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  1. 22 5月, 2012 1 次提交
    • T
      timers: Fixup the Kconfig consolidation fallout · 764e0da1
      由 Thomas Gleixner 提交于 
      Sigh, I missed to check which architecture Kconfig files actually
include the core Kconfig file. There are a few which did not. So we
broke them.

Instead of adding the includes to those, we are better off to move the
include to init/Kconfig like we did already with irqs and others.

This does not change anything for the architectures using the old
style periodic timer mode. It just solves the build wreckage there.

For those architectures which use the clock events infrastructure it
moves the include of the core Kconfig file to "General setup" which is
a way more logical place than having it at random locations specified
by the architecture specific Kconfigs.
Reported-by: NIngo Molnar <mingo@kernel.org>
Cc: Anna-Maria Gleixner <anna-maria@glx-um.de>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
      764e0da1
  3. 16 5月, 2012 12 次提交
  5. 26 4月, 2012 1 次提交
  7. 25 4月, 2012 2 次提交
    • P
      rcu: Reduce cache-miss initialization latencies for large systems · 8932a63d
      由 Paul E. McKenney 提交于 
      Commit #0209f649 (rcu: limit rcu_node leaf-level fanout) set an upper
limit of 16 on the leaf-level fanout for the rcu_node tree.  This was
needed to reduce lock contention that was induced by the synchronization
of scheduling-clock interrupts, which was in turn needed to improve
energy efficiency for moderate-sized lightly loaded servers.

However, reducing the leaf-level fanout means that there are more
leaf-level rcu_node structures in the tree, which in turn means that
RCU's grace-period initialization incurs more cache misses.  This is
not a problem on moderate-sized servers with only a few tens of CPUs,
but becomes a major source of real-time latency spikes on systems with
many hundreds of CPUs.  In addition, the workloads running on these large
systems tend to be CPU-bound, which eliminates the energy-efficiency
advantages of synchronizing scheduling-clock interrupts.  Therefore,
these systems need maximal values for the rcu_node leaf-level fanout.

This commit addresses this problem by introducing a new kernel parameter
named RCU_FANOUT_LEAF that directly controls the leaf-level fanout.
This parameter defaults to 16 to handle the common case of a moderate
sized lightly loaded servers, but may be set higher on larger systems.
Reported-by: NMike Galbraith <efault@gmx.de>
Reported-by: NDimitri Sivanich <sivanich@sgi.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      8932a63d
    • P
      rcu: Clarify help text for RCU_BOOST_PRIO · c9336643
      由 Paul E. McKenney 提交于 
      The old text confused real-time applications with real-time threads, so
that you pretty much needed to understand how this kernel configuration
parameter worked to understand the help text.  This commit therefore
attempts to make the help text human-readable.
Reported-by: NJörn Engel <joern@purestorage.com>
Signed-off-by: NPaul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      c9336643
  9. 20 4月, 2012 1 次提交
  11. 08 4月, 2012 1 次提交
  13. 29 3月, 2012 1 次提交
  15. 22 2月, 2012 1 次提交
  17. 18 1月, 2012 2 次提交
    • N
      Kernel: Audit Support For The ARM Platform · 29ef73b7
      由 Nathaniel Husted 提交于 
      This patch provides functionality to audit system call events on the
ARM platform. The implementation was based off the structure of the
MIPS platform and information in this
(http://lists.fedoraproject.org/pipermail/arm/2009-October/000382.html)
mailing list thread. The required audit_syscall_exit and
audit_syscall_entry checks were added to ptrace using the standard
registers for system call values (r0 through r3). A thread information
flag was added for auditing (TIF_SYSCALL_AUDIT) and a meta-flag was
added (_TIF_SYSCALL_WORK) to simplify modifications to the syscall
entry/exit. Now, if either the TRACE flag is set or the AUDIT flag is
set, the syscall_trace function will be executed. The prober changes
were made to Kconfig to allow CONFIG_AUDITSYSCALL to be enabled.

Due to platform availability limitations, this patch was only tested
on the Android platform running the modified "android-goldfish-2.6.29"
kernel. A test compile was performed using Code Sourcery's
cross-compilation toolset and the current linux-3.0 stable kernel. The
changes compile without error. I'm hoping, due to the simple modifications,
the patch is "obviously correct".
Signed-off-by: NNathaniel Husted <nhusted@gmail.com>
Signed-off-by: NEric Paris <eparis@redhat.com>
      29ef73b7
    • E
      audit: only allow tasks to set their loginuid if it is -1 · 633b4545
      由 Eric Paris 提交于 
      At the moment we allow tasks to set their loginuid if they have
CAP_AUDIT_CONTROL.  In reality we want tasks to set the loginuid when they
log in and it be impossible to ever reset.  We had to make it mutable even
after it was once set (with the CAP) because on update and admin might have
to restart sshd.  Now sshd would get his loginuid and the next user which
logged in using ssh would not be able to set his loginuid.

Systemd has changed how userspace works and allowed us to make the kernel
work the way it should.  With systemd users (even admins) are not supposed
to restart services directly.  The system will restart the service for
them.  Thus since systemd is going to loginuid==-1, sshd would get -1, and
sshd would be allowed to set a new loginuid without special permissions.

If an admin in this system were to manually start an sshd he is inserting
himself into the system chain of trust and thus, logically, it's his
loginuid that should be used!  Since we have old systems I make this a
Kconfig option.
Signed-off-by: NEric Paris <eparis@redhat.com>
      633b4545
  19. 13 1月, 2012 1 次提交
  21. 10 1月, 2012 1 次提交
  23. 13 12月, 2011 1 次提交
  25. 12 12月, 2011 1 次提交
  27. 03 11月, 2011 1 次提交
  29. 29 9月, 2011 1 次提交
    • P
      rcu: Drive configuration directly from SMP and PREEMPT · 8008e129
      由 Paul E. McKenney 提交于 
      This commit eliminates the possibility of running TREE_PREEMPT_RCU
when SMP=n and of running TINY_RCU when PREEMPT=y.  People who really
want these combinations can hand-edit init/Kconfig, but eliminating
them as choices for production systems reduces the amount of testing
required.  It will also allow cutting out a few #ifdefs.

Note that running TREE_RCU and TINY_RCU on single-CPU systems using
SMP-built kernels is still supported.
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
      8008e129
  31. 14 8月, 2011 1 次提交
  33. 26 7月, 2011 1 次提交
  35. 16 6月, 2011 2 次提交
  37. 09 6月, 2011 2 次提交
  39. 07 6月, 2011 1 次提交
  41. 27 5月, 2011 1 次提交
  43. 23 5月, 2011 1 次提交
    • L
      Give up on pushing CC_OPTIMIZE_FOR_SIZE · 281dc5c5
      由 Linus Torvalds 提交于 
      I still happen to believe that I$ miss costs are a major thing, but
sadly, -Os doesn't seem to be the solution.  With or without it, gcc
will miss some obvious code size improvements, and with it enabled gcc
will sometimes make choices that aren't good even with high I$ miss
ratios.

For example, with -Os, gcc on x86 will turn a 20-byte constant memcpy
into a "rep movsl".  While I sincerely hope that x86 CPU's will some day
do a good job at that, they certainly don't do it yet, and the cost is
higher than a L1 I$ miss would be.

Some day I hope we can re-enable this.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      281dc5c5
  45. 21 5月, 2011 1 次提交
  47. 11 5月, 2011 1 次提交
  49. 06 5月, 2011 1 次提交