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* revert "kswapd should only wait on IO if there is IO"Andrew Morton2008-03-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Revert commit f1a9ee758de7de1e040de849fdef46e6802ea117: Author: Rik van Riel <riel@redhat.com> Date: Thu Feb 7 00:14:08 2008 -0800 kswapd should only wait on IO if there is IO The current kswapd (and try_to_free_pages) code has an oddity where the code will wait on IO, even if there is no IO in flight. This problem is notable especially when the system scans through many unfreeable pages, causing unnecessary stalls in the VM. Additionally, tasks without __GFP_FS or __GFP_IO in the direct reclaim path will sleep if a significant number of pages are encountered that should be written out. This gives kswapd a chance to write out those pages, while the direct reclaim task sleeps. Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Because of large latencies and interactivity problems reported by Carlos, here: http://lkml.org/lkml/2008/3/22/211 Cc: Rik van Riel <riel@redhat.com> Cc: "Carlos R. Mafra" <crmafra2@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: move_lists on page not page_cgroupHugh Dickins2008-03-04
| | | | | | | | | | | | | | | | Each caller of mem_cgroup_move_lists is having to use page_get_page_cgroup: it's more convenient if it acts upon the page itself not the page_cgroup; and in a later patch this becomes important to handle within memcontrol.c. Signed-off-by: Hugh Dickins <hugh@veritas.com> Cc: David Rientjes <rientjes@google.com> Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hirokazu Takahashi <taka@valinux.co.jp> Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Memory controller: rename to Memory Resource ControllerBalbir Singh2008-03-04
| | | | | | | | | | | | Rename Memory Controller to Memory Resource Controller. Reflect the same changes in the CONFIG definition for the Memory Resource Controller. Group together the config options for Resource Counters and Memory Resource Controller. Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* per-zone and reclaim enhancements for memory controller: modifies vmscan.c ↵KAMEZAWA Hiroyuki2008-02-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | for isolate globa/cgroup lru activity When using memory controller, there are 2 levels of memory reclaim. 1. zone memory reclaim because of system/zone memory shortage. 2. memory cgroup memory reclaim because of hitting limit. These two can be distinguished by sc->mem_cgroup parameter. (scan_global_lru() macro) This patch tries to make memory cgroup reclaim routine avoid affecting system/zone memory reclaim. This patch inserts if (scan_global_lru()) and hook to memory_cgroup reclaim support functions. This patch can be a help for isolating system lru activity and group lru activity and shows what additional functions are necessary. * mem_cgroup_calc_mapped_ratio() ... calculate mapped ratio for cgroup. * mem_cgroup_reclaim_imbalance() ... calculate active/inactive balance in cgroup. * mem_cgroup_calc_reclaim_active() ... calculate the number of active pages to be scanned in this priority in mem_cgroup. * mem_cgroup_calc_reclaim_inactive() ... calculate the number of inactive pages to be scanned in this priority in mem_cgroup. * mem_cgroup_all_unreclaimable() .. checks cgroup's page is all unreclaimable or not. * mem_cgroup_get_reclaim_priority() ... * mem_cgroup_note_reclaim_priority() ... record reclaim priority (temporal) * mem_cgroup_remember_reclaim_priority() .... record reclaim priority as zone->prev_priority. This value is used for calc reclaim_mapped. [akpm@linux-foundation.org: fix unused var warning] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: David Rientjes <rientjes@google.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Kirill Korotaev <dev@sw.ru> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Paul Menage <menage@google.com> Cc: Pavel Emelianov <xemul@openvz.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* per-zone and reclaim enhancements for memory controller: add scan_global_lru ↵KAMEZAWA Hiroyuki2008-02-07
| | | | | | | | | | | | | | | | | | | | | | | macro This is used to detect which scan_control scans global lru or mem_cgroup lru. And compiled to be static value (1) when memory controller is not configured. This may make the meaning obvious. Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: David Rientjes <rientjes@google.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Kirill Korotaev <dev@sw.ru> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Paul Menage <menage@google.com> Cc: Pavel Emelianov <xemul@openvz.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memory cgroup enhancements: fix zone handling in try_to_free_mem_cgroup_pageKAMEZAWA Hiroyuki2008-02-07
