| Message ID | 334b5a46e31dbf3e8114e9ea8bafd92cf060f2af.1712837961.git.manos.pitsidianakis@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | convert LIBXL_DEVICE_MODEL_START_TIMEOUT to env var | expand |
On Thu, Apr 11, 2024 at 03:28:19PM +0300, Manos Pitsidianakis wrote: > diff --git a/docs/man/xl.1.pod.in b/docs/man/xl.1.pod.in > index bed8393473..c159877094 100644 > --- a/docs/man/xl.1.pod.in > +++ b/docs/man/xl.1.pod.in > @@ -1993,6 +1993,17 @@ Otherwise the build time default in LIBXL_BOOTLOADER_TIMEOUT will be used. > If defined the value must be an unsigned integer between 0 and INT_MAX, > otherwise behavior is undefined. Setting to 0 disables the timeout. I don't think a value of "0" would disable timeouts, did you try? It's more likely that the timeout will fire immediately. I'll had some comment later about this on case-by-case basis. > > +=item LIBXL_DEVICE_MODEL_START_TIMEOUT > + > +Timeout in seconds for starting the device model process. Useful in case the > +device model takes an unusual amount of time to start— for example in case of Could you use only ASCII characters, here ^ It's looks like it's the first UTF-8 chr in this document, and we can do without it. I just want to avoid find out later that something break because of that chr. > +very slow I/O, in case of slow performance due to memory sanitizer usage, etc. > + > +If undefined, the default hard-coded value of 60 seconds is used. > + > +If defined, the value must be an unsigned integer between 0 and INT_MAX, > +otherwise behaviour is undefined. Setting the value to 0 disables the timeout. > + > =back > > =head1 SEE ALSO > diff --git a/tools/libs/light/libxl_9pfs.c b/tools/libs/light/libxl_9pfs.c > index 48f894f070..950a464b45 100644 > --- a/tools/libs/light/libxl_9pfs.c > +++ b/tools/libs/light/libxl_9pfs.c > @@ -132,7 +132,7 @@ static int xen9pfsd_spawn(libxl__egc *egc, uint32_t domid, libxl_device_p9 *p9, > aop9->spawn.ao = aodev->ao; > aop9->spawn.what = "xen-9pfs daemon"; > aop9->spawn.xspath = GCSPRINTF("%s/state", path); > - aop9->spawn.timeout_ms = LIBXL_DEVICE_MODEL_START_TIMEOUT * 1000; > + aop9->spawn.timeout_ms = __libxl_device_model_start_timeout() * 1000; So this value is going to be used by libxl__spawn_spawn() then libxl__xswait_start(), and it's looks like a timeout of "0" will have the timeout fire immediately. Instead, a value of "-1" might disable the timeout, but I don't know how well it would work without a timeout. Timeout is setup with libxl__ev_time_register_rel(). > aop9->spawn.pidpath = GCSPRINTF("%s/pid", path); > aop9->spawn.midproc_cb = libxl__spawn_record_pid; > aop9->spawn.confirm_cb = xen9pfsd_confirm; > diff --git a/tools/libs/light/libxl_device.c b/tools/libs/light/libxl_device.c > index 6f0100d05e..452e55ba23 100644 > --- a/tools/libs/light/libxl_device.c > +++ b/tools/libs/light/libxl_device.c > @@ -1436,7 +1436,7 @@ int libxl__wait_for_device_model_deprecated(libxl__gc *gc, > > path = DEVICE_MODEL_XS_PATH(gc, dm_domid, domid, "/state"); > return libxl__xenstore_child_wait_deprecated(gc, domid, > - LIBXL_DEVICE_MODEL_START_TIMEOUT, > + __libxl_device_model_start_timeout(), This function will return an error immediately, without trying, with a timeout of "0", and "-1" isn't an option (well I guess it might be INT_MAX because it an unsigned value). > "Device Model", path, state, spawning, > check_callback, check_callback_userdata); > } > diff --git a/tools/libs/light/libxl_dm.c b/tools/libs/light/libxl_dm.c > index 0b03a7c747..4369fef161 100644 > --- a/tools/libs/light/libxl_dm.c > +++ b/tools/libs/light/libxl_dm.c > @@ -2629,7 +2629,7 @@ static void spawn_qmp_proxy(libxl__egc *egc, > sdss->qmp_proxy_spawn.pidpath = GCSPRINTF("%s/image/qmp-proxy-pid", dom_path); > sdss->qmp_proxy_spawn.xspath = DEVICE_MODEL_XS_PATH(gc, LIBXL_TOOLSTACK_DOMID, > dm_domid, "/qmp-proxy-state"); > - sdss->qmp_proxy_spawn.timeout_ms = LIBXL_DEVICE_MODEL_START_TIMEOUT * 1000; > + sdss->qmp_proxy_spawn.timeout_ms = __libxl_device_model_start_timeout() * 1000; That's used by libxl__spawn_spawn(). Already commented on it. > sdss->qmp_proxy_spawn.midproc_cb = libxl__spawn_record_pid; > sdss->qmp_proxy_spawn.confirm_cb = qmp_proxy_confirm; > sdss->qmp_proxy_spawn.failure_cb = qmp_proxy_startup_failed; > @@ -3011,7 +3011,7 @@ retry_transaction: > spawn->what = GCSPRINTF("domain %d device model", domid); > spawn->xspath = DEVICE_MODEL_XS_PATH(gc, LIBXL_TOOLSTACK_DOMID, domid, > "/state"); > - spawn->timeout_ms = LIBXL_DEVICE_MODEL_START_TIMEOUT * 1000; > + spawn->timeout_ms = __libxl_device_model_start_timeout() * 1000; That's used by libxl__spawn_spawn(). Already commented on it. > spawn->pidpath = GCSPRINTF("%s/image/device-model-pid", dom_path); > spawn->midproc_cb = libxl__spawn_record_pid; > spawn->confirm_cb = device_model_confirm; > @@ -3435,7 +3435,7 @@ void libxl__spawn_qdisk_backend(libxl__egc *egc, libxl__dm_spawn_state *dmss) > > dmss->spawn.what = GCSPRINTF("domain %u Qdisk backend", domid); > dmss->spawn.xspath = GCSPRINTF("device-model/%u/state", domid); > - dmss->spawn.timeout_ms = LIBXL_DEVICE_MODEL_START_TIMEOUT * 1000; > + dmss->spawn.timeout_ms = __libxl_device_model_start_timeout() * 1000; That's used by libxl__spawn_spawn(). Already commented on it. > /* > * We cannot save Qemu pid anywhere in the xenstore guest dir, > * because we will call this from unprivileged driver domains, > diff --git a/tools/libs/light/libxl_dom_suspend.c b/tools/libs/light/libxl_dom_suspend.c > index 6091a5f3f6..29e51f6c40 100644 > --- a/tools/libs/light/libxl_dom_suspend.c > +++ b/tools/libs/light/libxl_dom_suspend.c > @@ -517,7 +517,7 @@ void libxl__dm_resume(libxl__egc *egc, > rc = libxl__ev_time_register_rel(dmrs->ao, > &dmrs->time, > dm_resume_timeout, > - LIBXL_DEVICE_MODEL_START_TIMEOUT * 1000); > + __libxl_device_model_start_timeout() * 1000); libxl__ev_time_register_rel() just setup a timer, and I think with a timeout of 0, dm_resume_timeout() would be call immediately as soon as the current function returns, resulting in a failure. > if (rc) goto out; > > switch (libxl__device_model_version_running(gc, domid)) { > diff --git a/tools/libs/light/libxl_internal.h b/tools/libs/light/libxl_internal.h > index 803dbc1a03..684390f822 100644 > --- a/tools/libs/light/libxl_internal.h > +++ b/tools/libs/light/libxl_internal.h > @@ -97,6 +97,12 @@ > /* QEMU may be slow to load and start due to a bug in Linux where the I/O > * subsystem sometime produce high latency under load. */ > #define LIBXL_DEVICE_MODEL_START_TIMEOUT 60 > +static inline int __libxl_device_model_start_timeout(void) Could you rename that function? Probably: libxl__device_model_start_timeout() No leading '_', this is usually reserved, by glibc or C, I forgot the details. Also, internal libxl function have two '_', so full prefix is "libxl__". > +{ > + const char *timeout_env = getenv("LIBXL_DEVICE_MODEL_START_TIMEOUT"); > + return timeout_env ? atoi(timeout_env) That usage of atoi() isn't good, because on conversion error, 0 is returned, which disable the timeout. I would rather fallback when we don't have a number. One case that might be more problematic than other might be: LIBXL_DEVICE_MODEL_START_TIMEOUT= xl create I think we would have a timeout of 0, instead of a fallback to the default. > + : LIBXL_DEVICE_MODEL_START_TIMEOUT; > +} > #define LIBXL_DEVICE_MODEL_SAVE_FILE XEN_LIB_DIR "/qemu-save" /* .