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fix problems with block-cache chunked mprotects

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The problems don't show up with the current use of the block
cache, but repair mprotect tracking in case it matters in
the future.
This commit is contained in:
Matthew Flatt 2015-09-15 09:33:54 -06:00
parent 68f8d63222
commit 2616b06570
1 changed files with 17 additions and 9 deletions
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26
racket/src/racket/gc2/block_cache.c
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@ -200,8 +200,9 @@ static void *bc_alloc_std_page(BlockCache *bc, int dirty_ok, int expect_mprotect
*src_block = bd;
GC_ASSERT(!BD_MAP_GET_BIT(bd->alloc_map, pos));
BD_MAP_SET_BIT(bd->alloc_map, pos);
if (expect_mprotect) {
if (BD_MAP_GET_BIT(bd->protect_map, pos)) {
/* Unprotect a contiguous range of unallocated pages,
@ -209,11 +210,13 @@ static void *bc_alloc_std_page(BlockCache *bc, int dirty_ok, int expect_mprotect
the range costs much less than multiple unprotect
calls. */
int start_pos = pos, end_pos = pos + 1;
BD_MAP_UNSET_BIT(bd->protect_map, pos);
while (start_pos
&& !BD_MAP_GET_BIT(bd->alloc_map, start_pos)
&& BD_MAP_GET_BIT(bd->protect_map, start_pos)) {
BD_MAP_UNSET_BIT(bd->protect_map, start_pos);
&& !BD_MAP_GET_BIT(bd->alloc_map, (start_pos-1))
&& BD_MAP_GET_BIT(bd->protect_map, (start_pos-1))) {
--start_pos;
BD_MAP_UNSET_BIT(bd->protect_map, start_pos);
}
while ((end_pos < (bd->size >> LOG_APAGE_SIZE))
&& !BD_MAP_GET_BIT(bd->alloc_map, end_pos)
@ -221,7 +224,6 @@ static void *bc_alloc_std_page(BlockCache *bc, int dirty_ok, int expect_mprotect
BD_MAP_UNSET_BIT(bd->protect_map, end_pos);
end_pos++;
}
GC_MP_CNT_INC(mp_alloc_med_big_cnt);
os_protect_pages((char *)p - ((pos - start_pos) * APAGE_SIZE),
(end_pos - start_pos) * APAGE_SIZE,
@ -309,7 +311,7 @@ static ssize_t block_cache_free_page(BlockCache* bc, void *p, size_t len, int ty
fl->dirty = 1;
b->free = fl;
GC_ASSERT(BD_MAP_GET_BIT(b->alloc_map, pos));
BD_MAP_SET_BIT(b->alloc_map, pos);
BD_MAP_UNSET_BIT(b->alloc_map, pos);
gclist_move(&b->gclist, free_head);
b->freecnt++;
#if BC_ASSERTS
@ -431,10 +433,15 @@ static void block_cache_protect_one_page(BlockCache* bc, void *p, size_t len, in
int pos = BD_BLOCK_PTR_TO_POS(p, b);
GC_ASSERT(pos >= 0);
GC_ASSERT(pos < (b->size >> LOG_APAGE_SIZE));
if (BD_MAP_GET_BIT(b->protect_map, pos)) {
GC_ASSERT(BD_MAP_GET_BIT(b->alloc_map, pos));
if (writeable) {
GC_ASSERT(BD_MAP_GET_BIT(b->protect_map, pos));
BD_MAP_UNSET_BIT(b->protect_map, pos);
os_protect_pages(p, len, writeable);
} else {
GC_ASSERT(!BD_MAP_GET_BIT(b->protect_map, pos));
BD_MAP_SET_BIT(b->protect_map, pos);
}
os_protect_pages(p, len, writeable);
}
break;
default:
@ -455,7 +462,6 @@ static void block_cache_queue_protect_range(BlockCache* bc, void *p, size_t len,
{
block_desc *b = (block_desc *)*src_block;
b->in_queue = 1;
memset(b->protect_map, writeable ? 0 : 255, 1+(b->size >> (LOG_APAGE_SIZE + 3)));
}
return;
break;
@ -474,12 +480,14 @@ static void block_cache_flush_protect_ranges(BlockCache* bc, int writeable) {
if (b->in_queue) {
b->in_queue = 0;
page_range_add(bc->page_range, b->block, b->size, writeable);
memset(b->protect_map, writeable ? 0 : 255, 1+(b->size >> (LOG_APAGE_SIZE + 3)));
}
}
gclist_each_item(b, &bg->free, block_desc*, gclist) {
if (b->in_queue) {
b->in_queue = 0;
page_range_add(bc->page_range, b->block, b->size, writeable);
memset(b->protect_map, writeable ? 0 : 255, 1+(b->size >> (LOG_APAGE_SIZE + 3)));
}
}