| | | | | | | | | | | | | | | | | | | | | | | | Because NODE_DATA(node)->node_zonelists[] is guaranteed to contain all necessary zones, it is not necessary to use for_each_online_node. And this for_each_online_node() makes reclaim routine start always from node 0. This is not good. This patch makes reclaim start from caller's node and just use usual (default) zonelist order. [akpm@linux-foundation.org: fix warning] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelianov <xemul@openvz.org> Cc: Paul Menage <menage@google.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Kirill Korotaev <dev@sw.ru> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: David Rientjes <rientjes@google.com> Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kswapd should only wait on IO if there is IORik van Riel2008-02-07
| | | | | | | | | | | | | | | | The current kswapd (and try_to_free_pages) code has an oddity where the code will wait on IO, even if there is no IO in flight. This problem is notable especially when the system scans through many unfreeable pages, causing unnecessary stalls in the VM. Additionally, tasks without __GFP_FS or __GFP_IO in the direct reclaim path will sleep if a significant number of pages are encountered that should be written out. This gives kswapd a chance to write out those pages, while the direct reclaim task sleeps. Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Memory controller: make charging gfp mask awareBalbir Singh2008-02-07
| | | | | | | | | | | | | | | | | | | | | | | | | | Nick Piggin pointed out that swap cache and page cache addition routines could be called from non GFP_KERNEL contexts. This patch makes the charging routine aware of the gfp context. Charging might fail if the cgroup is over it's limit, in which case a suitable error is returned. This patch was tested on a Powerpc box. I am still looking at being able to test the path, through which allocations happen in non GFP_KERNEL contexts. [kamezawa.hiroyu@jp.fujitsu.com: problem with ZONE_MOVABLE] Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelianov <xemul@openvz.org> Cc: Paul Menage <menage@google.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Kirill Korotaev <dev@sw.ru> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: David Rientjes <rientjes@google.com> Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.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>
* Memory controller: make page_referenced() cgroup awareBalbir Singh2008-02-07
| | | | | | | | | | | | | | | | | | | | | Make page_referenced() cgroup aware. Without this patch, page_referenced() can cause a page to be skipped while reclaiming pages. This patch ensures that other cgroups do not hold pages in a particular cgroup hostage. It is required to ensure that shared pages are freed from a cgroup when they are not actively referenced from the cgroup that brought them in Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelianov <xemul@openvz.org> Cc: Paul Menage <menage@google.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Kirill Korotaev <dev@sw.ru> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: David Rientjes <rientjes@google.com> Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Memory controller: add per cgroup LRU and reclaimBalbir Singh2008-02-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add the page_cgroup to the per cgroup LRU. The reclaim algorithm has been modified to make the isolate_lru_pages() as a pluggable component. The scan_control data structure now accepts the cgroup on behalf of which reclaims are carried out. try_to_free_pages() has been extended to become cgroup aware. [akpm@linux-foundation.org: fix warning] [Lee.Schermerhorn@hp.com: initialize all scan_control's isolate_pages member] [bunk@kernel.org: make do_try_to_free_pages() static] [hugh@veritas.com: memcgroup: fix try_to_free order] [kamezawa.hiroyu@jp.fujitsu.com: this unlock_page_cgroup() is unnecessary] Signed-off-by: Pavel Emelianov <xemul@openvz.org> Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Paul Menage <menage@google.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Kirill Korotaev <dev@sw.ru> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: David Rientjes <rientjes@google.com> Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Hugh Dickins <hugh@veritas.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>
* spelling fixes: mm/Simon Arlott2007-10-19
| | | | | | | Spelling fixes in mm/. Signed-off-by: Simon Arlott <simon@fire.lp0.eu> Signed-off-by: Adrian Bunk <bunk@kernel.org>
* sparse pointer use of zero as nullStephen Hemminger2007-10-18
