- 28 8月, 2008 1 次提交
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由 Bharata B Rao 提交于
- During wake up of a new task, task_new_fair() can do a resched_task() on the current task. Later in the code path, check_preempt_curr() also ends up doing the same, which can be avoided. Check if TIF_NEED_RESCHED is already set for the current task. - task_new_fair() does a resched_task() on the current task unconditionally. This can be done only in case when child runs before the parent. So this is a small speedup. Signed-off-by: NBharata B Rao <bharata@linux.vnet.ibm.com> Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 26 8月, 2008 1 次提交
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由 Kevin Diggs 提交于
This patch adds kernel doc for the completion feature. An error in the split-man.pl PERL snippet in kernel-doc-nano-HOWTO.txt is also fixed. Signed-off-by: NKevin Diggs <kevdig@hypersurf.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 24 8月, 2008 1 次提交
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由 Adrian Bunk 提交于
This patch lets the files using linux/version.h match the files that #include it. Signed-off-by: NAdrian Bunk <bunk@kernel.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 22 8月, 2008 3 次提交
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由 Oleg Nesterov 提交于
wait_task_inactive() returns 1 when p->nvcsw == 0 || p->nvcsw == 1. This means that two subsequent calls can return the same number while the task was scheduled in between. Change the code to return "nvcsw | LONG_MIN" instead of "nvcsw ?: 1", now the overlap always needs LONG_MAX schedules. Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Oleg Nesterov 提交于
If wait_task_inactive() returns success the task was deactivated. In that case schedule() always increments ->nvcsw which alone can be used as a "generation counter". If the next call returns the same number, we can be sure that the task was unscheduled. Otherwise, because we know that .on_rq == 0 again, ->nvcsw should have been changed in between. Q: perhaps it is better to do "ncsw = (p->nvcsw << 1) | 1" ? This decreases the possibility of "was it unscheduled" false positive when ->nvcsw == 0. Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Oleg Nesterov 提交于
Change do_wait_for_common() to use signal_pending_state() instead of open coding. Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 21 8月, 2008 4 次提交
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由 Miao Xie 提交于
On the tickless system(CONFIG_NO_HZ=y and CONFIG_HIGH_RES_TIMERS=n), after I made an offlined cpu online, I found this cpu's event handler was tick_handle_periodic, not tick_nohz_handler. After debuging, I found this bug was caused by the wrong tick mode. the tick mode is not changed to NOHZ_MODE_INACTIVE when the cpu is offline. This patch fixes this bug. Signed-off-by: NMiao Xie <miaox@cn.fujitsu.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Randy Dunlap 提交于
Fix RCU's synchronize_rcu() so that it looks like a C function, enabling it to be recognized as a function with kernel-doc annotation. Warning(linux-2.6.26-git11//kernel/rcupdate.c:81): No description found for parameter 'synchronize_rcu' Warning(linux-2.6.26-git11//kernel/rcupdate.c:81): No description found for parameter 'call_rcu' [akpm@linux-foundation.org: fix comment] Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Peter Zijlstra 提交于
Yanmin reported a significant regression on his 16-core machine due to: commit 93b75217 Author: Peter Zijlstra <a.p.zijlstra@chello.nl> Date: Fri Jun 27 13:41:33 2008 +0200 Flip back to the old behaviour. Reported-by: N"Zhang, Yanmin" <yanmin_zhang@linux.intel.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Ken Chen 提交于
When user calls sys_setpriority(PRIO_PGRP ...) on a NPTL style multi-LWP process, only the task leader of the process is affected, all other sibling LWP threads didn't receive the setting. The problem was that the iterator used in sys_setpriority() only iteartes over one task for each process, ignoring all other sibling thread. Introduce a new macro do_each_pid_thread / while_each_pid_thread to walk each thread of a process. Convert 4 call sites in {set/get}priority and ioprio_{set/get}. Signed-off-by: NKen Chen <kenchen@google.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 20 8月, 2008 1 次提交
