add hazard pointer implementation. buggy

[nbds] / runtime / mem.c

diff --git a/runtime/mem.c b/runtime/mem.c
index e46eb7efbd8bf8278ba786666012e753bf6e9650..1787a6253f299e67c01c063758aa26399d64bc87 100644 (file)
--- a/runtime/mem.c
+++ b/runtime/mem.c
@@ -8,10 +8,10 @@
 #include <stdio.h>
 #include <errno.h>
 #include "common.h"
-#include "runtime_local.h"
+#include "rlocal.h"
 #include "lwt.h"
 
-#define GET_SCALE(n) (sizeof(n)*8-__builtin_clzl((n)-1)) // log2 of <n>, rounded up
+#define GET_SCALE(n) (sizeof(void *)*__CHAR_BIT__ - __builtin_clzl((n) - 1)) // log2 of <n>, rounded up
 #define MAX_SCALE 31 // allocate blocks up to 4GB in size (arbitrary, could be bigger)
 #define REGION_SCALE 22 // 4MB regions
 #define REGION_SIZE (1 << REGION_SCALE)
@@ -62,10 +62,14 @@ void mem_init (void) {
 //
 // TODO: maybe we want to munmap() larger size blocks to reclaim virtual address space?
 void nbd_free (void *x) {
+    assert(x);
     LOCALIZE_THREAD_LOCAL(tid_, int);
     block_t  *b = (block_t *)x;
     assert(((size_t)b >> REGION_SCALE) < ((1 << HEADER_REGION_SCALE) / sizeof(header_t)));
     header_t *h = region_header_ + ((size_t)b >> REGION_SCALE);
+#ifndef NDEBUG
+    memset(b, 0xcd, (1 << h->scale));
+#endif
     TRACE("m0", "nbd_free(): block %p scale %llu", b, h->scale);
     if (h->owner == tid_) {
         TRACE("m0", "nbd_free(): private block, free list head %p", 
@@ -75,8 +79,9 @@ void nbd_free (void *x) {
     } else {
         TRACE("m0", "nbd_free(): owner %llu free list head %p", 
                     h->owner, pub_free_list_[h->owner][h->scale][tid_]);
-        b->next = pub_free_list_[h->owner][h->scale][tid_];
-        pub_free_list_[h->owner][h->scale][tid_] = b;
+        do {
+            b->next = pub_free_list_[h->owner][h->scale][tid_];
+        } while (SYNC_CAS(&pub_free_list_[h->owner][h->scale][tid_], b->next, b) != b->next);
     }
 }
 
@@ -88,6 +93,7 @@ void nbd_free (void *x) {
 // on the private free list. If we didn't find any blocks on the public free lists, allocate a new
 // region, break it up into blocks and put them on the private free list.
 void *nbd_malloc (size_t n) {
+    assert(n);
     LOCALIZE_THREAD_LOCAL(tid_, int);
     if (n < sizeof(block_t)) {
         n = sizeof(block_t);
@@ -96,7 +102,7 @@ void *nbd_malloc (size_t n) {
     assert(b_scale <= MAX_SCALE);
     TRACE("m0", "nbd_malloc(): size %llu scale %llu", n, b_scale);
     private_list_t *pri = &pri_free_list_[tid_][b_scale]; // our private free list
-    TRACE("m0", "nbd_malloc(): private free list %p first block %p", pri->list, pri->head);
+    TRACE("m0", "nbd_malloc(): private free list first block %p", pri->head, 0);
 
     // If our private free list is empty, try to find blocks on our public free list. If that fails,
     // allocate a new region.
@@ -111,9 +117,9 @@ void *nbd_malloc (size_t n) {
                 uint32_t count = pri->count;
                 pri->count = 0;
                 // If our private list is empty and we haven't gotten at least half a region's worth 
-                // of block's from our public lists, we break open a new region. This guarentees 
-                // that we are amortizing the cost of accessing our public lists accross enough 
-                // nbd_malloc() calls.
+                // of block's from our public lists, we allocate a new region. This guarentees that
+                // we amortize the cost of accessing our public lists accross enough nbd_malloc() 
+                // calls.
                 uint32_t min_count = b_scale > REGION_SCALE ? 1 << (b_scale-REGION_SCALE-1) : 1;
                 if (count < min_count) {
                     char  *region = get_new_region(b_scale);
@@ -131,7 +137,7 @@ void *nbd_malloc (size_t n) {
 
             if (pubs[pri->next_pub] != NULL) {
                 block_t *stolen = SYNC_SWAP(&pubs[pri->next_pub], NULL);
-                TRACE("m0", "nbd_malloc(): stole list %p first block %p", stolen);
+                TRACE("m0", "nbd_malloc(): stole list %p", stolen, 0);
                 if (stolen == NULL)
                     continue;
                 pri->head = stolen;
@@ -143,7 +149,7 @@ void *nbd_malloc (size_t n) {
 
     // Pull a block off of our private free list.
     block_t *b = pri->head;
-    TRACE("m0", "nbd_malloc(): take block %p off of of private list (new head is %p)", b, pri->next);
+    TRACE("m0", "nbd_malloc(): take block %p off of of private list (new head is %p)", b, b->next);
     assert(b);
     pri->head = b->next;
     pri->count++;