| | | | | | | | | | | | | | | | | Get rid of sparse related warnings from places that use integer as NULL pointer. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org> Cc: Andi Kleen <ak@suse.de> Cc: Jeff Garzik <jeff@garzik.org> Cc: Matt Mackall <mpm@selenic.com> Cc: Ian Kent <raven@themaw.net> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Davide Libenzi <davidel@xmailserver.org> Cc: Stephen Smalley <sds@tycho.nsa.gov> 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: 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>
* make swappiness safer to useAndrea Arcangeli2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Swappiness isn't a safe sysctl. Setting it to 0 for example can hang a system. That's a corner case but even setting it to 10 or lower can waste enormous amounts of cpu without making much progress. We've customers who wants to use swappiness but they can't because of the current implementation (if you change it so the system stops swapping it really stops swapping and nothing works sane anymore if you really had to swap something to make progress). This patch from Kurt Garloff makes swappiness safer to use (no more huge cpu usage or hangs with low swappiness values). I think the prev_priority can also be nuked since it wastes 4 bytes per zone (that would be an incremental patch but I wait the nr_scan_[in]active to be nuked first for similar reasons). Clearly somebody at some point noticed how broken that thing was and they had to add min(priority, prev_priority) to give it some reliability, but they didn't go the last mile to nuke prev_priority too. Calculating distress only in function of not-racy priority is correct and sure more than enough without having to add randomness into the equation. Patch is tested on older kernels but it compiles and it's quite simple so... Overall I'm not very satisified by the swappiness tweak, since it doesn't rally do anything with the dirty pagecache that may be inactive. We need another kind of tweak that controls the inactive scan and tunes the can_writepage feature (not yet in mainline despite having submitted it a few times), not only the active one. That new tweak will tell the kernel how hard to scan the inactive list for pure clean pagecache (something the mainline kernel isn't capable of yet). We already have that feature working in all our enterprise kernels with the default reasonable tune, or they can't even run a readonly backup with tar without triggering huge write I/O. I think it should be available also in mainline later. Cc: Nick Piggin <npiggin@suse.de> Signed-off-by: Kurt Garloff <garloff@suse.de> Signed-off-by: Andrea Arcangeli <andrea@suse.de> Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Fix panic of cpu online with memory less nodeYasunori Goto2007-10-16
| | | | | | | | | | | | | When a cpu is onlined on memory-less-node box, kernel panics due to touch NULL pointer of pgdat->kswapd. Current kswapd runs only nodes which have memory. So, calling of set_cpus_allowed() is not necessary for memory-less node. This is fix for it. Signed-off-by: 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>
* Memoryless nodes: Add N_CPU node stateChristoph Lameter2007-10-16
| | | | | | | | | | | | | | | | We need the check for a node with cpu in zone reclaim. Zone reclaim will not allow remote zone reclaim if a node has a cpu. [Lee.Schermerhorn@hp.com: Move setup of N_CPU node state mask] Signed-off-by: Christoph Lameter <clameter@sgi.com> Tested-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Acked-by: Bob Picco <bob.picco@hp.com> Cc: Nishanth Aravamudan <nacc@us.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@skynet.ie> 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>
* Memoryless nodes: No need for kswapdChristoph Lameter2007-10-16
| | | | | | | | | | | | | | A node without memory does not need a kswapd. So use the memory map instead of the online map when starting kswapd. 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>
* mm: prevent kswapd from freeing excessive amounts of lowmemRik van Riel2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The current VM can get itself into trouble fairly easily on systems with a small ZONE_HIGHMEM, which is common on i686 computers with 1GB of memory. On one side, page_alloc() will allocate down to zone->pages_low, while on the other side, kswapd() and balance_pgdat() will try to free memory from every zone, until every zone has more free pages than zone->pages_high. Highmem can be filled up to zone->pages_low with page tables, ramfs, vmalloc allocations and other unswappable things quite easily and without many bad side effects, since we still have a huge ZONE_NORMAL to do future allocations from. However, as long as the number of free pages in the highmem zone is below zone->pages_high, kswapd will continue swapping things out from ZONE_NORMAL, too! Sami Farin managed to get his system into a stage where kswapd had freed about 700MB of low memory and was still "going strong". The attached patch will make kswapd stop paging out data from zones when there is more than enough memory free. We do go above zone->pages_high in order to keep pressure between zones equal in normal circumstances, but the patch should prevent the kind of excesses that made Sami's computer totally unusable. Signed-off-by: Rik van Riel <riel@redhat.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>
