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* [PATCH] Make vm86 support optionalMatt Mackall2006-01-081-0/+2
| | | | | | | | | | | | | | | | | | | This adds an option to remove vm86 support under CONFIG_EMBEDDED. Saves about 5k. This version eliminates most of the #ifdefs of the previous version and instead uses function stubs in vm86.h. Also, release_vm86_irqs is moved from asm-i386/irq.h to a more appropriate home in vm86.h so that the stubs can live together. $ size vmlinux-baseline vmlinux-novm86 text data bss dec hex filename 2920821 523232 190652 3634705 377611 vmlinux-baseline 2916268 523100 190492 3629860 376324 vmlinux-novm86 Signed-off-by: Matt Mackall <mpm@selenic.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] tiny: Make *[ug]id16 support optionalMatt Mackall2006-01-081-0/+19
| | | | | | | | | | | | | | | | | | | Configurable 16-bit UID and friends support This allows turning off the legacy 16 bit UID interfaces on embedded platforms. text data bss dec hex filename 3330172 529036 190556 4049764 3dcb64 vmlinux-baseline 3328268 529040 190556 4047864 3dc3f8 vmlinux From: Adrian Bunk <bunk@stusta.de> UID16 was accidentially disabled for !EMBEDDED. Signed-off-by: Matt Mackall <mpm@selenic.com> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] simplify k_getrusage()Oleg Nesterov2006-01-081-18/+11
| | | | | | | | | | | Factor out common code for different RUSAGE_xxx cases. Don't take ->sighand->siglock in RUSAGE_SELF case, suggested by Ravikiran G Thirumalai <kiran@scalex86.org>. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] fix workqueue oops during cpu offlineNathan Lynch2006-01-081-6/+10
| | | | | | | | | | | | | | | | | | | | | | | Use first_cpu(cpu_possible_map) for the single-thread workqueue case. We used to hardcode 0, but that broke on systems where !cpu_possible(0) when workqueue_struct->cpu_workqueue_struct was changed from a static array to alloc_percpu. Commit id bce61dd49d6ba7799be2de17c772e4c701558f14 ("Fix hardcoded cpu=0 in workqueue for per_cpu_ptr() calls") fixed that for Ben's funky sparc64 system, but it regressed my Power5. Offlining cpu 0 oopses upon the next call to queue_work for a single-thread workqueue, because now we try to manipulate per_cpu_ptr(wq->cpu_wq, 1), which is uninitialized. So we need to establish an unchanging "slot" for single-thread workqueues which will have a valid percpu allocation. Since alloc_percpu keys off of cpu_possible_map, which must not change after initialization, make this slot == first_cpu(cpu_possible_map). Signed-off-by: Nathan Lynch <ntl@pobox.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] kernel/module.c: remove redundant spinlock in resolve_symbol()Ashutosh Naik2006-01-081-2/+0
| | | | | | | | | | Remove the redundant spinlock in the function resolve_symbol() as we are not altering the module list, and we already hold the semaphore. Signed-off-by: Ashutosh Naik <ashutosh.naik@gmail.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] modules: mark TAINT_FORCED_RMMOD correctlyAkinobu Mita2006-01-081-5/+5
| | | | | | | | | | | | Currently TAINT_FORCED_RMMOD is totally unused. Because it is marked as TAINT_FORCED_MODULE instead when user forced a module unload. This patch marks it correctly Signed-off-by: Akinobu Mita <mita@miraclelinux.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Dave Jones <davej@codemonkey.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] modules: prevent overriding of symbolsAshutosh Naik2006-01-081-0/+39
| | | | | | | | | | | | | Ensure that an exported symbol does not already exist in the kernel or in some other module's exported symbol table. This is done by checking the symbol tables for the exported symbol at the time of loading the module. Currently this is done after the relocation of the symbol. Signed-off-by: Ashutosh Naik <ashutosh.naik@gmail.com> Signed-off-by: Anand Krishnan <anandhkrishnan@yahoo.co.in> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] copy_process: error path cleanupOleg Nesterov2006-01-081-6/+2
| | | | | | | | | | This patch moves 'fork_out:' under 'bad_fork_free:', and removes now unneeded 'if (retval)' check. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] setpgid: should not accept ptraced childsOleg Nesterov2006-01-081-1/+1
| | | | | | | | | | | | | sys_setpgid() allows to change ->pgrp of ptraced childs. 'man setpgid' does not tell anything about that, so I consider this behaviour is a bug. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Oren Laadan <orenl@cs.columbia.edu> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] setpgid: should work for sub-threadsOren Laadan2006-01-082-10/+8
| | | | | | | | | | | | | | setsid() does not work unless the calling process is a thread_group_leader(). 'man setpgid' does not tell anything about that, so I consider this behaviour is a bug. Signed-off-by: Oren Laadan <orenl@cs.columbia.edu> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] setpgid: should work for sub-threadsOleg Nesterov2006-01-081-5/+6
