Patchwork [v3] Add option to mlock qemu and guest memory

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Submitter Satoru Moriya
Date March 23, 2013, 3:57 a.m.
Message ID <8631DC5930FA9E468F04F3FD3A5D00721AFE03F0@USINDEM103.corp.hds.com>
Download mbox | patch
Permalink /patch/230303/
State New
Headers show

Comments

Satoru Moriya - March 23, 2013, 3:57 a.m.
ChangeLog:
v3
 - Modify os_mlock() to return error code
 - Update configure_realtime() to handle return value from os_mlock()
 - Change the variable name from is_mlock to enable_mlock in configure_realtime()
 - Rebase qemu version 1.4.50

v2
 - Change option name from -mlock to -realtime mlock=on|off
 - Rebase qemu version 1.3.91
 - Update patch description

We have some plans to migrate legacy enterprise systems which require
low latency (10 msec order) to kvm virtualized environment. In our
usecase, the system runs with other untrusted guests and so locking
memory which is used by the system is needed to avoid latency
impacts from other guests' memory activity.

---
In certain scenario, latency induced by paging is significant and
memory locking is needed. Also, in the scenario with untrusted
guests, latency improvement due to mlock is desired.

This patch introduces a following new option to mlock guest and
qemu memory:

-realtime mlock=on|off

Signed-off-by: Satoru Moriya <satoru.moriya@hds.com>

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>

Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>


---
 include/sysemu/os-posix.h |  1 +
 include/sysemu/os-win32.h |  5 +++++
 os-posix.c                | 12 ++++++++++++
 qemu-options.hx           | 13 +++++++++++++
 vl.c                      | 34 ++++++++++++++++++++++++++++++++++
 5 files changed, 65 insertions(+)

-- 
1.7.11.7
Anthony Liguori - March 26, 2013, 2:28 p.m.
Satoru Moriya <satoru.moriya@hds.com> writes:

> ChangeLog:
> v3
>  - Modify os_mlock() to return error code
>  - Update configure_realtime() to handle return value from os_mlock()
>  - Change the variable name from is_mlock to enable_mlock in configure_realtime()
>  - Rebase qemu version 1.4.50
>
> v2
>  - Change option name from -mlock to -realtime mlock=on|off
>  - Rebase qemu version 1.3.91
>  - Update patch description
>
> We have some plans to migrate legacy enterprise systems which require
> low latency (10 msec order) to kvm virtualized environment. In our
> usecase, the system runs with other untrusted guests and so locking
> memory which is used by the system is needed to avoid latency
> impacts from other guests' memory activity.
>
> ---

By putting this here, you're going to mess up the commit message.
Everything below '---' gets chopped off.

You want to move the changelog below the --- and the commit message
above it.

Please submit a v4 with a corrected commit message.

