Introduce the mem_pool type and wrap the existing mp_block in this new
type. The new mem_pool type will allow for the memory pool logic to be
reused outside of fast-import. This type will be moved into its own file
in a future commit.
Signed-off-by: Jameson Miller <jam...@microsoft.com>
---
fast-import.c | 108 +++++++++++++++++++++++++++++++++++++++++++++++-----------
1 file changed, 89 insertions(+), 19 deletions(-)
diff --git a/fast-import.c b/fast-import.c
index 6c3215d7c3..1262d9e6be 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -216,6 +216,19 @@ struct mp_block {
uintmax_t space[FLEX_ARRAY]; /* more */
};
+struct mem_pool {
+ struct mp_block *mp_block;
+
+ /*
+ * The amount of available memory to grow the pool by.
+ * This size does not include the overhead for the mp_block.
+ */
+ size_t block_alloc;
+
+ /* The total amount of memory allocated by the pool. */
+ size_t pool_alloc;
+};
+
struct atom_str {
struct atom_str *next_atom;
unsigned short str_len;
@@ -304,9 +317,7 @@ static int global_argc;
static const char **global_argv;
/* Memory pools */
-static size_t mem_pool_alloc = 2*1024*1024 - sizeof(struct mp_block);
-static size_t total_allocd;
-static struct mp_block *mp_block_head;
+static struct mem_pool fi_mem_pool = {0, 2*1024*1024 - sizeof(struct
mp_block), 0 };
/* Atom management */
static unsigned int atom_table_sz = 4451;
@@ -324,6 +335,7 @@ static off_t pack_size;
/* Table of objects we've written. */
static unsigned int object_entry_alloc = 5000;
static struct object_entry_pool *blocks;
+static size_t total_allocd = 0;
static struct object_entry *object_table[1 << 16];
static struct mark_set *marks;
static const char *export_marks_file;
@@ -634,6 +646,60 @@ static unsigned int hc_str(const char *s, size_t len)
return r;
}
+static struct mp_block *pool_alloc_block()
+{
+ struct mp_block *p;
+
+ fi_mem_pool.pool_alloc += sizeof(struct mp_block) +
fi_mem_pool.block_alloc;
+ p = xmalloc(st_add(sizeof(struct mp_block), fi_mem_pool.block_alloc));
+ p->next_block = fi_mem_pool.mp_block;
+ p->next_free = (char *)p->space;
+ p->end = p->next_free + fi_mem_pool.block_alloc;
+ fi_mem_pool.mp_block = p;
+
+ return p;
+}
+
+/*
+ * Allocates a block of memory with a specific size and
+ * appends it to the memory pool's list of blocks.
+ *
+ * This function is used to allocate blocks with sizes
+ * different than the default "block_alloc" size for the mem_pool.
+ *
+ * There are two use cases:
+ * 1) The initial block allocation for a memory pool.
+ *
+ * 2) large" blocks of a specific size, where the entire memory block
+ * is going to be used. This means the block will not have any
+ * available memory for future allocations. The block is placed at
+ * the end of the list so that it will be the last block searched
+ * for available space.
+ */
+static struct mp_block *pool_alloc_block_with_size(size_t block_alloc)
+{
+ struct mp_block *p, *block;
+
+ fi_mem_pool.pool_alloc += sizeof(struct mp_block) + block_alloc;
+ p = xmalloc(st_add(sizeof(struct mp_block), block_alloc));
+
+ block = fi_mem_pool.mp_block;
+ if (block) {
+ while (block->next_block)
+ block = block->next_block;
+
+ block->next_block = p;
+ } else {
+ fi_mem_pool.mp_block = p;
+ }
+
+ p->next_block = NULL;
+ p->next_free = (char *)p->space;
+ p->end = p->next_free + block_alloc;
+
+ return p;
+}
+
static void *pool_alloc(size_t len)
{
struct mp_block *p;
@@ -643,21 +709,25 @@ static void *pool_alloc(size_t len)
if (len & (sizeof(uintmax_t) - 1))
len += sizeof(uintmax_t) - (len & (sizeof(uintmax_t) - 1));
- for (p = mp_block_head; p; p = p->next_block)
- if ((p->end - p->next_free >= len))
- break;
+ p = fi_mem_pool.mp_block;
+
+ /*
+ * In performance profiling, there was a minor perf benefit to
+ * check for available memory in the head block via the if
+ * statement, and only going through the loop when needed.
+ */
+ if (p &&
+ (p->end - p->next_free < len)) {
+ for (p = p->next_block; p; p = p->next_block)
+ if (p->end - p->next_free >= len)
+ break;
+ }
if (!p) {
- if (len >= (mem_pool_alloc/2)) {
- total_allocd += len;
- return xmalloc(len);
- }
- total_allocd += sizeof(struct mp_block) + mem_pool_alloc;
- p = xmalloc(st_add(sizeof(struct mp_block), mem_pool_alloc));
- p->next_block = mp_block_head;
- p->next_free = (char *) p->space;
- p->end = p->next_free + mem_pool_alloc;
- mp_block_head = p;
+ if (len >= (fi_mem_pool.block_alloc / 2))
+ p = pool_alloc_block_with_size(len);
+ else
+ p = pool_alloc_block();
}
r = p->next_free;
@@ -667,7 +737,7 @@ static void *pool_alloc(size_t len)
static void *pool_calloc(size_t count, size_t size)
{
- size_t len = count * size;
+ size_t len = st_mult(count, size);
void *r = pool_alloc(len);
memset(r, 0, len);
return r;
@@ -3541,8 +3611,8 @@ int cmd_main(int argc, const char **argv)
fprintf(stderr, "Total branches: %10lu (%10lu loads )\n",
branch_count, branch_load_count);
fprintf(stderr, " marks: %10" PRIuMAX " (%10" PRIuMAX
" unique )\n", (((uintmax_t)1) << marks->shift) * 1024, marks_set_count);
fprintf(stderr, " atoms: %10u\n", atom_cnt);
- fprintf(stderr, "Memory total: %10" PRIuMAX " KiB\n",
(total_allocd + alloc_count*sizeof(struct object_entry))/1024);
- fprintf(stderr, " pools: %10lu KiB\n", (unsigned
long)(total_allocd/1024));
+ fprintf(stderr, "Memory total: %10" PRIuMAX " KiB\n",
(total_allocd + fi_mem_pool.pool_alloc + alloc_count*sizeof(struct
object_entry))/1024);
+ fprintf(stderr, " pools: %10lu KiB\n", (unsigned
long)((total_allocd + fi_mem_pool.pool_alloc) /1024));
fprintf(stderr, " objects: %10" PRIuMAX " KiB\n",
(alloc_count*sizeof(struct object_entry))/1024);
fprintf(stderr,
"---------------------------------------------------------------------\n");
pack_report();
--
2.14.3