| | | | | | | | | | | | | | setpgid(0, pgid) or setpgid(forked_child_pid, pgid) does not work unless the calling process is a thread_group_leader(). 'man setpgid' does not tell anything about that, so I consider this behaviour is a bug. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Oren Laadan <orenl@cs.columbia.edu> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] fork: fix race in setting child's pgrp and ttyOren Laadan2006-01-081-6/+3
| | | | | | | | | | | | | In fork, child should recopy parent's pgrp/tty after it has tasklist_lock. Otherwise following a setpgid() on the parent, *after* copy_signal(), the child will own a stale pgrp (which may be reused); (eg. if copy_mm() sleeps a long while due to memory pressure). Similar issue for the tty. Signed-off-by: Oren Laadan <orenl@cs.columbia.edu> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Don't attempt to power off if power off is not implementedEric W. Biederman2006-01-081-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The problem. It is expected that /sbin/halt -p works exactly like /sbin/halt, when the kernel does not implement power off functionality. The kernel can do a lot of work in the reboot notifiers and in device_shutdown before we even get to machine_power_off. Some of that shutdown is not safe if you are leaving the power on, and it definitely gets in the way of using sysrq or pressing ctrl-alt-del. Since the shutdown happens in generic code there is no way to fix this in architecture specific code :( Some machines are kernel oopsing today because of this. The simple solution is to turn LINUX_REBOOT_CMD_POWER_OFF into LINUX_REBOOT_CMD_HALT if power_off functionality is not implemented. This has the unfortunate side effect of disabling the power off functionality on architectures that leave pm_power_off to null and still implement something in machine_power_off. And it will break the build on some architectures that don't have a pm_power_off variable at all. On both counts I say tough. For architectures like alpha that don't implement the pm_power_off variable pm_power_off is declared in linux/pm.h and it is a generic part of our power management code, and all architectures should implement it. For architectures like parisc that have a default power off method in machine_power_off if pm_power_off is not implemented or fails. It is easy enough to set the pm_power_off variable. And nothing bad happens there, the machines just stop powering off. The current semantics are impossible without a flag at the top level so we can avoid the problem code if a power off is not implemented. pm_power_off is as good a flag as any with the bonus that it works without modification on at least x86, x86_64, powerpc, and ppc today. Andrew can you pick this up and put this in the mm tree. Kernels that don't compile or don't power off seem saner than kernels that oops or panic. Until we get the arch specific patches for the problem architectures this probably isn't smart to push into the stable kernel. Unfortunately I don't have the time at the moment to walk through every architecture and make them work. And even if I did I couldn't test it :( From: Hirokazu Takata <takata@linux-m32r.org> Add pm_power_off() for build fix of arch/m32r/kernel/process.c. From: Miklos Szeredi <miklos@szeredi.hu> UML build fix Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Hayato Fujiwara <fujiwara@linux-m32r.org> Signed-off-by: Hirokazu Takata <takata@linux-m32r.org> Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Extend RCU torture module to test tickless idle CPUSrivatsa Vaddagiri2006-01-081-5/+91
| | | | | | | | | | | | This patch forces RCU torture threads off various CPUs in the system allowing them to become idle and go tickless. Meant to test support for such tickless idle CPU in RCU. Signed-off-by: Srivatsa Vaddagiri <vatsa@in.ibm.com> Cc: Dipankar Sarma <dipankar@in.ibm.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Add tainting for proprietary helper modulesDave Jones2006-01-081-0/+5
| | | | | | | | | | | | Kernels that have had Windows drivers loaded into them are undebuggable. I've wasted a number of hours chasing bugs filed in Fedora bugzilla only to find out much later that the user had used such 'helpers', and their problems were unreproducable without them loaded. Acked-by: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Dave Jones <davej@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] shrink dentry structEric Dumazet2006-01-081-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some long time ago, dentry struct was carefully tuned so that on 32 bits UP, sizeof(struct dentry) was exactly 128, ie a power of 2, and a multiple of memory cache lines. Then RCU was added and dentry struct enlarged by two pointers, with nice results for SMP, but not so good on UP, because breaking the above tuning (128 + 8 = 136 bytes) This patch reverts this unwanted side effect, by using an union (d_u), where d_rcu and d_child are placed so that these two fields can share their memory needs. At the time d_free() is called (and d_rcu is really used), d_child is known to be empty and not touched by the dentry freeing. Lockless lookups only access d_name, d_parent, d_lock, d_op, d_flags (so the previous content of d_child is not needed if said dentry was unhashed but still accessed by a CPU because of RCU constraints) As dentry cache easily contains millions of entries, a size reduction is worth the extra complexity of the ugly C union. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Cc: Dipankar Sarma <dipankar@in.ibm.com> Cc: Maneesh Soni <maneesh@in.ibm.com> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Ian Kent <raven@themaw.net> Cc: Paul Jackson <pj@sgi.com> Cc: Al Viro <viro@ftp.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: Neil Brown <neilb@cse.unsw.edu.au> Cc: James Morris <jmorris@namei.org> Cc: Stephen Smalley <sds@epoch.ncsc.mil> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] remove unneeded sig->curr_target recalculationOleg Nesterov2006-01-081-2/+0
| | | | | | | | | | | | This patch removes unneeded sig->curr_target recalculation under 'if (atomic_dec_and_test(&sig->count))' in __exit_signal(). When sig->count == 0 the signal can't be sent to this task and next_thread(tsk) == tsk anyway. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] little do_group_exit() cleanupOleg Nesterov2006-01-081-1/+0
| | | | | | | | | zap_other_threads() sets SIGNAL_GROUP_EXIT at the very start, do_group_exit() doesn't need to do it. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] kill_proc_info_as_uid: don't use hardcoded constantsOleg Nesterov2006-01-081-2/+1
| | | | | | | | | Use symbolic names instead of hardcoded constants. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: Harald Welte <laforge@gnumonks.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Unchecked alloc_percpu() return in __create_workqueue()Ben Collins2006-01-081-0/+5
| | | | | | | | | | __create_workqueue() not checking return of alloc_percpu() NULL dereference was possible. Signed-off-by: Ben Collins <bcollins@ubuntu.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] sigaction should clear all signals on SIG_IGN, not just < 32George Anzinger2006-01-081-2/+32
| | | | | | | | | | | | | | | While rooting aroung in the signal code trying to understand how to fix the SIG_IGN ploy (set sig handler to SIG_IGN and flood system with high speed repeating timers) I came across what, I think, is a problem in sigaction() in that when processing a SIG_IGN request it flushes signals from 1 to SIGRTMIN and leaves the rest. Attempt to fix this. Signed-off-by: George Anzinger <george@mvista.com> Cc: Roland McGrath <roland@redhat.com> Cc: Linus Torvalds <torvalds@osdl.org> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] printk return value: fix itGuillaume Chazarain2006-01-081-3/+3
| | | | | | | | | | | | | | | | | | | | | | What's the true meaning of the printk return value? Should it include the priority prefix length of 3? and what about the timing information? In both cases it was broken: strace -e write echo 1 > /dev/kmsg => write(1, "1\n", 2) = 5 strace -e write echo "<1>1" > /dev/kmsg => write(1, "<1>1\n", 5) = 8 The returned length was "length of input string + 3", I made it "length of string output to the log buffer". Note that I couldn't find any printk caller in the kernel interested by its return value besides kmsg_write. Signed-off-by: Guillaume Chazarain <guichaz@yahoo.fr> Acked-By: Tim Bird <tim.bird@am.sony.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] use ptrace_get_task_struct in various placesChristoph Hellwig2006-01-081-31/+46
| | | | | | | | | | | | | | | | The ptrace_get_task_struct() helper that I added as part of the ptrace consolidation is useful in variety of places that currently opencode it. Switch them to the common helpers. Add a ptrace_traceme() helper that needs to be explicitly called, and simplify the ptrace_get_task_struct() interface. We don't need the request argument now, and we return the task_struct directly, using ERR_PTR() for error returns. It's a bit more code in the callers, but we have two sane routines that do one thing well now. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] rcu file: use atomic primitivesNick Piggin2006-01-082-15/+0
| | | | | | | | | Use atomic_inc_not_zero for rcu files instead of special case rcuref. Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] kernel/: small cleanupsAdrian Bunk2006-01-084-2/+5
| | | | | | | | | | | | This patch contains the following cleanups: - make needlessly global functions static - every file should include the headers containing the prototypes for it's global functions Signed-off-by: Adrian Bunk <bunk@stusta.de> Acked-by: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] cpuset: skip rcu check if task is in root cpusetPaul Jackson2006-01-081-4/+9
| | | | | | | | | | | | | | | | | For systems that aren't using cpusets, but have them CONFIG_CPUSET enabled in their kernel (eventually this may be most distribution kernels), this patch removes even the minimal rcu_read_lock() from the memory page allocation path. Actually, it removes that rcu call for any task that is in the root cpuset (top_cpuset), which on systems not actively using cpusets, is all tasks. We don't need the rcu check for tasks in the top_cpuset, because the top_cpuset is statically allocated, so at no risk of being freed out from underneath us. 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] cpuset: mark number_of_cpusets read_mostlyPaul Jackson2006-01-081-1/+1