* synchronous lumpy reclaim: wait for page writeback when directly reclaiming ↵Andy Whitcroft2007-08-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | contiguous areas Lumpy reclaim works by selecting a lead page from the LRU list and then selecting pages for reclaim from the order-aligned area of pages. In the situation were all pages in that region are inactive and not referenced by any process over time, it works well. In the situation where there is even light load on the system, the pages may not free quickly. Out of a area of 1024 pages, maybe only 950 of them are freed when the allocation attempt occurs because lumpy reclaim returned early. This patch alters the behaviour of direct reclaim for large contiguous blocks. The first attempt to call shrink_page_list() is asynchronous but if it fails, the pages are submitted a second time and the calling process waits for the IO to complete. This may stall allocators waiting for contiguous memory but that should be expected behaviour for high-order users. It is preferable behaviour to potentially queueing unnecessary areas for IO. Note that kswapd will not stall in this fashion. [apw@shadowen.org: update to version 2] [apw@shadowen.org: update to version 3] Signed-off-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* synchronous lumpy reclaim: ensure we count pages transitioning inactive via ↵Andy Whitcroft2007-08-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | clear_active_flags As pointed out by Mel when reclaim is applied at higher orders a significant amount of IO may be started. As this takes finite time to drain reclaim will consider more areas than ultimatly needed to satisfy the request. This leads to more reclaim than strictly required and reduced success rates. I was able to confirm Mel's test results on systems locally. These show that even under light load the success rates drop off far more than expected. Testing with a modified version of his patch (which follows) I was able to allocate almost all of ZONE_MOVABLE with a near idle system. I ran 5 test passes sequentially following system boot (the system has 29 hugepages in ZONE_MOVABLE): 2.6.23-rc1 11 8 6 7 7 sync_lumpy 28 28 29 29 26 These show that although hugely better than the near 0% success normally expected we can only allocate about a 1/4 of the zone. Using synchronous reclaim for these allocations we get close to 100% as expected. I have also run our standard high order tests and these show no regressions in allocation success rates at rest, and some significant improvements under load. This patch: We are transitioning pages from active to inactive in clear_active_flags, those need counting as PGDEACTIVATE vm events. Signed-off-by: Andy Whitcroft <apw@shadowen.org> Acked-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>
* Freezer: make kernel threads nonfreezable by defaultRafael J. Wysocki2007-07-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, the freezer treats all tasks as freezable, except for the kernel threads that explicitly set the PF_NOFREEZE flag for themselves. This approach is problematic, since it requires every kernel thread to either set PF_NOFREEZE explicitly, or call try_to_freeze(), even if it doesn't care for the freezing of tasks at all. It seems better to only require the kernel threads that want to or need to be frozen to use some freezer-related code and to remove any freezer-related code from the other (nonfreezable) kernel threads, which is done in this patch. The patch causes all kernel threads to be nonfreezable by default (ie. to have PF_NOFREEZE set by default) and introduces the set_freezable() function that should be called by the freezable kernel threads in order to unset PF_NOFREEZE. It also makes all of the currently freezable kernel threads call set_freezable(), so it shouldn't cause any (intentional) change of behaviour to appear. Additionally, it updates documentation to describe the freezing of tasks more accurately. [akpm@linux-foundation.org: build fixes] Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Nigel Cunningham <nigel@nigel.suspend2.net> Cc: Pavel Machek <pavel@ucw.cz> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: clean up and kernelify shrinker registrationRusty Russell2007-07-17
