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  1. 31 Mar, 2011 3 commits
    • Peter Zijlstra's avatar
      perf: Fix task context scheduling · ab711fe0
      Peter Zijlstra authored 
      Jiri reported:

 |
 | - once an event is created by sys_perf_event_open, task context
 |   is created and it stays even if the event is closed, until the
 |   task is finished ... thats what I see in code and I assume it's
 |   correct
 |
 | - when the task opens event, perf_sched_events jump label is
 |   incremented and following callbacks are started from scheduler
 |
 |         __perf_event_task_sched_in
 |         __perf_event_task_sched_out
 |
 |   These callback *in/out set/unset cpuctx->task_ctx value to the
 |   task context.
 |
 | - close is called on event on CPU 0:
 |         - the task is scheduled on CPU 0
 |         - __perf_event_task_sched_in is called
 |         - cpuctx->task_ctx is set
 |         - perf_sched_events jump label is decremented and == 0
 |         - __perf_event_task_sched_out is not called
 |         - cpuctx->task_ctx on CPU 0 stays set
 |
 | - exit is called on CPU 1:
 |         - the task is scheduled on CPU 1
 |         - perf_event_exit_task is called
 |         - task_ctx_sched_out unsets cpuctx->task_ctx on CPU 1
 |         - put_ctx destroys the context
 |
 | - another call of perf_rotate_context on CPU 0 will use invalid
 |   task_ctx pointer, and eventualy panic.
 |

Cure this the simplest possibly way by partially reverting the
jump_label optimization for the sched_out case.
Reported-and-tested-by: default avatarJiri Olsa <jolsa@redhat.com>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: <stable@kernel.org> # .37+
LKML-Reference: <1301520405.4859.213.camel@twins>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      ab711fe0
    • Frederic Weisbecker's avatar
      perf: mmap 512 kiB by default · 800cd25c
      Frederic Weisbecker authored 
      The default setting of perf record is to mmap 128 pages if the user
did not override with -m.

However the page size may vary accross different architecture
settings, giving different default size between each.

Moreover the kernel side still has a default max number of mlocked
pages of 512 kiB + 1 page for unprivileged users. 128 + 1 pages
with page size > 4096 overlaps this threshold.

Thus, better adapt to this limitation and set the default number of
pages to fit those 512 kiB + 1 page.
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
LKML-Reference: <1301535324-9735-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      800cd25c
    • Frederic Weisbecker's avatar
      perf: Rebase max unprivileged mlock threshold on top of page size · 20443384
      Frederic Weisbecker authored 
      Ensure we allow 512 kiB + 1 page for user control without
assuming a 4096 bytes page size.
Reported-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: <stable@kernel.org>
LKML-Reference: <1301535209-9679-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      20443384
  3. 30 Mar, 2011 2 commits
  5. 29 Mar, 2011 35 commits
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