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* 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>
* cpu hotplug: slab: fix memory leak in cpu hotplug error pathAkinobu Mita2007-10-18
| | | | | | | | | | | | | | | | This patch fixes memory leak in error path. In reality, we don't need to call cpuup_canceled(cpu) for now. But upcoming cpu hotplug error handling change needs this. Cc: Christoph Lameter <clameter@sgi.com> Cc: Gautham R Shenoy <ego@in.ibm.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Gautham R Shenoy <ego@in.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpu hotplug: slab: cleanup cpuup_callback()Akinobu Mita2007-10-18
| | | | | | | | | | | | | cpuup_callback() is too long. This patch factors out CPU_UP_CANCELLED and CPU_UP_PREPARE handlings from cpuup_callback(). Cc: Christoph Lameter <clameter@sgi.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Gautham R Shenoy <ego@in.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'xen-upstream' of ↵Linus Torvalds2007-10-17
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen * 'xen-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen: xfs: eagerly remove vmap mappings to avoid upsetting Xen xen: add some debug output for failed multicalls xen: fix incorrect vcpu_register_vcpu_info hypercall argument xen: ask the hypervisor how much space it needs reserved xen: lock pte pages while pinning/unpinning xen: deal with stale cr3 values when unpinning pagetables xen: add batch completion callbacks xen: yield to IPI target if necessary Clean up duplicate includes in arch/i386/xen/ remove dead code in pgtable_cache_init paravirt: clean up lazy mode handling paravirt: refactor struct paravirt_ops into smaller pv_*_ops
| * xen: lock pte pages while pinning/unpinningJeremy Fitzhardinge2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When a pagetable is created, it is made globally visible in the rmap prio tree before it is pinned via arch_dup_mmap(), and remains in the rmap tree while it is unpinned with arch_exit_mmap(). This means that other CPUs may race with the pinning/unpinning process, and see a pte between when it gets marked RO and actually pinned, causing any pte updates to fail with write-protect faults. As a result, all pte pages must be properly locked, and only unlocked once the pinning/unpinning process has finished. In order to avoid taking spinlocks for the whole pagetable - which may overflow the PREEMPT_BITS portion of preempt counter - it locks and pins each pte page individually, and then finally pins the whole pagetable. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickens <hugh@veritas.com> Cc: David Rientjes <rientjes@google.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andi Kleen <ak@suse.de> Cc: Keir Fraser <keir@xensource.com> Cc: Jan Beulich <jbeulich@novell.com>
* | security/ cleanupsAdrian Bunk2007-10-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch contains the following cleanups that are now possible: - remove the unused security_operations->inode_xattr_getsuffix - remove the no longer used security_operations->unregister_security - remove some no longer required exit code - remove a bunch of no longer used exports Signed-off-by: Adrian Bunk <bunk@kernel.org> Acked-by: James Morris <jmorris@namei.org> Cc: Chris Wright <chrisw@sous-sol.org> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: Serge Hallyn <serue@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Implement file posix capabilitiesSerge E. Hallyn2007-10-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Implement file posix capabilities. This allows programs to be given a subset of root's powers regardless of who runs them, without having to use setuid and giving the binary all of root's powers. This version works with Kaigai Kohei's userspace tools, found at http://www.kaigai.gr.jp/index.php. For more information on how to use this patch, Chris Friedhoff has posted a nice page at http://www.friedhoff.org/fscaps.html. Changelog: Nov 27: Incorporate fixes from Andrew Morton (security-introduce-file-caps-tweaks and security-introduce-file-caps-warning-fix) Fix Kconfig dependency. Fix change signaling behavior when file caps are not compiled in. Nov 13: Integrate comments from Alexey: Remove CONFIG_ ifdef from capability.h, and use %zd for printing a size_t. Nov 13: Fix endianness warnings by sparse as suggested by Alexey Dobriyan. Nov 09: Address warnings of unused variables at cap_bprm_set_security when file capabilities are disabled, and simultaneously clean up the code a little, by pulling the new code into a helper function. Nov 08: For pointers to required userspace tools and how to use them, see http://www.friedhoff.org/fscaps.html. Nov 07: Fix the calculation of the highest bit checked