| | | | | | | | | | | | | | | | | | | I can never remember what the function to register to receive VM pressure is called. I have to trace down from __alloc_pages() to find it. It's called "set_shrinker()", and it needs Your Help. 1) Don't hide struct shrinker. It contains no magic. 2) Don't allocate "struct shrinker". It's not helpful. 3) Call them "register_shrinker" and "unregister_shrinker". 4) Call the function "shrink" not "shrinker". 5) Reduce the 17 lines of waffly comments to 13, but document it properly. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: David Chinner <dgc@sgi.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> 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>
* Add suspend-related notifications for CPU hotplugRafael J. Wysocki2007-05-09
| | | | | | | | | | | | | | | | | | | | | Since nonboot CPUs are now disabled after tasks and devices have been frozen and the CPU hotplug infrastructure is used for this purpose, we need special CPU hotplug notifications that will help the CPU-hotplug-aware subsystems distinguish normal CPU hotplug events from CPU hotplug events related to a system-wide suspend or resume operation in progress. This patch introduces such notifications and causes them to be used during suspend and resume transitions. It also changes all of the CPU-hotplug-aware subsystems to take these notifications into consideration (for now they are handled in the same way as the corresponding "normal" ones). [oleg@tv-sign.ru: cleanups] Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Gautham R Shenoy <ego@in.ibm.com> Cc: Pavel Machek <pavel@ucw.cz> Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Factor outstanding I/O error handlingGuillaume Chazarain2007-05-08
| | | | | | | | | | Cleanup: setting an outstanding error on a mapping was open coded too many times. Factor it out in mapping_set_error(). Signed-off-by: Guillaume Chazarain <guichaz@yahoo.fr> Cc: Steven Whitehouse <swhiteho@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* freezer: fix racy usage of try_to_freeze in kswapdRafael J. Wysocki2007-05-07
| | | | | | | | | | | Currently we can miss freeze_process()->signal_wake_up() in kswapd() if it happens between try_to_freeze() and prepare_to_wait(). To prevent this from happening we should check freezing(current) before calling schedule(). Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] throttle_vm_writeout(): don't loop on GFP_NOFS and GFP_NOIO allocationsAndrew Morton2007-03-01
| | | | | | | | | | | | | | | | throttle_vm_writeout() is designed to wait for the dirty levels to subside. But if the caller holds IO or FS locks, we might be holding up that writeout. So change it to take a single nap to give other devices a chance to clean some memory, then return. Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Cc: Kumar Gala <galak@kernel.crashing.org> Cc: Pete Zaitcev <zaitcev@redhat.com> Cc: <stable@kernel.org> 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] shrink_all_memory(): fix lru_pages handlingAndrew Morton2007-01-06
| | | | | | | | | | | | | | | At the end of shrink_all_memory() we forget to recalculate lru_pages: it can be zero. Fix that up, and add a helper function for this operation too. Also, recalculate lru_pages each time around the inner loop to get the balancing correct. Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Buglet in vmscan.cShantanu Goel2006-12-30
| | | | | | | | | | Fix a rather obvious buglet. Noticed while instrumenting the VM using /proc/vmstat. Cc: Christoph Lameter <clameter@engr.sgi.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Fix swapped parameters in mm/vmscan.cNigel Cunningham2006-12-22
| | | | | | | | | | | | | The version of mm/vmscan.c in Linus' current tree has swapped parameters in the shrink_all_zones declaration and call, used by the various suspend-to-disk implementations. This doesn't seem to have any great adverse effect, but it's clearly wrong. Signed-off-by: Nigel Cunningham <nigel@suspend2.net> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] cpuset: rework cpuset_zone_allowed apiPaul Jackson2006-12-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Elaborate the API for calling cpuset_zone_allowed(), so that users have to explicitly choose between the two variants: cpuset_zone_allowed_hardwall() cpuset_zone_allowed_softwall() Until now, whether or not you got the hardwall flavor depended solely on whether or not you or'd in the __GFP_HARDWALL gfp flag to the gfp_mask argument. If you didn't specify __GFP_HARDWALL, you implicitly got the softwall version. Unfortunately, this meant that users would end up with the softwall version without thinking about it. Since only the softwall version might sleep, this led to bugs with possible sleeping in interrupt context on more than one occassion. The hardwall version requires that the current tasks mems_allowed allows the node of the specified zone (or that you're in interrupt or that __GFP_THISNODE is set or that you're on a one cpuset