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由 Roland McGrath 提交于
I outwitted myself again in commit 2b2a1ff6, and broke the SA_NOCLDWAIT behavior so it leaks zombies. This fixes it. Reported-by: NAndi Kleen <andi@firstfloor.org> Signed-off-by: NRoland McGrath <roland@redhat.com>
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- 18 8月, 2008 1 次提交
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由 Dmitry Baryshkov 提交于
Since f82b217e lockdep can output spurious warnings related to hwirqs due to hardirq_off shrinkage from int to bit-sized flag. Guard it with double negation to fix the warning. Signed-off-by: NDmitry Baryshkov <dbaryshkov@gmail.com> Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 16 8月, 2008 2 次提交
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由 Stephen Hemminger 提交于
If CONFIG_PROVE_LOCKING not defined, then no dependency information is available. Signed-off-by: NStephen Hemminger <shemminger@vyatta.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Peter Zijlstra 提交于
David reported that his Niagra spend a little too much time in tg_shares_up(), which considering he has a large cpu count makes sense. So scale the ratelimit value with the number of cpus like we do for other controls as well. Reported-by: NDavid Miller <davem@davemloft.net> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 15 8月, 2008 8 次提交
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由 Dave Chinner 提交于
m68k fails to build with these functions inlined in completion.h. Move them out of line into sched.c and export them to avoid this problem. Signed-off-by: NDave Chinner <david@fromorbit.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Andrew Morton 提交于
Functionally the same, but more conventional. Cc: Huang Ying <ying.huang@intel.com> Tested-by: NVivek Goyal <vgoyal@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Huang Ying 提交于
Ftrace depends on some processor state that we destroyed during kexec and restored by restore_processor_state(). So save_processor_state() and restore_processor_state() are moved into machine_kexec() and ftrace is restored after restore_processor_state(). Signed-off-by: NHuang Ying <ying.huang@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Huang Ying 提交于
Add device_pm_lock() and device_pm_unlock() in kernel_kexec() in sync with current hibernation implementation. Signed-off-by: NHuang Ying <ying.huang@intel.com> Acked-by: NPavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Huang Ying 提交于
Call kernel_restart_prepare() in kernel_kexec() instead of duplicating the code. Signed-off-by: NHuang Ying <ying.huang@intel.com> Acked-by: NPavel Machek <pavel@suse.cz> Acked-by: NVivek Goyal <vgoyal@redhat.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Huang Ying 提交于
Rename KEXEC_CONTROL_CODE_SIZE to KEXEC_CONTROL_PAGE_SIZE, because control page is used for not only code on some platform. For example in kexec jump, it is used for data and stack too. [akpm@linux-foundation.org: unbreak powerpc and arm, finish conversion] Signed-off-by: NHuang Ying <ying.huang@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Huang Ying 提交于
Move if (kexec_image->preserve_context) { ... } into #ifdef CONFIG_KEXEC_JUMP to make code looks cleaner. Fix no longer correct comments of kernel_kexec(). Signed-off-by: NHuang Ying <ying.huang@intel.com> Acked-by: NVivek Goyal <vgoyal@redhat.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Huang Ying 提交于
kernel/kexec.c: In function 'kernel_kexec': kernel/kexec.c:1506: warning: value computed is not used Signed-off-by: NHuang Ying <ying.huang@intel.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 14 8月, 2008 4 次提交
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由 Peter Zijlstra 提交于
When we hot-unplug a cpu and rebuild the sched-domain, all cpus will be detatched. Alex observed the case where a runqueue was stealing bandwidth from an already disabled runqueue to satisfy its own needs. Stop this by skipping over already disabled runqueues. Reported-by: NAlex Nixon <alex.nixon@citrix.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Tested-by: NAlex Nixon <alex.nixon@citrix.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 David Howells 提交于