in check_cap_sanity(). Nov 07: Allow file caps to be enabled without CONFIG_SECURITY, since capabilities are the default. Hook cap_task_setscheduler when !CONFIG_SECURITY. Move capable(TASK_KILL) to end of cap_task_kill to reduce audit messages. Nov 05: Add secondary calls in selinux/hooks.c to task_setioprio and task_setscheduler so that selinux and capabilities with file cap support can be stacked. Sep 05: As Seth Arnold points out, uid checks are out of place for capability code. Sep 01: Define task_setscheduler, task_setioprio, cap_task_kill, and task_setnice to make sure a user cannot affect a process in which they called a program with some fscaps. One remaining question is the note under task_setscheduler: are we ok with CAP_SYS_NICE being sufficient to confine a process to a cpuset? It is a semantic change, as without fsccaps, attach_task doesn't allow CAP_SYS_NICE to override the uid equivalence check. But since it uses security_task_setscheduler, which elsewhere is used where CAP_SYS_NICE can be used to override the uid equivalence check, fixing it might be tough. task_setscheduler note: this also controls cpuset:attach_task. Are we ok with CAP_SYS_NICE being used to confine to a cpuset? task_setioprio task_setnice sys_setpriority uses this (through set_one_prio) for another process. Need same checks as setrlimit Aug 21: Updated secureexec implementation to reflect the fact that euid and uid might be the same and nonzero, but the process might still have elevated caps. Aug 15: Handle endianness of xattrs. Enforce capability version match between kernel and disk. Enforce that no bits beyond the known max capability are set, else return -EPERM. With this extra processing, it may be worth reconsidering doing all the work at bprm_set_security rather than d_instantiate. Aug 10: Always call getxattr at bprm_set_security, rather than caching it at d_instantiate. [morgan@kernel.org: file-caps clean up for linux/capability.h] [bunk@kernel.org: unexport cap_inode_killpriv] Signed-off-by: Serge E. Hallyn <serue@us.ibm.com> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: James Morris <jmorris@namei.org> Cc: Chris Wright <chrisw@sous-sol.org> Cc: Andrew Morgan <morgan@kernel.org> Signed-off-by: Andrew Morgan <morgan@kernel.org> Signed-off-by: Adrian Bunk <bunk@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | remap_file_pages: kernel-doc correctionsRandy Dunlap2007-10-17
| | | | | | | | | | | | | | | | | | | | Fix kernel-doc for sys_remap_file_pages() and add info to the 'prot' NOTE. Rename __prot parameter to prot. Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Acked-by: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | r/o bind mounts: filesystem helpers for custom 'struct file'sDave Hansen2007-10-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Why do we need r/o bind mounts? This feature allows a read-only view into a read-write filesystem. In the process of doing that, it also provides infrastructure for keeping track of the number of writers to any given mount. This has a number of uses. It allows chroots to have parts of filesystems writable. It will be useful for containers in the future because users may have root inside a container, but should not be allowed to write to somefilesystems. This also replaces patches that vserver has had out of the tree for several years. It allows security enhancement by making sure that parts of your filesystem read-only (such as when you don't trust your FTP server), when you don't want to have entire new filesystems mounted, or when you want atime selectively updated. I've been using the following script to test that the feature is working as desired. It takes a directory and makes a regular bind and a r/o bind mount of it. It then performs some normal filesystem operations on the three directories, including ones that are expected to fail, like creating a file on the r/o mount. This patch: Some filesystems forego the vfs and may_open() and create their own 'struct file's. This patch creates a couple of helper functions which can be used by these filesystems, and will provide a unified place which the r/o bind mount code may patch. Also, rename an existing, static-scope init_file() to a less generic name. Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | writeback: remove unnecessary wait in throttle_vm_writeout()Fengguang Wu2007-10-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We don't want to introduce pointless delays in throttle_vm_writeout() when the writeback limits are not yet exceeded, do we? 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: Greg KH <greg@kroah.com> Reviewed-by: Rik van Riel <riel@redhat.com> 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>
