On Tue, Apr 07, 2026 at 20:13:33 +0200, Roman Bogorodskiy wrote:
FreeBSD supports resource limiting with the rctl(4) framework. It supports various resource types, including I/O resources. It allows to limit resources for users, processes, login classes, and jails.
To apply blkiotune limits set limits for the bhyve process.
I/O related resources supported by rctl(4) are:
readbps filesystem reads, in bytes per second writebps filesystem writes, in bytes per second readiops filesystem reads, in operations per second writeiops filesystem writes, in operations per second
Thus, the actual commands look like:
rctl -a process:$bhyvepid:writebps:throttle=10000000 rctl -a process:$bhyvepid:readbps:throttle=10000000 rctl -a process:$bhyvepid:writeiops:throttle=20000 rctl -a process:$bhyvepid:readiops:throttle=20000
This is different from the current blkiotune modeling in libvirt as it requires specific device to apply limits to. To adapt this model to per-domain I/O limits, update domain schema to specify "*" as a device name.
You've changed the schema and added examples, which is good, but didn't document this in formatdomain.rst.
The rctl(8) may be not available or not enabled, so add a capability check for that.
Per process rules get removed when the process disappears, so no special clean up is necessary.
Signed-off-by: Roman Bogorodskiy <bogorodskiy@gmail.com> --- src/bhyve/bhyve_capabilities.c | 25 +++++++- src/bhyve/bhyve_capabilities.h | 1 + src/bhyve/bhyve_domain.c | 6 ++ src/bhyve/bhyve_process.c | 59 +++++++++++++++++++ src/conf/schemas/domaincommon.rng | 5 +- ...yvexml2argv-blkiotune-multiple-devices.xml | 39 ++++++++++++ .../x86_64/bhyvexml2argv-blkiotune.args | 10 ++++ .../x86_64/bhyvexml2argv-blkiotune.ldargs | 4 ++ .../x86_64/bhyvexml2argv-blkiotune.xml | 32 ++++++++++ tests/bhyvexml2argvtest.c | 2 + .../x86_64/bhyvexml2xmlout-blkiotune.xml | 42 +++++++++++++ tests/bhyvexml2xmltest.c | 2 + 12 files changed, 225 insertions(+), 2 deletions(-) create mode 100644 tests/bhyvexml2argvdata/x86_64/bhyvexml2argv-blkiotune-multiple-devices.xml create mode 100644 tests/bhyvexml2argvdata/x86_64/bhyvexml2argv-blkiotune.args create mode 100644 tests/bhyvexml2argvdata/x86_64/bhyvexml2argv-blkiotune.ldargs create mode 100644 tests/bhyvexml2argvdata/x86_64/bhyvexml2argv-blkiotune.xml create mode 100644 tests/bhyvexml2xmloutdata/x86_64/bhyvexml2xmlout-blkiotune.xml
diff --git a/src/bhyve/bhyve_capabilities.c b/src/bhyve/bhyve_capabilities.c index c3fb88fe9f..1088d75407 100644 --- a/src/bhyve/bhyve_capabilities.c +++ b/src/bhyve/bhyve_capabilities.c @@ -24,6 +24,7 @@ #include <config.h> #include <sys/utsname.h> #include <dirent.h> +#include <sys/sysctl.h> #include <sys/types.h>
#include "viralloc.h" @@ -40,7 +41,6 @@
VIR_LOG_INIT("bhyve.bhyve_capabilities");
- virCaps * virBhyveCapsBuild(void) {
Spurious whithespace change.
@@ -334,6 +334,27 @@ bhyveProbeCapsVNCPassword(unsigned int *caps, char *binary) }
+static int +bhyveProbeCapsRctl(unsigned int *caps) +{ + bool racct_enable; + size_t racct_enable_len; + g_autofree char *rctl = NULL; + + if (!(rctl = virFindFileInPath("rctl"))) + return 0; + + racct_enable_len = sizeof(racct_enable); + if (sysctlbyname("kern.racct.enable", &racct_enable, + &racct_enable_len, NULL, 0) < 0) + return 0;
This returns 0 even on errors in this function. Change it to void if you don't plan to report errors.
