- 09 May, 2007 40 commits
-
-
Gautham R Shenoy authored
Since 2.6.18-something, the community has been bugged by the problem to provide a clean and a stable mechanism to postpone a cpu-hotplug event as lock_cpu_hotplug was badly broken. This is another proposal towards solving that problem. This one is along the lines of the solution provided in kernel/workqueue.c Instead of having a global mechanism like lock_cpu_hotplug, we allow the subsytems to define their own per-subsystem hot cpu mutexes. These would be taken(released) where ever we are currently calling lock_cpu_hotplug(unlock_cpu_hotplug). Also, in the per-subsystem hotcpu callback function,we take this mutex before we handle any pre-cpu-hotplug events and release it once we finish handling the post-cpu-hotplug events. A standard means for doing this has been provided in [PATCH 2/4] and demonstrated in [PATCH 3/4]. The ordering of these per-subsystem mutexes might still prove to be a problem, but hopefully lockdep should help us get out of that muddle. The patch set to be applied against linux-2.6.19-rc5 is as follows: [PATCH 1/4] : Extend notifier_call_chain with an option to specify the number of notifications to be sent and also count the number of notifications actually sent. [PATCH 2/4] : Define events CPU_LOCK_ACQUIRE and CPU_LOCK_RELEASE and send out notifications for these in _cpu_up and _cpu_down. This would help us standardise the acquire and release of the subsystem locks in the hotcpu callback functions of these subsystems. [PATCH 3/4] : Eliminate lock_cpu_hotplug from kernel/sched.c. [PATCH 4/4] : In workqueue_cpu_callback function, acquire(release) the workqueue_mutex while handling CPU_LOCK_ACQUIRE(CPU_LOCK_RELEASE). If the per-subsystem-locking approach survives the test of time, we can expect a slow phasing out of lock_cpu_hotplug, which has not yet been eliminated in these patches :) This patch: Provide notifier_call_chain with an option to call only a specified number of notifiers and also record the number of call to notifiers made. The need for this enhancement was identified in the post entitled "Slab - Eliminate lock_cpu_hotplug from slab" (http://lkml.org/lkml/2006/10/28/92) by Ravikiran G Thirumalai and Andrew Morton. This patch adds two additional parameters to notifier_call_chain API namely - int nr_to_calls : Number of notifier_functions to be called. The don't care value is -1. - unsigned int *nr_calls : Records the total number of notifier_funtions called by notifier_call_chain. The don't care value is NULL. [michal.k.k.piotrowski@gmail.com: build fix] Credit: Andrew Morton <akpm@osdl.org> Signed-off-by:
Gautham R Shenoy <ego@in.ibm.com> Signed-off-by:
Michal Piotrowski <michal.k.k.piotrowski@gmail.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
-
Tom Zanussi authored
relay doesn't need to use schedule_delayed_work() for waking readers when a simple timer will do. Signed-off-by:
Tom Zanussi <zanussi@comcast.net> Cc: Satyam Sharma <satyam.sharma@gmail.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by:
-
Andrew Morton authored
(akpm: bypassed maintainers, sorry. There are other patches which depend on this) Cc: "Maciej W. Rozycki" <macro@linux-mips.org> Cc: David Howells <dhowells@redhat.com> Cc: Jeff Garzik <jeff@garzik.org> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by:
-
Andrew Morton authored
(akpm: bypassed maintainers, sorry. There are other patches which depend on this) Cc: "Maciej W. Rozycki" <macro@linux-mips.org> Cc: David Howells <dhowells@redhat.com> Cc: Jeff Garzik <jeff@garzik.org> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Tejun Heo <htejun@gmail.com> Signed-off-by:
-
Andrew Morton authored
Switch e1000 over to flush_work_keventd(). This probably fixes a netdev-close versus linkwatch rtnl_lock() deadlock which nobody knew about. (akpm: bypassed maintainers, sorry. There are other patches which depend on this) Cc: "Maciej W. Rozycki" <macro@linux-mips.org> Cc: David Howells <dhowells@redhat.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jeff Garzik <jeff@garzik.org> Acked-by:
Auke Kok <auke-jan.h.kok@intel.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by:
-
Andrew Morton authored
Convert tg3 over to flush_work_keventd(). Remove nasty now-unneeded deadlock avoidance logic. (akpm: bypassed maintainers, sorry. There are other patches which depend on this) Cc: "Maciej W. Rozycki" <macro@linux-mips.org> Cc: David Howells <dhowells@redhat.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Michael Chan <mchan@broadcom.com> Cc: Jeff Garzik <jeff@garzik.org> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by:
-
Andrew Morton authored
