Re: [PATCH v5 1/1] util/async-teardown: wire up query-command-line-options
Thomas Huth writes: > On 28/03/2023 07.26, Markus Armbruster wrote: >> Paolo Bonzini writes: >> >>> I am honestly not a fan of adding a more complex option,.just because >>> query-command-line-options only returns the square holes whereas here we >>> got a round one. >>> >>> Can we imagine another functionality that would be added to -teardown? If >>> not, it's not a good design. If it works, I would add a completely dummy >>> (no suboptions) group "async-teardown" and not modify the parsing at all. >> >> Does v2 implement your suggestion? >> Message-Id: <20230320131648.61728-1-imbre...@linux.ibm.com> >> >> I dislike it, because it makes query-command-line-options claim >> -async-teardown has an option argument with unknown keys, which is >> plainly wrong, and must be treated as a special case. Worse, a new kind >> of special case. > > I agree with Markus, it sounds like a bad idea to create a new special case > for this. > > Paolo, what do you think of my "-run-with" suggestion here: > > > https://lore.kernel.org/qemu-devel/3237c289-b8c2-6ea2-8bfb-7eeed637e...@redhat.com/ > > I still think that this is a good idea, even if it is a "grab-bag" as Markus > said, it would give us a place where we could wire future similar options, > too, without running into this problem here again and again. > >> Can we have a QMP command, so libvirt can use query-qmp-schema? > > Question is whether this could be toggled during runtime...? Or did you mean > a command that just queries the setting of the option, e.g. > "query-async-teardown" which then reports whether it is enabled or not? Mildly ugly, as the command is pretty much useless except as a witness for the CLI option. We've done this before. >> In case QMP becomes functional too late for the command to actually >> work: make it always fail for now. It can still serve as a witness for >> -async-teardown. If we rework QEMU startup so that QMP can do >> everything the CLI can do, we'll make the QMP command work. > > Adding non-working functions sounds ugly... Non-working functions that could totally work with QEMU startup reworked are only mildly ugly, I think. > Anyway, we're slowly running out of time for QEMU 8.0 ... if we can't find an > easy solution, I think we should rather postpone this to the next cycle > instead of rushing unfinished stuff now. Yes. I think we can still do it if we agree quickly on which kind of ugly we hate the least. Adding -async-teardown as a stable interface was premature. We should have marked it unstable when no libvirt patch was ready when we cut QEMU 7.2. Adding new external interfaces is still not hard enough :)
Re: [PATCH v5 1/1] util/async-teardown: wire up query-command-line-options
On 28/03/2023 07.26, Markus Armbruster wrote: Paolo Bonzini writes: I am honestly not a fan of adding a more complex option,.just because query-command-line-options only returns the square holes whereas here we got a round one. Can we imagine another functionality that would be added to -teardown? If not, it's not a good design. If it works, I would add a completely dummy (no suboptions) group "async-teardown" and not modify the parsing at all. Does v2 implement your suggestion? Message-Id: <20230320131648.61728-1-imbre...@linux.ibm.com> I dislike it, because it makes query-command-line-options claim -async-teardown has an option argument with unknown keys, which is plainly wrong, and must be treated as a special case. Worse, a new kind of special case. I agree with Markus, it sounds like a bad idea to create a new special case for this. Paolo, what do you think of my "-run-with" suggestion here: https://lore.kernel.org/qemu-devel/3237c289-b8c2-6ea2-8bfb-7eeed637e...@redhat.com/ I still think that this is a good idea, even if it is a "grab-bag" as Markus said, it would give us a place where we could wire future similar options, too, without running into this problem here again and again. Can we have a QMP command, so libvirt can use query-qmp-schema? Question is whether this could be toggled during runtime...? Or did you mean a command that just queries the setting of the option, e.g. "query-async-teardown" which then reports whether it is enabled or not? In case QMP becomes functional too late for the command to actually work: make it always fail for now. It can still serve as a witness for -async-teardown. If we rework QEMU startup so that QMP can do everything the CLI can do, we'll make the QMP command work. Adding non-working functions sounds ugly... Anyway, we're slowly running out of time for QEMU 8.0 ... if we can't find an easy solution, I think we should rather postpone this to the next cycle instead of rushing unfinished stuff now. Thomas
Re: [PATCH v5 1/1] util/async-teardown: wire up query-command-line-options
Paolo Bonzini writes: > I am honestly not a fan of adding a more complex option,.just because > query-command-line-options only returns the square holes whereas here we > got a round one. > > Can we imagine another functionality that would be added to -teardown? If > not, it's not a good design. If it works, I would add a completely dummy > (no suboptions) group "async-teardown" and not modify the parsing at all. Does v2 implement your suggestion? Message-Id: <20230320131648.61728-1-imbre...@linux.ibm.com> I dislike it, because it makes query-command-line-options claim -async-teardown has an option argument with unknown keys, which is plainly wrong, and must be treated as a special case. Worse, a new kind of special case. Can we have a QMP command, so libvirt can use query-qmp-schema? In case QMP becomes functional too late for the command to actually work: make it always fail for now. It can still serve as a witness for -async-teardown. If we rework QEMU startup so that QMP can do everything the CLI can do, we'll make the QMP command work.
