Skip to content

L
linux
Switch branch/tag
  1. 21 Dec, 2011 1 commit
  3. 18 Dec, 2011 1 commit
  5. 14 Dec, 2011 1 commit
    • Fernando Luis Vázquez Cao's avatar
      x86: Add per-cpu stat counter for APIC ICR read tries · 346b46be
      Fernando Luis Vázquez Cao authored 
      In the IPI delivery slow path (NMI delivery) we retry the ICR
read to check for delivery completion a limited number of times.

[ The reason for the limited retries is that some of the places
  where it is used (cpu boot, kdump, etc) IPI delivery might not
  succeed (due to a firmware bug or system crash, for example)
  and in such a case it is better to give up and resume
  execution of other code. ]

This patch adds a new entry to /proc/interrupts, RTR, which
tells user space the number of times we retried the ICR read in
the IPI delivery slow path.

This should give some insight into how well the APIC
message delivery hardware is working - if the counts are way
too large then we are hitting a (very-) slow path way too
often.
Signed-off-by: default avatarFernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Cc: Jörn Engel <joern@logfs.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/n/tip-vzsp20lo2xdzh5f70g0eis2s@git.kernel.org
[ extended the changelog ]
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      346b46be
  7. 06 Dec, 2011 2 commits
  9. 05 Dec, 2011 3 commits
  11. 04 Dec, 2011 1 commit
    • Linus Torvalds's avatar
      x86: Fix boot failures on older AMD CPU's · 8e8da023
      Linus Torvalds authored 
      People with old AMD chips are getting hung boots, because commit
bcb80e53 ("x86, microcode, AMD: Add microcode revision to
/proc/cpuinfo") moved the microcode detection too early into
"early_init_amd()".

At that point we are *so* early in the booth that the exception tables
haven't even been set up yet, so the whole

	rdmsr_safe(MSR_AMD64_PATCH_LEVEL, &c->microcode, &dummy);

doesn't actually work: if the rdmsr does a GP fault (due to non-existant
MSR register on older CPU's), we can't fix it up yet, and the boot fails.

Fix it by simply moving the code to a slightly later point in the boot
(init_amd() instead of early_init_amd()), since the kernel itself
doesn't even really care about the microcode patchlevel at this point
(or really ever: it's made available to user space in /proc/cpuinfo, and
updated if you do a microcode load).
Reported-tested-and-bisected-by: default avatarLarry Finger <Larry.Finger@lwfinger.net>
Tested-by: default avatarBob Tracy <rct@gherkin.frus.com>
Acked-by: default avatarBorislav Petkov <borislav.petkov@amd.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8e8da023
  13. 03 Dec, 2011 1 commit
    • Konrad Rzeszutek Wilk's avatar
      xen/pm_idle: Make pm_idle be default_idle under Xen. · e5fd47bf
      Konrad Rzeszutek Wilk authored 
      The idea behind commit d91ee586 ("cpuidle: replace xen access to x86
pm_idle and default_idle") was to have one call - disable_cpuidle()
which would make pm_idle not be molested by other code.  It disallows
cpuidle_idle_call to be set to pm_idle (which is excellent).

But in the select_idle_routine() and idle_setup(), the pm_idle can still
be set to either: amd_e400_idle, mwait_idle or default_idle.  This
depends on some CPU flags (MWAIT) and in AMD case on the type of CPU.

In case of mwait_idle we can hit some instances where the hypervisor
(Amazon EC2 specifically) sets the MWAIT and we get:

  Brought up 2 CPUs
  invalid opcode: 0000 [#1] SMP

  Pid: 0, comm: swapper Not tainted 3.1.0-0.rc6.git0.3.fc16.x86_64 #1
  RIP: e030:[<ffffffff81015d1d>]  [<ffffffff81015d1d>] mwait_idle+0x6f/0xb4
  ...
  Call Trace:
   [<ffffffff8100e2ed>] cpu_idle+0xae/0xe8
   [<ffffffff8149ee78>] cpu_bringup_and_idle+0xe/0x10
  RIP  [<ffffffff81015d1d>] mwait_idle+0x6f/0xb4
   RSP <ffff8801d28ddf10>

In the case of amd_e400_idle we don't get so spectacular crashes, but we
do end up making an MSR which is trapped in the hypervisor, and then
follow it up with a yield hypercall.  Meaning we end up going to
hypervisor twice instead of just once.

The previous behavior before v3.0 was that pm_idle was set to
default_idle regardless of select_idle_routine/idle_setup.

We want to do that, but only for one specific case: Xen.  This patch
does that.

Fixes RH BZ #739499 and Ubuntu #881076
Reported-by: default avatarStefan Bader <stefan.bader@canonical.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      e5fd47bf
  15. 02 Dec, 2011 14 commits
  17. 01 Dec, 2011 16 commits
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7