From f496b6095bf96eb8931b78054a272a5aaf70a2d9 Mon Sep 17 00:00:00 2001 Message-ID: From: Peter Krempa Date: Fri, 23 Jan 2026 17:18:14 +0100 Subject: [PATCH] qemu: Setup disk latency histograms on startup/hotplug/update Setup the histograms on startup and hotplug of devices via 'qemuProcessSetupDiskPropsRuntime' and facilitate update/reset/disable of histogram collection via 'qemuDomainChangeDiskLive'. The latter allows to use the update device API to either clear the bins or select new bin configuration or disable the histogram altogether without the need for a specific API. Signed-off-by: Peter Krempa Reviewed-by: Michal Privoznik (cherry picked from commit 5787326541be4eafaa7ae3b4f866b3da793d44fe) https://issues.redhat.com/browse/RHEL-147866 [rhel-9.8] https://issues.redhat.com/browse/RHEL-131335 [rhel-10.2] --- src/qemu/qemu_domain.c | 17 +++++++++++++++++ src/qemu/qemu_domain.h | 3 +++ src/qemu/qemu_hotplug.c | 29 +++++++++++++++++++++++++++++ src/qemu/qemu_process.c | 10 ++++++++++ 4 files changed, 59 insertions(+) diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c index 8e1ebe7799..bdab117e96 100644 --- a/src/qemu/qemu_domain.c +++ b/src/qemu/qemu_domain.c @@ -10463,6 +10463,23 @@ qemuDomainInitializePflashStorageSource(virDomainObj *vm, } +/** + * qemuDomainDiskHasLatencyHistogram: + * @disk: disk definition + * + * Returns whether @disk has any latency histogram settings configured. + */ +bool +qemuDomainDiskHasLatencyHistogram(virDomainDiskDef *disk) +{ + return disk->histogram_boundaries || + disk->histogram_boundaries_read || + disk->histogram_boundaries_write || + disk->histogram_boundaries_zone || + disk->histogram_boundaries_flush; +} + + /** * qemuDomainDiskBlockJobIsSupported: * diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h index 3361e97315..30ca67bf76 100644 --- a/src/qemu/qemu_domain.h +++ b/src/qemu/qemu_domain.h @@ -1078,6 +1078,9 @@ int qemuDomainInitializePflashStorageSource(virDomainObj *vm, virQEMUDriverConfig *cfg); +bool +qemuDomainDiskHasLatencyHistogram(virDomainDiskDef *disk); + bool qemuDomainDiskBlockJobIsSupported(virDomainDiskDef *disk); diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c index f2dc4469a3..9445599d2c 100644 --- a/src/qemu/qemu_hotplug.c +++ b/src/qemu/qemu_hotplug.c @@ -7310,6 +7310,35 @@ qemuDomainChangeDiskLive(virDomainObj *vm, dev->data.disk->src = NULL; } + if (qemuDomainDiskHasLatencyHistogram(disk) || + qemuDomainDiskHasLatencyHistogram(orig_disk)) { + int rc; + + qemuDomainObjEnterMonitor(vm); + rc = qemuMonitorBlockLatencyHistogramSet(qemuDomainGetMonitor(vm), + QEMU_DOMAIN_DISK_PRIVATE(orig_disk)->qomName, + disk->histogram_boundaries, + disk->histogram_boundaries_read, + disk->histogram_boundaries_write, + disk->histogram_boundaries_zone, + disk->histogram_boundaries_flush); + qemuDomainObjExitMonitor(vm); + + if (rc < 0) + return -1; + + g_clear_pointer(&orig_disk->histogram_boundaries, g_free); + g_clear_pointer(&orig_disk->histogram_boundaries_read, g_free); + g_clear_pointer(&orig_disk->histogram_boundaries_write, g_free); + g_clear_pointer(&orig_disk->histogram_boundaries_zone, g_free); + g_clear_pointer(&orig_disk->histogram_boundaries_flush, g_free); + orig_disk->histogram_boundaries = g_steal_pointer(&disk->histogram_boundaries); + orig_disk->histogram_boundaries_read = g_steal_pointer(&disk->histogram_boundaries_read); + orig_disk->histogram_boundaries_write = g_steal_pointer(&disk->histogram_boundaries_write); + orig_disk->histogram_boundaries_zone = g_steal_pointer(&disk->histogram_boundaries_zone); + orig_disk->histogram_boundaries_flush = g_steal_pointer(&disk->histogram_boundaries_flush); + } + /* in case when we aren't updating disk source we update startup policy here */ orig_disk->startupPolicy = dev->data.disk->startupPolicy; orig_disk->snapshot = dev->data.disk->snapshot; diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index aadfaa92b0..37e688018c 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c @@ -7959,6 +7959,16 @@ qemuProcessSetupDiskPropsRuntime(qemuMonitor *mon, &disk->blkdeviotune) < 0) return -1; + if (qemuDomainDiskHasLatencyHistogram(disk) && + qemuMonitorBlockLatencyHistogramSet(mon, + QEMU_DOMAIN_DISK_PRIVATE(disk)->qomName, + disk->histogram_boundaries, + disk->histogram_boundaries_read, + disk->histogram_boundaries_write, + disk->histogram_boundaries_zone, + disk->histogram_boundaries_flush) < 0) + return -1; + return 0; } -- 2.53.0