[PATCH] add vmalloc stats to meminfo

[Dave Hansen <haveblue@us.ibm.com>]

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Some workloads like to eat up a lot of vmalloc space.  It is often hard to tell
whether this is because the area is too small, or just too fragmented.  This 
makes it easy to determine.

-- 
Dave Hansen
haveblue@us.ibm.com


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diff -ur linux-2.5.34-mm4/fs/proc/proc_misc.c linux-2.5.34-mm4-vmalloc-stats/fs/proc/proc_misc.c
--- linux-2.5.34-mm4/fs/proc/proc_misc.c	Sat Sep 14 21:23:54 2002
+++ linux-2.5.34-mm4-vmalloc-stats/fs/proc/proc_misc.c	Sat Sep 14 22:38:12 2002
@@ -38,6 +38,7 @@
 #include <linux/smp_lock.h>
 #include <linux/seq_file.h>
 #include <linux/times.h>
+#include <linux/vmalloc.h>
 
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
@@ -128,6 +129,40 @@
 	return proc_calc_metrics(page, start, off, count, eof, len);
 }
 
+struct vmalloc_info {
+	unsigned long used;
+	unsigned long largest_chunk;
+};
+
+static struct vmalloc_info get_vmalloc_info(void)
+{
+	unsigned long prev_end = VMALLOC_START;
+	struct vm_struct* vma;
+	struct vmalloc_info vmi;
+	vmi.used = 0;
+
+	read_lock(&vmlist_lock);
+	
+	if(!vmlist) 
+		vmi.largest_chunk = (VMALLOC_END-VMALLOC_START);
+	else 
+		vmi.largest_chunk = 0;
+	
+	for (vma = vmlist; vma; vma = vma->next) {
+		unsigned long free_area_size = 
+			(unsigned long)vma->addr - prev_end;
+		vmi.used += vma->size;
+		if (vmi.largest_chunk < free_area_size ) 
+			vmi.largest_chunk = free_area_size;
+		prev_end = vma->size + (unsigned long)vma->addr;
+	}
+	if(VMALLOC_END-prev_end > vmi.largest_chunk)
+		vmi.largest_chunk = VMALLOC_END-prev_end;
+	
+	read_unlock(&vmlist_lock);
+	return vmi;
+}
+
 extern atomic_t vm_committed_space;
 
 static int meminfo_read_proc(char *page, char **start, off_t off,
@@ -138,6 +173,8 @@
 	struct page_state ps;
 	unsigned long inactive;
 	unsigned long active;
+	unsigned long vmtot;
+	struct vmalloc_info vmi;
 
 	get_page_state(&ps);
 	get_zone_counts(&active, &inactive);
@@ -150,6 +187,11 @@
 	si_swapinfo(&i);
 	committed = atomic_read(&vm_committed_space);
 
+	vmtot = (VMALLOC_END-VMALLOC_START)>>10;
+	vmi = get_vmalloc_info();
+	vmi.used >>= 10;
+	vmi.largest_chunk >>= 10;
+
 	/*
 	 * Tagged format, for easy grepping and expansion.
 	 */
@@ -174,7 +216,10 @@
 		"Slab:         %8lu kB\n"
 		"Committed_AS: %8u kB\n"
 		"PageTables:   %8lu kB\n"
-		"ReverseMaps:  %8lu\n",
+		"ReverseMaps:  %8lu\n"
+		"VmalTotal:    %8lu kB\n"
+		"VmalUsed:     %8lu kB\n"
+		"VmalChunk:    %8lu kB\n",
 		K(i.totalram),
 		K(i.freeram),
 		K(i.sharedram),
@@ -195,7 +240,10 @@
 		K(ps.nr_slab),
 		K(committed),
 		K(ps.nr_page_table_pages),
-		ps.nr_reverse_maps
+		ps.nr_reverse_maps,
+		vmtot,
+		vmi.used,
+		vmi.largest_chunk
 		);
 
 #ifdef CONFIG_HUGETLB_PAGE