* | introduce I_SYNCJoern Engel2007-10-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I_LOCK was used for several unrelated purposes, which caused deadlock situations in certain filesystems as a side effect. One of the purposes now uses the new I_SYNC bit. Also document the various bits and change their order from historical to logical. [bunk@stusta.de: make fs/inode.c:wake_up_inode() static] Signed-off-by: Joern Engel <joern@wohnheim.fh-wedel.de> Cc: Dave Kleikamp <shaggy@linux.vnet.ibm.com> Cc: David Chinner <dgc@sgi.com> Cc: Anton Altaparmakov <aia21@cam.ac.uk> Cc: Al Viro <viro@ftp.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | writeback: introduce writeback_control.more_io to indicate more ioFengguang Wu2007-10-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After making dirty a 100M file, the normal behavior is to start the writeback for all data after 30s delays. But sometimes the following happens instead: - after 30s: ~4M - after 5s: ~4M - after 5s: all remaining 92M Some analyze shows that the internal io dispatch queues goes like this: s_io s_more_io ------------------------- 1) 100M,1K 0 2) 1K 96M 3) 0 96M 1) initial state with a 100M file and a 1K file 2) 4M written, nr_to_write <= 0, so write more 3) 1K written, nr_to_write > 0, no more writes(BUG) nr_to_write > 0 in (3) fools the upper layer to think that data have all been written out. The big dirty file is actually still sitting in s_more_io. We cannot simply splice s_more_io back to s_io as soon as s_io becomes empty, and let the loop in generic_sync_sb_inodes() continue: this may starve newly expired inodes in s_dirty. It is also not an option to draw inodes from both s_more_io and s_dirty, an let the loop go on: this might lead to live locks, and might also starve other superblocks in sync time(well kupdate may still starve some superblocks, that's another bug). We have to return when a full scan of s_io completes. So nr_to_write > 0 does not necessarily mean that "all data are written". This patch introduces a flag writeback_control.more_io to indicate this situation. With it the big dirty file no longer has to wait for the next kupdate invocation 5s later. Cc: David Chinner <dgc@sgi.com> Cc: Ken Chen <kenchen@google.com> 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>
* | Delete gcc-2.95 compatible structure definition.Robert P. J. Day2007-10-17
| | | | | | | | | | | | | | | | | | Since nothing earlier than gcc-3.2 is supported for kernel compilation, that 2.95 hack can be removed. Signed-off-by: Robert P. J. Day <rpjday@mindspring.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Drop some headers from mm.hAlexey Dobriyan2007-10-17
| | | | | | | | | | | | | | | | | | | | | | mm.h doesn't use directly anything from mutex.h and backing-dev.h, so remove them and add them back to files which need them. Cross-compile tested on many configs and archs. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | SLAB_PANIC more (proc, posix-timers, shmem)Alexey Dobriyan2007-10-17
| | | | | | | | | | | | | | | | These aren't modular, so SLAB_PANIC is OK. Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | writeback: don't propagate AOP_WRITEPAGE_ACTIVATEAndrew Morton2007-10-17
| | | | | | | | | | | | | | | | | | This is a writeback-internal marker but we're propagating it all the way back to userspace!. Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: document tree_lock->zone.lock lockorderNick Piggin2007-10-17
| | | | | | | | | | | | | | | | | | | | | | | | | | zone->lock is quite an "inner" lock and mostly constrained to page alloc as well, so like slab locks, it probably isn't something that is critically important to document here. However unlike slab locks, zone lock could be used more widely in future, and page_alloc.c might possibly have more business to do tricky things with pagecache than does slab. So... I don't think it hurts to document it. Signed-off-by: Nick Piggin <npiggin@suse.de> 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: convert zone_scan_lock from mutex to spinlockDavid Rientjes2007-10-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | There's no reason to sleep in try_set_zone_oom() or clear_zonelist_oom() if the lock can't be acquired; it will be available soon enough once the zonelist scanning is done. All other threads waiting for the OOM killer are also contingent on the exiting task being able to acquire the lock in clear_zonelist_oom() so it doesn't make sense to put it to sleep. 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: do not take callback_mutexDavid Rientjes2007-10-17
| | | | | | | | | | | | | | | | | | | | | | | | Since no task descriptor's 'cpuset' field is dereferenced in the execution of the OOM killer anymore, it is no longer necessary to take callback_mutex. [akpm@linux-foundation.org: restore cpuset_lock for other patches] 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>
