From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6B518C76190 for ; Mon, 22 Jul 2019 13:42:26 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 40039216C8 for ; Mon, 22 Jul 2019 13:42:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 40039216C8 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:33746 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hpYa9-0002vq-0Y for qemu-devel@archiver.kernel.org; Mon, 22 Jul 2019 09:42:25 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:54687) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hpYZD-0007kn-R2 for qemu-devel@nongnu.org; Mon, 22 Jul 2019 09:41:28 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hpYZC-0005Gi-0g for qemu-devel@nongnu.org; Mon, 22 Jul 2019 09:41:27 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49994) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hpYZB-0005G2-RD; Mon, 22 Jul 2019 09:41:25 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 0E08785363; Mon, 22 Jul 2019 13:41:25 +0000 (UTC) Received: from t460s.redhat.com (ovpn-116-75.ams2.redhat.com [10.36.116.75]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8231B1001B12; Mon, 22 Jul 2019 13:41:23 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Date: Mon, 22 Jul 2019 15:41:05 +0200 Message-Id: <20190722134108.22151-4-david@redhat.com> In-Reply-To: <20190722134108.22151-1-david@redhat.com> References: <20190722134108.22151-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Mon, 22 Jul 2019 13:41:25 +0000 (UTC) Content-Transfer-Encoding: quoted-printable 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] [PATCH-for-4.1 v3 3/6] virtio-balloon: Simplify deflate with pbp X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Michael S . Tsirkin" , David Hildenbrand , qemu-stable@nongnu.org, Stefan Hajnoczi , Igor Mammedov , David Gibson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Let's simplify this - the case we are optimizing for is very hard to trigger and not worth the effort. If we're switching from inflation to deflation, let's reset the pbp. Acked-by: David Gibson Signed-off-by: David Hildenbrand --- hw/virtio/virtio-balloon.c | 26 +++++--------------------- 1 file changed, 5 insertions(+), 21 deletions(-) diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c index a78d2d2184..04a7e6c772 100644 --- a/hw/virtio/virtio-balloon.c +++ b/hw/virtio/virtio-balloon.c @@ -117,7 +117,7 @@ static void balloon_deflate_page(VirtIOBalloon *ballo= on, void *addr =3D memory_region_get_ram_ptr(mr) + offset; RAMBlock *rb; size_t rb_page_size; - ram_addr_t ram_offset, host_page_base; + ram_addr_t ram_offset; void *host_addr; int ret; =20 @@ -125,27 +125,11 @@ static void balloon_deflate_page(VirtIOBalloon *bal= loon, * host address? */ rb =3D qemu_ram_block_from_host(addr, false, &ram_offset); rb_page_size =3D qemu_ram_pagesize(rb); - host_page_base =3D ram_offset & ~(rb_page_size - 1); - - if (balloon->pbp - && rb =3D=3D balloon->pbp->rb - && host_page_base =3D=3D balloon->pbp->base) { - int subpages =3D rb_page_size / BALLOON_PAGE_SIZE; =20 - /* - * This means the guest has asked to discard some of the 4kiB - * subpages of a host page, but then changed its mind and - * asked to keep them after all. It's exceedingly unlikely - * for a guest to do this in practice, but handle it anyway, - * since getting it wrong could mean discarding memory the - * guest is still using. */ - clear_bit((ram_offset - balloon->pbp->base) / BALLOON_PAGE_SIZE, - balloon->pbp->bitmap); - - if (bitmap_empty(balloon->pbp->bitmap, subpages)) { - g_free(balloon->pbp); - balloon->pbp =3D NULL; - } + if (balloon->pbp) { + /* Let's play safe and always reset the pbp on deflation request= s. */ + g_free(balloon->pbp); + balloon->pbp =3D NULL; } =20 host_addr =3D (void *)((uintptr_t)addr & ~(rb_page_size - 1)); --=20 2.21.0 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1685CC7618B for ; Thu, 25 Jul 2019 15:33:26 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DFFC0229F3 for ; Thu, 25 Jul 2019 15:33:25 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DFFC0229F3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:33024 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hqfkC-00089o-H8 for qemu-devel@archiver.kernel.org; Thu, 25 Jul 2019 11:33:24 