From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36103) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zs7Zg-0005e9-IO for qemu-devel@nongnu.org; Fri, 30 Oct 2015 07:10:25 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Zs7Zd-0002Y5-96 for qemu-devel@nongnu.org; Fri, 30 Oct 2015 07:10:24 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53103) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zs7Zd-0002Xd-3b for qemu-devel@nongnu.org; Fri, 30 Oct 2015 07:10:21 -0400 From: Gerd Hoffmann Date: Fri, 30 Oct 2015 12:09:56 +0100 Message-Id: <1446203414-4013-2-git-send-email-kraxel@redhat.com> In-Reply-To: <1446203414-4013-1-git-send-email-kraxel@redhat.com> References: <1446203414-4013-1-git-send-email-kraxel@redhat.com> Subject: [Qemu-devel] [PATCH 01/19] buffer: make the Buffer capacity increase in powers of two List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: pl@kamp.de, Gerd Hoffmann From: Peter Lieven This makes sure the number of reallocs is in O(log N). Signed-off-by: Peter Lieven [ rebased to util/buffer.c ] Signed-off-by: Gerd Hoffmann --- util/buffer.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/util/buffer.c b/util/buffer.c index cedd055..7ddd693 100644 --- a/util/buffer.c +++ b/util/buffer.c @@ -20,10 +20,13 @@ #include "qemu/buffer.h" +#define BUFFER_MIN_INIT_SIZE 4096 + void buffer_reserve(Buffer *buffer, size_t len) { if ((buffer->capacity - buffer->offset) < len) { - buffer->capacity += (len + 1024); + buffer->capacity = pow2ceil(buffer->offset + len); + buffer->capacity = MAX(buffer->capacity, BUFFER_MIN_INIT_SIZE); buffer->buffer = g_realloc(buffer->buffer, buffer->capacity); } } -- 1.8.3.1