+ + if (racct_enable) + *caps |= BHYVE_CAP_RCTL; + + return 0; +} + int virBhyveProbeCaps(unsigned int *caps) { @@ -356,6 +377,8 @@ virBhyveProbeCaps(unsigned int *caps) if ((ret = bhyveProbeCapsVNCPassword(caps, binary))) goto out;
+ if ((ret = bhyveProbeCapsRctl(caps))) + goto out;
out: VIR_FREE(binary); diff --git a/src/bhyve/bhyve_capabilities.h b/src/bhyve/bhyve_capabilities.h index 31fd9ab86a..0302b68e22 100644 --- a/src/bhyve/bhyve_capabilities.h +++ b/src/bhyve/bhyve_capabilities.h @@ -57,6 +57,7 @@ typedef enum { BHYVE_CAP_NVME = 1 << 11, BHYVE_CAP_ACPI = 1 << 12, BHYVE_CAP_NUMA = 1 << 13, + BHYVE_CAP_RCTL = 1 << 14, } virBhyveCapsFlags;
int virBhyveProbeGrubCaps(virBhyveGrubCapsFlags *caps); diff --git a/src/bhyve/bhyve_domain.c b/src/bhyve/bhyve_domain.c index 4594d7673f..48e1451d8b 100644 --- a/src/bhyve/bhyve_domain.c +++ b/src/bhyve/bhyve_domain.c @@ -464,6 +464,12 @@ bhyveDomainDefValidate(const virDomainDef *def, } }
+ if (def->blkio.ndevices > 1) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", + _("Per device I/O tuning is not supported")); + return -1; + }
This validates only that you have just 1 "device" but doesn't validate that the single device has the special '*' path to mean all devices should be throttled. Users thus could spcify a single entry here with an actual path and have result which doesn't reflect the configuration. You also likely want to reject any 'weight' setting if this can't be honoured.
+ if (!def->os.loader) return 0;
diff --git a/src/bhyve/bhyve_process.c b/src/bhyve/bhyve_process.c index 1d436da609..b5ebe0aa61 100644 --- a/src/bhyve/bhyve_process.c +++ b/src/bhyve/bhyve_process.c @@ -34,6 +34,7 @@
#include "bhyve_device.h" #include "bhyve_driver.h" +#include "bhyve_capabilities.h" #include "bhyve_command.h" #include "bhyve_firmware.h" #include "bhyve_monitor.h" @@ -132,6 +133,61 @@ bhyveProcessStopHook(struct _bhyveConn *driver, VIR_HOOK_SUBOP_END, NULL, xml, NULL); }
+static int +bhyveSetResourceLimits(struct _bhyveConn *driver, virDomainObj *vm) +{ + virBlkioDevice *device; + char **rules = NULL; + size_t i, nrules = 0;
one decl per line
+ int ret = -1; + + if (!vm->def->blkio.ndevices)
'ndevices' is a number, not a boolean/pointer. Use an explicit comparison against 0.
+ return 0; + + if ((bhyveDriverGetBhyveCaps(driver) & BHYVE_CAP_RCTL) == 0) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", + _("Cannot set resource limits: RACCT/RCTL is either not supported or not enabled")); + return ret; + } + + device = &vm->def->blkio.devices[0]; + +#define BHYVE_APPEND_RCTL_RULE(field, type, format) \ + do { \ + if ((field)) { \ + virBuffer buf = VIR_BUFFER_INITIALIZER; \ + char *rule; \ + virBufferAsprintf(&buf, "process:%d:" type ":throttle=" format, \ + vm->pid, (field)); \ + rule = virBufferContentAndReset(&buf); \ + VIR_APPEND_ELEMENT(rules, nrules, rule); \ + } \ + } while (0) + + BHYVE_APPEND_RCTL_RULE(device->riops, "readiops", "%u"); + BHYVE_APPEND_RCTL_RULE(device->wiops, "writeiops", "%u"); + BHYVE_APPEND_RCTL_RULE(device->rbps, "readbps", "%llu"); + BHYVE_APPEND_RCTL_RULE(device->wbps, "writebps", "%llu"); + +#undef BHYVE_APPEND_RCTL_RULE + + for (i = 0; i < nrules; i++) { + g_autoptr(virCommand) cmd = virCommandNew("rctl"); + virCommandAddArgList(cmd, "-a", rules[i], NULL); + + if (virCommandRun(cmd, NULL) < 0) + goto cleanup;
Since this executes once per rule, you might as well as directly do this in the macro rather than costructing a list and then walking it to apply the rule.
+ } + + ret = 0; + + cleanup: + for (i = 0; i < nrules; i++) + VIR_FREE(rules[i]); + VIR_FREE(rules); + return ret; +} + static int virBhyveProcessStartImpl(struct _bhyveConn *driver, virDomainObj *vm, @@ -258,6 +314,9 @@ virBhyveProcessStartImpl(struct _bhyveConn *driver, BHYVE_STATE_DIR) < 0) goto cleanup;
+ if (bhyveSetResourceLimits(driver, vm) < 0) + goto cleanup; + if (bhyveProcessStartHook(driver, vm, VIR_HOOK_BHYVE_OP_STARTED) < 0) goto cleanup;
diff --git a/src/conf/schemas/domaincommon.rng b/src/conf/schemas/domaincommon.rng index db1dcd3bb7..c7f442a4c1 100644 --- a/src/conf/schemas/domaincommon.rng +++ b/src/conf/schemas/domaincommon.rng @@ -1049,7 +1049,10 @@ <element name="device"> <interleave> <element name="path"> - <ref name="absFilePath"/> + <choice> + <ref name="absFilePath"/> + <value>*</value> + </choice> </element> <optional> <element name="weight">