Size RUMP_MEMLIMIT dynamically based on domU memory

RUMP_MEMLIMIT was previously hardcoded to 8MB. We size it dynamically
based on domU memory allocation, with the rump kernel getting 50%.

Signed-off-by: Martin Lucina <martin@lucina.net>

diff --git a/include/mini-os/mm.h b/include/mini-os/mm.h
index 56b2eb2834db3e4c425573f1c97d01a8675f62f0..148ea3cf30f86d25cfdfb01c9f6b497f6ac8169d 100644 (file)
--- a/include/mini-os/mm.h
+++ b/include/mini-os/mm.h
@@ -76,5 +76,6 @@ unsigned long alloc_contig_pages(int order, unsigned int addr_bits);
 
 int free_physical_pages(xen_pfn_t *mfns, int n);
 void fini_mm(void);
+uint64_t minios_get_memsize(void);
 
 #endif /* _MINIOS_MM_H_ */

diff --git a/rumphyper_base.c b/rumphyper_base.c
index 0f8e05d21def04913b0fc67704f2c93f094a694a..ce204aab8046474e3fa8aea78a847cee8cfd1ece 100644 (file)
--- a/rumphyper_base.c
+++ b/rumphyper_base.c
@@ -29,6 +29,7 @@
 #include <xen/io/console.h>
 #include <mini-os/xmalloc.h>
 #include <mini-os/blkfront.h>
+#include <mini-os/mm.h>
 
 #include <errno.h>
 #include <fcntl.h>
@@ -89,34 +90,58 @@ rumpuser_dprintf(const char *fmt, ...)
        minios_free_pages(buf, 0);
 }
 
-static struct {
-       const char *name;
-       const char *value;
-} envtab[] = {
-       { RUMPUSER_PARAM_NCPU, "1" },
-       { RUMPUSER_PARAM_HOSTNAME, "rump4xen" },
-       { "RUMP_VERBOSE", "1" },
-       { "RUMP_MEMLIMIT", "8m" },
-       { NULL, NULL },
-};
-
 int
-rumpuser_getparam(const char *name, void *buf, size_t blen)
+rumpuser_getparam(const char *name, void *buf, size_t buflen)
 {
-       int i;
+       int rv = 0;
+
+       if (buflen <= 1)
+               return EINVAL;
+
+       if (strcmp(name, RUMPUSER_PARAM_NCPU) == 0
+           || strcmp(name, "RUMP_VERBOSE") == 0) {
+               strncpy(buf, "1", buflen-1);
+
+       } else if (strcmp(name, RUMPUSER_PARAM_HOSTNAME) == 0) {
+               strncpy(buf, "rump-xen", buflen-1);
+
+       /* for memlimit, we have to implement int -> string ... */
+       } else if (strcmp(name, "RUMP_MEMLIMIT") == 0) {
+               uint64_t memsize;
+               char tmp[64];
+               char *res = buf;
+               unsigned i, j;
+
+               /* use up to 50% memory for rump kernel */
+               memsize = minios_get_memsize() / 2;
+               if (memsize < (8 * 1024 * 1024)) {
+                       minios_printk("rumphyper: warning: low on physical "
+                                     "memory (%llu bytes), "
+                                     "suggest increasing domU allocation\n",
+                                     memsize);
+                       memsize = 8 * 1024 * 1024;
+               }
 
-       for (i = 0; envtab[i].name; i++) {
-               if (strcmp(name, envtab[i].name) == 0) {
-                       if (blen < strlen(envtab[i].value)+1) {
+               for (i = 0; memsize > 0; i++) {
+                       if (i >= sizeof(tmp)-1)
                                return E2BIG;
-                       } else {
-                               strcpy(buf, envtab[i].value);
-                               return 0;
+                       tmp[i] = (memsize % 10) + '0';
+                       memsize = memsize / 10;
+               }
+               if (i >= buflen) {
+                       rv = 1;
+               } else {
+                       res[i] = '\0';
+                       for (j = i; i > 0; i--) {
+                               res[j-i] = tmp[i-1];
                        }
                }
+
+       } else {
+               rv = ENOENT;
        }
 
-        return ENOENT;
+       return rv;
 }
 
 /* Use same values both for absolute and relative clock. */

diff --git a/xen/mm.c b/xen/mm.c
index 58c7118184a0c61abe2a03800f070a89c302d4c3..14b3419166513dfa0004b2b5edd644f5e9aa996e 100644 (file)
--- a/xen/mm.c
+++ b/xen/mm.c
@@ -376,8 +376,11 @@ int free_physical_pages(xen_pfn_t *mfns, int n)
 }
 #endif
 
-
-
+static uint64_t memsize = 0;
+uint64_t minios_get_memsize(void)
+{
+    return memsize;
+}
 
 void init_mm(void)
 {
@@ -395,6 +398,7 @@ void init_mm(void)
            (u_long)to_virt(PFN_PHYS(max_pfn)), PFN_PHYS(max_pfn));
     init_page_allocator(PFN_PHYS(start_pfn), PFN_PHYS(max_pfn));
     minios_printk("MM: done\n");
+    memsize = PFN_PHYS(max_pfn) - PFN_PHYS(start_pfn);
 
     arch_init_p2m(max_pfn);