Fix the setting of PF_SUPERPRIV by __capable() as it could corrupt the flags the target process if that is not the current process and it is trying to change its own flags in a different way at the same time. __capable() is using neither atomic ops nor locking to protect t->flags. This patch removes __capable() and introduces has_capability() that doesn't set PF_SUPERPRIV on the process being queried. This patch further splits security_ptrace() in two: (1) security_ptrace_may_access(). This passes judgement on whether one process may access another only (PTRACE_MODE_ATTACH for ptrace() and PTRACE_MODE_READ for /proc), and takes a pointer to the child process. current is the parent. (2) security_ptrace_traceme(). This passes judgement on PTRACE_TRACEME only, and takes only a pointer to the parent process. current is the child. In Smack and commoncap, this uses has_capability() to determine whether the parent will be permitted to use PTRACE_ATTACH if normal checks fail. This does not set PF_SUPERPRIV. Two of the instances of __capable() actually only act on current, and so have been changed to calls to capable(). Of the places that were using __capable(): (1) The OOM killer calls __capable() thrice when weighing the killability of a process. All of these now use has_capability(). (2) cap_ptrace() and smack_ptrace() were using __capable() to check to see whether the parent was allowed to trace any process. As mentioned above, these have been split. For PTRACE_ATTACH and /proc, capable() is now used, and for PTRACE_TRACEME, has_capability() is used. (3) cap_safe_nice() only ever saw current, so now uses capable(). (4) smack_setprocattr() rejected accesses to tasks other than current just after calling __capable(), so the order of these two tests have been switched and capable() is used instead. (5) In smack_file_send_sigiotask(), we need to allow privileged processes to receive SIGIO on files they're manipulating. (6) In smack_task_wait(), we let a process wait for a privileged process, whether or not the process doing the waiting is privileged. I've tested this with the LTP SELinux and syscalls testscripts. Signed-off-by: NDavid Howells <dhowells@redhat.com> Acked-by: NSerge Hallyn <serue@us.ibm.com> Acked-by: NCasey Schaufler <casey@schaufler-ca.com> Acked-by: NAndrew G. Morgan <morgan@kernel.org> Acked-by: NAl Viro <viro@zeniv.linux.org.uk> Signed-off-by: NJames Morris <jmorris@namei.org>
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由 Zhang, Yanmin 提交于
With 2.6.27-rc3, I hit a kernel panic when running volanoMark on my new x86_64 machine. I also hit it with other 2.6.27-rc kernels. See below log. Basically, function walk_tg_tree and sched_create_group have a race between accessing and initiating tg->children. Below patch fixes it by moving tg->children initiation to the front of linking tg->siblings to parent->children. {----------------panic log------------} BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 IP: [<ffffffff802292ab>] walk_tg_tree+0x45/0x7f PGD 1be1c4067 PUD 1bdd8d067 PMD 0 Oops: 0000 [1] SMP CPU 11 Modules linked in: igb Pid: 22979, comm: java Not tainted 2.6.27-rc3 #1 RIP: 0010:[<ffffffff802292ab>] [<ffffffff802292ab>] walk_tg_tree+0x45/0x7f RSP: 0018:ffff8801bfbbbd18 EFLAGS: 00010083 RAX: 0000000000000000 RBX: ffff8800be0dce40 RCX: ffffffffffffffc0 RDX: ffff880102c43740 RSI: 0000000000000000 RDI: ffff8800be0dce40 RBP: ffff8801bfbbbd48 R08: ffff8800ba437bc8 R09: 0000000000001f40 R10: ffff8801be812100 R11: ffffffff805fdf44 R12: ffff880102c43740 R13: 0000000000000000 R14: ffffffff8022cf0f R15: ffffffff8022749f FS: 00000000568ac950(0063) GS:ffff8801bfa26d00(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000000 CR3: 00000001bd848000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process java (pid: 22979, threadinfo ffff8801b145a000, task ffff8801bf18e450) Stack: 0000000000000001 ffff8800ba5c8d60 0000000000000001 0000000000000001 ffff8800bad1ccb8 0000000000000000 ffff8801bfbbbd98 ffffffff8022ed37 0000000000000001 0000000000000286 ffff8801bd5ee180 ffff8800ba437bc8 Call Trace: <IRQ> [<ffffffff8022ed37>] try_to_wake_up+0x71/0x24c [<ffffffff80247177>] autoremove_wake_function+0x9/0x2e [<ffffffff80228039>] ? __wake_up_common+0x46/0x76 [<ffffffff802296d5>] __wake_up+0x38/0x4f [<ffffffff806169cc>] tcp_v4_rcv+0x380/0x62e Signed-off-by: NZhang Yanmin <yanmin_zhang@linux.intel.com> Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Arjan van de Ven 提交于
