diff options
| -rw-r--r-- | softmmu/physmem.c | 70 |
1 files changed, 39 insertions, 31 deletions
diff --git a/softmmu/physmem.c b/softmmu/physmem.c index 9b171c9dbe..f1275b61f8 100644 --- a/softmmu/physmem.c +++ b/softmmu/physmem.c @@ -3684,56 +3684,64 @@ void mtree_print_dispatch(AddressSpaceDispatch *d, MemoryRegion *root) } } -/* - * If positive, discarding RAM is disabled. If negative, discarding RAM is - * required to work and cannot be disabled. - */ -static int ram_block_discard_disabled; +static unsigned int ram_block_discard_required_cnt; +static unsigned int ram_block_discard_disabled_cnt; +static QemuMutex ram_block_discard_disable_mutex; + +static void ram_block_discard_disable_mutex_lock(void) +{ + static gsize initialized; + + if (g_once_init_enter(&initialized)) { + qemu_mutex_init(&ram_block_discard_disable_mutex); + g_once_init_leave(&initialized, 1); + } + qemu_mutex_lock(&ram_block_discard_disable_mutex); +} + +static void ram_block_discard_disable_mutex_unlock(void) +{ + qemu_mutex_unlock(&ram_block_discard_disable_mutex); +} int ram_block_discard_disable(bool state) { - int old; + int ret = 0; + ram_block_discard_disable_mutex_lock(); if (!state) { - qatomic_dec(&ram_block_discard_disabled); - return 0; + ram_block_discard_disabled_cnt--; + } else if (!ram_block_discard_required_cnt) { + ram_block_discard_disabled_cnt++; + } else { + ret = -EBUSY; } - - do { - old = qatomic_read(&ram_block_discard_disabled); - if (old < 0) { - return -EBUSY; - } - } while (qatomic_cmpxchg(&ram_block_discard_disabled, - old, old + 1) != old); - return 0; + ram_block_discard_disable_mutex_unlock(); + return ret; } int ram_block_discard_require(bool state) { - int old; + int ret = 0; + ram_block_discard_disable_mutex_lock(); if (!state) { - qatomic_inc(&ram_block_discard_disabled); - return 0; + ram_block_discard_required_cnt--; + } else if (!ram_block_discard_disabled_cnt) { + ram_block_discard_required_cnt++; + } else { + ret = -EBUSY; } - - do { - old = qatomic_read(&ram_block_discard_disabled); - if (old > 0) { - return -EBUSY; - } - } while (qatomic_cmpxchg(&ram_block_discard_disabled, - old, old - 1) != old); - return 0; + ram_block_discard_disable_mutex_unlock(); + return ret; } bool ram_block_discard_is_disabled(void) { - return qatomic_read(&ram_block_discard_disabled) > 0; + return qatomic_read(&ram_block_discard_disabled_cnt); } bool ram_block_discard_is_required(void) { - return qatomic_read(&ram_block_discard_disabled) < 0; + return qatomic_read(&ram_block_discard_required_cnt); } |