Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Tested-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Acked-by: Christoph Lameter <clameter@sgi.com> Cc: Andi Kleen <ak@suse.de> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Remove the arm26 portAdrian Bunk2007-07-31
| | | | | | | | | | | | The arm26 port has been in a state where it was far from even compiling for quite some time. Ian Molton agreed with the removal. Signed-off-by: Adrian Bunk <bunk@stusta.de> Cc: Ian Molton <spyro@f2s.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Lumpy Reclaim V4Andy Whitcroft2007-07-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When we are out of memory of a suitable size we enter reclaim. The current reclaim algorithm targets pages in LRU order, which is great for fairness at order-0 but highly unsuitable if you desire pages at higher orders. To get pages of higher order we must shoot down a very high proportion of memory; >95% in a lot of cases. This patch set adds a lumpy reclaim algorithm to the allocator. It targets groups of pages at the specified order anchored at the end of the active and inactive lists. This encourages groups of pages at the requested orders to move from active to inactive, and active to free lists. This behaviour is only triggered out of direct reclaim when higher order pages have been requested. This patch set is particularly effective when utilised with an anti-fragmentation scheme which groups pages of similar reclaimability together. This patch set is based on Peter Zijlstra's lumpy reclaim V2 patch which forms the foundation. Credit to Mel Gorman for sanitity checking. Mel said: The patches have an application with hugepage pool resizing. When lumpy-reclaim is used used with ZONE_MOVABLE, the hugepages pool can be resized with greater reliability. Testing on a desktop machine with 2GB of RAM showed that growing the hugepage pool with ZONE_MOVABLE on it's own was very slow as the success rate was quite low. Without lumpy-reclaim, each attempt to grow the pool by 100 pages would yield 1 or 2 hugepages. With lumpy-reclaim, getting 40 to 70 hugepages on each attempt was typical. [akpm@osdl.org: ia64 pfn_to_nid fixes and loop cleanup] [bunk@stusta.de: static declarations for internal functions] [a.p.zijlstra@chello.nl: initial lumpy V2 implementation] Signed-off-by: Andy Whitcroft <apw@shadowen.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Mel Gorman <mel@csn.ul.ie> Cc: Bob Picco <bob.picco@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Create the ZONE_MOVABLE zoneMel Gorman2007-07-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The following 8 patches against 2.6.20-mm2 create a zone called ZONE_MOVABLE that is only usable by allocations that specify both __GFP_HIGHMEM and __GFP_MOVABLE. This has the effect of keeping all non-movable pages within a single memory partition while allowing movable allocations to be satisfied from either partition. The patches may be applied with the list-based anti-fragmentation patches that groups pages together based on mobility. The size of the zone is determined by a kernelcore= parameter specified at boot-time. This specifies how much memory is usable by non-movable allocations and the remainder is used for ZONE_MOVABLE. Any range of pages within ZONE_MOVABLE can be released by migrating the pages or by reclaiming. When selecting a zone to take pages from for ZONE_MOVABLE, there are two things to consider. First, only memory from the highest populated zone is used for ZONE_MOVABLE. On the x86, this is probably going to be ZONE_HIGHMEM but it would be ZONE_DMA on ppc64 or possibly ZONE_DMA32 on x86_64. Second, the amount of memory usable by the kernel will be spread evenly throughout NUMA nodes where possible. If the nodes are not of equal size, the amount of memory usable by the kernel on some nodes may be greater than others. By default, the zone is not as useful for hugetlb allocations because they are pinned and non-migratable (currently at least). A sysctl is provided that allows huge pages to be allocated from that zone. This means that the huge page pool can be resized to the size of ZONE_MOVABLE during the lifetime of the system assuming that pages are not mlocked. Despite huge pages being non-movable, we do not introduce additional external fragmentation of note as huge pages are always the largest contiguous block we care about. Credit goes to Andy Whitcroft for catching a large variety of problems during review of the patches. This patch creates an additional zone, ZONE_MOVABLE. This zone is only usable by allocations which specify both __GFP_HIGHMEM and __GFP_MOVABLE. Hot-added memory continues to be placed in their existing destination as there is no mechanism to redirect them to a specific zone. [y-goto@jp.fujitsu.com: Fix section mismatch of memory hotplug related code] [akpm@linux-foundation.org: various fixes] Signed-off-by: Mel Gorman <mel@csn.ul.ie> Cc: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com> Cc: William Lee Irwin III <wli@holomorphy.