From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50231) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XFo9q-0004Jj-MY for qemu-devel@nongnu.org; Fri, 08 Aug 2014 13:40:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XFo9k-0006hD-FS for qemu-devel@nongnu.org; Fri, 08 Aug 2014 13:40:50 -0400 Received: from mx1.redhat.com ([209.132.183.28]:11324) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XFo9k-0006h2-7j for qemu-devel@nongnu.org; Fri, 08 Aug 2014 13:40:44 -0400 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s78HehG0001555 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Fri, 8 Aug 2014 13:40:43 -0400 From: Kevin Wolf Date: Fri, 8 Aug 2014 19:39:28 +0200 Message-Id: <1407519603-6635-28-git-send-email-kwolf@redhat.com> In-Reply-To: <1407519603-6635-1-git-send-email-kwolf@redhat.com> References: <1407519603-6635-1-git-send-email-kwolf@redhat.com> Subject: [Qemu-devel] [PULL 27/62] coroutine: make pool size dynamic List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com From: Stefan Hajnoczi 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 Reviewed-by: Eric Blake --- 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