system.) The softwall version, depending on the gfp_mask, might allow a node if it was allowed in the nearest enclusing cpuset marked mem_exclusive (which requires taking the cpuset lock 'callback_mutex' to evaluate.) This patch removes the cpuset_zone_allowed() call, and forces the caller to explicitly choose between the hardwall and the softwall case. If the caller wants the gfp_mask to determine this choice, they should (1) be sure they can sleep or that __GFP_HARDWALL is set, and (2) invoke the cpuset_zone_allowed_softwall() routine. This adds another 100 or 200 bytes to the kernel text space, due to the few lines of nearly duplicate code at the top of both cpuset_zone_allowed_* routines. It should save a few instructions executed for the calls that turned into calls of cpuset_zone_allowed_hardwall, thanks to not having to set (before the call) then check (within the call) the __GFP_HARDWALL flag. For the most critical call, from get_page_from_freelist(), the same instructions are executed as before -- the old cpuset_zone_allowed() routine it used to call is the same code as the cpuset_zone_allowed_softwall() routine that it calls now. Not a perfect win, but seems worth it, to reduce this chance of hitting a sleeping with irq off complaint again. Signed-off-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] hotplug CPU: clean up hotcpu_notifier() useIngo Molnar2006-12-07
| | | | | | | | | | | | | | | | | | There was lots of #ifdef noise in the kernel due to hotcpu_notifier(fn, prio) not correctly marking 'fn' as used in the !HOTPLUG_CPU case, and thus generating compiler warnings of unused symbols, hence forcing people to add #ifdefs. the compiler can skip truly unused functions just fine: text data bss dec hex filename 1624412 728710 3674856 6027978 5bfaca vmlinux.before 1624412 728710 3674856 6027978 5bfaca vmlinux.after [akpm@osdl.org: topology.c fix] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Add include/linux/freezer.h and move definitions from sched.hNigel Cunningham2006-12-07
| | | | | | | | | | | | | Move process freezing functions from include/linux/sched.h to freezer.h, so that modifications to the freezer or the kernel configuration don't require recompiling just about everything. [akpm@osdl.org: fix ueagle driver] Signed-off-by: Nigel Cunningham <nigel@suspend2.net> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] swsusp: Improve handling of highmemRafael J. Wysocki2006-12-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently swsusp saves the contents of highmem pages by copying them to the normal zone which is quite inefficient (eg. it requires two normal pages to be used for saving one highmem page). This may be improved by using highmem for saving the contents of saveable highmem pages. Namely, during the suspend phase of the suspend-resume cycle we try to allocate as many free highmem pages as there are saveable highmem pages. If there are not enough highmem image pages to store the contents of all of the saveable highmem pages, some of them will be stored in the "normal" memory. Next, we allocate as many free "normal" pages as needed to store the (remaining) image data. We use a memory bitmap to mark the allocated free pages (ie. highmem as well as "normal" image pages). Now, we use another memory bitmap to mark all of the saveable pages (highmem as well as "normal") and the contents of the saveable pages are copied into the image pages. Then, the second bitmap is used to save the pfns corresponding to the saveable pages and the first one is used to save their data. During the resume phase the pfns of the pages that were saveable during the suspend are loaded from the image and used to mark the "unsafe" page frames. Next, we try to allocate as many free highmem page frames as to load all of the image data that had been in the highmem before the suspend and we allocate so many free "normal" page frames that the total number of allocated free pages (highmem and "normal") is equal to the size of the image. While doing this we have to make sure that there will be some extra free "normal" and "safe" page frames for two lists of PBEs constructed later. Now, the image data are loaded, if possible, into their "original" page frames. The image data that cannot be written into their "original" page frames are loaded into "safe" page frames and their "original" kernel virtual addresses, as well as the addresses of the "safe" pages containing their copies, are stored in one of two lists of PBEs. One list of PBEs is for the copies of "normal" suspend pages (ie. "normal" pages that were saveable during the suspend) and it is used in the same way as previously (ie. by the architecture-dependent parts of swsusp). The other list of PBEs is for the copies of highmem suspend pages. The pages in this list are restored (in a reversible way) right before the arch-dependent code is called. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] balance_pdgat() cleanupAndrew Morton2006-12-07
