Load page count from region

Author: yuyichao

src/gc-debug.c

@@ -133,7 +133,7 @@ static void clear_mark(int bits)
         region_t *region = &regions[h];
         if (!region->pages)
             break;
-        for (int pg_i = 0; pg_i < REGION_PG_COUNT/32; pg_i++) {
+        for (int pg_i = 0; pg_i < region->pg_cnt / 32; pg_i++) {
             uint32_t line = region->freemap[pg_i];
             if (!!~line) {
                 for (int j = 0; j < 32; j++) {

src/gc.c

@@ -462,20 +462,20 @@ static NOINLINE void *malloc_page(void)
             region->meta = (jl_gc_pagemeta_t*)(mem + pages_sz +freemap_sz);
             region->lb = 0;
             region->ub = 0;
+            region->pg_cnt = REGION_PG_COUNT;
 #ifdef _OS_WINDOWS_
-            VirtualAlloc(region->freemap, REGION_PG_COUNT / 8,
+            VirtualAlloc(region->freemap, region->pg_cnt / 8,
                          MEM_COMMIT, PAGE_READWRITE);
-            VirtualAlloc(region->meta,
-                         REGION_PG_COUNT * sizeof(jl_gc_pagemeta_t),
+            VirtualAlloc(region->meta, region->pg_cnt * sizeof(jl_gc_pagemeta_t),
                          MEM_COMMIT, PAGE_READWRITE);
 #endif
-            memset(region->freemap, 0xff, REGION_PG_COUNT/8);
+            memset(region->freemap, 0xff, region->pg_cnt / 8);
         }
-        for (i = region->lb; i < REGION_PG_COUNT/32; i++) {
+        for (i = region->lb; i < region->pg_cnt / 32; i++) {
             if (region->freemap[i])
                 break;
         }
-        if (i == REGION_PG_COUNT/32) {
+        if (i == region->pg_cnt / 32) {
             // region full
             region_i++;
             continue;
@@ -516,12 +516,15 @@ static void free_page(void *p)
 {
     int pg_idx = -1;
     int i;
-    for(i = 0; i < REGION_COUNT && regions[i].pages != NULL; i++) {
-        pg_idx = page_index(&regions[i], p);
-        if (pg_idx >= 0 && pg_idx < REGION_PG_COUNT) break;
+    region_t *region = regions;
+    for (i = 0; i < REGION_COUNT && regions[i].pages != NULL; i++) {
+        region = &regions[i];
+        pg_idx = page_index(region, p);
+        if (pg_idx >= 0 && pg_idx < region->pg_cnt) {
+            break;
+        }
     }
-    assert(i < REGION_COUNT && regions[i].pages != NULL);
-    region_t *region = &regions[i];
+    assert(i < REGION_COUNT && region->pages != NULL);
     uint32_t msk = (uint32_t)(1 << (pg_idx % 32));
     assert(!(region->freemap[pg_idx/32] & msk));
     region->freemap[pg_idx/32] ^= msk;
@@ -534,7 +537,7 @@ static void free_page(void *p)
         decommit_size = jl_page_size;
         p = (void*)((uintptr_t)region->pages[pg_idx].data & ~(jl_page_size - 1)); // round down to the nearest page
         pg_idx = page_index(region, p);
-        if (pg_idx + n_pages > REGION_PG_COUNT) goto no_decommit;
+        if (pg_idx + n_pages > region->pg_cnt) goto no_decommit;
         for (; n_pages--; pg_idx++) {
             msk = (uint32_t)(1 << ((pg_idx % 32)));
             if (!(region->freemap[pg_idx/32] & msk)) goto no_decommit;

src/gc.h

@@ -191,9 +191,10 @@ typedef struct {
     //  Blocks: osize * n
     //    Tag: sizeof_jl_taggedvalue_t
     //    Data: <= osize - sizeof_jl_taggedvalue_t
-    jl_gc_page_t *pages; // [REGION_PG_COUNT] // must be first, to preserve page alignment
-    uint32_t *freemap; // [REGION_PG_COUNT/32]
-    jl_gc_pagemeta_t *meta; // [REGION_PG_COUNT]
+    jl_gc_page_t *pages; // [pg_cnt]; must be first, to preserve page alignment
+    uint32_t *freemap; // [pg_cnt / 32]
+    jl_gc_pagemeta_t *meta; // [pg_cnt]
+    int pg_cnt;
     // store a lower bound of the first free page in each region
     int lb;
     // an upper bound of the last non-free page
@@ -287,10 +288,12 @@ STATIC_INLINE region_t *find_region(void *ptr, int maybe)
 {
     // on 64bit systems we could probably use a single region and remove this loop
     for (int i = 0; i < REGION_COUNT && regions[i].pages; i++) {
-        char *begin = regions[i].pages->data;
-        char *end = begin + sizeof(jl_gc_page_t) * REGION_PG_COUNT;
-        if ((char*)ptr >= begin && (char*)ptr <= end)
-            return &regions[i];
+        region_t *region = &regions[i];
+        char *begin = region->pages->data;
+        char *end = begin + region->pg_cnt * sizeof(jl_gc_page_t);
+        if ((char*)ptr >= begin && (char*)ptr <= end) {
+            return region;
+        }
     }
     (void)maybe;
     assert(maybe && "find_region failed");