From patchwork Fri May 29 09:24:53 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alberto Garcia X-Patchwork-Id: 477699 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 D3691140E55 for ; Fri, 29 May 2015 19:25:56 +1000 (AEST) Received: from localhost ([::1]:34582 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YyGY6-0005sn-Qg for incoming@patchwork.ozlabs.org; Fri, 29 May 2015 05:25:54 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59093) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YyGXX-00055O-P5 for qemu-devel@nongnu.org; Fri, 29 May 2015 05:25:20 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YyGXS-0000Om-1C for qemu-devel@nongnu.org; Fri, 29 May 2015 05:25:19 -0400 Received: from smtp3.mundo-r.com ([212.51.32.191]:63503 helo=smtp4.mundo-r.com) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YyGXR-0000OE-Q4; Fri, 29 May 2015 05:25:13 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AhUGAAIwaFVbdWOb/2dsb2JhbABcgxCBMqwOAQEBAQEBBQGBBAGYUwKBR0wBAQEBAQGBC4QjAQEEJ1IQUTwbGYgxAdQIAQEIIoYZijAHFoQXBZ4ch3iFIooYI2GBKRyBVDwxgkcBAQE X-IPAS-Result: AhUGAAIwaFVbdWOb/2dsb2JhbABcgxCBMqwOAQEBAQEBBQGBBAGYUwKBR0wBAQEBAQGBC4QjAQEEJ1IQUTwbGYgxAdQIAQEIIoYZijAHFoQXBZ4ch3iFIooYI2GBKRyBVDwxgkcBAQE X-IronPort-AV: E=Sophos;i="5.13,516,1427752800"; d="scan'208";a="362752994" Received: from fanzine.igalia.com ([91.117.99.155]) by smtp4.mundo-r.com with ESMTP; 29 May 2015 11:25:06 +0200 Received: from [192.168.13.244] (helo=perseus.local) by fanzine.igalia.com with esmtpsa (Cipher TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim) id 1YyGXK-0003b5-RO; Fri, 29 May 2015 11:25:06 +0200 Received: from berto by perseus.local with local (Exim 4.85) (envelope-from ) id 1YyGXK-0004wI-O8; Fri, 29 May 2015 12:25:06 +0300 From: Alberto Garcia To: qemu-devel@nongnu.org Date: Fri, 29 May 2015 11:24:53 +0200 Message-Id: <3587410bf941dc495ec4e41201d1d53a21f7e6fb.1432891306.git.berto@igalia.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: References: In-Reply-To: References: X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 212.51.32.191 Cc: Kevin Wolf , Alberto Garcia , qemu-block@nongnu.org, Max Reitz , Stefan Hajnoczi Subject: [Qemu-devel] [PATCH 1/3] qcow2: mark the memory as no longer needed after qcow2_cache_empty() X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org After having emptied the cache, the data in the cache tables is no longer useful, so we can tell the kernel that we are done with it. In Linux this frees the resources associated with it. The effect of this can be seen in the HMP commit operation: it moves data from the top to the base image (and fills both caches), then it empties the top image. At this point the data in that cache is no longer needed so it's just wasting memory. Signed-off-by: Alberto Garcia Reviewed-by: Max Reitz --- block/qcow2-cache.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/block/qcow2-cache.c b/block/qcow2-cache.c index ed92a09..ed14a92 100644 --- a/block/qcow2-cache.c +++ b/block/qcow2-cache.c @@ -22,8 +22,10 @@ * THE SOFTWARE. */ +#include #include "block/block_int.h" #include "qemu-common.h" +#include "qemu/osdep.h" #include "qcow2.h" #include "trace.h" @@ -60,6 +62,22 @@ static inline int qcow2_cache_get_table_idx(BlockDriverState *bs, return idx; } +static void qcow2_cache_table_release(BlockDriverState *bs, Qcow2Cache *c, + int i, int num_tables) +{ +#if QEMU_MADV_DONTNEED != QEMU_MADV_INVALID + BDRVQcowState *s = bs->opaque; + void *t = qcow2_cache_get_table_addr(bs, c, i); + long align = sysconf(_SC_PAGESIZE); + size_t mem_size = (size_t) s->cluster_size * num_tables; + size_t offset = QEMU_ALIGN_UP((uintptr_t) t, align) - (uintptr_t) t; + size_t length = QEMU_ALIGN_DOWN(mem_size - offset, align); + if (length > 0) { + qemu_madvise((uint8_t *) t + offset, length, QEMU_MADV_DONTNEED); + } +#endif +} + Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables) { BDRVQcowState *s = bs->opaque; @@ -237,6 +255,8 @@ int qcow2_cache_empty(BlockDriverState *bs, Qcow2Cache *c) c->entries[i].lru_counter = 0; } + qcow2_cache_table_release(bs, c, 0, c->size); + c->lru_counter = 0; return 0;