* | oom: compare cpuset mems_allowed instead of exclusive ancestorsDavid Rientjes2007-10-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of testing for overlap in the memory nodes of the the nearest exclusive ancestor of both current and the candidate task, it is better to simply test for intersection between the task's mems_allowed in their task descriptors. This does not require taking callback_mutex since it is only used as a hint in the badness scoring. Tasks that do not have an intersection in their mems_allowed with the current task are not explicitly restricted from being OOM killed because it is quite possible that the candidate task has allocated memory there before and has since changed its mems_allowed. 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>
* | oom: suppress extraneous stack and memory dumpDavid Rientjes2007-10-17
| | | | | | | | | | | | | | | | | | | | | | | | | | Suppresses the extraneous stack and memory dump when a parallel OOM killing has been found. There's no need to fill the ring buffer with this information if its already been printed and the condition that triggered the previous OOM killer has not yet been alleviated. 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>
* | oom: add oom_kill_allocating_task sysctlDavid Rientjes2007-10-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Adds a new sysctl, 'oom_kill_allocating_task', which will automatically kill the OOM-triggering task instead of scanning through the tasklist to find a memory-hogging target. This is helpful for systems with an insanely large number of tasks where scanning the tasklist significantly degrades performance. 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>
* | oom: serialize out of memory callsDavid Rientjes2007-10-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A final allocation attempt with a very high watermark needs to be attempted before invoking out_of_memory(). OOM killer serialization needs to occur before this final attempt, otherwise tasks attempting to OOM-lock all zones in its zonelist may spin and acquire the lock unnecessarily after the OOM condition has already been alleviated. If the final allocation does succeed, the zonelist is simply OOM-unlocked and __alloc_pages() returns the page. Otherwise, the OOM killer is invoked. If the task cannot acquire OOM-locks on all zones in its zonelist, it is put to sleep and the allocation is retried when it gets rescheduled. One of its zones is already marked as being in the OOM killer so it'll hopefully be getting some free memory soon, at least enough to satisfy a high watermark allocation attempt. This prevents needlessly killing a task when the OOM condition would have already been alleviated if it had simply been given enough time. 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>
* | 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>
* | oom: move constraints to enumDavid Rientjes2007-10-17
| | | | | | | | | | | | | | | | | | | | | | The OOM killer's CONSTRAINT definitions are really more appropriate in an enum, so define them in include/linux/oom.h. 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>
* | oom: move prototypes to appropriate header fileDavid Rientjes2007-10-17
| | | | | | | | | | | | | | | | | | | | | | | | | | Move the OOM killer's extern function prototypes to include/linux/oom.h and include it where necessary. [clg@fr.ibm.com: build fix] Cc: Andrea Arcangeli <andrea@suse.de> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Cedric Le Goater <clg@fr.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Slab API: remove useless ctor parameter and reorder parametersChristoph Lameter2007-10-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Slab constructors currently have a flags parameter that is never used. And the order of the arguments is opposite to other slab functions. The object pointer is placed before the kmem_cache pointer. Convert ctor(void *object, struct kmem_cache *s, unsigned long flags) to ctor(struct kmem_cache *s, void *object) throughout the kernel [akpm@linux-foundation.org: coupla fixes] 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>
* | SLUB: simplify IRQ off handlingChristoph Lameter2007-10-17
| | | | | | | | | | | | | | | | | | | | Move irq handling out of new slab into __slab_alloc. That is useful for Mathieu's cmpxchg_local patchset and also allows us to remove the crude local_irq_off in early_kmem_cache_alloc(). 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>
