From: Martin Lucina <martin@lucina.net>
Date: Fri, 21 Nov 2014 18:00:07 +0000 (+0100)
Subject: Size RUMP_MEMLIMIT dynamically based on domU memory
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=f147e0a8af105699043e81c56416cfae6031301e;p=rumpuser-xen.git

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 56b2eb2..148ea3c 100644
--- 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 0f8e05d..ce204aa 100644
--- 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 58c7118..14b3419 100644
--- 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);