$domid */ > #define LIBXL_DEVICE_MODEL_RESTORE_FILE XEN_LIB_DIR "/qemu-resume" /* .$domid */ > #define LIBXL_QMP_CMD_TIMEOUT 10 > diff --git a/tools/libs/light/libxl_pci.c b/tools/libs/light/libxl_pci.c > index 96cb4da079..7bdd9f6c3b 100644 > --- a/tools/libs/light/libxl_pci.c > +++ b/tools/libs/light/libxl_pci.c > @@ -1157,7 +1157,7 @@ static void do_pci_add(libxl__egc *egc, > pas->xswait.what = "Device Model"; > pas->xswait.path = DEVICE_MODEL_XS_PATH(gc, > libxl_get_stubdom_id(CTX, domid), domid, "/state"); > - pas->xswait.timeout_ms = LIBXL_DEVICE_MODEL_START_TIMEOUT * 1000; > + pas->xswait.timeout_ms = __libxl_device_model_start_timeout() * 1000; That used by libxl__xswait_start(), and "0" seems to result in a failure. > pas->xswait.callback = pci_add_qemu_trad_watch_state_cb; > rc = libxl__xswait_start(gc, &pas->xswait); > if (rc) goto out; > @@ -1719,7 +1719,7 @@ static void device_pci_add_stubdom_wait(libxl__egc *egc, > rc = libxl__ev_devstate_wait(ao, &pas->pciback_ds, > device_pci_add_stubdom_ready, > state_path, XenbusStateConnected, > - LIBXL_DEVICE_MODEL_START_TIMEOUT * 1000); > + __libxl_device_model_start_timeout() * 1000); That value will be use by libxl__xswait_start(). > if (rc) goto out; > return; > out: > @@ -1976,7 +1976,7 @@ static void do_pci_remove(libxl__egc *egc, pci_remove_state *prs) > prs->xswait.what = "Device Model"; > prs->xswait.path = DEVICE_MODEL_XS_PATH(gc, > libxl_get_stubdom_id(CTX, domid), domid, "/state"); > - prs->xswait.timeout_ms = LIBXL_DEVICE_MODEL_START_TIMEOUT * 1000; > + prs->xswait.timeout_ms = __libxl_device_model_start_timeout() * 1000; That value will be use by libxl__xswait_start(). > prs->xswait.callback = pci_remove_qemu_trad_watch_state_cb; > rc = libxl__xswait_start(gc, &prs->xswait); > if (rc) goto out_fail; So, overall, I'm fine with been able to change the timeout via env var, but disabling the timeout might not be easy or possible, even if "-1" might be an option, or -1000 in most case. So, you change the man page to only allow value>0 ? And a timeout of 0 might be best to revert to the default. Thanks,
Hello Anthony, thank you very much for your review comments! They are very thorough and knowledgeable. I unfortunately only just saw them, I don't know why I missed them back in April but doesn't matter. I am not going to continue work on these patches due to circumstances changing for me, if the community deems them useful with your corrections applied I hope someone else picks them up in the future. Thanks again, -- Manos Pitsidianakis, Virtualization Engineer at Linaro