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* change zonelist order: zonelist order selection logicKAMEZAWA Hiroyuki2007-07-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make zonelist creation policy selectable from sysctl/boot option v6. This patch makes NUMA's zonelist (of pgdat) order selectable. Available order are Default(automatic)/ Node-based / Zone-based. [Default Order] The kernel selects Node-based or Zone-based order automatically. [Node-based Order] This policy treats the locality of memory as the most important parameter. Zonelist order is created by each zone's locality. This means lower zones (ex. ZONE_DMA) can be used before higher zone (ex. ZONE_NORMAL) exhausion. IOW. ZONE_DMA will be in the middle of zonelist. current 2.6.21 kernel uses this. Pros. * A user can expect local memory as much as possible. Cons. * lower zone will be exhansted before higher zone. This may cause OOM_KILL. Maybe suitable if ZONE_DMA is relatively big and you never see OOM_KILL because of ZONE_DMA exhaution and you need the best locality. (example) assume 2 node NUMA. node(0) has ZONE_DMA/ZONE_NORMAL, node(1) has ZONE_NORMAL. *node(0)'s memory allocation order: node(0)'s NORMAL -> node(0)'s DMA -> node(1)'s NORMAL. *node(1)'s memory allocation order: node(1)'s NORMAL -> node(0)'s NORMAL -> node(0)'s DMA. [Zone-based order] This policy treats the zone type as the most important parameter. Zonelist order is created by zone-type order. This means lower zone never be used bofere higher zone exhaustion. IOW. ZONE_DMA will be always at the tail of zonelist. Pros. * OOM_KILL(bacause of lower zone) occurs only if the whole zones are exhausted. Cons. * memory locality may not be best. (example) assume 2 node NUMA. node(0) has ZONE_DMA/ZONE_NORMAL, node(1) has ZONE_NORMAL. *node(0)'s memory allocation order: node(0)'s NORMAL -> node(1)'s NORMAL -> node(0)'s DMA. *node(1)'s memory allocation order: node(1)'s NORMAL -> node(0)'s NORMAL -> node(0)'s DMA. bootoption "numa_zonelist_order=" and proc/sysctl is supporetd. command: %echo N > /proc/sys/vm/numa_zonelist_order Will rebuild zonelist in Node-based order. command: %echo Z > /proc/sys/vm/numa_zonelist_order Will rebuild zonelist in Zone-based order. Thanks to Lee Schermerhorn, he gives me much help and codes. [Lee.Schermerhorn@hp.com: add check_highest_zone to build_zonelists_in_zone_order] [akpm@linux-foundation.org: build fix] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Christoph Lameter <clameter@sgi.com> Cc: Andi Kleen <ak@suse.de> Cc: "jesse.barnes@intel.com" <jesse.barnes@intel.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Move remote node draining out of slab allocatorsChristoph Lameter2007-05-09
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently the slab allocators contain callbacks into the page allocator to perform the draining of pagesets on remote nodes. This requires SLUB to have a whole subsystem in order to be compatible with SLAB. Moving node draining out of the slab allocators avoids a section of code in SLUB. Move the node draining so that is is done when the vm statistics are updated. At that point we are already touching all the cachelines with the pagesets of a processor. Add a expire counter there. If we have to update per zone or global vm statistics then assume that the pageset will require subsequent draining. The expire counter will be decremented on each vm stats update pass until it reaches zero. Then we will drain one batch from the pageset. The draining will cause vm counter updates which will then cause another expiration until the pcp is empty. So we will drain a batch every 3 seconds. Note that remote node draining is a somewhat esoteric feature that is required on large NUMA systems because otherwise significant portions of system memory can become trapped in pcp queues. The number of pcp is determined by the number of processors and nodes in a system. A system with 4 processors and 2 nodes has 8 pcps which is okay. But a system with 1024 processors and 512 nodes has 512k pcps with a high potential for large amount of memory being caught in them. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* add pfn_valid_within helper for sub-MAX_ORDER hole detectionAndy Whitcroft2007-05-07