| | | | | | | Despaghettify balance_pdgat() a bit. Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Use min of two prio settings in calculating distress for reclaimMartin Bligh2006-10-28
| | | | | | | | | | | | | | | | | | | | | | If try_to_free_pages / balance_pgdat are called with a gfp_mask specifying GFP_IO and/or GFP_FS, they will reclaim the requisite number of pages, and the reset prev_priority to DEF_PRIORITY (or to some other high (ie: unurgent) value). However, another reclaimer without those gfp_mask flags set (say, GFP_NOIO) may still be struggling to reclaim pages. The concurrent overwrite of zone->prev_priority will cause this GFP_NOIO thread to unexpectedly cease deactivating mapped pages, thus causing reclaim difficulties. Fix this is to key the distress calculation not off zone->prev_priority, but also take into account the local caller's priority by using min(zone->prev_priority, sc->priority) Signed-off-by: Martin J. Bligh <mbligh@google.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] vmscan: Fix temp_priority raceMartin Bligh2006-10-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The temp_priority field in zone is racy, as we can walk through a reclaim path, and just before we copy it into prev_priority, it can be overwritten (say with DEF_PRIORITY) by another reclaimer. The same bug is contained in both try_to_free_pages and balance_pgdat, but it is fixed slightly differently. In balance_pgdat, we keep a separate priority record per zone in a local array. In try_to_free_pages there is no need to do this, as the priority level is the same for all zones that we reclaim from. Impact of this bug is that temp_priority is copied into prev_priority, and setting this artificially high causes reclaimers to set distress artificially low. They then fail to reclaim mapped pages, when they are, in fact, under severe memory pressure (their priority may be as low as 0). This causes the OOM killer to fire incorrectly. From: Andrew Morton <akpm@osdl.org> __zone_reclaim() isn't modifying zone->prev_priority. But zone->prev_priority is used in the decision whether or not to bring mapped pages onto the inactive list. Hence there's a risk here that __zone_reclaim() will fail because zone->prev_priority ir large (ie: low urgency) and lots of mapped pages end up stuck on the active list. Fix that up by decreasing (ie making more urgent) zone->prev_priority as __zone_reclaim() scans the zone's pages. This bug perhaps explains why ZONE_RECLAIM_PRIORITY was created. It should be possible to remove that now, and to just start out at DEF_PRIORITY? Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Christoph Lameter <clameter@engr.sgi.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] separate bdi congestion functions from queue congestion functionsAndrew Morton2006-10-20
| | | | | | | | | | | | | | | | | | | Separate out the concept of "queue congestion" from "backing-dev congestion". Congestion is a backing-dev concept, not a queue concept. The blk_* congestion functions are retained, as wrappers around the core backing-dev congestion functions. This proper layering is needed so that NFS can cleanly use the congestion functions, and so that CONFIG_BLOCK=n actually links. Cc: "Thomas Maier" <balagi@justmail.de> Cc: "Jens Axboe" <jens.axboe@oracle.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: David Howells <dhowells@redhat.com> Cc: Peter Osterlund <petero2@telia.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] invalidate: remove_mapping() fixAndrew Morton2006-10-17
| | | | | | | | | | | | | | | | | | | If remove_mapping() failed to remove the page from its mapping, don't go and mark it not uptodate! Makes kernel go dead. (Actually, I don't think the ClearPageUptodate is needed there at all). Says Nick Piggin: "Right, it isn't needed because at this point the page is guaranteed by remove_mapping to have no references (except us) and cannot pick up any new ones because it is removed from pagecache. We can delete it." Signed-off-by: Andrew Morton <akpm@osdl.org> Acked-by: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] page invalidation cleanupNick Piggin2006-09-27
| | | | | | | | | | Clean up the invalidate code, and use a common function to safely remove the page from pagecache. Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] vm: add per-zone writeout counterAndrew Morton2006-09-27
