On 10.02.2015 16:35, Martin Kletzander wrote:
> This function uses sched_setscheduler() function so it works with
> processes and threads as well (even threads not created by us, which is
> what we'll need in the future).
>
> Signed-off-by: Martin Kletzander <mkletzan@xxxxxxxxxx>
> ---
> configure.ac | 4 +-
> src/libvirt_private.syms | 1 +
> src/util/virprocess.c | 104 ++++++++++++++++++++++++++++++++++++++++++++++-
> src/util/virprocess.h | 20 ++++++++-
> 4 files changed, 124 insertions(+), 5 deletions(-)
>
> diff --git a/configure.ac b/configure.ac
> index 99a2283..b3e99e7 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -1,6 +1,6 @@
> dnl Process this file with autoconf to produce a configure script.
>
> -dnl Copyright (C) 2005-2014 Red Hat, Inc.
> +dnl Copyright (C) 2005-2015 Red Hat, Inc.
> dnl
> dnl This library is free software; you can redistribute it and/or
> dnl modify it under the terms of the GNU Lesser General Public
> @@ -275,7 +275,7 @@ dnl and various less common threadsafe functions
> AC_CHECK_FUNCS_ONCE([cfmakeraw fallocate geteuid getgid getgrnam_r \
> getmntent_r getpwuid_r getuid kill mmap newlocale posix_fallocate \
> posix_memalign prlimit regexec sched_getaffinity setgroups setns \
> - setrlimit symlink sysctlbyname getifaddrs])
> + setrlimit symlink sysctlbyname getifaddrs sched_setscheduler])
>
> dnl Availability of pthread functions. Because of $LIB_PTHREAD, we
> dnl cannot use AC_CHECK_FUNCS_ONCE. LIB_PTHREAD and LIBMULTITHREAD
> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
> index 376c69b..79fc14f 100644
> --- a/src/libvirt_private.syms
> +++ b/src/libvirt_private.syms
> @@ -1915,6 +1915,7 @@ virProcessSetMaxFiles;
> virProcessSetMaxMemLock;
> virProcessSetMaxProcesses;
> virProcessSetNamespaces;
> +virProcessSetScheduler;
> virProcessTranslateStatus;
> virProcessWait;
>
> diff --git a/src/util/virprocess.c b/src/util/virprocess.c
> index d0a1500..c030d74 100644
> --- a/src/util/virprocess.c
> +++ b/src/util/virprocess.c
> @@ -1,7 +1,7 @@
> /*
> * virprocess.c: interaction with processes
> *
> - * Copyright (C) 2010-2014 Red Hat, Inc.
> + * Copyright (C) 2010-2015 Red Hat, Inc.
> *
> * This library is free software; you can redistribute it and/or
> * modify it under the terms of the GNU Lesser General Public
> @@ -32,7 +32,9 @@
> # include <sys/time.h>
> # include <sys/resource.h>
> #endif
> -#include <sched.h>
> +#if HAVE_SCHED_SETSCHEDULER
> +# include <sched.h>
> +#endif
>
> #if defined(__FreeBSD__) || HAVE_BSD_CPU_AFFINITY
> # include <sys/param.h>
> @@ -104,6 +106,13 @@ static inline int setns(int fd ATTRIBUTE_UNUSED, int nstype ATTRIBUTE_UNUSED)
> }
> #endif
>
> +VIR_ENUM_IMPL(virProcessSchedPolicy, VIR_PROC_POLICY_LAST,
> + "none",
> + "batch",
> + "idle",
> + "fifo",
> + "rr");
> +
> /**
> * virProcessTranslateStatus:
> * @status: child exit status to translate
> @@ -1052,3 +1061,94 @@ virProcessExitWithStatus(int status)
> }
> exit(value);
> }
> +
> +#if HAVE_SCHED_SETSCHEDULER
> +
> +static int
> +virProcessSchedTranslatePolicy(virProcessSchedPolicy policy)
> +{
> + switch (policy) {
> + case VIR_PROC_POLICY_NONE:
> + return SCHED_OTHER;
> +
> + case VIR_PROC_POLICY_BATCH:
> + return SCHED_BATCH;
> +
> + case VIR_PROC_POLICY_IDLE:
> + return SCHED_IDLE;
> +
> + case VIR_PROC_POLICY_FIFO:
> + return SCHED_FIFO;
> +
> + case VIR_PROC_POLICY_RR:
> + return SCHED_RR;
> +
> + case VIR_PROC_POLICY_LAST:
> + /* nada */
> + break;
> + }
> +
> + return -1;
> +}
> +
> +int
> +virProcessSetScheduler(pid_t pid, virProcessSchedPolicy policy, int priority)
> +{
> + struct sched_param param = {0};
> + int pol = virProcessSchedTranslatePolicy(policy);
> +
> + VIR_DEBUG("pid=%d, policy=%d, priority=%u", pid, policy, priority);
> +
> + if (!policy)
> + return 0;
In order to do this, you have to make sure enum has a zero value
element. I think compilers don't guarantee enum values <-> integer
mapping unless told so.