| | | | | | | | | | | | | | | | | Mark cpuset global 'number_of_cpusets' as __read_mostly. This global is accessed everytime a zone is considered in the zonelist loops beneath __alloc_pages, looking for a free memory page. If number_of_cpusets is just one, then we can short circuit the mems_allowed check. Since this global is read alot on a hot path, and written rarely, it is an excellent candidate for __read_mostly. Thanks to Christoph Lameter for the suggestion. 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] cpuset: use rcu directly optimizationPaul Jackson2006-01-081-10/+30
| | | | | | | | | | | | | | | | | | | | | | | Optimize the cpuset impact on page allocation, the most performance critical cpuset hook in the kernel. On each page allocation, the cpuset hook needs to check for a possible change in the current tasks cpuset. It can now handle the common case, of no change, without taking any spinlock or semaphore, thanks to RCU. Convert a spinlock on the current task to an rcu_read_lock(), saving approximately a memory barrier and an atomic op, depending on architecture. This is done by adding rcu_assign_pointer() and synchronize_rcu() calls to the write side of the task->cpuset pointer, in cpuset.c:attach_task(), to delay freeing up a detached cpuset until after any critical sections referencing that pointer. Thanks to Andi Kleen, Nick Piggin and Eric Dumazet for ideas. 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] cpuset: remove test for null cpuset from alloc code pathPaul Jackson2006-01-081-6/+16
| | | | | | | | | | | | | | | | | | Remove a couple of more lines of code from the cpuset hooks in the page allocation code path. There was a check for a NULL cpuset pointer in the routine cpuset_update_task_memory_state() that was only needed during system boot, after the memory subsystem was initialized, before the cpuset subsystem was initialized, to catch a NULL task->cpuset pointer. Add a cpuset_init_early() routine, just before the mem_init() call in init/main.c, that sets up just enough of the init tasks cpuset structure to render cpuset_update_task_memory_state() calls harmless. 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] cpuset: migrate all tasks in cpuset at oncePaul Jackson2006-01-081-13/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | Given the mechanism in the previous patch to handle rebinding the per-vma mempolicies of all tasks in a cpuset that changes its memory placement, it is now easier to handle the page migration requirements of such tasks at the same time. The previous code didn't actually attempt to migrate the pages of the tasks in a cpuset whose memory placement changed until the next time each such task tried to allocate memory. This was undesirable, as users invoking memory page migration exected to happen when the placement changed, not some unspecified time later when the task needed more memory. It is now trivial to handle the page migration at the same time as the per-vma rebinding is done. The routine cpuset.c:update_nodemask(), which handles changing a cpusets memory placement ('mems') now checks for the special case of being asked to write a placement that is the same as before. It was harmless enough before to just recompute everything again, even though nothing had changed. But page migration is a heavy weight operation - moving pages about. So now it is worth avoiding that if asked to move a cpuset to its current location. 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] cpuset: rebind vma mempolicies fixPaul Jackson2006-01-081-0/+90
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix more of longstanding bug in cpuset/mempolicy interaction. NUMA mempolicies (mm/mempolicy.c) are constrained by the current tasks cpuset to just the Memory Nodes allowed by that cpuset. The kernel maintains internal state for each mempolicy, tracking what nodes are used for the MPOL_INTERLEAVE, MPOL_BIND or MPOL_PREFERRED policies. When a tasks cpuset memory placement changes, whether because the cpuset changed, or because the task was attached to a different cpuset, then the tasks mempolicies have to be rebound to the new cpuset placement, so as to preserve the cpuset-relative numbering of the nodes in that policy. An earlier fix handled such mempolicy rebinding for mempolicies attached to a task. This fix rebinds mempolicies attached to vma's (address ranges in a tasks address space.) Due to the need to hold the task->mm->mmap_sem semaphore while updating vma's, the rebinding of vma mempolicies has to be done when the cpuset memory placement is changed, at which time mmap_sem can be safely acquired. The tasks mempolicy is rebound later, when the task next attempts to allocate memory and notices that its task->cpuset_mems_generation is out-of-date with its cpusets mems_generation. Because walking the tasklist to find all tasks attached