| | | | | | | | | | | | | The VM is supposed to minimise the number of pages which get written off the LRU (for IO scheduling efficiency, and for high reclaim-success rates). But we don't actually have a clear way of showing how true this is. So add `nr_vmscan_write' to /proc/vmstat and /proc/zoneinfo - the number of pages which have been written by the vm scanner in this zone and globally. Cc: Christoph Lameter <clameter@engr.sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] NUMA: Add zone_to_nid functionChristoph Lameter2006-09-26
| | | | | | | | | | | There are many places where we need to determine the node of a zone. Currently we use a difficult to read sequence of pointer dereferencing. Put that into an inline function and use throughout VM. Maybe we can find a way to optimize the lookup in the future. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] zone reclaim with slab: avoid unecessary off node allocationsChristoph Lameter2006-09-26
| | | | | | | | | | | | Minor performance fix. If we reclaimed enough slab pages from a zone then we can avoid going off node with the current allocation. Take care of updating nr_reclaimed when reclaiming from the slab. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] zone_reclaim: dynamic slab reclaimChristoph Lameter2006-09-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently one can enable slab reclaim by setting an explicit option in /proc/sys/vm/zone_reclaim_mode. Slab reclaim is then used as a final option if the freeing of unmapped file backed pages is not enough to free enough pages to allow a local allocation. However, that means that the slab can grow excessively and that most memory of a node may be used by slabs. We have had a case where a machine with 46GB of memory was using 40-42GB for slab. Zone reclaim was effective in dealing with pagecache pages. However, slab reclaim was only done during global reclaim (which is a bit rare on NUMA systems). This patch implements slab reclaim during zone reclaim. Zone reclaim occurs if there is a danger of an off node allocation. At that point we 1. Shrink the per node page cache if the number of pagecache pages is more than min_unmapped_ratio percent of pages in a zone. 2. Shrink the slab cache if the number of the nodes reclaimable slab pages (patch depends on earlier one that implements that counter) are more than min_slab_ratio (a new /proc/sys/vm tunable). The shrinking of the slab cache is a bit problematic since it is not node specific. So we simply calculate what point in the slab we want to reach (current per node slab use minus the number of pages that neeed to be allocated) and then repeately run the global reclaim until that is unsuccessful or we have reached the limit. I hope we will have zone based slab reclaim at some point which will make that easier. The default for the min_slab_ratio is 5% Also remove the slab option from /proc/sys/vm/zone_reclaim_mode. [akpm@osdl.org: cleanups] Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] ZVC: Support NR_SLAB_RECLAIMABLE / NR_SLAB_UNRECLAIMABLEChristoph Lameter2006-09-26
| | | | | | | | | | | | | Remove the atomic counter for slab_reclaim_pages and replace the counter and NR_SLAB with two ZVC counter that account for unreclaimable and reclaimable slab pages: NR_SLAB_RECLAIMABLE and NR_SLAB_UNRECLAIMABLE. Change the check in vmscan.c to refer to to NR_SLAB_RECLAIMABLE. The intend seems to be to check for slab pages that could be freed. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Replace min_unmapped_ratio by min_unmapped_pages in struct zoneChristoph Lameter2006-09-26
| | | | | | | | *_pages is a better description of the role of the variable. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] oom: reclaim_mapped on oomNick Piggin2006-09-26
| | | | | | | | | | | | | | | | | | | | | Potentially it takes several scans of the lru lists before we can even start reclaiming pages. mapped pages, with young ptes can take 2 passes on the active list + one on the inactive list. But reclaim_mapped may not always kick in instantly, so it could take even more than that. Raise the threshold for marking a zone as all_unreclaimable from a factor of 4 time the pages in the zone to 6. Introduce a mechanism to force reclaim_mapped if we've reached a factor 3 and still haven't made progress. Previously, a customer doing stress testing was able to easily OOM the box after using only a small fraction of its swap (~100MB). After the patches, it would only OOM after having used up all swap (~800MB). Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] oom: use unreclaimable infoNick Piggin2006-09-26
| | | | | | | | | | | | __alloc_pages currently starts shooting if page reclaim has failed to free up swap_cluster_max pages in one run through the priorities. This is not always a good indicator on its own, so make use of the all_unreclaimable logic as well: don't consider going OOM until all zones we're interested in are unreclaimable. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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