* | mm: dirty balancing for tasksPeter Zijlstra2007-10-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Based on ideas of Andrew: http://marc.info/?l=linux-kernel&m=102912915020543&w=2 Scale the bdi dirty limit inversly with the tasks dirty rate. This makes heavy writers have a lower dirty limit than the occasional writer. Andrea proposed something similar: http://lwn.net/Articles/152277/ The main disadvantage to his patch is that he uses an unrelated quantity to measure time, which leaves him with a workload dependant tunable. Other than that the two approaches appear quite similar. [akpm@linux-foundation.org: fix warning] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: per device dirty thresholdPeter Zijlstra2007-10-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Scale writeback cache per backing device, proportional to its writeout speed. By decoupling the BDI dirty thresholds a number of problems we currently have will go away, namely: - mutual interference starvation (for any number of BDIs); - deadlocks with stacked BDIs (loop, FUSE and local NFS mounts). It might be that all dirty pages are for a single BDI while other BDIs are idling. By giving each BDI a 'fair' share of the dirty limit, each one can have dirty pages outstanding and make progress. A global threshold also creates a deadlock for stacked BDIs; when A writes to B, and A generates enough dirty pages to get throttled, B will never start writeback until the dirty pages go away. Again, by giving each BDI its own 'independent' dirty limit, this problem is avoided. So the problem is to determine how to distribute the total dirty limit across the BDIs fairly and efficiently. A DBI that has a large dirty limit but does not have any dirty pages outstanding is a waste. What is done is to keep a floating proportion between the DBIs based on writeback completions. This way faster/more active devices get a larger share than slower/idle devices. [akpm@linux-foundation.org: fix warnings] [hugh@veritas.com: Fix occasional hang when a task couldn't get out of balance_dirty_pages] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> 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: count writeback pages per BDIPeter Zijlstra2007-10-17
| | | | | | | | | | | | | | | | Count per BDI writeback pages. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: count reclaimable pages per BDIPeter Zijlstra2007-10-17
| | | | | | | | | | | | | | | | Count per BDI reclaimable pages; nr_reclaimable = nr_dirty + nr_unstable. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: scalable bdi statistics countersPeter Zijlstra2007-10-17
| | | | | | | | | | | | | | | | Provide scalable per backing_dev_info statistics counters. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: bdi init hooksPeter Zijlstra2007-10-17
| | | | | | | | | | | | | | | | | | provide BDI constructor/destructor hooks [akpm@linux-foundation.org: compile fix] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | nfs: remove congestion_end()Peter Zijlstra2007-10-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | These patches aim to improve balance_dirty_pages() and directly address three issues: 1) inter device starvation 2) stacked device deadlocks 3) inter process starvation 1 and 2 are a direct result from removing the global dirty limit and using per device dirty limits. By giving each device its own dirty limit is will no longer starve another device, and the cyclic dependancy on the dirty limit is broken. In order to efficiently distribute the dirty limit across the independant devices a floating proportion is used, this will allocate a share of the total limit proportional to the device's recent activity. 3 is done by also scaling the dirty limit proportional to the current task's recent dirty rate. This patch: nfs: remove congestion_end(). It's redundant, clear_bdi_congested() already wakes the waiters. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: "J. Bruce Fields" <bfields@fieldses.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Merge branch 'for-linus' of git://git.kernel.dk/data/git/linux-2.6-blockLinus Torvalds2007-10-16
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 'for-linus' of git://git.kernel.dk/data/git/linux-2.6-block: (63 commits) Fix memory leak in dm-crypt SPARC64: sg chaining support SPARC: sg chaining support PPC: sg chaining support PS3: sg chaining support IA64: sg chaining support x86-64: enable sg chaining x86-64: update pci-gart iommu to sg helpers x86-64: update nommu to sg helpers x86-64: update calgary iommu to sg helpers swiotlb: sg chaining support i386: enable sg chaining i386 dma_map_sg: convert to using sg helpers mmc: need to zero sglist on init Panic in blk_rq_map_sg() from CCISS driver remove sglist_len remove blk_queue_max_phys_segments in libata revert sg segment size ifdefs Fixup u14-34f ENABLE_SG_CHAINING qla1280: enable use_sg_chaining option ...
