[PATCH v1 08/10] libxl: introduce libxl_get_memory_static_max

[Wei Liu <wei.liu2@citrix.com>]

... which returns the "static-max" knob of a domain. It will be used in
later patch to retrieve memory static-max value of a domain.

As libxl_get_memory_{target, static_max} have similar logic, a macro is
introduced to avoid code duplication. libxl__fill_dom0_memory_info is
adjusted as needed.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
 tools/libxl/libxl.c |  101 ++++++++++++++++++++++++++++++++-------------------
 tools/libxl/libxl.h |    8 ++++
 2 files changed, 72 insertions(+), 37 deletions(-)

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index 69d94b1..49d7ef6 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -4187,7 +4187,8 @@ out:
     return rc;
 }
 
-static int libxl__fill_dom0_memory_info(libxl__gc *gc, uint32_t *target_memkb)
+static int libxl__fill_dom0_memory_info(libxl__gc *gc, uint32_t *target_memkb,
+                                        uint32_t *max_memkb)
 {
     int rc;
     libxl_dominfo info;
@@ -4221,6 +4222,16 @@ retry_transaction:
         }
     }
 
+    if (staticmax) {
+        *max_memkb = strtoul(staticmax, &endptr, 10);
+        if (*endptr != '\0') {
+            LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR,
+                    "invalid memory static-max %s from %s\n", staticmax, max_path);
+            rc = ERROR_FAIL;
+            goto out;
+        }
+    }
+
     rc = libxl_domain_info(ctx, &info, 0);
     if (rc < 0)
         goto out;
@@ -4267,12 +4278,12 @@ static int libxl__get_free_memory_slack(libxl__gc *gc, uint32_t *free_mem_slack)
     int rc;
     char *free_mem_slack_path = "/local/domain/0/memory/freemem-slack";
     char *free_mem_slack_s, *endptr;
-    uint32_t target_memkb;
+    uint32_t target_memkb, max_memkb;
 
 retry:
     free_mem_slack_s = libxl__xs_read(gc, XBT_NULL, free_mem_slack_path);
     if (!free_mem_slack_s) {
-        rc = libxl__fill_dom0_memory_info(gc, &target_memkb);
+        rc = libxl__fill_dom0_memory_info(gc, &target_memkb, &max_memkb);
         if (rc < 0)
             return rc;
         goto retry;
@@ -4295,6 +4306,7 @@ int libxl_set_memory_target(libxl_ctx *ctx, uint32_t domid,
     int rc = 1, abort_transaction = 0;
     uint32_t memorykb = 0, videoram = 0;
     uint32_t current_target_memkb = 0, new_target_memkb = 0;
+    uint32_t current_max_memkb = 0;
     char *memmax, *endptr, *videoram_s = NULL, *target = NULL;
     char *dompath = libxl__xs_get_dompath(gc, domid);
     xc_domaininfo_t info;
@@ -4310,7 +4322,8 @@ retry_transaction:
     if (!target && !domid) {
         if (!xs_transaction_end(ctx->xsh, t, 1))
             goto out_no_transaction;
-        rc = libxl__fill_dom0_memory_info(gc, &current_target_memkb);
+        rc = libxl__fill_dom0_memory_info(gc, &current_target_memkb,
+                                          &current_max_memkb);
         if (rc < 0)
             goto out_no_transaction;
         goto retry_transaction;
@@ -4425,41 +4438,55 @@ out_no_transaction:
     return rc;
 }
 