to a changing cpuset requires holding tasklist_lock, a spinlock, one cannot update the vma's of the affected tasks while doing the tasklist scan. In general, one cannot acquire a semaphore (which can sleep) while already holding a spinlock (such as tasklist_lock). So a list of mm references has to be built up during the tasklist scan, then the tasklist lock dropped, then for each mm, its mmap_sem acquired, and the vma's in that mm rebound. Once the tasklist lock is dropped, affected tasks may fork new tasks, before their mm's are rebound. A kernel global 'cpuset_being_rebound' is set to point to the cpuset being rebound (there can only be one; cpuset modifications are done under a global 'manage_sem' semaphore), and the mpol_copy code that is used to copy a tasks mempolicies during fork catches such forking tasks, and ensures their children are also rebound. When a task is moved to a different cpuset, it is easier, as there is only one task involved. It's mm->vma's are scanned, using the same mpol_rebind_policy() as used above. It may happen that both the mpol_copy hook and the update done via the tasklist scan update the same mm twice. This is ok, as the mempolicies of each vma in an mm keep track of what mems_allowed they are relative to, and safely no-op a second request to rebind to the same nodes. 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] cpuset: number_of_cpusets optimizationPaul Jackson2006-01-081-1/+11
| | | | | | | | | | | | | | | | Easy little optimization hack to avoid actually having to call cpuset_zone_allowed() and check mems_allowed, in the main page allocation routine, __alloc_pages(). This saves several CPU cycles per page allocation on systems not using cpusets. A counter is updated each time a cpuset is created or removed, and whenever there is only one cpuset in the system, it must be the root cpuset, which contains all CPUs and all Memory Nodes. In that case, when the counter is one, all allocations are allowed. 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] cpuset: numa_policy_rebind cleanupPaul Jackson2006-01-081-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Cleanup, reorganize and make more robust the mempolicy.c code to rebind mempolicies relative to the containing cpuset after a tasks memory placement changes. The real motivator for this cleanup patch is to lay more groundwork for the upcoming patch to correctly rebind NUMA mempolicies that are attached to vma's after the containing cpuset memory placement changes. NUMA mempolicies are constrained by the cpuset their task is a member of. When either (1) a task is moved to a different cpuset, or (2) the 'mems' mems_allowed of a cpuset is changed, then the NUMA mempolicies have embedded node numbers (for MPOL_BIND, MPOL_INTERLEAVE and MPOL_PREFERRED) that need to be recalculated, relative to their new cpuset placement. The old code used an unreliable method of determining what was the old mems_allowed constraining the mempolicy. It just looked at the tasks mems_allowed value. This sort of worked with the present code, that just rebinds the -task- mempolicy, and leaves any -vma- mempolicies broken, referring to the old nodes. But in an upcoming patch, the vma mempolicies will be rebound as well. Then the order in which the various task and vma mempolicies are updated will no longer be deterministic, and one can no longer count on the task->mems_allowed holding the old value for as long as needed. It's not even clear if the current code was guaranteed to work reliably for task mempolicies. So I added a mems_allowed field to each mempolicy, stating exactly what mems_allowed the policy is relative to, and updated synchronously and reliably anytime that the mempolicy is rebound. Also removed a useless wrapper routine, numa_policy_rebind(), and had its caller, cpuset_update_task_memory_state(), call directly to the rewritten policy_rebind() routine, and made that rebind routine extern instead of static, and added a "mpol_" prefix to its name, making it mpol_rebind_policy(). 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] cpuset: implement cpuset_mems_allowedPaul Jackson2006-01-081-3/+26
| | | | | | | | | | Provide a cpuset_mems_allowed() method, which the sys_migrate_pages() code needed, to obtain the mems_allowed vector of a cpuset, and replaced the workaround in sys_migrate_pages() to call this new method. 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] cpuset: combine refresh_mems and update_memsPaul Jackson2006-01-081-54/+41