Switch the kblockd flushing from a global flush to a more specific flush_work(). (akpm: bypassed maintainers, sorry. There are other patches which depend on this) Cc: "Maciej W. Rozycki" <macro@linux-mips.org> Cc: David Howells <dhowells@redhat.com> Cc: Jens Axboe <axboe@suse.de> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by:
-
Andrew Morton authored
Migrate AIO over to use flush_work(). Cc: "Maciej W. Rozycki" <macro@linux-mips.org> Cc: David Howells <dhowells@redhat.com> Cc: Zach Brown <zach.brown@oracle.com> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by:
-
Oleg Nesterov authored
Now when we have ->current_work we can avoid adding a barrier and waiting for its completition when cwq's queue is empty. Note: this change is also useful if we change flush_workqueue() to also check the dead CPUs. Signed-off-by:
Oleg Nesterov <oleg@tv-sign.ru> Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com> Cc: Gautham Shenoy <ego@in.ibm.com> Signed-off-by:
-
Andrew Morton authored
Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com> Cc: Gautham Shenoy <ego@in.ibm.com> Signed-off-by:
-
Oleg Nesterov authored
A basic problem with flush_scheduled_work() is that it blocks behind _all_ presently-queued works, rather than just the work whcih the caller wants to flush. If the caller holds some lock, and if one of the queued work happens to want that lock as well then accidental deadlocks can occur. One example of this is the phy layer: it wants to flush work while holding rtnl_lock(). But if a linkwatch event happens to be queued, the phy code will deadlock because the linkwatch callback function takes rtnl_lock. So we implement a new function which will flush a *single* work - just the one which the caller wants to free up. Thus we avoid the accidental deadlocks which can arise from unrelated subsystems' callbacks taking shared locks. flush_work() non-blockingly dequeues the work_struct which we want to kill, then it waits for its handler to complete on all CPUs. Add ->current_work to the "struct cpu_workqueue_struct", it points to currently running "struct work_struct". When flush_work(work) detects ->current_work == work, it inserts a barrier at the _head_ of ->worklist (and thus right _after_ that work) and waits for completition. This means that the next work fired on that CPU will be this barrier, or another barrier queued by concurrent flush_work(), so the caller of flush_work() will be woken before any "regular" work has a chance to run. When wait_on_work() unlocks workqueue_mutex (or whatever we choose to protect against CPU hotplug), CPU may go away. But in that case take_over_work() will move a barrier we queued to another CPU, it will be fired sometime, and wait_on_work() will be woken. Actually, we are doing cleanup_workqueue_thread()->kthread_stop() before take_over_work(), so cwq->thread should complete its ->worklist (and thus the barrier), because currently we don't check kthread_should_stop() in run_workqueue(). But even if we did, everything should be ok. [akpm@osdl.org: cleanup] [akpm@osdl.org: add flush_work_keventd() wrapper] Signed-off-by:
-
Oleg Nesterov authored
Remove ->remove_sequence, ->insert_sequence, and ->work_done from struct cpu_workqueue_struct. To implement flush_workqueue() we can queue a barrier work on each CPU and wait for its completition. The barrier is queued under workqueue_mutex to ensure that per cpu wq->cpu_wq is alive, we drop this mutex before going to sleep. If CPU goes down while we are waiting for completition, take_over_work() will move the barrier on another CPU, and the handler will wake up us eventually. Signed-off-by:
-
Andrew Morton authored
We take workqueue_mutex in there to keep CPU hotplug away. But preempt_disable() will suffice for that. Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by:
-
Haavard Skinnemoen authored
Now that the cpu_is_xxx() macros are available both on AVR32 and AT91, we can remove a couple of #ifdefs from this driver. One of them is actually wrong -- new_1 should be set on AVR32 but isn't. This causes the bus clock to run at twice the speed it is configured to. Signed-off-by:
Haavard Skinnemoen <hskinnemoen@atmel.com> Cc: David Brownell <david-b@pacbell.net> Acked-by:
Andrew Victor <andrew@sanpeople.com> Cc: Nicolas Ferre <nicolas.ferre@rfo.atmel.com> Signed-off-by:
-
Haavard Skinnemoen authored
Several drivers shared between AT91 and AVR32 chips use cpu_is_xxx() to handle CPU-specific differences. Currently, such code needs to be inside #ifdef CONFIG_ARCH_AT91 because the macros don't exist on AVR32. By defining the same macros on both AT91 and AVR32, these #ifdefs can be eliminated. Since the macros will evaluate to a constant value for CPUs that aren't supported by the current architecture, any code that is only needed on AT91 will be optimized away on AVR32 and vice versa. Signed-off-by:
-
David Howells authored
Implement support for writing to regular AFS files, including: (1) write (2) truncate (3) fsync, fdatasync (4) chmod, chown, chgrp, utime. AFS writeback attempts to batch writes into as chunks as large as it can manage up to the point that it writes back 65535 pages in one chunk or it meets a locked page. Furthermore, if a page has been written to using a particular key, then should another write to that page use some other key, the first write will be flushed before the second is allowed to take place. If the first write fails due to a security error, then the page will be scrapped and reread before the second write takes place. If a page is dirty and the callback on it is broken by the server, then the dirty data is not discarded (same behaviour as NFS). Shared-writable mappings are not supported by this patch. [akpm@linux-foundation.org: fix a bunch of warnings] Signed-off-by:
David Howells <dhowells@redhat.com> Signed-off-by:
-
David Howells authored
Make some miscellaneous changes to the AFS filesystem: (1) Assert RCU barriers on module exit to make sure RCU has finished with callbacks in this module. (2) Correctly handle the AFS server returning a zero-length read. (3) Split out data zapping calls into one function (afs_zap_data). (4) Rename some afs_file_*() functions to afs_*() where they apply to non-regular files too. (5) Be consistent about the presentation of volume ID:vnode ID in debugging output. Signed-off-by: -
David Howells authored
Export a couple of core functions for AFS write support to use: find_get_pages_contig() find_get_pages_tag() Signed-off-by:
-
David Miller authored
u64 and s64 are not necessarily 'long long' on some 64-bit platforms, so explicit the type to kill the compiler warnings. Also consistently use '%Lu' which is unsigned. Signed-off-by:
David S. Miller <davem@davemloft.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by:
-
Borislav Petkov authored
Get the kernel version string only once from the environment, thus slightly speeding up kernel-doc. Signed-off-by:
Borislav Petkov <bbpetkov@yahoo.de> Signed-off-by:
Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by:
-
Randy Dunlap authored
It seems that we need to clarify that a patch series is a series of related patches rather than "here are some of my patches as multiple (numbered) emails." Signed-off-by:
-
Josef 'Jeff' Sipek authored
Since path_walk sets the total_link_count to 0 and calls link_path_walk, we can just call path_walk directly. Signed-off-by:
Josef 'Jeff' Sipek <jsipek@cs.sunysb.edu> Acked-by:
Christoph Hellwig <hch@infradead.org> Signed-off-by:
-
Josef 'Jeff' Sipek authored
Signed-off-by:
-
Daniel Walker authored
There's more that need fixing, and fix my own subject spelling error too. Signed-off-by:
Daniel Walker <dwalker@mvista.com> Signed-off-by:
-
Andrew Morton authored
It's not sane to use mutex_lock_interruptible() and to then ignore the result. Ditto down_interruptible(), but I'm lazy. Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by:
-
Paul Fulghum authored
Fix tty_set_ldisc in tty_io.c so that tty->receive_room is only cleared if actually changing line disciplines. Without this fix a problem occurs when requesting the line discipline to change to the same line discipline. In this case tty->receive_room is cleared but ldisc->open() is not called to set tty->receive_room back to a sane value. The result is that tty->receive_room is stuck at 0 preventing the tty flip buffer from passing receive data to the line discipline. For example: a switch from N_TTY to N_TTY followed by a select() call for read input results in data never being received because tty->receive_room is stuck at zero. A switch from N_TTY to N_TTY followed by a read() call works because the read() call itself sets tty->receive_room correctly (but select does not). Previously (< 2.6.18) this was not a problem because the tty flip buffer pushed data to the line discipline without regard for tty->receive room. Signed-off-by:
Paul Fulghum <paulkf@microgate.com> Acked-by:
Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by:
-
Roland McGrath authored
This patch moves the sig_kernel_* and related macros from kernel/signal.c to linux/signal.h, and cleans them up slightly. I need the sig_kernel_* macros for default signal behavior in the utrace code, and want to avoid duplication or overhead to share the knowledge. Signed-off-by:
Roland McGrath <roland@redhat.com> Signed-off-by:
-
WANG Cong authored
[akpm@linux-foundation.org: fix it] Signed-off-by:
WANG Cong <xiyou.wangcong@gmail.com> Cc: Paul Clements <paul.clements@steeleye.com> Signed-off-by:
-
Olof Johansson authored
Driver for the on-chip hardware random number generator on PA Semi PA6T-1682M. Signed-off-by:
Egor Martovetsky <egor@pasemi.com> Signed-off-by:
Olof Johansson <olof@lixom.net> Signed-off-by:
Michael Buesch <mb@bu3sch.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Kumar Gala <galak@gate.crashing.org> Signed-off-by:
-
Roland Dreier authored
Signed-off-by:
Roland Dreier <rolandd@cisco.com> Signed-off-by:
-
Ken Chen authored
When cpuset is configured, it breaks the strict hugetlb page reservation as the accounting is done on a global variable. Such reservation is completely rubbish in the presence of cpuset because the reservation is not checked against page availability for the current cpuset. Application can still potentially OOM'ed by kernel with lack of free htlb page in cpuset that the task is in. Attempt to enforce strict accounting with cpuset is almost impossible (or too ugly) because cpuset is too fluid that task or memory node can be dynamically moved between cpusets. The change of semantics for shared hugetlb mapping with cpuset is undesirable. However, in order to preserve some of the semantics, we fall back to check against current free page availability as a best attempt and hopefully to minimize the impact of changing semantics that cpuset has on hugetlb. Signed-off-by:
Ken Chen <kenchen@google.com> Cc: Paul Jackson <pj@sgi.com> Cc: Christoph Lameter <clameter@engr.sgi.com> Signed-off-by:
-
Akinobu Mita authored
Cleanup using simple_read_from_buffer() for /dev/cpuset/tasks and /proc/config.gz. Cc: Paul Jackson <pj@sgi.com> Cc: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by:
Akinobu Mita <akinobu.mita@gmail.com> Signed-off-by:
-
Akinobu Mita authored
Cleanup using simple_read_from_buffer() in binfmt_misc, configfs, and sysfs. Cc: Greg Kroah-Hartman <gregkh@suse.de> Cc: Joel Becker <joel.becker@oracle.com> Signed-off-by:
-
Akinobu Mita authored
Cleanup using bitrev8 in cm4000_cs driver. Cc: Harald Welte <laforge@gnumonks.org> Signed-off-by:
-
Akinobu Mita authored
This patch fixes error paths in module_init and probe functions in cm4000_cs and cm4040_cs drivers. Cc: Harald Welte <laforge@gnumonks.org> Signed-off-by:
-
James Bottomley authored
The MCA bus has a few "integrated" functions, which are effectively virtual slots on the bus. The problem is that these special functions don't have dedicated pos IDs, so we have to manufacture ids for them outside the pos space ... and these ids can't be matched by the standard matching function, so add a special registration that requests a list of pos ids or a particular integrated function. Signed-off-by:
James Bottomley <James.Bottomley@SteelEye.com> Signed-off-by:
-
James Bottomley authored
There's a bug in the MCA bus matching algorithm in that it promotes from signed short to int before comparing with the actual id and does sign extension on anything > 0x7fff (which means that pos ids > 0x7fff never get correctly matched). Signed-off-by:
-
Fernando Luis Vazquez Cao authored
Always ask the hardware to determine the hardware processor id in both UP and SMP kernels. Signed-off-by:
Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Andi Kleen <ak@suse.de> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by:
-
Fernando Luis Vazquez Cao authored
hard_smp_processor_id used to be just a macro that hard-coded hard_smp_processor_id to 0 in the non SMP case. When booting non SMP kernels on hardware where the boot ioapic id is not 0 this turns out to be a problem. This is happens frequently in the case of kdump and once in a great while in the case of real hardware. Use the APIC to determine the hardware processor id in both UP and SMP kernels to fix this issue. Notice that hard_smp_processor_id is only used by SMP code or by code that works with apics so we do not need to handle the case when apics are not present and hard_smp_processor_id should never be called there. Signed-off-by:
Andi Kleen <ak@suse.de> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by:
-
Fernando Luis Vazquez Cao authored
hard_smp_processor_id used to be just a macro that hard-coded hard_smp_processor_id to 0 in the non SMP case. When booting non SMP kernels on hardware where the boot ioapic id is not 0 this turns out to be a problem. This is happens frequently in the case of kdump and once in a great while in the case of real hardware. Use the APIC to determine the hardware processor id in both UP and SMP kernels to fix this issue. Notice that hard_smp_processor_id is only used by SMP code or by code that works with apics so we do not need to handle the case when apics are not present and hard_smp_processor_id should never be called there. Signed-off-by:
-
