libxl: Adjustments to memset/memmax handling

I think xl memset should change the memory currently used by the guest
and xl memmax should change the size of the guest's address space and
not the population.  For this reason libxl_set_memory_target should
provide a way to enforce the memory target, calling
xc_domain_setmaxmem.  On the other hand xl memmax shouldn't call
xc_domain_setmaxmem because that is the upper bound of the memory
reservation, it should just change static-max, that at the moment
wouldn't do much, but we can imagine that in the future could trigger
something useful in the guest.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Acked-by: Jonathan Knowles <Jonathan.Knowles@eu.citrix.com>=20

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index 967f804037b6dfdde0d078eda1f276c2e6fb584c..c00e08fe2d93fb9d09d077f831eaef467516efa0 100644 (file)
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -2468,7 +2468,6 @@ int libxl_domain_setmaxmem(struct libxl_ctx *ctx, uint32_t domid, uint32_t max_m
     char *mem, *endptr;
     uint32_t memorykb;
     char *dompath = libxl_xs_get_dompath(ctx, domid);
-    int rc;
 
     mem = libxl_xs_read(ctx, XBT_NULL, libxl_sprintf(ctx, "%s/memory/target", dompath));
     if (!mem) {
@@ -2486,20 +2485,16 @@ int libxl_domain_setmaxmem(struct libxl_ctx *ctx, uint32_t domid, uint32_t max_m
         return 1;
     }
 
-    rc = xc_domain_setmaxmem(ctx->xch, domid, max_memkb);
-    if (rc != 0)
-        return rc;
-
     if (domid != 0)
         libxl_xs_write(ctx, XBT_NULL, libxl_sprintf(ctx, "%s/memory/static-max", dompath), "%lu", max_memkb);
 
-    return rc;
+    return 0;
 }
 
-int libxl_set_memory_target(struct libxl_ctx *ctx, uint32_t domid, uint32_t target_memkb)
+int libxl_set_memory_target(struct libxl_ctx *ctx, uint32_t domid, uint32_t target_memkb, int enforce)
 {
     int rc = 0;
-    uint32_t memorykb, videoram;
+    uint32_t memorykb = 0, videoram = 0;
     char *memmax, *endptr, *videoram_s = NULL;
     char *dompath = libxl_xs_get_dompath(ctx, domid);
     xc_domaininfo_t info;
@@ -2539,6 +2534,11 @@ int libxl_set_memory_target(struct libxl_ctx *ctx, uint32_t domid, uint32_t targ
     uuid = libxl_uuid2string(ctx, ptr.uuid);
     libxl_xs_write(ctx, XBT_NULL, libxl_sprintf(ctx, "/vm/%s/memory", uuid), "%lu", target_memkb / 1024);
 
+    if (enforce || !domid)
+        memorykb = target_memkb;
+    rc = xc_domain_setmaxmem(ctx->xch, domid, memorykb + LIBXL_MAXMEM_CONSTANT);
+    if (rc != 0)
+        return rc;
     rc = xc_domain_memory_set_pod_target(ctx->xch, domid, (target_memkb - videoram) / 4, NULL, NULL, NULL);
     return rc;
 }

diff --git a/tools/libxl/libxl.h b/tools/libxl/libxl.h
index 130af2442d0a571d571c951ae20edea4191b6a24..e951111fcfd0beb46de11d9551d7e153800dec45 100644 (file)
--- a/tools/libxl/libxl.h
+++ b/tools/libxl/libxl.h
@@ -340,7 +340,7 @@ int libxl_domain_pause(struct libxl_ctx *ctx, uint32_t domid);
 int libxl_domain_unpause(struct libxl_ctx *ctx, uint32_t domid);
 
 int libxl_domain_setmaxmem(struct libxl_ctx *ctx, uint32_t domid, uint32_t target_memkb);
-int libxl_set_memory_target(struct libxl_ctx *ctx, uint32_t domid, uint32_t target_memkb);
+int libxl_set_memory_target(struct libxl_ctx *ctx, uint32_t domid, uint32_t target_memkb, int enforce);
 
 int libxl_console_attach(struct libxl_ctx *ctx, uint32_t domid, int cons_num);
 

diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index aa079965106660aa644af19afd7d57a2d5c6a3ec..2101ee58d0ab72f183fccc11445f9b21c88b8dfb 100644 (file)
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -1262,7 +1262,7 @@ void set_memory_target(char *p, char *mem)
         exit(3);
     }
     printf("setting domid %d memory to : %d\n", domid, memorykb);
-    libxl_set_memory_target(&ctx, domid, memorykb);
+    libxl_set_memory_target(&ctx, domid, memorykb, /* enforce */ 1);
 }
 
 int main_memset(int argc, char **argv)