| | | | | | | | | | | | | | | | | | | | | The important code paths through alloc_pages_current() and alloc_page_vma(), by which most kernel page allocations go, both called cpuset_update_current_mems_allowed(), which in turn called refresh_mems(). -Both- of these latter two routines did a tasklock, got the tasks cpuset pointer, and checked for out of date cpuset->mems_generation. That was a silly duplication of code and waste of CPU cycles on an important code path. Consolidated those two routines into a single routine, called cpuset_update_task_memory_state(), since it updates more than just mems_allowed. Changed all callers of either routine to call the new consolidated routine. 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] cpuset: fork hook fixPaul Jackson2006-01-082-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | Fix obscure, never seen in real life, cpuset fork race. The cpuset_fork() call in fork.c was setting up the correct task->cpuset pointer after the tasklist_lock was dropped, which briefly exposed the newly forked process with an unsafe (copied from parent without locks or usage counter increment) cpuset pointer. In theory, that exposed cpuset pointer could have been pointing at a cpuset that was already freed and removed, and in theory another task that had been sitting on the tasklist_lock waiting to scan the task list could have raced down the entire tasklist, found our new child at the far end, and dereferenced that bogus cpuset pointer. To fix, setup up the correct cpuset pointer in the new child by calling cpuset_fork() before the new task is linked into the tasklist, and with that, add a fork failure case, to dereference that cpuset, if the fork fails along the way, after cpuset_fork() was called. Had to remove a BUG_ON() from cpuset_exit(), because it was no longer valid - the call to cpuset_exit() from a failed fork would not have PF_EXITING set. 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] cpuset: update_nodemask code reformatPaul Jackson2006-01-081-10/+15
| | | | | | | | | | | Restructure code layout of the kernel/cpuset.c update_nodemask() routine, removing embedded returns and nested if's in favor of goto completion labels. This is being done in anticipation of adding more logic to this routine, which will favor the goto style structure. 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] cpuset: minor spacing initializer fixesPaul Jackson2006-01-081-6/+3
| | | | | | | | | Four trivial cpuset fixes: remove extra spaces, remove useless initializers, mark one __read_mostly. 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] cpuset: memory pressure meterPaul Jackson2006-01-081-2/+191
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Provide a simple per-cpuset metric of memory pressure, tracking the -rate- that the tasks in a cpuset call try_to_free_pages(), the synchronous (direct) memory reclaim code. This enables batch managers monitoring jobs running in dedicated cpusets to efficiently detect what level of memory pressure that job is causing. This is useful both on tightly managed systems running a wide mix of submitted jobs, which may choose to terminate or reprioritize jobs that are trying to use more memory than allowed on the nodes assigned them, and with tightly coupled, long running, massively parallel scientific computing jobs that will dramatically fail to meet required performance goals if they start to use more memory than allowed to them. This patch just provides a very economical way for the batch manager to monitor a cpuset for signs of memory pressure. It's up to the batch manager or other user code to decide what to do about it and take action. ==> Unless this feature is enabled by writing "1" to the special file /dev/cpuset/memory_pressure_enabled, the hook in the rebalance code of __alloc_pages() for this metric reduces to simply noticing that the cpuset_memory_pressure_enabled flag is zero. So only systems that enable this feature will compute the metric. Why a per-cpuset, running average: Because this meter is per-cpuset, rather than per-task or mm, the system load imposed by a batch scheduler monitoring this metric is sharply reduced on large systems, because a scan of the tasklist can be avoided on each set of queries. Because this meter is a running average, instead of an accumulating counter, a batch scheduler can detect memory pressure with a single read, instead of having to read and accumulate results for a period of time. Because this meter is per-cpuset rather than per-task or mm, the batch scheduler can obtain the key information, memory pressure in a cpuset, with a single read, rather than having to query and accumulate results over all the (dynamically changing) set of tasks in the cpuset. A per-cpuset simple digital filter (requires a spinlock and 3 words of data per-cpuset) is kept, and updated by any task attached to that cpuset, if it enters the synchronous (direct) page reclaim code. A per-cpuset file provides an integer number representing the recent (half-life of 10 seconds) rate of direct page reclaims caused by the tasks in the cpuset, in units of reclaims attempted per second, times 1000. 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] cpuset: mempolicy one more nodemask conversionPaul Jackson2006-01-081-10/+0
| | | | | | | | | | | | | | | Finish converting mm/mempolicy.c from bitmaps to nodemasks. The previous conversion had left one routine using bitmaps, since it involved a corresponding change to kernel/cpuset.c Fix that interface by replacing with a simple macro that calls nodes_subset(), or if !CONFIG_CPUSET, returns (1). Signed-off-by: Paul Jackson <pj@sgi.com> Cc: Christoph Lameter <christoph@lameter.com> Cc: Andi Kleen <ak@muc.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Simpler signal-exit concurrency handlingPaul E. McKenney2006-01-081-5/+6
