diff options
| author | Stephen Rothwell <sfr@canb.auug.org.au> | 2009-11-25 16:21:15 +1100 |
|---|---|---|
| committer | Stephen Rothwell <sfr@canb.auug.org.au> | 2009-11-25 16:21:19 +1100 |
| commit | 527d0fc6098e5a383efebe56bd2860d85eebfdba (patch) | |
| tree | 4e55006eeb9d7d9686c3d6ee8b5366f56350de29 /Documentation | |
| parent | cbfb19fbfd007f8e7d57bb6ff86aad0cd64ac758 (diff) | |
| parent | 59cc907eaaf64b29a8e6b44355b79d19f840d3ce (diff) | |
Merge branch 'quilt/rr'
Conflicts:
arch/arm/kernel/vmlinux.lds.S
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/cpu-hotplug.txt | 49 | ||||
| -rw-r--r-- | Documentation/lguest/lguest.c | 1 |
2 files changed, 17 insertions, 33 deletions
diff --git a/Documentation/cpu-hotplug.txt b/Documentation/cpu-hotplug.txt index 4d4a644b505e..a99d7031cdf9 100644 --- a/Documentation/cpu-hotplug.txt +++ b/Documentation/cpu-hotplug.txt @@ -315,41 +315,26 @@ A: The following are what is required for CPU hotplug infrastructure to work Q: I need to ensure that a particular cpu is not removed when there is some work specific to this cpu is in progress. -A: First switch the current thread context to preferred cpu +A: There are two ways. If your code can be run in interrupt context, use + smp_call_function_single(), otherwise use work_on_cpu(). Note that + work_on_cpu() is slow, and can fail due to out of memory: int my_func_on_cpu(int cpu) { - cpumask_t saved_mask, new_mask = CPU_MASK_NONE; - int curr_cpu, err = 0; - - saved_mask = current->cpus_allowed; - cpu_set(cpu, new_mask); - err = set_cpus_allowed(current, new_mask); - - if (err) - return err; - - /* - * If we got scheduled out just after the return from - * set_cpus_allowed() before running the work, this ensures - * we stay locked. - */ - curr_cpu = get_cpu(); - - if (curr_cpu != cpu) { - err = -EAGAIN; - goto ret; - } else { - /* - * Do work : But cant sleep, since get_cpu() disables preempt - */ - } - ret: - put_cpu(); - set_cpus_allowed(current, saved_mask); - return err; - } - + int err; + get_online_cpus(); + if (!cpu_online(cpu)) + err = -EINVAL; + else +#if NEEDS_BLOCKING + err = work_on_cpu(cpu, __my_func_on_cpu, NULL); +#else + smp_call_function_single(cpu, __my_func_on_cpu, &err, + true); +#endif + put_online_cpus(); + return err; + } Q: How do we determine how many CPUs are available for hotplug. A: There is no clear spec defined way from ACPI that can give us that diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c index 098de5bce00a..9fdfbb969b12 100644 --- a/Documentation/lguest/lguest.c +++ b/Documentation/lguest/lguest.c @@ -34,7 +34,6 @@ #include <sys/uio.h> #include <termios.h> #include <getopt.h> -#include <zlib.h> #include <assert.h> #include <sched.h> #include <limits.h> |