> +
> + if (pol == SCHED_FIFO || pol == SCHED_RR) {
> + int min = 0;
> + int max = 0;
> +
> + if ((min = sched_get_priority_min(pol)) < 0) {
> + virReportSystemError(errno, "%s",
> + _("Cannot get minimum scheduler "
> + "priority value"));
> + return -1;
> + }
> +
> + if ((max = sched_get_priority_max(pol)) < 0) {
> + virReportSystemError(errno, "%s",
> + _("Cannot get maximum scheduler "
> + "priority value"));
> + return -1;
> + }
> +
> + if (priority < min || priority > max) {
> + virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> + _("Scheduler priority %d out of range [%d, %d]"),
> + priority, min, max);
CONFIG? I'd say ARGUMENT, but we have the mess in error codes anyway and
this doesn't make situation any worse :)
> + return -1;
> + }
> +
> + param.sched_priority = priority;
> + }
> +
> + if (sched_setscheduler(pid, pol, ¶m) < 0) {
> + virReportSystemError(errno,
> + _("Cannot set scheduler parameters for pid %d"),
> + pid);
> + return -1;
> + }
> +
> + return 0;
> +}
> +
> +#else /* ! HAVE_SCHED_SETSCHEDULER */
> +
> +int
> +virProcessSetScheduler(pid_t pid, int policy, int priority)
ATTRIBUTE_UNUSED for arguments ^^. Although, would it be worth to copy
the check I've pointed out in here too? That is, even if
sched_setscheduler() is not available, and virProcessSetScheduler(pid,
0, prio); is called, return success instead of error (of course return
error for any other policy than VIR_PROC_POLICY_NONE).
> +{
> + virReportSystemError(ENOSYS, "%s",
> + _("Process CPU scheduling is not supported "
> + "on this platform"));
> + return -1;
> +}
> +
> +#endif /* !HAVE_SCHED_SETSCHEDULER */
> diff --git a/src/util/virprocess.h b/src/util/virprocess.h
> index bcaede5..8b95560 100644
> --- a/src/util/virprocess.h
> +++ b/src/util/virprocess.h
> @@ -1,7 +1,7 @@
> /*
> * virprocess.h: interaction with processes
> *
> - * Copyright (C) 2010-2014 Red Hat, Inc.
> + * Copyright (C) 2010-2015 Red Hat, Inc.
> *
> * This library is free software; you can redistribute it and/or
> * modify it under the terms of the GNU Lesser General Public
> @@ -26,6 +26,19 @@
>
> # include "internal.h"
> # include "virbitmap.h"
> +# include "virutil.h"
> +
> +typedef enum {
> + VIR_PROC_POLICY_NONE,
> + VIR_PROC_POLICY_BATCH,
> + VIR_PROC_POLICY_IDLE,
> + VIR_PROC_POLICY_FIFO,
> + VIR_PROC_POLICY_RR,
> +
> + VIR_PROC_POLICY_LAST
> +} virProcessSchedPolicy;
> +
> +VIR_ENUM_DECL(virProcessSchedPolicy);
This ^^ introduces virProcessSchedPolicyType{From,To}String(). However,
I don't see the symbols exported.
>
> char *
> virProcessTranslateStatus(int status);
> @@ -73,4 +86,9 @@ typedef int (*virProcessNamespaceCallback)(pid_t pid, void *opaque);
> int virProcessRunInMountNamespace(pid_t pid,
> virProcessNamespaceCallback cb,
> void *opaque);
> +
> +int virProcessSetScheduler(pid_t pid,
> + virProcessSchedPolicy policy,
> + int priority);
> +
> #endif /* __VIR_PROCESS_H__ */
>
ACK with all of that fixed.
Michal
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