Re: [libvirt] [PATCH 2/2] qemu: Introduce qemuGetHupageMemPath

[Peter Krempa]

On Mon, Sep 19, 2016 at 07:55:48 +0200, Michal Privoznik wrote:
> Now that we have two same implementations for getting path for
> huge pages backed guest memory, lets merge them into one function.
> 
> Signed-off-by: Michal Privoznik 
> ---
>  src/qemu/qemu_command.c | 63 
> -
>  src/qemu/qemu_conf.c| 50 +++
>  src/qemu/qemu_conf.h|  4 
>  3 files changed, 59 insertions(+), 58 deletions(-)

ACK

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[libvirt] [PATCH 2/2] qemu: Introduce qemuGetHupageMemPath

[Michal Privoznik]

Now that we have two same implementations for getting path for
huge pages backed guest memory, lets merge them into one function.

Signed-off-by: Michal Privoznik 
---
 src/qemu/qemu_command.c | 63 -
 src/qemu/qemu_conf.c| 50 +++
 src/qemu/qemu_conf.h|  4 
 3 files changed, 59 insertions(+), 58 deletions(-)

diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index 0bafc3f..051a0bc 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -3275,35 +3275,9 @@ qemuBuildMemoryBackendStr(unsigned long long size,
 if (!(props = virJSONValueNewObject()))
 return -1;
 
-if (pagesize || hugepage) {
-if (pagesize) {
-/* Now lets see, if the huge page we want to use is even mounted
- * and ready to use */
-for (i = 0; i < cfg->nhugetlbfs; i++) {
-if (cfg->hugetlbfs[i].size == pagesize)
-break;
-}
-
-if (i == cfg->nhugetlbfs) {
-virReportError(VIR_ERR_INTERNAL_ERROR,
-   _("Unable to find any usable hugetlbfs mount 
for %llu KiB"),
-   pagesize);
-goto cleanup;
-}
-
-if (!(mem_path = qemuGetHugepagePath(>hugetlbfs[i])))
-goto cleanup;
-} else {
-if (!cfg->nhugetlbfs) {
-virReportError(VIR_ERR_INTERNAL_ERROR,
-   "%s", _("hugetlbfs filesystem is not mounted "
-   "or disabled by administrator config"));
-goto cleanup;
-}
-if (!(mem_path = qemuGetDefaultHugepath(cfg->hugetlbfs,
-cfg->nhugetlbfs)))
-goto cleanup;
-}
+if (pagesize) {
+if (qemuGetHupageMemPath(cfg, pagesize, _path) < 0)
+goto cleanup;
 
 *backendType = "memory-backend-file";
 
@@ -7272,7 +7246,6 @@ qemuBuildMemPathStr(virQEMUDriverConfigPtr cfg,
 {
 const long system_page_size = virGetSystemPageSizeKB();
 char *mem_path = NULL;
-size_t i = 0;
 
 /*
  *  No-op if hugepages were not requested.
@@ -7287,13 +7260,6 @@ qemuBuildMemPathStr(virQEMUDriverConfigPtr cfg,
 if (def->mem.hugepages[0].size == system_page_size)
 return 0;
 
-if (!cfg->nhugetlbfs) {
-virReportError(VIR_ERR_INTERNAL_ERROR,
-   "%s", _("hugetlbfs filesystem is not mounted "
-   "or disabled by administrator config"));
-return -1;
-}
-
 if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_MEM_PATH)) {
 virReportError(VIR_ERR_INTERNAL_ERROR,
_("hugepage backing not supported by '%s'"),
@@ -7301,27 +7267,8 @@ qemuBuildMemPathStr(virQEMUDriverConfigPtr cfg,
 return -1;
 }
 
-if (!def->mem.hugepages[0].size) {
-if (!(mem_path = qemuGetDefaultHugepath(cfg->hugetlbfs,
-cfg->nhugetlbfs)))
-return -1;
-} else {
-for (i = 0; i < cfg->nhugetlbfs; i++) {
-if (cfg->hugetlbfs[i].size == def->mem.hugepages[0].size)
-break;
-}
-
-if (i == cfg->nhugetlbfs) {
-virReportError(VIR_ERR_INTERNAL_ERROR,
-   _("Unable to find any usable hugetlbfs "
- "mount for %llu KiB"),
-   def->mem.hugepages[0].size);
-return -1;
-}
-
-if (!(mem_path = qemuGetHugepagePath(>hugetlbfs[i])))
-return -1;
-}
+if (qemuGetHupageMemPath(cfg, def->mem.hugepages[0].size, _path) < 0)
+return -1;
 
 virCommandAddArgList(cmd, "-mem-prealloc", "-mem-path", mem_path, NULL);
 VIR_FREE(mem_path);
diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c
index dad8334..5a97e96 100644
--- a/src/qemu/qemu_conf.c
+++ b/src/qemu/qemu_conf.c
@@ -1465,3 +1465,53 @@ qemuGetDefaultHugepath(virHugeTLBFSPtr hugetlbfs,
 
 return qemuGetHugepagePath([i]);
 }
+
+
+/**
+ * qemuGetHupageMemPath: Construct HP enabled memory backend path
+ *
+ * If no specific hugepage size is requested (@pagesize is zero)
+ * the default hugepage size is used).
+ * The resulting path is stored at @memPath.
+ *
+ * Returns 0 on success,
+ *-1 otherwise.
+ */
+int
+qemuGetHupageMemPath(virQEMUDriverConfigPtr cfg,
+ unsigned long long pagesize,
+ char **memPath)
+{
+size_t i = 0;
+
+if (!cfg->nhugetlbfs) {
+virReportError(VIR_ERR_INTERNAL_ERROR,
+   "%s", _("hugetlbfs filesystem is not mounted "
+   "or disabled by administrator config"));
+return -1;
+}
+
+if (!pagesize) {
+if (!(*memPath =