From 832422457214421211304bfb0c92b00546dcec53 Mon Sep 17 00:00:00 2001
From: Pavel Hrdina <phrdina@redhat.com>
Date: Fri, 17 Aug 2018 16:58:40 +0200
Subject: [PATCH] vircgroup: introduce virCgroupV2(Set|Get)CpuCfsPeriod

In order to set CPU cfs period using cgroup v2 'cpu.max' interface
we need to load the current value of CPU cfs quota first because
format of 'cpu.max' interface is '$quota $period' and in order to
change 'period' we need to write 'quota' as well.  Writing only one
number changes only 'quota'.

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
---
 src/util/vircgroupv2.c | 68 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 68 insertions(+)

diff --git a/src/util/vircgroupv2.c b/src/util/vircgroupv2.c
index 912cc7b810..69b7174c34 100644
--- a/src/util/vircgroupv2.c
+++ b/src/util/vircgroupv2.c
@@ -1324,6 +1324,72 @@ virCgroupV2GetCpuShares(virCgroupPtr group,
 }
 
 
+static int
+virCgroupV2SetCpuCfsPeriod(virCgroupPtr group,
+                           unsigned long long cfs_period)
+{
+    VIR_AUTOFREE(char *) value = NULL;
+    VIR_AUTOFREE(char *) str = NULL;
+    char *tmp;
+
+    /* The cfs_period should be greater or equal than 1ms, and less or equal
+     * than 1s.
+     */
+    if (cfs_period < 1000 || cfs_period > 1000000) {
+        virReportError(VIR_ERR_INVALID_ARG,
+                       _("cfs_period '%llu' must be in range (1000, 1000000)"),
+                       cfs_period);
+        return -1;
+    }
+
+    if (virCgroupGetValueStr(group, VIR_CGROUP_CONTROLLER_CPU,
+                             "cpu.max", &str) < 0) {
+        return -1;
+    }
+
+    if (!(tmp = strchr(str, ' '))) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("Invalid 'cpu.max' data."));
+        return -1;
+    }
+    *tmp = '\n';
+
+    if (virAsprintf(&value, "%s %llu", str, cfs_period) < 0)
+        return -1;
+
+    return virCgroupSetValueStr(group, VIR_CGROUP_CONTROLLER_CPU,
+                                "cpu.max", value);
+}
+
+
+static int
+virCgroupV2GetCpuCfsPeriod(virCgroupPtr group,
+                           unsigned long long *cfs_period)
+{
+    VIR_AUTOFREE(char *) str = NULL;
+    char *tmp;
+
+    if (virCgroupGetValueStr(group, VIR_CGROUP_CONTROLLER_CPU,
+                             "cpu.max", &str) < 0) {
+        return -1;
+    }
+
+    if (!(tmp = strchr(str, ' '))) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("Invalid 'cpu.max' data."));
+        return -1;
+    }
+
+    if (virStrToLong_ull(tmp, NULL, 10, cfs_period) < 0) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("Failed to parse value '%s' from cpu.max."), str);
+        return -1;
+    }
+
+    return 0;
+}
+
+
 virCgroupBackend virCgroupV2Backend = {
     .type = VIR_CGROUP_BACKEND_TYPE_V2,
 
@@ -1374,6 +1440,8 @@ virCgroupBackend virCgroupV2Backend = {
 
     .setCpuShares = virCgroupV2SetCpuShares,
     .getCpuShares = virCgroupV2GetCpuShares,
+    .setCpuCfsPeriod = virCgroupV2SetCpuCfsPeriod,
+    .getCpuCfsPeriod = virCgroupV2GetCpuCfsPeriod,
 };
 
 
-- 
2.47.2