diff --git a/docs/man/xl.1.pod.in b/docs/man/xl.1.pod.in index bed8393473..c159877094 100644 --- a/docs/man/xl.1.pod.in +++ b/docs/man/xl.1.pod.in @@ -1993,6 +1993,17 @@ Otherwise the build time default in LIBXL_BOOTLOADER_TIMEOUT will be used. If defined the value must be an unsigned integer between 0 and INT_MAX, otherwise behavior is undefined. Setting to 0 disables the timeout. +=item LIBXL_DEVICE_MODEL_START_TIMEOUT + +Timeout in seconds for starting the device model process. Useful in case the +device model takes an unusual amount of time to start— for example in case of +very slow I/O, in case of slow performance due to memory sanitizer usage, etc. + +If undefined, the default hard-coded value of 60 seconds is used. + +If defined, the value must be an unsigned integer between 0 and INT_MAX, +otherwise behaviour is undefined. Setting the value to 0 disables the timeout. + =back =head1 SEE ALSO diff --git a/tools/libs/light/libxl_9pfs.c b/tools/libs/light/libxl_9pfs.c index 48f894f070..950a464b45 100644 --- a/tools/libs/light/libxl_9pfs.c +++ b/tools/libs/light/libxl_9pfs.c @@ -132,7 +132,7 @@ static int xen9pfsd_spawn(libxl__egc *egc, uint32_t domid, libxl_device_p9 *p9, aop9->spawn.ao = aodev->ao; aop9->spawn.what = "xen-9pfs daemon"; aop9->spawn.xspath = GCSPRINTF("%s/state", path); - aop9->spawn.timeout_ms = LIBXL_DEVICE_MODEL_START_TIMEOUT * 1000; + aop9->spawn.timeout_ms = __libxl_device_model_start_timeout() * 1000; aop9->spawn.pidpath = GCSPRINTF("%s/pid", path); aop9->spawn.midproc_cb = libxl__spawn_record_pid; aop9->spawn.confirm_cb = xen9pfsd_confirm; diff --git a/tools/libs/light/libxl_device.c b/tools/libs/light/libxl_device.c index 6f0100d05e..452e55ba23 100644 --- a/tools/libs/light/libxl_device.c +++ b/tools/libs/light/libxl_device.c @@ -1436,7 +1436,7 @@ int libxl__wait_for_device_model_deprecated(libxl__gc *gc, path = DEVICE_MODEL_XS_PATH(gc, dm_domid, domid, "/state"); return libxl__xenstore_child_wait_deprecated(gc, domid, - LIBXL_DEVICE_MODEL_START_TIMEOUT, + __libxl_device_model_start_timeout(), "Device Model", path, state, spawning, check_callback, check_callback_userdata); } diff --git a/tools/libs/light/libxl_dm.c b/tools/libs/light/libxl_dm.c index 0b03a7c747..4369fef161 100644 --- a/tools/libs/light/libxl_dm.c +++ b/tools/libs/light/libxl_dm.c @@ -2629,7 +2629,7 @@ static void spawn_qmp_proxy(libxl__egc *egc, sdss->qmp_proxy_spawn.pidpath = GCSPRINTF("%s/image/qmp-proxy-pid", dom_path); sdss->qmp_proxy_spawn.xspath = DEVICE_MODEL_XS_PATH(gc, LIBXL_TOOLSTACK_DOMID, dm_domid, "/qmp-proxy-state"); - sdss->qmp_proxy_spawn.timeout_ms = LIBXL_DEVICE_MODEL_START_TIMEOUT * 1000; + sdss->qmp_proxy_spawn.timeout_ms = __libxl_device_model_start_timeout() * 1000; sdss->qmp_proxy_spawn.midproc_cb = libxl__spawn_record_pid; sdss->qmp_proxy_spawn.confirm_cb = qmp_proxy_confirm; sdss->qmp_proxy_spawn.failure_cb = qmp_proxy_startup_failed; @@ -3011,7 +3011,7 @@ retry_transaction: spawn->what = GCSPRINTF("domain %d device model", domid); spawn->xspath = DEVICE_MODEL_XS_PATH(gc, LIBXL_TOOLSTACK_DOMID, domid, "/state"); - spawn->timeout_ms = LIBXL_DEVICE_MODEL_START_TIMEOUT * 1000; + spawn->timeout_ms = __libxl_device_model_start_timeout() * 1000; spawn->pidpath = GCSPRINTF("%s/image/device-model-pid", dom_path); spawn->midproc_cb = libxl__spawn_record_pid; spawn->confirm_cb = device_model_confirm; @@ -3435,7 +3435,7 @@ void libxl__spawn_qdisk_backend(libxl__egc *egc, libxl__dm_spawn_state *dmss) dmss->spawn.what = GCSPRINTF("domain %u Qdisk backend", domid); dmss->spawn.xspath = GCSPRINTF("device-model/%u/state", domid); - dmss->spawn.timeout_ms = LIBXL_DEVICE_MODEL_START_TIMEOUT * 1000; + dmss->spawn.timeout_ms = __libxl_device_model_start_timeout() * 1000; /* * We cannot save Qemu pid anywhere in the xenstore guest dir, * because we will call this from unprivileged driver domains, diff --git a/tools/libs/light/libxl_dom_suspend.c