| * | block: Initial support for data-less (or empty) barrier supportJens Axboe2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | This implements functionality to pass down or insert a barrier in a queue, without having data attached to it. The ->prepare_flush_fn() infrastructure from data barriers are reused to provide this functionality. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* | | mm/vmstat.c: cleanupsAdrian Bunk2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch contains the following cleanups: - make the needlessly global setup_vmstat() static - remove the unused refresh_vm_stats() Signed-off-by: Adrian Bunk <bunk@stusta.de> 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>
* | | mm/mempolicy.c: cleanupsAdrian Bunk2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch contains the following cleanups: - every file should include the headers containing the prototypes for its global functions - make the follosing needlessly global functions static: - migrate_to_node() - do_mbind() - sp_alloc() - mpol_rebind_policy() [akpm@linux-foundation.org: fix uninitialised var warning] Signed-off-by: Adrian Bunk <bunk@stusta.de> 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>
* | | mm/shmem.c: make 3 functions staticAdrian Bunk2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | This patch makes three needlessly global functions static. Signed-off-by: Adrian Bunk <bunk@stusta.de> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | hugetlb: fix dynamic pool resize failure caseAdam Litke2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When gather_surplus_pages() fails to allocate enough huge pages to satisfy the requested reservation, it frees what it did allocate back to the buddy allocator. put_page() should be called instead of update_and_free_page() to ensure that pool counters are updated as appropriate and the page's refcount is decremented. Signed-off-by: Adam Litke <agl@us.ibm.com> Acked-by: Dave Hansen <haveblue@us.ibm.com> Cc: David Gibson <hermes@gibson.dropbear.id.au> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: Badari Pulavarty <pbadari@us.ibm.com> Cc: Ken Chen <kenchen@google.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | hugetlb: fix hugepage allocation with memoryless nodesNishanth Aravamudan2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Anton found a problem with the hugetlb pool allocation when some nodes have no memory (http://marc.info/?l=linux-mm&m=118133042025995&w=2). Lee worked on versions that tried to fix it, but none were accepted. Christoph has created a set of patches which allow for GFP_THISNODE allocations to fail if the node has no memory. Currently, alloc_fresh_huge_page() returns NULL when it is not able to allocate a huge page on the current node, as specified by its custom interleave variable. The callers of this function, though, assume that a failure in alloc_fresh_huge_page() indicates no hugepages can be allocated on the system period. This might not be the case, for instance, if we have an uneven NUMA system, and we happen to try to allocate a hugepage on a node with less memory and fail, while there is still plenty of free memory on the other nodes. To correct this, make alloc_fresh_huge_page() search through all online nodes before deciding no hugepages can be allocated. Add a helper function for actually allocating the hugepage. Use a new global nid iterator to control which nid to allocate on. Note: we expect particular semantics for __GFP_THISNODE, which are now enforced even for memoryless nodes. That is, there is should be no fallback to other nodes. Therefore, we rely on the nid passed into alloc_pages_node() to be the nid the page comes from. If this is incorrect, accounting will break. Tested on x86 !NUMA, x86 NUMA, x86_64 NUMA and ppc64 NUMA (with 2 memoryless nodes). Before on the ppc64 box: Trying to clear the hugetlb pool Done. 0 free Trying to resize the pool to 100 Node 0 HugePages_Free: 25 Node 1 HugePages_Free: 75 Node 2 HugePages_Free: 0 Node 3 HugePages_Free: 0 Done. Initially 100 free Trying to resize the pool to 200 Node 0 HugePages_Free: 50 Node 1 HugePages_Free: 150 Node 2 HugePages_Free: 0 Node 3 HugePages_Free: 0 Done. 200 free After: Trying to clear the hugetlb pool Done. 0 free Trying to resize the pool to 100 Node 0 HugePages_Free: 50 Node 1 HugePages_Free: 50 Node 2 HugePages_Free: 0 Node 3 HugePages_Free: 0 Done. Initially 100 free Trying to resize the pool to 200 Node 0 HugePages_Free: 100 Node 1 HugePages_Free: 100 Node 2 HugePages_Free: 0 Node 3 HugePages_Free: 0 Done. 200 free Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com> Acked-by: Christoph Lameter <clameter@sgi.com> Cc: Adam Litke <agl@us.ibm.com> Cc: David Gibson <hermes@gibson.dropbear.id.au> Cc: Badari Pulavarty <pbadari@us.ibm.com> Cc: Ken Chen <kenchen@google.com> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> 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>
