From: David van Moolenbroek <david@minix3.org>
Date: Fri, 9 Oct 2015 18:48:05 +0000 (+0000)
Subject: VM: expose virtual process size
X-Git-Url: http://zhaoyanbai.com/repos/man.dnssec-keyfromlabel.html?a=commitdiff_plain;h=refs%2Fchanges%2F42%2F3242%2F2;p=minix.git

VM: expose virtual process size

So far, VM reported only the number of bytes actually allocated to
each process.  This patch adds two additional fields: the sum of the
byte sizes of all the virtual address ranges in the process, and that
number minus the part of the process stack that is not actually
mapped in.  Unfortunately, we have to guess where the process stack
is, so the second field is not necessarily accurate.

Change-Id: If9e07c20e8588bc3e11601ec79bdcebc06eba6ee
---

diff --git a/minix/include/minix/vm.h b/minix/include/minix/vm.h
index bedd6607d..149efd1f0 100644
--- a/minix/include/minix/vm.h
+++ b/minix/include/minix/vm.h
@@ -49,9 +49,11 @@ struct vm_stats_info {
 };
 
 struct vm_usage_info {
-  vir_bytes vui_total;		/* total amount of process memory */
+  vir_bytes vui_total;		/* total amount of mapped process memory */
   vir_bytes vui_common;		/* part of memory mapped in more than once */
   vir_bytes vui_shared;		/* shared (non-COW) part of common memory */
+  vir_bytes vui_virtual;	/* total size of virtual address space */
+  vir_bytes vui_mvirtual;	/* idem but minus unmapped stack pages */
 };
 
 struct vm_region_info {
diff --git a/minix/servers/vm/region.c b/minix/servers/vm/region.c
index 2afc4080a..fed1e97f4 100644
--- a/minix/servers/vm/region.c
+++ b/minix/servers/vm/region.c
@@ -1359,6 +1359,8 @@ void get_usage_info_kernel(struct vm_usage_info *vui)
 	memset(vui, 0, sizeof(*vui));
 	vui->vui_total = kernel_boot_info.kernel_allocated_bytes +
 		kernel_boot_info.kernel_allocated_bytes_dynamic;
+	/* All of the kernel's pages are actually mapped in. */
+	vui->vui_virtual = vui->vui_mvirtual = vui->vui_total;
 }
 
 static void get_usage_info_vm(struct vm_usage_info *vui)
@@ -1366,6 +1368,25 @@ static void get_usage_info_vm(struct vm_usage_info *vui)
 	memset(vui, 0, sizeof(*vui));
 	vui->vui_total = kernel_boot_info.vm_allocated_bytes +
 		get_vm_self_pages() * VM_PAGE_SIZE;
+	/* All of VM's pages are actually mapped in. */
+	vui->vui_virtual = vui->vui_mvirtual = vui->vui_total;
+}
+
+/*
+ * Return whether the given region is for the associated process's stack.
+ * Unfortunately, we do not actually have this information: in most cases, VM
+ * is not responsible for actually setting up the stack in the first place.
+ * Fortunately, this is only for statistical purposes, so we can get away with
+ * guess work.  However, it is certainly not accurate in the light of userspace
+ * thread stacks, or if the process is messing with its stack in any way, or if
+ * (currently) VFS decides to put the stack elsewhere, etcetera.
+ */
+static int
+is_stack_region(struct vir_region * vr)
+{
+
+	return (vr->vaddr == VM_STACKTOP - DEFAULT_STACK_LIMIT &&
+	    vr->length == DEFAULT_STACK_LIMIT);
 }
 
 /*========================================================================*
@@ -1392,8 +1413,15 @@ void get_usage_info(struct vmproc *vmp, struct vm_usage_info *vui)
 	}
 
 	while((vr = region_get_iter(&v_iter))) {
+		vui->vui_virtual += vr->length;
+		vui->vui_mvirtual += vr->length;
 		for(voffset = 0; voffset < vr->length; voffset += VM_PAGE_SIZE) {
-			if(!(ph = physblock_get(vr, voffset))) continue;
+			if(!(ph = physblock_get(vr, voffset))) {
+				/* mvirtual: discount unmapped stack pages. */
+				if (is_stack_region(vr))
+					vui->vui_mvirtual -= VM_PAGE_SIZE;
+				continue;
+			}
 			/* All present pages are counted towards the total. */
 			vui->vui_total += VM_PAGE_SIZE;