| | | | | | | | | | Some simplification in checking signal delivery against concurrent exit. Instead of using get_task_struct_rcu(), which increments the task_struct reference count, check the reference count after acquiring sighand lock. Signed-off-by: "Paul E. McKenney" <paulmck@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] RCU signal handlingIngo Molnar2006-01-086-27/+111
| | | | | | | | | | | | | | RCU tasklist_lock and RCU signal handling: send signals RCU-read-locked instead of tasklist_lock read-locked. This is a scalability improvement on SMP and a preemption-latency improvement under PREEMPT_RCU. Signed-off-by: Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: William Irwin <wli@holomorphy.com> Cc: Roland McGrath <roland@redhat.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Change maxaligned_in_smp alignemnt macros to internodealigned_in_smp ↵Ravikiran G Thirumalai2006-01-081-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | macros ____cacheline_maxaligned_in_smp is currently used to align critical structures and avoid false sharing. It uses per-arch L1_CACHE_SHIFT_MAX and people find L1_CACHE_SHIFT_MAX useless. However, we have been using ____cacheline_maxaligned_in_smp to align structures on the internode cacheline size. As per Andi's suggestion, following patch kills ____cacheline_maxaligned_in_smp and introduces INTERNODE_CACHE_SHIFT, which defaults to L1_CACHE_SHIFT for all arches. Arches needing L3/Internode cacheline alignment can define INTERNODE_CACHE_SHIFT in the arch asm/cache.h. Patch replaces ____cacheline_maxaligned_in_smp with ____cacheline_internodealigned_in_smp With this patch, L1_CACHE_SHIFT_MAX can be killed Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org> Signed-off-by: Shai Fultheim <shai@scalex86.org> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] cpusets: swap migration interfacePaul Jackson2006-01-081-2/+36
| | | | | | | | | | | | | | | | | | | | | | Add a boolean "memory_migrate" to each cpuset, represented by a file containing "0" or "1" in each directory below /dev/cpuset. It defaults to false (file contains "0"). It can be set true by writing "1" to the file. If true, then anytime that a task is attached to the cpuset so marked, the pages of that task will be moved to that cpuset, preserving, to the extent practical, the cpuset-relative placement of the pages. Also anytime that a cpuset so marked has its memory placement changed (by writing to its "mems" file), the tasks in that cpuset will have their pages moved to the cpusets new nodes, preserving, to the extent practical, the cpuset-relative placement of the moved pages. Signed-off-by: Paul Jackson <pj@sgi.com> Cc: Christoph Lameter <christoph@lameter.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Swap Migration V5: sys_migrate_pages interfaceChristoph Lameter2006-01-081-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | sys_migrate_pages implementation using swap based page migration This is the original API proposed by Ray Bryant in his posts during the first half of 2005 on linux-mm@kvack.org and linux-kernel@vger.kernel.org. The intent of sys_migrate is to migrate memory of a process. A process may have migrated to another node. Memory was allocated optimally for the prior context. sys_migrate_pages allows to shift the memory to the new node. sys_migrate_pages is also useful if the processes available memory nodes have changed through cpuset operations to manually move the processes memory. Paul Jackson is working on an automated mechanism that will allow an automatic migration if the cpuset of a process is changed. However, a user may decide to manually control the migration. This implementation is put into the policy layer since it uses concepts and functions that are also needed for mbind and friends. The patch also provides a do_migrate_pages function that may be useful for cpusets to automatically move memory. sys_migrate_pages does not modify policies in contrast to Ray's implementation. The current code here is based on the swap based page migration capability and thus is not able to preserve the physical layout relative to it containing nodeset (which may be a cpuset). When direct page migration becomes available then the implementation needs to be changed to do a isomorphic move of pages between different nodesets. The current implementation simply evicts all pages in source nodeset that are not in the target nodeset. Patch supports ia64, i386 and x86_64. 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] add schedule_on_each_cpu()Christoph Lameter2006-01-081-0/+19