* | | hugetlb: fix pool resizing corner caseAdam Litke2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When shrinking the size of the hugetlb pool via the nr_hugepages sysctl, we are careful to keep enough pages around to satisfy reservations. But the calculation is flawed for the following scenario: Action Pool Counters (Total, Free, Resv) ====== ============= Set pool to 1 page 1 1 0 Map 1 page MAP_PRIVATE 1 1 0 Touch the page to fault it in 1 0 0 Set pool to 3 pages 3 2 0 Map 2 pages MAP_SHARED 3 2 2 Set pool to 2 pages 2 1 2 <-- Mistake, should be 3 2 2 Touch the 2 shared pages 2 0 1 <-- Program crashes here The last touch above will terminate the process due to lack of huge pages. This patch corrects the calculation so that it factors in pages being used for private mappings. Andrew, this is a standalone fix suitable for mainline. It is also now corrected in my latest dynamic pool resizing patchset which I will send out soon. Signed-off-by: Adam Litke <agl@us.ibm.com> Acked-by: Ken Chen <kenchen@google.com> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: Badari Pulavarty <pbadari@us.ibm.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>
* | | hugetlb: Add hugetlb_dynamic_pool sysctlAdam Litke2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The maximum size of the huge page pool can be controlled using the overall size of the hugetlb filesystem (via its 'size' mount option). However in the common case the this will not be set as the pool is traditionally fixed in size at boot time. In order to maintain the expected semantics, we need to prevent the pool expanding by default. This patch introduces a new sysctl controlling dynamic pool resizing. When this is enabled the pool will expand beyond its base size up to the size of the hugetlb filesystem. It is disabled by default. Signed-off-by: Adam Litke <agl@us.ibm.com> Acked-by: Andy Whitcroft <apw@shadowen.org> Acked-by: Dave McCracken <dave.mccracken@oracle.com> Cc: William Irwin <bill.irwin@oracle.com> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: Ken Chen <kenchen@google.com> Cc: Badari Pulavarty <pbadari@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | hugetlb: Try to grow hugetlb pool for MAP_SHARED mappingsAdam Litke2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Shared mappings require special handling because the huge pages needed to fully populate the VMA must be reserved at mmap time. If not enough pages are available when making the reservation, allocate all of the shortfall at once from the buddy allocator and add the pages directly to the hugetlb pool. If they cannot be allocated, then fail the mapping. The page surplus is accounted for in the same way as for private mappings; faulted surplus pages will be freed at unmap time. Reserved, surplus pages that have not been used must be freed separately when their reservation has been released. Signed-off-by: Adam Litke <agl@us.ibm.com> Acked-by: Andy Whitcroft <apw@shadowen.org> Acked-by: Dave McCracken <dave.mccracken@oracle.com> Cc: William Irwin <bill.irwin@oracle.com> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: Ken Chen <kenchen@google.com> Cc: Badari Pulavarty <pbadari@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | hugetlb: Try to grow hugetlb pool for MAP_PRIVATE mappingsAdam Litke2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Because we overcommit hugepages for MAP_PRIVATE mappings, it is possible that the hugetlb pool will be exhausted or completely reserved when a hugepage is needed to satisfy a page fault. Before killing the process in this situation, try to allocate a hugepage directly from the buddy allocator. The explicitly configured pool size becomes a low watermark. When dynamically grown, the allocated huge pages are accounted as a surplus over the watermark. As huge pages are freed on a node, surplus pages are released to the buddy allocator so that the pool will shrink back to the watermark. Surplus accounting also allows for friendlier explicit pool resizing. When shrinking a pool that is fully in-use, increase the surplus so pages will be returned to the buddy allocator as soon as they are freed. When growing a pool that has a surplus, consume the surplus first and then allocate new pages. Signed-off-by: Adam Litke <agl@us.ibm.com> Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Andy Whitcroft <apw@shadowen.org> Acked-by: Dave McCracken <dave.mccracken@oracle.com> Cc: William Irwin <bill.irwin@oracle.com> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: Ken Chen <kenchen@google.com> Cc: Badari Pulavarty <pbadari@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | hugetlb: Move update_and_free_pageAdam Litke2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Dynamic huge page pool resizing. In most real-world scenarios, configuring the size of the hugetlb pool correctly is a difficult task. If too few pages are allocated to the pool, applications using MAP_SHARED may fail to mmap() a hugepage region and applications using MAP_PRIVATE may receive SIGBUS. Isolating too much memory in the hugetlb pool means it is not available for other uses, especially those programs not using huge pages. The obvious answer is to let the hugetlb pool grow and shrink in response to the runtime demand for