Use WARN() instead of a printk+WARN_ON() pair; this way the message becomes part of the warning section for better reporting/collection. Signed-off-by: NArjan van de Ven <arjan@linux.intel.com> Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
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- 13 8月, 2008 4 次提交
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由 Andrew Morton 提交于
fix: WARNING: EXPORT_SYMBOL(foo); should immediately follow its function/variable #46: FILE: kernel/spinlock.c:326: +EXPORT_SYMBOL(_spin_lock_nest_lock); total: 0 errors, 1 warnings, 26 lines checked Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Ingo Molnar 提交于
fix: kernel/built-in.o: In function `lockdep_stats_show': lockdep_proc.c:(.text+0x3cb2f): undefined reference to `lockdep_count_forward_deps' kernel/built-in.o: In function `l_show': lockdep_proc.c:(.text+0x3d02b): undefined reference to `lockdep_count_forward_deps' lockdep_proc.c:(.text+0x3d047): undefined reference to `lockdep_count_backward_deps' Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Alexey Dobriyan 提交于
Switch /proc/irq/*/smp_affinity , /proc/irq/default_smp_affinity to seq_files. cat(1) reads with 1024 chunks by default, with high enough NR_CPUS, there will be -EINVAL. As side effect, there are now two less users of the ->read_proc interface. Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com> Cc: Paul Jackson <pj@sgi.com> Cc: Mike Travis <travis@sgi.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Heiko Carstens 提交于
s390 doesn't support the additional_cpus kernel parameter anymore since a long time. So we better update the code and documentation to reflect that. Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 12 8月, 2008 4 次提交
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由 Nick Piggin 提交于
> > Nick Piggin (1): > > generic-ipi: fix stack and rcu interaction bug in > > smp_call_function_mask() > > I'm still not 100% sure that I have this patch right... I might have seen > a lockup trace implicating the smp call function path... which may have > been due to some other problem or a different bug in the new call function > code, but if some more people can take a look at it before merging? OK indeed it did have a couple of bugs. Firstly, I wasn't freeing the data properly in the alloc && wait case. Secondly, I wasn't resetting CSD_FLAG_WAIT in the for each cpu loop (so only the first CPU would wait). After those fixes, the patch boots and runs with the kmalloc commented out (so it always executes the slowpath). Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Li Zefan 提交于
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com> Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
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由 Arjan van de Ven 提交于
The kernel has this really nice facility where if you put "initcall_debug" on the kernel commandline, it'll print which function it's going to execute just before calling an initcall, and then after the call completes it will 1) print if it had an error code 2) checks for a few simple bugs (like leaving irqs off) and 3) print how long the init call took in milliseconds. While trying to optimize the boot speed of my laptop, I have been loving number 3 to figure out what to optimize... ... and then I wished that the same thing was done for module loading. This patch makes the module loader use this exact same functionality; it's a logical extension in my view (since modules are just sort of late binding initcalls anyway) and so far I've found it quite useful in finding where things are too slow in my boot. Signed-off-by: NArjan van de Ven <arjan@linux.intel.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
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由 Peter Zijlstra 提交于