| | | | | | | | | | | | | | | | | | | swap migration's isolate_lru_page() currently uses an IPI to notify other processors that the lru caches need to be drained if the page cannot be found on the LRU. The IPI interrupt may interrupt a processor that is just processing lru requests and cause a race condition. This patch introduces a new function run_on_each_cpu() that uses the keventd() to run the LRU draining on each processor. Processors disable preemption when dealing the LRU caches (these are per processor) and thus executing LRU draining from another process is safe. Thanks to Lee Schermerhorn <lee.schermerhorn@hp.com> for finding this race condition. 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] Make high and batch sizes of per_cpu_pagelists configurableRohit Seth2006-01-081-0/+12
| | | | | | | | | | | | | | | | | | | As recently there has been lot of traffic on the right values for batch and high water marks for per_cpu_pagelists. This patch makes these two variables configurable through /proc interface. A new tunable /proc/sys/vm/percpu_pagelist_fraction is added. This entry controls the fraction of pages at most in each zone that are allocated for each per cpu page list. The min value for this is 8. It means that we don't allow more than 1/8th of pages in each zone to be allocated in any single per_cpu_pagelist. The batch value of each per cpu pagelist is also updated as a result. It is set to pcp->high/4. The upper limit of batch is (PAGE_SHIFT * 8) Signed-off-by: Rohit Seth <rohit.seth@intel.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] drop-pagecacheAndrew Morton2006-01-081-0/+10
| | | | | | | | | | | | | | | | | | | | | | Add /proc/sys/vm/drop_caches. When written to, this will cause the kernel to discard as much pagecache and/or reclaimable slab objects as it can. THis operation requires root permissions. It won't drop dirty data, so the user should run `sync' first. Caveats: a) Holds inode_lock for exorbitant amounts of time. b) Needs to be taught about NUMA nodes: propagate these all the way through so the discarding can be controlled on a per-node basis. This is a debugging feature: useful for getting consistent results between filesystem benchmarks. We could possibly put it under a config option, but it's less than 300 bytes. Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Fix posix-cpu-timers sched_time accumulationDavid S. Miller2006-01-061-12/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I've spent the past 3 days digging into a glibc testsuite failure in current CVS, specifically libc/rt/tst-cputimer1.c The thr1 and thr2 timers fire too early in the second pass of this test. The second pass is noteworthy because it makes use of intervals, whereas the first pass does not. All throughout the posix-cpu-timers.c code, the calculation of the process sched_time sum is implemented roughly as: unsigned long long sum; sum = tsk->signal->sched_time; t = tsk; do { sum += t->sched_time; t = next_thread(t); } while (t != tsk); In fact this is the exact scheme used by check_process_timers(). In the case of check_process_timers(), current->sched_time has just been updated (via scheduler_tick(), which is invoked by update_process_times(), which subsequently invokes run_posix_cpu_timers()) So there is no special processing necessary wrt. that. In other contexts, we have to allot for the fact that tsk->sched_time might be a bit out of date if we are current. And the posix-cpu-timers.c code uses current_sched_time() to deal with that. Unfortunately it does so in an erroneous and inconsistent manner in one spot which is what results in the early timer firing. In cpu_clock_sample_group_locked(), it does this: cpu->sched = p->signal->sched_time; /* Add in each other live thread. */ while ((t = next_thread(t)) != p) { cpu->sched += t->sched_time; } if (p->tgid == current->tgid) { /* * We're sampling ourselves, so include the * cycles not yet banked. We still omit * other threads running on other CPUs, * so the total can always be behind as * much as max(nthreads-1,ncpus) * (NSEC_PER_SEC/HZ). */ cpu->sched += current_sched_time(current); } else { cpu->sched += p->sched_time; } The problem is the "p->tgid == current->tgid" test. If "p" is not current, and the tgids are the same, we will add the process t->sched_time twice into cpu->sched and omit "p"'s sched_time which is very very very wrong. posix-cpu-timers.c has a helper function, sched_ns(p) which takes care of this, so my fix is to use that here instead of this special tgid test. The fact that current can be one of the sub-threads of "p" points out that we could make things a little bit more accurate, perhaps by using sched_ns() on every thread we process in these loops. It also points out that we don't use the most accurate value for threads in the group actively running other cpus (and this is mentioned in the comment). But that is a future enhancement, and this fix here definitely makes sense. Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] kernel/module.c: removed dead codeJayachandran C2006-01-061-2/+1
| | | | | | | | | | | | | | This patch fixes an issue reported by Coverity in kernel/module.c Error reported: Cannot reach this line of code "else return ptr;" Patch description: This is the error path, so 'err' will be negative, the else case is not required, this patch removes it. Signed-off-by: Jayachandran C. <c.jayachandran@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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