b/tools/libs/light/libxl_dom_suspend.c index 6091a5f3f6..29e51f6c40 100644 --- a/tools/libs/light/libxl_dom_suspend.c +++ b/tools/libs/light/libxl_dom_suspend.c @@ -517,7 +517,7 @@ void libxl__dm_resume(libxl__egc *egc, rc = libxl__ev_time_register_rel(dmrs->ao, &dmrs->time, dm_resume_timeout, - LIBXL_DEVICE_MODEL_START_TIMEOUT * 1000); + __libxl_device_model_start_timeout() * 1000); if (rc) goto out; switch (libxl__device_model_version_running(gc, domid)) { diff --git a/tools/libs/light/libxl_internal.h b/tools/libs/light/libxl_internal.h index 803dbc1a03..684390f822 100644 --- a/tools/libs/light/libxl_internal.h +++ b/tools/libs/light/libxl_internal.h @@ -97,6 +97,12 @@ /* QEMU may be slow to load and start due to a bug in Linux where the I/O * subsystem sometime produce high latency under load. */ #define LIBXL_DEVICE_MODEL_START_TIMEOUT 60 +static inline int __libxl_device_model_start_timeout(void) +{ + const char *timeout_env = getenv("LIBXL_DEVICE_MODEL_START_TIMEOUT"); + return timeout_env ? atoi(timeout_env) + : LIBXL_DEVICE_MODEL_START_TIMEOUT; +} #define LIBXL_DEVICE_MODEL_SAVE_FILE XEN_LIB_DIR "/qemu-save" /* .$domid */ #define LIBXL_DEVICE_MODEL_RESTORE_FILE XEN_LIB_DIR "/qemu-resume" /* .$domid */ #define LIBXL_QMP_CMD_TIMEOUT 10 diff --git a/tools/libs/light/libxl_pci.c b/tools/libs/light/libxl_pci.c index 96cb4da079..7bdd9f6c3b 100644 --- a/tools/libs/light/libxl_pci.c +++ b/tools/libs/light/libxl_pci.c @@ -1157,7 +1157,7 @@ static void do_pci_add(libxl__egc *egc, pas->xswait.what = "Device Model"; pas->xswait.path = DEVICE_MODEL_XS_PATH(gc, libxl_get_stubdom_id(CTX, domid), domid, "/state"); - pas->xswait.timeout_ms = LIBXL_DEVICE_MODEL_START_TIMEOUT * 1000; + pas->xswait.timeout_ms = __libxl_device_model_start_timeout() * 1000; pas->xswait.callback = pci_add_qemu_trad_watch_state_cb; rc = libxl__xswait_start(gc, &pas->xswait); if (rc) goto out; @@ -1719,7 +1719,7 @@ static void device_pci_add_stubdom_wait(libxl__egc *egc, rc = libxl__ev_devstate_wait(ao, &pas->pciback_ds, device_pci_add_stubdom_ready, state_path, XenbusStateConnected, - LIBXL_DEVICE_MODEL_START_TIMEOUT * 1000); + __libxl_device_model_start_timeout() * 1000); if (rc) goto out; return; out: @@ -1976,7 +1976,7 @@ static void do_pci_remove(libxl__egc *egc, pci_remove_state *prs) prs->xswait.what = "Device Model"; prs->xswait.path = DEVICE_MODEL_XS_PATH(gc, libxl_get_stubdom_id(CTX, domid), domid, "/state"); - prs->xswait.timeout_ms = LIBXL_DEVICE_MODEL_START_TIMEOUT * 1000; + prs->xswait.timeout_ms = __libxl_device_model_start_timeout() * 1000; prs->xswait.callback = pci_remove_qemu_trad_watch_state_cb; rc = libxl__xswait_start(gc, &prs->xswait); if (rc) goto out_fail;
When debugging QEMU, the need to run it under Valgrind and asan meant the compile-time define LIBXL_DEVICE_MODEL_START_TIMEOUT must be changed to allow for `xl` to wait longer while the instrumented QEMU initializes. This commit adds support for reading the environment variable LIBXL_DEVICE_MODEL_START_TIMEOUT to configure the timeout value and otherwise fall back to the default 60. Signed-off-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org> --- docs/man/xl.1.pod.in | 11 +++++++++++ tools/libs/light/libxl_9pfs.c | 2 +- tools/libs/light/libxl_device.c | 2 +- tools/libs/light/libxl_dm.c | 6 +++--- tools/libs/light/libxl_dom_suspend.c | 2 +- tools/libs/light/libxl_internal.h | 6 ++++++ tools/libs/light/libxl_pci.c | 6 +++--- 7 files changed, 26 insertions(+), 9 deletions(-)