When the libxl driver is initialized, it creates a virDomainDef
object for dom0 and adds it to the list of domains. Total memory
for dom0 was being set from the max_memkb field of libxl_dominfo
struct retrieved from libxl, but this field can be set to
LIBXL_MEMKB_DEFAULT (~0ULL) if dom0 maximum memory has not been
explicitly set by the user.
This patch adds some simple parsing of the Xen commandline,
looking for a dom0_mem parameter that also specifies a 'max' value.
If not specified, dom0 maximum memory is effectively all physical
host memory.
Signed-off-by: Jim Fehlig <jfehlig@xxxxxxxx>
---
V2: Check return value of libxl_get_physinfo and
libxlDriverGetDom0MaxmemConf.
src/libxl/libxl_conf.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++++
src/libxl/libxl_conf.h | 4 +++
src/libxl/libxl_driver.c | 5 +++-
3 files changed, 85 insertions(+), 1 deletion(-)
diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c
index 28b05e1..7e30c7d 100644
--- a/src/libxl/libxl_conf.c
+++ b/src/libxl/libxl_conf.c
@@ -34,6 +34,7 @@
#include "internal.h"
#include "virlog.h"
#include "virerror.h"
+#include "c-ctype.h"
#include "datatypes.h"
#include "virconf.h"
#include "virfile.h"
@@ -1533,6 +1534,82 @@ int libxlDriverConfigLoadFile(libxlDriverConfigPtr cfg,
}
+/*
+ * dom0's maximum memory can be controled by the user with the 'dom0_mem' Xen
+ * command line parameter. E.g. to set dom0's initial memory to 4G and max
+ * memory to 8G: dom0_mem=4G,max:8G
+ *
+ * If not constrained by the user, dom0 can effectively use all host memory.
+ * This function returns the configured maximum memory for dom0 in kilobytes,
+ * either the user-specified value or total physical memory as a default.
+ */
+int
+libxlDriverGetDom0MaxmemConf(libxlDriverConfigPtr cfg,
+ unsigned long long *maxmem)
+{
+ char **cmd_tokens = NULL;
+ char **mem_tokens = NULL;
+ size_t i;
+ size_t j;
+ libxl_physinfo physinfo;
+ int ret = -1;
+
+ if (cfg->verInfo->commandline == NULL ||
+ !(cmd_tokens = virStringSplit(cfg->verInfo->commandline, " ", 0)))
+ goto physmem;
+
+ for (i = 0; cmd_tokens[i] != NULL; i++) {
+ if (!STRPREFIX(cmd_tokens[i], "dom0_mem="))
+ continue;
+
+ if (!(mem_tokens = virStringSplit(cmd_tokens[i], ",", 0)))
+ break;
+ for (j = 0; mem_tokens[j] != NULL; j++) {
+ if (STRPREFIX(mem_tokens[j], "max:")) {
+ char *p = mem_tokens[j] + 4;
+ unsigned long long multiplier = 1;
+
+ while (c_isdigit(*p))
+ p++;
+ if (virStrToLong_ull(mem_tokens[j] + 4, &p, 10, maxmem) < 0)
+ break;
+ if (*p) {
+ switch (*p) {
+ case 'm':
+ case 'M':
+ multiplier = 1024;
+ break;
+ case 'g':
+ case 'G':
+ multiplier = 1024 * 1024;
+ break;
+ }
+ }
+ *maxmem = *maxmem * multiplier;
+ ret = 0;
+ goto cleanup;
+ }
+ }
+ }
+
+ physmem:
+ /* No 'max' specified in dom0_mem, so dom0 can use all physical memory */
+ libxl_physinfo_init(&physinfo);
+ if (libxl_get_physinfo(cfg->ctx, &physinfo)) {
+ VIR_WARN("libxl_get_physinfo failed");
+ goto cleanup;
+ }
+ *maxmem = (physinfo.total_pages * cfg->verInfo->pagesize) / 1024;
+ libxl_physinfo_dispose(&physinfo);
+ ret = 0;
+
+ cleanup:
+ virStringListFree(cmd_tokens);
+ virStringListFree(mem_tokens);
+ return ret;
+}
+
+
#ifdef LIBXL_HAVE_DEVICE_CHANNEL
static int
libxlPrepareChannel(virDomainChrDefPtr channel,
diff --git a/src/libxl/libxl_conf.h b/src/libxl/libxl_conf.h
index 69d7885..4942171 100644
--- a/src/libxl/libxl_conf.h
+++ b/src/libxl/libxl_conf.h
@@ -174,6 +174,10 @@ int libxlDriverConfigLoadFile(libxlDriverConfigPtr cfg,
const char *filename);
int
+libxlDriverGetDom0MaxmemConf(libxlDriverConfigPtr cfg,
+ unsigned long long *maxmem);
+
+int
libxlMakeDisk(virDomainDiskDefPtr l_dev, libxl_device_disk *x_dev);
int
libxlMakeNic(virDomainDefPtr def,
diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c
index 040b986..1558d5b 100644
--- a/src/libxl/libxl_driver.c
+++ b/src/libxl/libxl_driver.c
@@ -576,6 +576,7 @@ libxlAddDom0(libxlDriverPrivatePtr driver)
virDomainObjPtr vm = NULL;
virDomainDefPtr oldDef = NULL;
libxl_dominfo d_info;
+ unsigned long long maxmem;
int ret = -1;
libxl_dominfo_init(&d_info);
@@ -615,7 +616,9 @@ libxlAddDom0(libxlDriverPrivatePtr driver)
if (virDomainDefSetVcpus(vm->def, d_info.vcpu_online) < 0)
goto cleanup;
vm->def->mem.cur_balloon = d_info.current_memkb;
- virDomainDefSetMemoryTotal(vm->def, d_info.max_memkb);
+ if (libxlDriverGetDom0MaxmemConf(cfg, &maxmem) < 0)
+ maxmem = d_info.current_memkb;
+ virDomainDefSetMemoryTotal(vm->def, maxmem);
ret = 0;
--
2.9.2
--
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