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memory: compress phys_map node pointers to 16 bits

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Use an expanding vector to store nodes.  Allocation is baroque to g_renew()
potentially invalidating pointers; this will be addressed later.

Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Avi Kivity 2012-02-12 20:12:49 +02:00
parent 5312bd8b31
commit d6f2ea22a0
1 changed files with 45 additions and 9 deletions
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54
exec.c
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@ -201,13 +201,19 @@ static uint16_t phys_section_unassigned;
struct PhysPageEntry {
union {
uint16_t leaf; /* index into phys_sections */
PhysPageEntry *node;
uint16_t node; /* index into phys_map_nodes */
} u;
};
/* Simple allocator for PhysPageEntry nodes */
static PhysPageEntry (*phys_map_nodes)[L2_SIZE];
static unsigned phys_map_nodes_nb, phys_map_nodes_nb_alloc;
#define PHYS_MAP_NODE_NIL ((uint16_t)~0)
/* This is a multi-level map on the physical address space.
The bottom level has pointers to PhysPageDesc. */
static PhysPageEntry phys_map;
static PhysPageEntry phys_map = { .u.node = PHYS_MAP_NODE_NIL };
static void io_mem_init(void);
static void memory_map_init(void);
@ -403,6 +409,32 @@ static inline PageDesc *page_find(tb_page_addr_t index)
}
#if !defined(CONFIG_USER_ONLY)
static PhysPageEntry *phys_map_node_alloc(uint16_t *ptr)
{
unsigned i;
uint16_t ret;
/* Assign early to avoid the pointer being invalidated by g_renew() */
*ptr = ret = phys_map_nodes_nb++;
assert(ret != PHYS_MAP_NODE_NIL);
if (ret == phys_map_nodes_nb_alloc) {
typedef PhysPageEntry Node[L2_SIZE];
phys_map_nodes_nb_alloc = MAX(phys_map_nodes_nb_alloc * 2, 16);
phys_map_nodes = g_renew(Node, phys_map_nodes,
phys_map_nodes_nb_alloc);
}
for (i = 0; i < L2_SIZE; ++i) {
phys_map_nodes[ret][i].u.node = PHYS_MAP_NODE_NIL;
}
return phys_map_nodes[ret];
}
static void phys_map_nodes_reset(void)
{
phys_map_nodes_nb = 0;
}
static uint16_t *phys_page_find_alloc(target_phys_addr_t index, int alloc)
{
PhysPageEntry *lp, *p;
@ -412,18 +444,20 @@ static uint16_t *phys_page_find_alloc(target_phys_addr_t index, int alloc)
/* Level 1..N. */
for (i = P_L2_LEVELS - 1; i >= 0; i--) {
if (lp->u.node == NULL) {
if (lp->u.node == PHYS_MAP_NODE_NIL) {
if (!alloc) {
return NULL;
}
lp->u.node = p = g_malloc0(sizeof(PhysPageEntry) * L2_SIZE);
p = phys_map_node_alloc(&lp->u.node);
if (i == 0) {
for (j = 0; j < L2_SIZE; j++) {
p[j].u.leaf = phys_section_unassigned;
}
}
} else {
p = phys_map_nodes[lp->u.node];
}
lp = &lp->u.node[(index >> (i * L2_BITS)) & (L2_SIZE - 1)];
lp = &p[(index >> (i * L2_BITS)) & (L2_SIZE - 1)];
}
return &lp->u.leaf;
@ -2538,12 +2572,13 @@ static void destroy_page_desc(uint16_t section_index)
static void destroy_l2_mapping(PhysPageEntry *lp, unsigned level)
{
unsigned i;
PhysPageEntry *p = lp->u.node;
PhysPageEntry *p;
if (!p) {
if (lp->u.node == PHYS_MAP_NODE_NIL) {
return;
}
p = phys_map_nodes[lp->u.node];
for (i = 0; i < L2_SIZE; ++i) {
if (level > 0) {
destroy_l2_mapping(&p[i], level - 1);
@ -2551,13 +2586,13 @@ static void destroy_l2_mapping(PhysPageEntry *lp, unsigned level)
destroy_page_desc(p[i].u.leaf);
}
}
g_free(p);
lp->u.node = NULL;
lp->u.node = PHYS_MAP_NODE_NIL;
}
static void destroy_all_mappings(void)
{
destroy_l2_mapping(&phys_map, P_L2_LEVELS - 1);
phys_map_nodes_reset();
}
static uint16_t phys_section_add(MemoryRegionSection *section)
@ -3543,6 +3578,7 @@ static void core_begin(MemoryListener *listener)
{
destroy_all_mappings();
phys_sections_clear();
phys_map.u.node = PHYS_MAP_NODE_NIL;
phys_section_unassigned = dummy_section(&io_mem_unassigned);
}