When we enable DEBUG_LOCK_ALLOC but do not enable PROVE_LOCKING and or LOCK_STAT, lock_alloc() and lock_release() turn into nops, even though we should be doing hlock checking (check=1). This causes a false warning and a lockdep self-disable. Rectify this. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 11 8月, 2008 6 次提交
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由 Dmitry Adamushko 提交于
Mark Langsdorf reported: > One of my co-workers noticed that the powernow-k8 > driver no longer restarts when a CPU core is > hot-disabled and then hot-enabled on AMD quad-core > systems. > > The following comands work fine on 2.6.26 and fail > on 2.6.27-rc1: > > echo 0 > /sys/devices/system/cpu/cpu3/online > echo 1 > /sys/devices/system/cpu/cpu3/online > find /sys -name cpufreq > > For 2.6.26, the find will return a cpufreq > directory for each processor. In 2.6.27-rc1, > the cpu3 directory is missing. > > After digging through the code, the following > logic is failing when the core is hot-enabled > at runtime. The code works during the boot > sequence. > > cpumask_t = current->cpus_allowed; > set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu)); > if (smp_processor_id() != cpu) > return -ENODEV; So set the CPU active before calling the CPU_ONLINE notifier chain, there are a handful of notifiers that use set_cpus_allowed(). This fix also solves the problem with x86-microcode. I've sent alternative patches for microcode, but as this "rely on set_cpus_allowed_ptr() being workable in cpu-hotplug(CPU_ONLINE, ...)" assumption seems to be more broad than what we thought, perhaps this fix should be applied. With this patch we define that by the moment CPU_ONLINE is being sent, a 'cpu' is online and ready for tasks to be migrated onto it. Signed-off-by: NDmitry Adamushko <dmitry.adamushko@gmail.com> Reported-by: NMark Langsdorf <mark.langsdorf@amd.com> Tested-by: NMark Langsdorf <mark.langsdorf@amd.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Nick Piggin 提交于
* Venki Pallipadi <venkatesh.pallipadi@intel.com> wrote: > Found a OOPS on a big SMP box during an overnight reboot test with > upstream git. > > Suresh and I looked at the oops and looks like the root cause is in > generic_smp_call_function_interrupt() and smp_call_function_mask() with > wait parameter. > > The actual oops looked like > > [ 11.277260] BUG: unable to handle kernel paging request at ffff8802ffffffff > [ 11.277815] IP: [<ffff8802ffffffff>] 0xffff8802ffffffff > [ 11.278155] PGD 202063 PUD 0 > [ 11.278576] Oops: 0010 [1] SMP > [ 11.279006] CPU 5 > [ 11.279336] Modules linked in: > [ 11.279752] Pid: 0, comm: swapper Not tainted 2.6.27-rc2-00020-g685d87f7 #290 > [ 11.280039] RIP: 0010:[<ffff8802ffffffff>] [<ffff8802ffffffff>] 0xffff8802ffffffff > [ 11.280692] RSP: 0018:ffff88027f1f7f70 EFLAGS: 00010086 > [ 11.280976] RAX: 00000000ffffffff RBX: 0000000000000000 RCX: 0000000000000000 > [ 11.281264] RDX: 0000000000004f4e RSI: 0000000000000001 RDI: 0000000000000000 > [ 11.281624] RBP: ffff88027f1f7f98 R08: 0000000000000001 R09: ffffffff802509af > [ 11.281925] R10: ffff8800280c2780 R11: 0000000000000000 R12: ffff88027f097d48 > [ 11.282214] R13: ffff88027f097d70 R14: 0000000000000005 R15: ffff88027e571000 > [ 11.282502] FS: 0000000000000000(0000) GS:ffff88027f1c3340(0000) knlGS:0000000000000000 > [ 11.283096] CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b > [ 11.283382] CR2: ffff8802ffffffff CR3: 0000000000201000 CR4: 00000000000006e0 > [ 11.283760] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > [ 11.284048] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 > [ 11.284337] Process swapper (pid: 0, threadinfo ffff88027f1f2000, task ffff88027f1f0640) > [ 11.284936] Stack: ffffffff80250963 0000000000000212 0000000000ee8c78 0000000000ee8a66 > [ 11.285802] ffff88027e571550 ffff88027f1f7fa8 ffffffff8021adb5 ffff88027f1f3e40 > [ 11.286599] ffffffff8020bdd6 ffff88027f1f3e40 <EOI> ffff88027f1f3ef8 0000000000000000 > [ 11.287120] Call Trace: > [ 11.287768] <IRQ> [<ffffffff80250963>] ? generic_smp_call_function_interrupt+0x61/0x12c > [ 11.288354] [<ffffffff8021adb5>] smp_call_function_interrupt+0x17/0x27 > [ 11.288744] [<ffffffff8020bdd6>] call_function_interrupt+0x66/0x70 > [ 