| | | | | | | | | | | | | | | | | | | Generally we work under the assumption that memory the mem_map array is contigious and valid out to MAX_ORDER_NR_PAGES block of pages, ie. that if we have validated any page within this MAX_ORDER_NR_PAGES block we need not check any other. This is not true when CONFIG_HOLES_IN_ZONE is set and we must check each and every reference we make from a pfn. Add a pfn_valid_within() helper which should be used when scanning pages within a MAX_ORDER_NR_PAGES block when we have already checked the validility of the block normally with pfn_valid(). This can then be optimised away when we do not have holes within a MAX_ORDER_NR_PAGES block of pages. Signed-off-by: Andy Whitcroft <apw@shadowen.org> Acked-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Bob Picco <bob.picco@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] optional ZONE_DMA: optional ZONE_DMA in the VMChristoph Lameter2007-02-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Make ZONE_DMA optional in core code. - ifdef all code for ZONE_DMA and related definitions following the example for ZONE_DMA32 and ZONE_HIGHMEM. - Without ZONE_DMA, ZONE_HIGHMEM and ZONE_DMA32 we get to a ZONES_SHIFT of 0. - Modify the VM statistics to work correctly without a DMA zone. - Modify slab to not create DMA slabs if there is no ZONE_DMA. [akpm@osdl.org: cleanup] [jdike@addtoit.com: build fix] [apw@shadowen.org: Simplify calculation of the number of bits we need for ZONES_SHIFT] Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Andi Kleen <ak@suse.de> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Matthew Wilcox <willy@debian.org> Cc: James Bottomley <James.Bottomley@steeleye.com> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] Drop __get_zone_counts()Christoph Lameter2007-02-11
| | | | | | | | Values are readily available via ZVC per node and global sums. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] Reorder ZVCs according to cachelineChristoph Lameter2007-02-11
| | | | | | | | | | | | The global and per zone counter sums are in arrays of longs. Reorder the ZVCs so that the most frequently used ZVCs are put into the same cacheline. That way calculations of the global, node and per zone vm state touches only a single cacheline. This is mostly important for 64 bit systems were one 128 byte cacheline takes only 8 longs. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] Use ZVC for free_pagesChristoph Lameter2007-02-11
| | | | | | | | | | | This is again simplifies some of the VM counter calculations through the use of the ZVC consolidated counters. [michal.k.k.piotrowski@gmail.com: build fix] Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Michal Piotrowski <michal.k.k.piotrowski@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] Use ZVC for inactive and active countsChristoph Lameter2007-02-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The determination of the dirty ratio to determine writeback behavior is currently based on the number of total pages on the system. However, not all pages in the system may be dirtied. Thus the ratio is always too low and can never reach 100%. The ratio may be particularly skewed if large hugepage allocations, slab allocations or device driver buffers make large sections of memory not available anymore. In that case we may get into a situation in which f.e. the background writeback ratio of 40% cannot be reached anymore which leads to undesired writeback behavior. This patchset fixes that issue by determining the ratio based on the actual pages that may potentially be dirty. These are the pages on the active and the inactive list plus free pages. The problem with those counts has so far been that it is expensive to calculate these because counts from multiple nodes and multiple zones will have to be summed up. This patchset makes these counters ZVC counters. This means that a current sum per zone, per node and for the whole system is always available via global variables and not expensive anymore to calculate. The patchset results in some other good side effects: - Removal of the various functions that sum up free, active and inactive page counts - Cleanup of the functions that display information via the proc filesystem. This patch: The use of a ZVC for nr_inactive and nr_active allows a simplification of some counter operations. More ZVC functionality is used for sums etc in the following patches. [akpm@osdl.org: UP build fix] Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] Fix sparsemem on CellDave Hansen2007-01-11
| | | | | | | | | | | | | | | | | | | | | Fix an oops experienced on the Cell architecture when init-time functions, early_*(), are called at runtime. It alters the call paths to make sure that the callers explicitly say whether the call is being made on behalf of a hotplug even, or happening at boot-time. It has been compile tested on ppc64, ia64, s390, i386 and x86_64. Acked-by: Arnd Bergmann <arndb@de.ibm.com> Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Cc: Yasunori Goto <y-goto@jp.fujitsu.com> Acked-by: Andy Whitcroft <apw@shadowen.org> Cc: Christoph Lameter <clameter@engr.sgi.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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