util: Add virHostCPUGetHaltPollTime

Add helper function virHostCPUGetHaltPollTime to obtain halt polling
time. If the kernel support halt polling time statistic, and mount
debugfs. This function will take effect on KVM VMs.

Signed-off-by: Yang Fei <yangfei85@huawei.com>
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Michal Privoznik <mprivozn@redhat.com>

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 5c7f6bf8092a0c45b8d7267a9ec1c5cdffa5a979..43493ea76e33e94e334ceed59c48942c894097e7 100644 (file)
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -2376,6 +2376,7 @@ virHookPresent;
 # util/virhostcpu.h
 virHostCPUGetAvailableCPUsBitmap;
 virHostCPUGetCount;
+virHostCPUGetHaltPollTime;
 virHostCPUGetInfo;
 virHostCPUGetKVMMaxVCPUs;
 virHostCPUGetMap;

diff --git a/src/util/virhostcpu.c b/src/util/virhostcpu.c
index bf7fda23af3d4e3b5eb738629c5dc7ade875c56f..7aa92ad11d2052fea6eb8a0055feccd150fbcf99 100644 (file)
--- a/src/util/virhostcpu.c
+++ b/src/util/virhostcpu.c
@@ -1535,3 +1535,42 @@ virHostCPUGetSignature(char **signature)
 }
 
 #endif /* __linux__ */
+
+int
+virHostCPUGetHaltPollTime(pid_t pid,
+                      unsigned long long *haltPollSuccess,
+                      unsigned long long *haltPollFail)
+{
+    g_autofree char *pidToStr = NULL;
+    g_autofree char *debugFsPath = NULL;
+    g_autofree char *kvmPath = NULL;
+    struct dirent *ent = NULL;
+    g_autoptr(DIR) dir = NULL;
+    bool found = false;
+
+    if (!(debugFsPath = virFileFindMountPoint("debugfs")))
+        return -1;
+
+    kvmPath = g_strdup_printf("%s/%s", debugFsPath, "kvm");
+    if (virDirOpenQuiet(&dir, kvmPath) != 1)
+        return -1;
+
+    pidToStr = g_strdup_printf("%lld-", (long long)pid);
+    while (virDirRead(dir, &ent, NULL) > 0) {
+        if (STRPREFIX(ent->d_name, pidToStr)) {
+            found = true;
+            break;
+        }
+    }
+
+    if (!found)
+        return -1;
+
+    if (virFileReadValueUllongQuiet(haltPollSuccess, "%s/%s/%s", kvmPath,
+                                    ent->d_name, "halt_poll_success_ns") < 0 ||
+        virFileReadValueUllongQuiet(haltPollFail, "%s/%s/%s", kvmPath,
+                                    ent->d_name, "halt_poll_fail_ns") < 0)
+        return -1;
+
+    return 0;
+}

diff --git a/src/util/virhostcpu.h b/src/util/virhostcpu.h
index fc717250d93e573f7d54ccd773c07b604822d385..d98385d53fb4d7b371e16f220fbc57bef4d4864b 100644 (file)
--- a/src/util/virhostcpu.h
+++ b/src/util/virhostcpu.h
@@ -83,3 +83,7 @@ int virHostCPUGetMSR(unsigned long index,
 virHostCPUTscInfo *virHostCPUGetTscInfo(void);
 
 int virHostCPUGetSignature(char **signature);
+
+int virHostCPUGetHaltPollTime(pid_t pid,
+                              unsigned long long *haltPollSuccess,
+                              unsigned long long *haltPollFail);