Re: [PATCH v5 1/1] util/async-teardown: wire up query-command-line-options
I am honestly not a fan of adding a more complex option,.just because
query-command-line-options only returns the square holes whereas here we
got a round one.
Can we imagine another functionality that would be added to -teardown? If
not, it's not a good design. If it works, I would add a completely dummy
(no suboptions) group "async-teardown" and not modify the parsing at all.
Paolo
Il lun 27 mar 2023, 15:35 Claudio Imbrenda ha
scritto:
> Add new -teardown option with an async=on|off parameter. It is visible
> in the output of query-command-line-options QMP command, so it can be
> discovered and used by libvirt.
>
> The option -async-teardown is now redundant. We'd normally deprecate it
> and remove it after a grace period, but it was introduced only in the
> previous version and it had no users, since it was not visible in the
> query-command-line-options QMP command. Drop it.
>
> Reported-by: Boris Fiuczynski
> Fixes: c891c24b1a ("os-posix: asynchronous teardown for shutdown on Linux")
> Signed-off-by: Claudio Imbrenda
> ---
> docs/about/removed-features.rst | 5 +
> os-posix.c | 15 +--
> qemu-options.hx | 33 +++--
> util/async-teardown.c | 21 +
> 4 files changed, 58 insertions(+), 16 deletions(-)
>
> diff --git a/docs/about/removed-features.rst
> b/docs/about/removed-features.rst
> index 5b258b446b..6d89f69be9 100644
> --- a/docs/about/removed-features.rst
> +++ b/docs/about/removed-features.rst
> @@ -416,6 +416,11 @@ Input parameters that take a size value should only
> use a size suffix
> the value is hexadecimal. That is, '0x20M' should be written either as
> '32M' or as '0x200'.
>
> +``-async-teardown`` (removed in 8.0)
> +
> +
> +Use ``-teardown async=on`` instead.
> +
> ``-chardev`` backend aliases ``tty`` and ``parport`` (removed in 8.0)
> '
>
> diff --git a/os-posix.c b/os-posix.c
> index 5adc69f560..c1ca7b1cb3 100644
> --- a/os-posix.c
> +++ b/os-posix.c
> @@ -36,6 +36,8 @@
> #include "qemu/log.h"
> #include "sysemu/runstate.h"
> #include "qemu/cutils.h"
> +#include "qemu/config-file.h"
> +#include "qemu/option.h"
>
> #ifdef CONFIG_LINUX
> #include
> @@ -132,6 +134,8 @@ static bool os_parse_runas_uid_gid(const char *optarg)
> */
> int os_parse_cmd_args(int index, const char *optarg)
> {
> +QemuOpts *opts;
> +
> switch (index) {
> case QEMU_OPTION_runas:
> user_pwd = getpwnam(optarg);
> @@ -152,8 +156,15 @@ int os_parse_cmd_args(int index, const char *optarg)
> daemonize = 1;
> break;
> #if defined(CONFIG_LINUX)
> -case QEMU_OPTION_asyncteardown:
> -init_async_teardown();
> +case QEMU_OPTION_teardown:
> +opts = qemu_opts_parse_noisily(qemu_find_opts("teardown"),
> + optarg, false);
> +if (!opts) {
> +exit(1);
> +}
> +if (qemu_opt_get_bool(opts, "async", false)) {
> +init_async_teardown();
> +}
> break;
> #endif
> default:
> diff --git a/qemu-options.hx b/qemu-options.hx
> index d42f60fb91..6a69b84f3c 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -4763,23 +4763,28 @@ DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "",
> QEMU_ARCH_ALL)
> DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL)
>
> #ifdef __linux__
> -DEF("async-teardown", 0, QEMU_OPTION_asyncteardown,
> -"-async-teardown enable asynchronous teardown\n",
> +DEF("teardown", HAS_ARG, QEMU_OPTION_teardown,
> +"-teardown async[=on|off]\n"
> +"process teardown options\n"
> +"async=on enables asynchronous teardown\n"
> + ,
> QEMU_ARCH_ALL)
> -#endif
> SRST
> -``-async-teardown``
> -Enable asynchronous teardown. A new process called
> "cleanup/"
> -will be created at startup sharing the address space with the main
> qemu
> -process, using clone. It will wait for the main qemu process to
> -terminate completely, and then exit.
> -This allows qemu to terminate very quickly even if the guest was
> -huge, leaving the teardown of the address space to the cleanup
> -process. Since the cleanup process shares the same cgroups as the
> -main qemu process, accounting is performed correctly. This only
> -works if the cleanup process is not forcefully killed with SIGKILL
> -before the main qemu process has terminated completely.
> +``-teardown``
> +Set process teardown options.
