[PATCH] Make per_cpu_info[] dynamically allocated and extendable

diff --git a/blkparse.c b/blkparse.c
index 4ae8857e568af81bdfb579cfdcc491cef3c751a7..8884e9d8b24212b3aab4c8312541c574f3ddf0a1 100644 (file)
--- a/blkparse.c
+++ b/blkparse.c
@@ -32,8 +32,6 @@
 #include "blktrace.h"
 #include "rbtree.h"
 
-#define MAX_CPUS       (512)
-
 #define SECONDS(x)     ((unsigned long long)(x) / 1000000000)
 #define NANO_SECONDS(x)        ((unsigned long long)(x) % 1000000000)
 
@@ -85,17 +83,42 @@ struct trace {
        struct rb_node rb_node;
 };
 
-static struct per_cpu_info per_cpu_info[MAX_CPUS];
+static int max_cpus;
+static struct per_cpu_info *per_cpu_info;
 
 static unsigned long long events;
 
-static int max_cpus;
-
 static char *dev, *output_name;
 
 #define is_done()      (*(volatile int *)(&done))
 static volatile int done;
 
+static void resize_cpu_info(int cpuid)
+{
+       int new_space, new_max = cpuid + 1;
+       char *new_start;
+
+       per_cpu_info = realloc(per_cpu_info, new_max * sizeof(*per_cpu_info));
+       if (!per_cpu_info) {
+               fprintf(stderr, "Cannot allocate CPU info -- %d x %d bytes\n",
+                       new_max, (int) sizeof(*per_cpu_info));
+               exit(1);
+       }
+
+       new_start = (char *)per_cpu_info + (max_cpus * sizeof(*per_cpu_info));
+       new_space = (new_max - max_cpus) * sizeof(*per_cpu_info);
+       memset(new_start, 0, new_space);
+       max_cpus = new_max;
+}
+
+static struct per_cpu_info *get_cpu_info(int cpu)
+{
+       if (cpu >= max_cpus)
+               resize_cpu_info(cpu);
+
+       return &per_cpu_info[cpu];
+}
+
 static inline void check_time(struct blk_io_trace *bit)
 {
        unsigned long long this = bit->time;
@@ -374,7 +397,7 @@ static void show_stats(void)
 
        memset(&foo, 0, sizeof(foo));
 
-       for (i = 0; i < MAX_CPUS; i++) {
+       for (i = 0; i < max_cpus; i++) {
                pci = &per_cpu_info[i];
 
                if (!pci->nelems)
@@ -452,8 +475,7 @@ static int sort_entries(void *traces, unsigned long offset, int nr)
                if (verify_trace(bit))
                        break;
 
-               pci = &per_cpu_info[bit->cpu];
-
+               pci = get_cpu_info(bit->cpu);
                pci->nelems++;
 
                if (trace_rb_insert(t))
@@ -545,15 +567,14 @@ static int read_data(int fd, void *buffer, int bytes, int block)
 
 static int do_file(void)
 {
-       int i, ret, nfiles;
+       int i, nfiles;
 
-       nfiles = 0;
-       max_cpus = 0;
-       for (i = 0; i < MAX_CPUS; i++, nfiles++, max_cpus++) {
-               struct per_cpu_info *pci = &per_cpu_info[i];
+       for (i = 0, nfiles = 0;; i++, nfiles++) {
+               struct per_cpu_info *pci;
                struct stat st;
                void *tb;
 
+               pci = get_cpu_info(i);
                pci->cpu = i;
                pci->ofp = NULL;
 
@@ -576,8 +597,7 @@ static int do_file(void)
                if (read_data(pci->fd, tb, st.st_size, 1))
                        break;
 
-               ret = sort_entries(tb, st.st_size, ~0U);
-               if (ret == -1)
+               if (sort_entries(tb, st.st_size, ~0U) == -1)
                        break;
 
                close(pci->fd);
@@ -676,7 +696,7 @@ static void flush_output(void)
 {
        int i;
 
-       for (i = 0; i < MAX_CPUS; i++) {
+       for (i = 0; i < max_cpus; i++) {
                struct per_cpu_info *pci = &per_cpu_info[i];
 
                if (pci->ofp) {
@@ -721,7 +741,6 @@ int main(int argc, char *argv[])
                return 1;
        }
 
-       memset(per_cpu_info, 0, sizeof(per_cpu_info));
        memset(&rb_root, 0, sizeof(rb_root));
 
        signal(SIGINT, handle_sigint);