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[Qemu-devel] [PULL 27/62] coroutine: make pool size dynamic
From: |
Kevin Wolf |
Subject: |
[Qemu-devel] [PULL 27/62] coroutine: make pool size dynamic |
Date: |
Fri, 8 Aug 2014 19:39:28 +0200 |
From: Stefan Hajnoczi <address@hidden>
Allow coroutine users to adjust the pool size. For example, if the
guest has multiple emulated disk drives we should keep around more
coroutines.
Signed-off-by: Stefan Hajnoczi <address@hidden>
Reviewed-by: Eric Blake <address@hidden>
---
include/block/coroutine.h | 11 +++++++++++
qemu-coroutine.c | 26 +++++++++++++++++++++++---
2 files changed, 34 insertions(+), 3 deletions(-)
diff --git a/include/block/coroutine.h b/include/block/coroutine.h
index b408f96..b9b7f48 100644
--- a/include/block/coroutine.h
+++ b/include/block/coroutine.h
@@ -223,4 +223,15 @@ void coroutine_fn co_aio_sleep_ns(AioContext *ctx,
QEMUClockType type,
* Note that this function clobbers the handlers for the file descriptor.
*/
void coroutine_fn yield_until_fd_readable(int fd);
+
+/**
+ * Add or subtract from the coroutine pool size
+ *
+ * The coroutine implementation keeps a pool of coroutines to be reused by
+ * qemu_coroutine_create(). This makes coroutine creation cheap. Heavy
+ * coroutine users should call this to reserve pool space. Call it again with
+ * a negative number to release pool space.
+ */
+void qemu_coroutine_adjust_pool_size(int n);
+
#endif /* QEMU_COROUTINE_H */
diff --git a/qemu-coroutine.c b/qemu-coroutine.c
index 4708521..bd574aa 100644
--- a/qemu-coroutine.c
+++ b/qemu-coroutine.c
@@ -19,14 +19,14 @@
#include "block/coroutine_int.h"
enum {
- /* Maximum free pool size prevents holding too many freed coroutines */
- POOL_MAX_SIZE = 64,
+ POOL_DEFAULT_SIZE = 64,
};
/** Free list to speed up creation */
static QemuMutex pool_lock;
static QSLIST_HEAD(, Coroutine) pool = QSLIST_HEAD_INITIALIZER(pool);
static unsigned int pool_size;
+static unsigned int pool_max_size = POOL_DEFAULT_SIZE;
Coroutine *qemu_coroutine_create(CoroutineEntry *entry)
{
@@ -55,7 +55,7 @@ static void coroutine_delete(Coroutine *co)
{
if (CONFIG_COROUTINE_POOL) {
qemu_mutex_lock(&pool_lock);
- if (pool_size < POOL_MAX_SIZE) {
+ if (pool_size < pool_max_size) {
QSLIST_INSERT_HEAD(&pool, co, pool_next);
co->caller = NULL;
pool_size++;
@@ -137,3 +137,23 @@ void coroutine_fn qemu_coroutine_yield(void)
self->caller = NULL;
coroutine_swap(self, to);
}
+
+void qemu_coroutine_adjust_pool_size(int n)
+{
+ qemu_mutex_lock(&pool_lock);
+
+ pool_max_size += n;
+
+ /* Callers should never take away more than they added */
+ assert(pool_max_size >= POOL_DEFAULT_SIZE);
+
+ /* Trim oversized pool down to new max */
+ while (pool_size > pool_max_size) {
+ Coroutine *co = QSLIST_FIRST(&pool);
+ QSLIST_REMOVE_HEAD(&pool, pool_next);
+ pool_size--;
+ qemu_coroutine_delete(co);
+ }
+
+ qemu_mutex_unlock(&pool_lock);
+}
--
1.8.3.1
- [Qemu-devel] [PULL 18/62] qdev-monitor: include QOM properties in -device FOO, help output, (continued)
- [Qemu-devel] [PULL 18/62] qdev-monitor: include QOM properties in -device FOO, help output, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 17/62] qmp: hide "hotplugged" device property from device-list-properties, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 19/62] qemu-iotests: Add data pattern in version3 VMDK sample image in 059, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 21/62] qemu-img info: show nocow info, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 20/62] vmdk: Optimize cluster allocation, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 24/62] block/archipelago: Add support for creating images, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 23/62] block/archipelago: Implement bdrv_parse_filename(), Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 25/62] QMP: Add support for Archipelago, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 22/62] block: Support Archipelago as a QEMU block backend, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 26/62] qemu-iotests: add support for Archipelago protocol, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 27/62] coroutine: make pool size dynamic,
Kevin Wolf <=
- [Qemu-devel] [PULL 28/62] block: bump coroutine pool size for drives, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 29/62] thread-pool: avoid per-thread-pool EventNotifier, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 30/62] thread-pool: avoid deadlock in nested aio_poll() calls, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 31/62] block: vhdx - add error check, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 32/62] block: VHDX endian fixes, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 33/62] test-coroutine: add baseline test that times the cost of function calls, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 34/62] block: allow bdrv_unref() to be passed NULL pointers, Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 36/62] block: use the standard 'ret' instead of 'result', Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 39/62] block: Introduce qemu_try_blockalign(), Kevin Wolf, 2014/08/08
- [Qemu-devel] [PULL 37/62] block: vpc - use block layer ops in vpc_create, instead of posix calls, Kevin Wolf, 2014/08/08