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:49224) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hqfj9-00054B-4o for qemu-devel@nongnu.org; Thu, 25 Jul 2019 11:32:20 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hqfj6-0002HF-RY for qemu-devel@nongnu.org; Thu, 25 Jul 2019 11:32:18 -0400 Received: from mail-qt1-f175.google.com ([209.85.160.175]:34087) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1hqfj3-00027j-8s for qemu-devel@nongnu.org; Thu, 25 Jul 2019 11:32:14 -0400 Received: by mail-qt1-f175.google.com with SMTP id k10so49553532qtq.1 for ; Thu, 25 Jul 2019 08:32:06 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=/hrcl/m7AfRfxAabgjr0nGL2uw+WOg+32XDf093oxBo=; b=iy1GiWlqOa9SOupkrJHyM40CVf4SvlXY6soE0zbPl1FBWS/QByn9n7vGP5WC3apD4u 7j+Zef9ZOqCvDlyK/dXMvSLFdNBJ6NjNlU4c1W6pQUu8PSpfmO7wo66yee+9ggSPJhJC ycX4+FEHfV67OD7dEKISvJUIppixn3bxjcxLaYHzCq7cP8RD6L+iJkF8AgapG+IqdoNh ez2fYjApy0lC5/VRjBAQrW7cG4TXKvjzntF0RmtnNC6JNBSAXEDjcSMUnEJuWIXTvjJ+ edBoI3G1S5RBe40dDSL2jVSpasJwuowS7tPvB6MYeRVqSYtQ02BVSpddCy+lbyrqVeJp a5xg== X-Gm-Message-State: APjAAAX/rYn2XsM2cEwm+wZAQ1nwyJ3jN1/PDyNCPA4uihYTev0aUbqu 4gLLUpvc6uuzNe0IY3wh3M5jtb/703Inaw== X-Google-Smtp-Source: APXvYqzRq9g5v37UH6i9NTuyNepc7XCuaUkfipDFnkWEyW29Y5OwMxXnMyP9gcZHcMf22/a/R5K78w== X-Received: by 2002:aed:22f2:: with SMTP id q47mr63734786qtc.106.1564068724236; Thu, 25 Jul 2019 08:32:04 -0700 (PDT) Received: from redhat.com (bzq-79-181-91-42.red.bezeqint.net. [79.181.91.42]) by smtp.gmail.com with ESMTPSA id n5sm28211627qta.29.2019.07.25.08.32.02 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Thu, 25 Jul 2019 08:32:03 -0700 (PDT) Date: Thu, 25 Jul 2019 11:32:00 -0400 From: "Michael S. Tsirkin" To: qemu-devel@nongnu.org Message-ID: <20190722134108.22151-4-david@redhat.com> References: <20190725153059.7313-1-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline In-Reply-To: <20190725153059.7313-1-mst@redhat.com> X-Mailer: git-send-email 2.22.0.678.g13338e74b8 X-Mutt-Fcc: =sent X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.85.160.175 Subject: [Qemu-devel] [PULL 07/12] virtio-balloon: Simplify deflate with pbp X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , David Gibson , David Hildenbrand Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Message-ID: <20190725153200.NertaDcoBPgQu47aBB_ekDX62mzzjtcCRsREVlxDizU@z> From: David Hildenbrand Let's simplify this - the case we are optimizing for is very hard to trigger and not worth the effort. If we're switching from inflation to deflation, let's reset the pbp. Acked-by: David Gibson Signed-off-by: David Hildenbrand Message-Id: <20190722134108.22151-4-david@redhat.com> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/virtio/virtio-balloon.c | 26 +++++--------------------- 1 file changed, 5 insertions(+), 21 deletions(-) diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c index a78d2d2184..04a7e6c772 100644 --- a/hw/virtio/virtio-balloon.c +++ b/hw/virtio/virtio-balloon.c @@ -117,7 +117,7 @@ static void balloon_deflate_page(VirtIOBalloon *balloon, void *addr = memory_region_get_ram_ptr(mr) + offset; RAMBlock *rb; size_t rb_page_size; - ram_addr_t ram_offset, host_page_base; + ram_addr_t ram_offset; void *host_addr; int ret; @@ -125,27 +125,11 @@ static void balloon_deflate_page(VirtIOBalloon *balloon, * host address? */ rb = qemu_ram_block_from_host(addr, false, &ram_offset); rb_page_size = qemu_ram_pagesize(rb); - host_page_base = ram_offset & ~(rb_page_size - 1); - - if (balloon->pbp - && rb == balloon->pbp->rb - && host_page_base == balloon->pbp->base) { - int subpages = rb_page_size / BALLOON_PAGE_SIZE; - /* - * This means the guest has asked to discard some of the 4kiB - * subpages of a host page, but then changed its mind and - * asked to keep them after all. It's exceedingly unlikely - * for a guest to do this in practice, but handle it anyway, - * since getting it wrong could mean discarding memory the - * guest is still using. */ - clear_bit((ram_offset - balloon->pbp->base) / BALLOON_PAGE_SIZE, - balloon->pbp->bitmap); - - if (bitmap_empty(balloon->pbp->bitmap, subpages)) { - g_free(balloon->pbp); - balloon->pbp = NULL; - } + if (balloon->pbp) { + /* Let's play safe and always reset the pbp on deflation requests. */ + g_free(balloon->pbp); + balloon->pbp = NULL; } host_addr = (void *)((uintptr_t)addr & ~(rb_page_size - 1)); -- MST