Regards,

Anthony Liguori

> In certain scenario, latency induced by paging is significant and
> memory locking is needed. Also, in the scenario with untrusted
> guests, latency improvement due to mlock is desired.
>
> This patch introduces a following new option to mlock guest and
> qemu memory:
>
> -realtime mlock=on|off
>
> Signed-off-by: Satoru Moriya <satoru.moriya@hds.com>
> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
> Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
>
> ---
>  include/sysemu/os-posix.h |  1 +
>  include/sysemu/os-win32.h |  5 +++++
>  os-posix.c                | 12 ++++++++++++
>  qemu-options.hx           | 13 +++++++++++++
>  vl.c                      | 34 ++++++++++++++++++++++++++++++++++
>  5 files changed, 65 insertions(+)
>
> diff --git a/include/sysemu/os-posix.h b/include/sysemu/os-posix.h
> index 7f198e4..25d0b2a 100644
> --- a/include/sysemu/os-posix.h
> +++ b/include/sysemu/os-posix.h
> @@ -31,6 +31,7 @@ void os_set_proc_name(const char *s);
>  void os_setup_signal_handling(void);
>  void os_daemonize(void);
>  void os_setup_post(void);
> +int os_mlock(void);
>  
>  typedef struct timeval qemu_timeval;
>  #define qemu_gettimeofday(tp) gettimeofday(tp, NULL)
> diff --git a/include/sysemu/os-win32.h b/include/sysemu/os-win32.h
> index 71f5fa0..bf8523a 100644
> --- a/include/sysemu/os-win32.h
> +++ b/include/sysemu/os-win32.h
> @@ -106,4 +106,9 @@ static inline bool is_daemonized(void)
>      return false;
>  }
>  
> +static inline int os_mlock(void)
> +{
> +    return -ENOSYS;
> +}
> +
>  #endif
> diff --git a/os-posix.c b/os-posix.c
> index 5c64518..d39261d 100644
> --- a/os-posix.c
> +++ b/os-posix.c
> @@ -363,3 +363,15 @@ bool is_daemonized(void)
>  {
>      return daemonize;
>  }
> +
> +int os_mlock(void)
> +{
> +    int ret = 0;
> +
> +    ret = mlockall(MCL_CURRENT | MCL_FUTURE);
> +    if (ret < 0) {
> +        perror("mlockall");
> +    }
> +
> +    return ret;
> +}
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 06dd565..1ec9541 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -2569,6 +2569,19 @@ STEXI
>  Do not start CPU at startup (you must type 'c' in the monitor).
>  ETEXI
>  
> +DEF("realtime", HAS_ARG, QEMU_OPTION_realtime,
> +    "-realtime [mlock=on|off]\n"
> +    "                run qemu with realtime features\n"
> +    "                mlock=on|off controls mlock support (default: on)\n",
> +    QEMU_ARCH_ALL)
> +STEXI
> +@item -realtime mlock=on|off
> +@findex -realtime
> +Run qemu with realtime features.
> +mlocking qemu and guest memory can be enabled via @option{mlock=on}
> +(enabled by default).
> +ETEXI
> +
>  DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \
>      "-gdb dev        wait for gdb connection on 'dev'\n", QEMU_ARCH_ALL)
>  STEXI
> diff --git a/vl.c b/vl.c
> index aeed7f4..71bbcf1 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -521,6 +521,18 @@ static QemuOptsList qemu_tpmdev_opts = {
>      },
>  };
>  
> +static QemuOptsList qemu_realtime_opts = {
> +    .name = "realtime",
> +    .head = QTAILQ_HEAD_INITIALIZER(qemu_realtime_opts.head),
> +    .desc = {
> +        {
> +            .name = "mlock",
> +            .type = QEMU_OPT_BOOL,
> +        },
> +        { /* end of list */ }
> +    },
> +};
> +
>  const char *qemu_get_vm_name(void)
>  {
>      return qemu_name;
> @@ -1420,6 +1432,20 @@ static void smp_parse(const char *optarg)
>          max_cpus = smp_cpus;
>  }
>  
> +static void configure_realtime(QemuOpts *opts)
> +{
> +    bool enable_mlock;
> +
> +    enable_mlock = qemu_opt_get_bool(opts, "mlock", true);
> +
> +    if (enable_mlock) {
> +        if (os_mlock() < 0) {
> +            fprintf(stderr, "qemu: locking memory failed\n");
> +            exit(1);
> +        }
> +    }
> +}
> +
>  /***********************************************************/
>  /* USB devices */
>  
> @@ -2909,6 +2935,7 @@ int main(int argc, char **argv, char **envp)
>      qemu_add_opts(&qemu_add_fd_opts);
>      qemu_add_opts(&qemu_object_opts);
>      qemu_add_opts(&qemu_tpmdev_opts);
> +    qemu_add_opts(&qemu_realtime_opts);
>  
>      runstate_init();
>  
> @@ -3878,6 +3905,13 @@ int main(int argc, char **argv, char **envp)
>                      exit(1);
>                  }
>                  break;
> +            case QEMU_OPTION_realtime:
> +                opts = qemu_opts_parse(qemu_find_opts("realtime"), optarg, 0);
> +                if (!opts) {
> +                    exit(1);
> +                }
> +                configure_realtime(opts);
> +                break;
>              default:
>                  os_parse_cmd_args(popt->index, optarg);
>              }
> -- 
> 1.7.11.7
Satoru Moriya - March 26, 2013, 2:40 p.m.
> -----Original Message-----

> From: Anthony Liguori [mailto:aliguori@us.ibm.com]

> Sent: Tuesday, March 26, 2013 10:28 AM

> To: Satoru Moriya; qemu-devel@nongnu.org

> Cc: Jan Kiszka; dle-develop@lists.sourceforge.net; Seiji Aguchi; Paolo Bonzini; mtosatti@redhat.com;

> Tomoki Sekiyama; satoru.moriya.br@hitachi.com

> Subject: Re: [Qemu-devel] [PATCH v3] Add option to mlock qemu and guest memory

> 

> Satoru Moriya <satoru.moriya@hds.com> writes:

> 

> > ChangeLog:

> > v3

> >  - Modify os_mlock() to return error code

> >  - Update configure_realtime() to handle return value from os_mlock()

> >  - Change the variable name from is_mlock to enable_mlock in

> > configure_realtime()

> >  - Rebase qemu version 1.4.50

> >

> > v2

> >  - Change option name from -mlock to -realtime mlock=on|off

> >  - Rebase qemu version 1.3.91

> >  - Update patch description

> >

> > We have some plans to migrate legacy enterprise systems which require

> > low latency (10 msec order) to kvm virtualized environment. In our

> > usecase, the system runs with other untrusted guests and so locking

> > memory which is used by the system is needed to avoid latency impacts

> > from other guests' memory activity.