huge pages. The work Mel Gorman has been doing to establish a memory zone for movable memory allocations makes dynamically resizing the hugetlb pool reliable within the limits of that zone. This patch series implements dynamic pool resizing for private and shared mappings while being careful to maintain existing semantics. Please reply with your comments and feedback; even just to say whether it would be a useful feature to you. Thanks. How it works ============ Upon depletion of the hugetlb pool, rather than reporting an error immediately, first try and allocate the needed huge pages directly from the buddy allocator. Care must be taken to avoid unbounded growth of the hugetlb pool, so the hugetlb filesystem quota is used to limit overall pool size. The real work begins when we decide there is a shortage of huge pages. What happens next depends on whether the pages are for a private or shared mapping. Private mappings are straightforward. At fault time, if alloc_huge_page() fails, we allocate a page from the buddy allocator and increment the source node's surplus_huge_pages counter. When free_huge_page() is called for a page on a node with a surplus, the page is freed directly to the buddy allocator instead of the hugetlb pool. Because shared mappings require all of the pages to be reserved up front, some additional work must be done at mmap() to support them. We determine the reservation shortage and allocate the required number of pages all at once. These pages are then added to the hugetlb pool and marked reserved. Where that is not possible the mmap() will fail. As with private mappings, the appropriate surplus counters are updated. Since reserved huge pages won't necessarily be used by the process, we can't be sure that free_huge_page() will always be called to return surplus pages to the buddy allocator. To prevent the huge page pool from bloating, we must free unused surplus pages when their reservation has ended. Controlling it ============== With the entire patch series applied, pool resizing is off by default so unless specific action is taken, the semantics are unchanged. To take advantage of the flexibility afforded by this patch series one must tolerate a change in semantics. To control hugetlb pool growth, the following techniques can be employed: * A sysctl tunable to enable/disable the feature entirely * The size= mount option for hugetlbfs filesystems to limit pool size Performance =========== When contiguous memory is readily available, it is expected that the cost of dynamicly resizing the pool will be small. This series has been performance tested with 'stream' to measure this cost. Stream (http://www.cs.virginia.edu/stream/) was linked with libhugetlbfs to enable remapping of the text and data/bss segments into huge pages. Stream with small array ----------------------- Baseline: nr_hugepages = 0, No libhugetlbfs segment remapping Preallocated: nr_hugepages = 5, Text and data/bss remapping Dynamic: nr_hugepages = 0, Text and data/bss remapping Rate (MB/s) Function Baseline Preallocated Dynamic Copy: 4695.6266 5942.8371 5982.2287 Scale: 4451.5776 5017.1419 5658.7843 Add: 5815.8849 7927.7827 8119.3552 Triad: 5949.4144 8527.6492 8110.6903 Stream with large array ----------------------- Baseline: nr_hugepages = 0, No libhugetlbfs segment remapping Preallocated: nr_hugepages = 67, Text and data/bss remapping Dynamic: nr_hugepages = 0, Text and data/bss remapping Rate (MB/s) Function Baseline Preallocated Dynamic Copy: 2227.8281 2544.2732 2546.4947 Scale: 2136.3208 2430.7294 2421.2074 Add: 2773.1449 4004.0021 3999.4331 Triad: 2748.4502 3777.0109 3773.4970 * All numbers are averages taken from 10 consecutive runs with a maximum standard deviation of 1.3 percent noted. This patch: Simply move update_and_free_page() so that it can be reused later in this patch series. The implementation is not changed. Signed-off-by: Adam Litke <agl@us.ibm.com> Acked-by: Andy Whitcroft <apw@shadowen.org> Acked-by: Dave McCracken <dave.mccracken@oracle.com> Acked-by: William Irwin <bill.irwin@oracle.com> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: Ken Chen <kenchen@google.com> Cc: Badari Pulavarty <pbadari@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | memory hotplug: Hot-add with sparsemem-vmemmapYasunori Goto2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch is to avoid panic when memory hot-add is executed with sparsemem-vmemmap. Current vmemmap-sparsemem code doesn't support memory hot-add. Vmemmap must be populated when hot-add. This is for 2.6.23-rc2-mm2. Todo: # Even if this patch is applied, the message "[xxxx-xxxx] potential offnode page_structs" is displayed. To allocate memmap on its node, memmap (and pgdat) must be initialized itself like chicken and egg relationship. # vmemmap_unpopulate will be necessary for followings. - For cancel hot-add due to error. - For unplug. Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com> Cc: Andy Whitcroft <apw@shadowen.org> Cc: Christoph Lameter <clameter@sgi.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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