-int libxl_get_memory_target(libxl_ctx *ctx, uint32_t domid, uint32_t *out_target)
-{
-    GC_INIT(ctx);
-    int rc = 1;
-    char *target = NULL, *endptr = NULL;
-    char *dompath = libxl__xs_get_dompath(gc, domid);
-    uint32_t target_memkb;
-
-    target = libxl__xs_read(gc, XBT_NULL, libxl__sprintf(gc,
-                "%s/memory/target", dompath));
-    if (!target && !domid) {
-        rc = libxl__fill_dom0_memory_info(gc, &target_memkb);
-        if (rc < 0)
-            goto out;
-    } else if (!target) {
-        LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR,
-                "cannot get target memory info from %s/memory/target\n",
-                dompath);
-        goto out;
-    } else {
-        target_memkb = strtoul(target, &endptr, 10);
-        if (*endptr != '\0') {
-            LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR,
-                    "invalid memory target %s from %s/memory/target\n",
-                    target, dompath);
-            goto out;
-        }
+/* This macro generates:
+ *   libxl_get_memory_target
+ *   libxl_get_memory_static_max
+ */
+#define DEFINE_GET_MEMORY(name, node)                                   \
+    int libxl_get_memory_##name(libxl_ctx *ctx, uint32_t domid,         \
+                                uint32_t *out)                          \
+    {                                                                   \
+        GC_INIT(ctx);                                                   \
+        int rc = 1;                                                     \
+        char *val = NULL, *endptr = NULL;                               \
+        char *dompath = libxl__xs_get_dompath(gc, domid);               \
+        uint32_t result;                                                \
+        uint32_t target, static_max;                                    \
+                                                                        \
+        val = libxl__xs_read(gc, XBT_NULL,                              \
+                             libxl__sprintf(gc, "%s/memory/"node,       \
+                                            dompath));                  \
+        if (!val && !domid) {                                           \
+            rc = libxl__fill_dom0_memory_info(gc, &target,              \
+                                              &static_max);             \
+            if (rc < 0)                                                 \
+                goto out;                                               \
+            result = name;                                              \
+        } else if (!val) {                                              \
+            LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR,                     \
+                             "cannot not get memory info from %s/memory/"node"\n", \
+                             dompath);                                  \
+            goto out;                                                   \
+        } else {                                                        \
+            result = strtoul(val, &endptr, 10);                         \
+            if (*endptr != '\0') {                                      \
+                LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR,                 \
+                                 "invalid value %s from %s/memory/"node"\n", \
+                                 val, dompath);                         \
+                goto out;                                               \
+            }                                                           \
+        }                                                               \
+        *out = result;                                                  \
+        rc = 0;                                                         \
+                                                                        \
+    out:                                                                \
+        GC_FREE;                                                        \
+        return rc;                                                      \
     }
-    *out_target = target_memkb;
-    rc = 0;
 
-out:
-    GC_FREE;
-    return rc;
-}
+DEFINE_GET_MEMORY(target, "target")
+DEFINE_GET_MEMORY(static_max, "static-max")
+#undef DEFINE_GET_MEMORY
 
 int libxl_domain_need_memory(libxl_ctx *ctx, libxl_domain_build_info *b_info,
                              uint32_t *need_memkb)
diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
index 2dc6a51..f9eb0f1 100644
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -358,6 +358,13 @@ typedef struct libxl__ctx libxl_ctx;
 #endif
 #endif
 
+/* LIBXL_HAVE_GET_MEMORY_STATIC_MAX
+ *
+ * If this is defined we have an API called libxl_get_memory_static_max
+ * to return the memory "static-max" value from xenstore.
+ */
+#define LIBXL_HAVE_GET_MEMORY_STATIC_MAX 1
+
 /*
  * LIBXL_HAVE_BUILDINFO_VCPU_AFFINITY_ARRAYS
  *
@@ -886,6 +893,7 @@ int libxl_domain_core_dump(libxl_ctx *ctx, uint32_t domid,
 int libxl_domain_setmaxmem(libxl_ctx *ctx, uint32_t domid, uint32_t target_memkb);
 int libxl_set_memory_target(libxl_ctx *ctx, uint32_t domid, int32_t target_memkb, int relative, int enforce);
 int libxl_get_memory_target(libxl_ctx *ctx, uint32_t domid, uint32_t *out_target);
+int libxl_get_memory_static_max(libxl_ctx *ctx, uint32_t domid, uint32_t *out_max_memkb);
 
 
 /*
-- 
1.7.10.4