11.289030] <EOI> [<ffffffff8024ab3b>] ? clockevents_notify+0x19/0x73 > [ 11.289380] [<ffffffff803b9b75>] ? acpi_idle_enter_simple+0x18b/0x1fa > [ 11.289760] [<ffffffff803b9b6b>] ? acpi_idle_enter_simple+0x181/0x1fa > [ 11.290051] [<ffffffff8053aeca>] ? cpuidle_idle_call+0x70/0xa2 > [ 11.290338] [<ffffffff80209f61>] ? cpu_idle+0x5f/0x7d > [ 11.290723] [<ffffffff8060224a>] ? start_secondary+0x14d/0x152 > [ 11.291010] > [ 11.291287] > [ 11.291654] Code: Bad RIP value. > [ 11.292041] RIP [<ffff8802ffffffff>] 0xffff8802ffffffff > [ 11.292380] RSP <ffff88027f1f7f70> > [ 11.292741] CR2: ffff8802ffffffff > [ 11.310951] ---[ end trace 137c54d525305f1c ]--- > > The problem is with the following sequence of events: > > - CPU A calls smp_call_function_mask() for CPU B with wait parameter > - CPU A sets up the call_function_data on the stack and does an rcu add to > call_function_queue > - CPU A waits until the WAIT flag is cleared > - CPU B gets the call function interrupt and starts going through the > call_function_queue > - CPU C also gets some other call function interrupt and starts going through > the call_function_queue > - CPU C, which is also going through the call_function_queue, starts referencing > CPU A's stack, as that element is still in call_function_queue > - CPU B finishes the function call that CPU A set up and as there are no other > references to it, rcu deletes the call_function_data (which was from CPU A > stack) > - CPU B sees the wait flag and just clears the flag (no call_rcu to free) > - CPU A which was waiting on the flag continues executing and the stack > contents change > > - CPU C is still in rcu_read section accessing the CPU A's stack sees > inconsistent call_funation_data and can try to execute > function with some random pointer, causing stack corruption for A > (by clearing the bits in mask field) and oops. Nice debugging work. I'd suggest something like the attached (boot tested) patch as the simple fix for now. I expect the benefits from the less synchronized, multiple-in-flight-data global queue will still outweigh the costs of dynamic allocations. But if worst comes to worst then we just go back to a globally synchronous one-at-a-time implementation, but that would be pretty sad! Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Mike Galbraith 提交于
Defer commit 6d299f1b to the next release. Testing of the tip/sched/clock tree revealed a mysql+oltp regression which bisection eventually traced back to this commit in mainline. Pertinent test results: Three run sysbench averages, throughput units in read/write requests/sec. clients 1 2 4 8 16 32 64 6e0534f2 9646 17876 34774 33868 32230 30767 29441 2.6.26.1 9112 17936 34652 33383 31929 30665 29232 6d299f1b 9112 14637 28370 33339 32038 30762 29204 Note: subsequent commits hide the majority of this regression until you apply the clock fixes, at which time it reemerges at full magnitude. We cannot see anything bad about the change itself so we defer it to the next release until this problem is fully analysed. Signed-off-by: NMike Galbraith <efault@gmx.de> Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Cc: Gregory Haskins <ghaskins@novell.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Ingo Molnar 提交于
the names were too generic: drivers/uio/uio.c:87: error: expected identifier or '(' before 'do' drivers/uio/uio.c:87: error: expected identifier or '(' before 'while' drivers/uio/uio.c:113: error: 'map_release' undeclared here (not in a function) Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Rabin Vincent 提交于
Solve this by marking the classes as unused and not printing information about the unused classes. Reported-by: NEric Sesterhenn <snakebyte@gmx.de> Signed-off-by: NRabin Vincent <rabin@rab.in> Acked-by: NHuang Ying <ying.huang@intel.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Peter Zijlstra 提交于
Expose the new lock protection lock. This can be used to annotate places where we take multiple locks of the same class and avoid deadlocks by always taking another (top-level) lock first. NOTE: we're still bound to the MAX_LOCK_DEPTH (48) limit. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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