> >

> > ---

> 

> By putting this here, you're going to mess up the commit message.

> Everything below '---' gets chopped off.

> 

> You want to move the changelog below the --- and the commit message above it.

> 

> Please submit a v4 with a corrected commit message.


Thanks.

I'll post v4 soon.

Regards,
Satoru

Patch

diff --git a/include/sysemu/os-posix.h b/include/sysemu/os-posix.h

index 7f198e4..25d0b2a 100644

--- a/include/sysemu/os-posix.h

+++ b/include/sysemu/os-posix.h

@@ -31,6 +31,7 @@  void os_set_proc_name(const char *s);

 void os_setup_signal_handling(void);
 void os_daemonize(void);
 void os_setup_post(void);
+int os_mlock(void);

 
 typedef struct timeval qemu_timeval;
 #define qemu_gettimeofday(tp) gettimeofday(tp, NULL)
diff --git a/include/sysemu/os-win32.h b/include/sysemu/os-win32.h

index 71f5fa0..bf8523a 100644

--- a/include/sysemu/os-win32.h

+++ b/include/sysemu/os-win32.h

@@ -106,4 +106,9 @@  static inline bool is_daemonized(void)

     return false;
 }
 
+static inline int os_mlock(void)

+{

+    return -ENOSYS;

+}

+

 #endif
diff --git a/os-posix.c b/os-posix.c

index 5c64518..d39261d 100644

--- a/os-posix.c

+++ b/os-posix.c

@@ -363,3 +363,15 @@  bool is_daemonized(void)

 {
     return daemonize;
 }
+

+int os_mlock(void)

+{

+    int ret = 0;

+

+    ret = mlockall(MCL_CURRENT | MCL_FUTURE);

+    if (ret < 0) {

+        perror("mlockall");

+    }

+

+    return ret;

+}

diff --git a/qemu-options.hx b/qemu-options.hx

index 06dd565..1ec9541 100644

--- a/qemu-options.hx

+++ b/qemu-options.hx

@@ -2569,6 +2569,19 @@  STEXI

 Do not start CPU at startup (you must type 'c' in the monitor).
 ETEXI
 
+DEF("realtime", HAS_ARG, QEMU_OPTION_realtime,

+    "-realtime [mlock=on|off]\n"

+    "                run qemu with realtime features\n"

+    "                mlock=on|off controls mlock support (default: on)\n",

+    QEMU_ARCH_ALL)

+STEXI

+@item -realtime mlock=on|off

+@findex -realtime

+Run qemu with realtime features.

+mlocking qemu and guest memory can be enabled via @option{mlock=on}

+(enabled by default).

+ETEXI

+

 DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \
     "-gdb dev        wait for gdb connection on 'dev'\n", QEMU_ARCH_ALL)
 STEXI
diff --git a/vl.c b/vl.c

index aeed7f4..71bbcf1 100644

--- a/vl.c

+++ b/vl.c

@@ -521,6 +521,18 @@  static QemuOptsList qemu_tpmdev_opts = {

     },
 };
 
+static QemuOptsList qemu_realtime_opts = {

+    .name = "realtime",

+    .head = QTAILQ_HEAD_INITIALIZER(qemu_realtime_opts.head),

+    .desc = {

+        {

+            .name = "mlock",

+            .type = QEMU_OPT_BOOL,

+        },

+        { /* end of list */ }

+    },

+};

+

 const char *qemu_get_vm_name(void)
 {
     return qemu_name;
@@ -1420,6 +1432,20 @@  static void smp_parse(const char *optarg)

         max_cpus = smp_cpus;
 }
 
+static void configure_realtime(QemuOpts *opts)

+{

+    bool enable_mlock;

+

+    enable_mlock = qemu_opt_get_bool(opts, "mlock", true);

+

+    if (enable_mlock) {

+        if (os_mlock() < 0) {

+            fprintf(stderr, "qemu: locking memory failed\n");

+            exit(1);

+        }

+    }

+}

+

 /***********************************************************/
 /* USB devices */
 
@@ -2909,6 +2935,7 @@  int main(int argc, char **argv, char **envp)

     qemu_add_opts(&qemu_add_fd_opts);
     qemu_add_opts(&qemu_object_opts);
     qemu_add_opts(&qemu_tpmdev_opts);
+    qemu_add_opts(&qemu_realtime_opts);

 
     runstate_init();
 
@@ -3878,6 +3905,13 @@  int main(int argc, char **argv, char **envp)

                     exit(1);
                 }
                 break;
+            case QEMU_OPTION_realtime:

+                opts = qemu_opts_parse(qemu_find_opts("realtime"), optarg, 0);

+                if (!opts) {

+                    exit(1);

+                }

+                configure_realtime(opts);

+                break;

             default:
                 os_parse_cmd_args(popt->index, optarg);
             }