> +
> +``async=on`` enables asynchronous teardown. A new process called
> +"cleanup/" will be created at startup sharing the address
> +space with the main QEMU process, using clone. It will wait for the
> +main QEMU process to terminate completely, and then exit. This allows
> +QEMU to terminate very quickly even if the
[PATCH v5 1/1] util/async-teardown: wire up query-command-line-options
Add new -teardown option with an async=on|off parameter. It is visible
in the output of query-command-line-options QMP command, so it can be
discovered and used by libvirt.
The option -async-teardown is now redundant. We'd normally deprecate it
and remove it after a grace period, but it was introduced only in the
previous version and it had no users, since it was not visible in the
query-command-line-options QMP command. Drop it.
Reported-by: Boris Fiuczynski
Fixes: c891c24b1a ("os-posix: asynchronous teardown for shutdown on Linux")
Signed-off-by: Claudio Imbrenda
---
docs/about/removed-features.rst | 5 +
os-posix.c | 15 +--
qemu-options.hx | 33 +++--
util/async-teardown.c | 21 +
4 files changed, 58 insertions(+), 16 deletions(-)
diff --git a/docs/about/removed-features.rst b/docs/about/removed-features.rst
index 5b258b446b..6d89f69be9 100644
--- a/docs/about/removed-features.rst
+++ b/docs/about/removed-features.rst
@@ -416,6 +416,11 @@ Input parameters that take a size value should only use a
size suffix
the value is hexadecimal. That is, '0x20M' should be written either as
'32M' or as '0x200'.
+``-async-teardown`` (removed in 8.0)
+
+
+Use ``-teardown async=on`` instead.
+
``-chardev`` backend aliases ``tty`` and ``parport`` (removed in 8.0)
'
diff --git a/os-posix.c b/os-posix.c
index 5adc69f560..c1ca7b1cb3 100644
--- a/os-posix.c
+++ b/os-posix.c
@@ -36,6 +36,8 @@
#include "qemu/log.h"
#include "sysemu/runstate.h"
#include "qemu/cutils.h"
+#include "qemu/config-file.h"
+#include "qemu/option.h"
#ifdef CONFIG_LINUX
#include
@@ -132,6 +134,8 @@ static bool os_parse_runas_uid_gid(const char *optarg)
*/
int os_parse_cmd_args(int index, const char *optarg)
{
+QemuOpts *opts;
+
switch (index) {
case QEMU_OPTION_runas:
user_pwd = getpwnam(optarg);
@@ -152,8 +156,15 @@ int os_parse_cmd_args(int index, const char *optarg)
daemonize = 1;
break;
#if defined(CONFIG_LINUX)
-case QEMU_OPTION_asyncteardown:
-init_async_teardown();
+case QEMU_OPTION_teardown:
+opts = qemu_opts_parse_noisily(qemu_find_opts("teardown"),
+ optarg, false);
+if (!opts) {
+exit(1);
+}
+if (qemu_opt_get_bool(opts, "async", false)) {
+init_async_teardown();
+}
break;
#endif
default:
diff --git a/qemu-options.hx b/qemu-options.hx
index d42f60fb91..6a69b84f3c 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -4763,23 +4763,28 @@ DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "",
QEMU_ARCH_ALL)
DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL)
#ifdef __linux__
-DEF("async-teardown", 0, QEMU_OPTION_asyncteardown,
-"-async-teardown enable asynchronous teardown\n",
+DEF("teardown", HAS_ARG, QEMU_OPTION_teardown,
+"-teardown async[=on|off]\n"
+"process teardown options\n"
+"async=on enables asynchronous teardown\n"
+ ,
QEMU_ARCH_ALL)
-#endif
SRST
-``-async-teardown``
-Enable asynchronous teardown. A new process called "cleanup/"
-will be created at startup sharing the address space with the main qemu
-process, using clone. It will wait for the main qemu process to
-terminate completely, and then exit.
-This allows qemu to terminate very quickly even if the guest was
-huge, leaving the teardown of the address space to the cleanup
-process. Since the cleanup process shares the same cgroups as the
-main qemu process, accounting is performed correctly. This only
-works if the cleanup process is not forcefully killed with SIGKILL
-before the main qemu process has terminated completely.
+``-teardown``
+Set process teardown options.
+
+``async=on`` enables asynchronous teardown. A new process called
+"cleanup/" will be created at startup sharing the address
+space with the main QEMU process, using clone. It will wait for the
+main QEMU process to terminate completely, and then exit. This allows
+QEMU to terminate very quickly even if the guest was huge, leaving the
+teardown of the address space to the cleanup process. Since the cleanup
+process shares the same cgroups as the main QEMU process, accounting is
+performed correctly. This only works if the cleanup process is not
+forcefully killed with SIGKILL before the main QEMU process has
+terminated completely.
ERST
+#endif
DEF("msg", HAS_ARG, QEMU_OPTION_msg,
"-msg [timestamp[=on|off]][,guest-name=[on|off]]\n"
diff --git a/util/async-teardown.c b/util/async-teardown.c
index 62cdeb0f20..4a5dbce958 100644
--- a/util/async-teardown.c
+++ b/util/async-teardown.c
@@ -12,6 +12,9 @@
*/
#include "qemu/osdep.h"
