Am 12.10.2016 um 23:18 schrieb Michael R. Hines:
Peter,
Greetings from DigitalOcean. We're experiencing the same symptoms
without this patch.
We have, collectively, many gigabytes of un-planned-for RSS being
used per-hypervisor
that we would like to get rid of =).
Without explicitly trying this patch (will do that ASAP), we
immediately noticed that the
192MB mentioned immediately melts away (Yay) when we disabled the
coroutine thread pool explicitly,
with another ~100MB in additional stack usage that would likely also
go away if we
applied the entirety of your patch.
Is there any chance you have revisited this or have a timeline for it?
Hi Michael,
the current master already includes some of the patches of this
original series. There are still some changes left, but
what works for me is the current master +
diff --git a/util/qemu-coroutine.c b/util/qemu-coroutine.c
index 5816702..3eaef68 100644
--- a/util/qemu-coroutine.c
+++ b/util/qemu-coroutine.c
@@ -25,8 +25,6 @@ enum {
};
/** Free list to speed up creation */
-static QSLIST_HEAD(, Coroutine) release_pool =
QSLIST_HEAD_INITIALIZER(pool);
-static unsigned int release_pool_size;
static __thread QSLIST_HEAD(, Coroutine) alloc_pool =
QSLIST_HEAD_INITIALIZER(pool);
static __thread unsigned int alloc_pool_size;
static __thread Notifier coroutine_pool_cleanup_notifier;
@@ -49,20 +47,10 @@ Coroutine *qemu_coroutine_create(CoroutineEntry
*entry)
if (CONFIG_COROUTINE_POOL) {
co = QSLIST_FIRST(&alloc_pool);
if (!co) {
- if (release_pool_size > POOL_BATCH_SIZE) {
- /* Slow path; a good place to register the
destructor, too. */
- if (!coroutine_pool_cleanup_notifier.notify) {
- coroutine_pool_cleanup_notifier.notify =
coroutine_pool_cleanup;
- qemu_thread_atexit_add(&coroutine_pool_cleanup_notifier);
- }
-
- /* This is not exact; there could be a little skew
between
- * release_pool_size and the actual size of
release_pool. But
- * it is just a heuristic, it does not need to be
perfect.
- */
- alloc_pool_size = atomic_xchg(&release_pool_size, 0);
- QSLIST_MOVE_ATOMIC(&alloc_pool, &release_pool);
- co = QSLIST_FIRST(&alloc_pool);
+ /* Slow path; a good place to register the destructor,
too. */
+ if (!coroutine_pool_cleanup_notifier.notify) {
+ coroutine_pool_cleanup_notifier.notify =
coroutine_pool_cleanup;
+ qemu_thread_atexit_add(&coroutine_pool_cleanup_notifier);
}
}
if (co) {
@@ -85,11 +73,6 @@ static void coroutine_delete(Coroutine *co)
co->caller = NULL;
if (CONFIG_COROUTINE_POOL) {
- if (release_pool_size < POOL_BATCH_SIZE * 2) {
- QSLIST_INSERT_HEAD_ATOMIC(&release_pool, co, pool_next);
- atomic_inc(&release_pool_size);
- return;
- }
if (alloc_pool_size < POOL_BATCH_SIZE) {
QSLIST_INSERT_HEAD(&alloc_pool, co, pool_next);
alloc_pool_size++;
+ invoking qemu with the following environemnet variable set:
MALLOC_MMAP_THRESHOLD_=32768 qemu-system-x86_64 ....
The last one makes glibc automatically using mmap when the malloced
memory exceeds 32kByte.