[Qemu-devel] [RFC PATCH 1/3] Revert "coroutine: make pool size dynamic"

[Peter Lieven <pl@kamp.de>]

This reverts commit ac2662a913ee5854b1269256adbdc14e57ba480a.
---
 include/block/coroutine.h |   11 -----------
 qemu-coroutine.c          |   26 +++-----------------------
 2 files changed, 3 insertions(+), 34 deletions(-)

diff --git a/include/block/coroutine.h b/include/block/coroutine.h
index 793df0e..1d9343d 100644
--- a/include/block/coroutine.h
+++ b/include/block/coroutine.h
@@ -215,15 +215,4 @@ 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 bd574aa..4708521 100644
--- a/qemu-coroutine.c
+++ b/qemu-coroutine.c
@@ -19,14 +19,14 @@
 #include "block/coroutine_int.h"
 
 enum {
-    POOL_DEFAULT_SIZE = 64,
+    /* Maximum free pool size prevents holding too many freed coroutines */
+    POOL_MAX_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++;
@@ -137,23 +137,3 @@ 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);
-}
-- 
1.7.9.5