From patchwork Fri Jun 17 13:06:50 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Amit Shah X-Patchwork-Id: 637006 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 3rWLHN168wz9t2B for ; Fri, 17 Jun 2016 23:11:28 +1000 (AEST) Received: from localhost ([::1]:57384 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bDtYT-0003XJ-JS for incoming@patchwork.ozlabs.org; Fri, 17 Jun 2016 09:11:25 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56023) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bDtUk-0007ig-4x for qemu-devel@nongnu.org; Fri, 17 Jun 2016 09:07:35 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bDtUh-00088l-TA for qemu-devel@nongnu.org; Fri, 17 Jun 2016 09:07:33 -0400 Received: from mx1.redhat.com ([209.132.183.28]:35518) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bDtUh-00088X-Kx for qemu-devel@nongnu.org; Fri, 17 Jun 2016 09:07:31 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4C2BE6266E; Fri, 17 Jun 2016 13:07:31 +0000 (UTC) Received: from localhost (ovpn-116-17.sin2.redhat.com [10.67.116.17]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u5HD7SbT003202; Fri, 17 Jun 2016 09:07:29 -0400 From: Amit Shah To: Peter Maydell Date: Fri, 17 Jun 2016 18:36:50 +0530 Message-Id: <33d151f4188a40faee224aba1c7b9ad7b1568eb4.1466168448.git.amit.shah@redhat.com> In-Reply-To: References: In-Reply-To: References: X-Scanned-By: MIMEDefang 2.68 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Fri, 17 Jun 2016 13:07:31 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PULL 11/13] migration: refine the decompression code X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Juan Quintela , liang.z.li@intel.com, qemu list , "Dr. David Alan Gilbert" , Amit Shah , den@openvz.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" From: Liang Li The current code for multi-thread decompression is not clear, especially in the aspect of using lock. Refine the code to make it clear. Signed-off-by: Liang Li Message-Id: <1462433579-13691-9-git-send-email-liang.z.li@intel.com> Signed-off-by: Amit Shah --- migration/ram.c | 50 +++++++++++++++++++++++++------------------------- 1 file changed, 25 insertions(+), 25 deletions(-) diff --git a/migration/ram.c b/migration/ram.c index 59473d9..a44b4f0 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -264,7 +264,6 @@ struct CompressParam { typedef struct CompressParam CompressParam; struct DecompressParam { - bool start; bool done; bool quit; QemuMutex mutex; @@ -830,15 +829,6 @@ static int do_compress_ram_page(QEMUFile *f, RAMBlock *block, return bytes_sent; } -static inline void start_decompression(DecompressParam *param) -{ - param->done = false; - qemu_mutex_lock(¶m->mutex); - param->start = true; - qemu_cond_signal(¶m->cond); - qemu_mutex_unlock(¶m->mutex); -} - static uint64_t bytes_transferred; static void flush_compressed_data(QEMUFile *f) @@ -2198,30 +2188,37 @@ static void *do_data_decompress(void *opaque) { DecompressParam *param = opaque; unsigned long pagesize; + uint8_t *des; + int len; + qemu_mutex_lock(¶m->mutex); while (!param->quit) { - qemu_mutex_lock(¶m->mutex); - while (!param->start && !param->quit) { - qemu_cond_wait(¶m->cond, ¶m->mutex); - } - if (!param->quit) { + if (param->des) { + des = param->des; + len = param->len; + param->des = 0; + qemu_mutex_unlock(¶m->mutex); + pagesize = TARGET_PAGE_SIZE; /* uncompress() will return failed in some case, especially * when the page is dirted when doing the compression, it's * not a problem because the dirty page will be retransferred * and uncompress() won't break the data in other pages. */ - uncompress((Bytef *)param->des, &pagesize, - (const Bytef *)param->compbuf, param->len); - } - param->start = false; - qemu_mutex_unlock(¶m->mutex); + uncompress((Bytef *)des, &pagesize, + (const Bytef *)param->compbuf, len); - qemu_mutex_lock(&decomp_done_lock); - param->done = true; - qemu_cond_signal(&decomp_done_cond); - qemu_mutex_unlock(&decomp_done_lock); + qemu_mutex_lock(&decomp_done_lock); + param->done = true; + qemu_cond_signal(&decomp_done_cond); + qemu_mutex_unlock(&decomp_done_lock); + + qemu_mutex_lock(¶m->mutex); + } else { + qemu_cond_wait(¶m->cond, ¶m->mutex); + } } + qemu_mutex_unlock(¶m->mutex); return NULL; } @@ -2298,10 +2295,13 @@ static void decompress_data_with_multi_threads(QEMUFile *f, while (true) { for (idx = 0; idx < thread_count; idx++) { if (decomp_param[idx].done) { + decomp_param[idx].done = false; + qemu_mutex_lock(&decomp_param[idx].mutex); qemu_get_buffer(f, decomp_param[idx].compbuf, len); decomp_param[idx].des = host; decomp_param[idx].len = len; - start_decompression(&decomp_param[idx]); + qemu_cond_signal(&decomp_param[idx].cond); + qemu_mutex_unlock(&decomp_param[idx].mutex); break; } }