- 28 Apr, 2016 1 commit
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Ingo Molnar authored
Some architectures (such as Alpha) rely on include/linux/sched.h definitions in their mmu_context.h files. So include sched.h before mmu_context.h. Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-kernel@vger.kernel.org Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by:
Ingo Molnar <mingo@kernel.org>
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- 21 Feb, 2014 1 commit
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Martin Schwidefsky authored
The finish_arch_post_lock_switch is called at the end of the task switch after all locks have been released. In concept it is paired with the switch_mm function, but the current code only does the call in finish_task_switch. Add the call to idle_task_exit and use_mm. One use case for the additional calls is s390 which will use finish_arch_post_lock_switch to wait for the completion of TLB flush operations. Signed-off-by:
Martin Schwidefsky <schwidefsky@de.ibm.com>
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- 08 May, 2013 1 commit
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Zach Brown authored
Bunch of performance improvements and cleanups Zach Brown and I have been working on. The code should be pretty solid at this point, though it could of course use more review and testing. The results in my testing are pretty impressive, particularly when an ioctx is being shared between multiple threads. In my crappy synthetic benchmark, with 4 threads submitting and one thread reaping completions, I saw overhead in the aio code go from ~50% (mostly ioctx lock contention) to low single digits. Performance with ioctx per thread improved too, but I'd have to rerun those benchmarks. The reason I've been focused on performance when the ioctx is shared is that for a fair number of real world completions, userspace needs the completions aggregated somehow - in practice people just end up implementing this aggregation in userspace today, but if it's done right we can do it much more efficiently in the kernel. Performance wise, the end result of this patch series is that submitting a kiocb writes to _no_ shared cachelines - the penalty for sharing an ioctx is gone there. There's still going to be some cacheline contention when we deliver the completions to the aio ringbuffer (at least if you have interrupts being delivered on multiple cores, which for high end stuff you do) but I have a couple more patches not in this series that implement coalescing for that (by taking advantage of interrupt coalescing). With that, there's basically no bottlenecks or performance issues to speak of in the aio code. This patch: use_mm() is used in more places than just aio. There's no need to mention callers when describing the function. Signed-off-by:
Zach Brown <zab@redhat.com> Signed-off-by:
Kent Overstreet <koverstreet@google.com> Cc: Felipe Balbi <balbi@ti.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Jens Axboe <axboe@kernel.dk> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Acked-by:
Jeff Moyer <jmoyer@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Benjamin LaHaise <bcrl@kvack.org> Reviewed-by:
"Theodore Ts'o" <tytso@mit.edu> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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- 22 Mar, 2012 1 commit
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David Rientjes authored
sync_mm_rss() can only be used for current to avoid race conditions in iterating and clearing its per-task counters. Remove the task argument for it and its helper function, __sync_task_rss_stat(), to avoid thinking it can be used safely for anything other than current. Signed-off-by:
David Rientjes <rientjes@google.com> Acked-by:
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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- 31 Oct, 2011 1 commit
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Paul Gortmaker authored
The files changed within are only using the EXPORT_SYMBOL macro variants. They are not using core modular infrastructure and hence don't need module.h but only the export.h header. Signed-off-by:
Paul Gortmaker <paul.gortmaker@windriver.com>
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- 24 Mar, 2010 1 commit
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Michael S. Tsirkin authored
In 2.6.34-rc1, removing vhost_net module causes an oops in sync_mm_rss (called from do_exit) when workqueue is destroyed. This does not happen on net-next, or with vhost on top of to 2.6.33. The issue seems to be introduced by 34e55232 ("mm: avoid false sharing of mm_counter) which added sync_mm_rss() that is passed task->mm, and dereferences it without checking. If task is a kernel thread, mm might be NULL. I think this might also happen e.g. with aio. This patch fixes the oops by calling sync_mm_rss when task->mm is set to NULL. I also added BUG_ON to detect any other cases where counters get incremented while mm is NULL. The oops I observed looks like this: BUG: unable to handle kernel NULL pointer dereference at 00000000000002a8 IP: [<ffffffff810b436d>] sync_mm_rss+0x33/0x6f PGD 0 Oops: 0002 [#1] SMP last sysfs file: /sys/devices/system/cpu/cpu7/cache/index2/shared_cpu_map CPU 2 Modules linked in: vhost_net(-) tun bridge stp sunrpc...
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- 15 Jan, 2010 1 commit
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Michael S. Tsirkin authored
vhost net module wants to do copy to/from user from a kernel thread, which needs use_mm. Export it to modules. Acked-by:
Andrea Arcangeli <aarcange@redhat.com> Acked-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Michael S. Tsirkin <mst@redhat.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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- 22 Sep, 2009 2 commits
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Michael S. Tsirkin authored
When the mm being switched to matches the active mm, we don't need to increment and then drop the mm count. In a simple benchmark this happens in about 50% of time. Making that conditional reduces contention on that cacheline on SMP systems. Acked-by:
Andrea Arcangeli <aarcange@redhat.com> Signed-off-by:
Michael S. Tsirkin <mst@redhat.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Michael S. Tsirkin authored
Anyone who wants to do copy to/from user from a kernel thread, needs use_mm (like what fs/aio has). Move that into mm/, to make reusing and exporting easier down the line, and make aio use it. Next intended user, besides aio, will be vhost-net. Acked-by:
Andrea Arcangeli <aarcange@redhat.com> Signed-off-by:
Michael S. Tsirkin <mst@redhat.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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