[Xen-devel] [PATCH v6 07/12] xl: add global grant limit config items

[Juergen Gross <jgross@xxxxxxxx>]

Add xl.conf config items for default values of grant limits:

max_grant_frames will set the default for the maximum number of grant
frames for a domain which will take effect if the domain's config file
doesn't specify a value. If max_grant_frames isn't set in xl.conf it
will default to 32 for hosts with all memory below 16TB and to 64 for
hosts with memory above 16TB.

max_maptrack_frames will set the default for the maximum number of
maptrack frames for a domain. If max_maptrack_frames isn't set in
xl.conf it will default to 0, as normally only backend domains need
maptrack frames.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
 docs/man/xl.conf.pod.5  | 12 ++++++++++++
 tools/libxl/libxl.h     |  9 ++++++++-
 tools/libxl/libxl_mem.c |  5 +++++
 tools/xl/xl.c           | 14 ++++++++++++++
 tools/xl/xl.h           |  2 ++
 5 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/docs/man/xl.conf.pod.5 b/docs/man/xl.conf.pod.5
index 88ab506609..fe2cf27ea4 100644
--- a/docs/man/xl.conf.pod.5
+++ b/docs/man/xl.conf.pod.5
@@ -77,6 +77,18 @@ operations (primarily domain creation).
 
 Default: C</var/lock/xl>
 
+=item B<max_grant_frames=NUMBER>
+
+Sets the default value for the C<max_grant_frames> domain config value.
+
+Default: C<32> on hosts up to 16TB of memory, C<64> on hosts larger than 16TB
+
+=item B<max_maptrack_frames=NUMBER>
+
+Sets the default value for the C<max_maptrack_frames> domain config value.
+
+Default: C<0>
+
 =item B<vif.default.script="PATH">
 
 Configures the default hotplug script used by virtual network devices.
diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
index 91408b47b5..9c455e59f9 100644
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -311,6 +311,12 @@
 #define LIBXL_HAVE_P9S 1
 
 /*
+ * LIBXL_HAVE_GET_MAX_HOST_MFN indicates that libxl_get_max_host_mfn() is
+ * available.
+ */
+#define LIBXL_HAVE_GET_MAX_HOST_MFN 1
+
+/*
  * libxl ABI compatibility
  *
  * The only guarantee which libxl makes regarding ABI compatibility
@@ -1473,6 +1479,7 @@ int libxl_get_memory_target(libxl_ctx *ctx, uint32_t 
domid, uint64_t *out_target
 int libxl_get_memory_target_0x040700(libxl_ctx *ctx, uint32_t domid,
                                      uint32_t *out_target)
     LIBXL_EXTERNAL_CALLERS_ONLY;
+int libxl_get_max_host_mfn(libxl_ctx *ctx, unsigned long *max_mfn);
 
 /*
  * WARNING
@@ -1517,7 +1524,7 @@ int libxl_wait_for_memory_target(libxl_ctx *ctx, uint32_t 
domid, int wait_secs);
 #define libxl_domain_need_memory libxl_domain_need_memory_0x040700
 #define libxl_get_free_memory libxl_get_free_memory_0x040700
 #endif
-
+ 
 int libxl_vncviewer_exec(libxl_ctx *ctx, uint32_t domid, int autopass);
 
 /*
diff --git a/tools/libxl/libxl_mem.c b/tools/libxl/libxl_mem.c
index f5d2530d8c..5e4096c104 100644
--- a/tools/libxl/libxl_mem.c
+++ b/tools/libxl/libxl_mem.c
@@ -592,6 +592,11 @@ out:
     return rc;
 }
 
+int libxl_get_max_host_mfn(libxl_ctx *ctx, unsigned long *max_mfn)
+{
+    return xc_maximum_ram_page(ctx->xch, max_mfn) ? ERROR_FAIL : 0;
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/tools/xl/xl.c b/tools/xl/xl.c
index 02179a6229..1d54e4939e 100644
--- a/tools/xl/xl.c
+++ b/tools/xl/xl.c
@@ -45,6 +45,8 @@ char *default_colo_proxy_script = NULL;
 enum output_format default_output_format = OUTPUT_FORMAT_JSON;
 int claim_mode = 1;
 bool progress_use_cr = 0;
+int max_grant_frames = -1;
+int max_maptrack_frames = 0;
 
 xentoollog_level minmsglevel = minmsglevel_default;
 
@@ -88,6 +90,7 @@ static void parse_global_config(const char *configfile,
     XLU_Config *config;
     int e;
     const char *buf;
+    unsigned long max_mfn;
 
     config = xlu_cfg_init(stderr, configfile);
     if (!config) {
@@ -188,6 +191,17 @@ static void parse_global_config(const char *configfile,
     xlu_cfg_replace_string (config, "colo.default.proxyscript",
         &default_colo_proxy_script, 0);
 
+    if (!xlu_cfg_get_long (config, "max_grant_frames", &l, 0))
+        max_grant_frames = l;
+    else {
+        if (libxl_get_max_host_mfn(ctx, &max_mfn) || !(max_mfn >> 32))
+            max_grant_frames = 32;
+        else
+            max_grant_frames = 64;
+    }
+    if (!xlu_cfg_get_long (config, "max_maptrack_frames", &l, 0))
+        max_maptrack_frames = l;
+
     xlu_cfg_destroy(config);
 }
 
diff --git a/tools/xl/xl.h b/tools/xl/xl.h
index 01c2af64a6..178a0da05c 100644
--- a/tools/xl/xl.h
+++ b/tools/xl/xl.h
@@ -272,6 +272,8 @@ extern char *default_vifbackend;
 extern char *default_remus_netbufscript;
 extern char *default_colo_proxy_script;
 extern char *blkdev_start;
+extern int max_grant_frames;
+extern int max_maptrack_frames;
 
 enum output_format {
     OUTPUT_FORMAT_JSON,
-- 
2.12.3


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