From nobody Sat Feb 7 22:55:15 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1498676599087501.0713282347431; Wed, 28 Jun 2017 12:03:19 -0700 (PDT) Received: from localhost ([::1]:35251 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dQIFB-0005XE-Ll for importer@patchew.org; Wed, 28 Jun 2017 15:03:17 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40181) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dQIDM-0004Iq-QO for qemu-devel@nongnu.org; Wed, 28 Jun 2017 15:01:25 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dQIDH-0007yE-Uj for qemu-devel@nongnu.org; Wed, 28 Jun 2017 15:01:24 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45556) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dQIDH-0007y0-LX for qemu-devel@nongnu.org; Wed, 28 Jun 2017 15:01:19 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 6F2E230AF51; Wed, 28 Jun 2017 19:01:18 +0000 (UTC) Received: from dgilbert-t530.redhat.com (ovpn-117-210.ams2.redhat.com [10.36.117.210]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2167C17D5D; Wed, 28 Jun 2017 19:01:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 6F2E230AF51 Authentication-Results: ext-mx05.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx05.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=dgilbert@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 6F2E230AF51 From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, a.perevalov@samsung.com, marcandre.lureau@redhat.com, maxime.coquelin@redhat.com, mst@redhat.com, quintela@redhat.com, peterx@redhat.com, lvivier@redhat.com, aarcange@redhat.com Date: Wed, 28 Jun 2017 20:00:20 +0100 Message-Id: <20170628190047.26159-3-dgilbert@redhat.com> In-Reply-To: <20170628190047.26159-1-dgilbert@redhat.com> References: <20170628190047.26159-1-dgilbert@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Wed, 28 Jun 2017 19:01:18 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [RFC 02/29] migrate: Update ram_block_discard_range for shared 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: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" From: "Dr. David Alan Gilbert" The choice of call to discard a block is getting more complicated for other cases. We use fallocate PUNCH_HOLE in any file cases; it works for both hugepage and for tmpfs. We use the DONTNEED for non-hugepage cases either where they're anonymous or where they're private. Care should be taken when trying other backing files. Signed-off-by: Dr. David Alan Gilbert --- exec.c | 28 ++++++++++++++++------------ trace-events | 3 +++ 2 files changed, 19 insertions(+), 12 deletions(-) diff --git a/exec.c b/exec.c index 69fc5c9b07..4e61226a16 100644 --- a/exec.c +++ b/exec.c @@ -3557,6 +3557,7 @@ int ram_block_discard_range(RAMBlock *rb, uint64_t st= art, size_t length) } =20 if ((start + length) <=3D rb->used_length) { + bool need_madvise, need_fallocate; uint8_t *host_endaddr =3D host_startaddr + length; if ((uintptr_t)host_endaddr & (rb->page_size - 1)) { error_report("ram_block_discard_range: Unaligned end address: = %p", @@ -3566,23 +3567,26 @@ int ram_block_discard_range(RAMBlock *rb, uint64_t = start, size_t length) =20 errno =3D ENOTSUP; /* If we are missing MADVISE etc */ =20 - if (rb->page_size =3D=3D qemu_host_page_size) { -#if defined(CONFIG_MADVISE) - /* Note: We need the madvise MADV_DONTNEED behaviour of defini= tely - * freeing the page. - */ - ret =3D madvise(host_startaddr, length, MADV_DONTNEED); -#endif - } else { - /* Huge page case - unfortunately it can't do DONTNEED, but - * it can do the equivalent by FALLOC_FL_PUNCH_HOLE in the - * huge page file. - */ + /* The logic here is messy; + * madvise DONTNEED fails for hugepages + * fallocate works on hugepages and shmem + */ + need_madvise =3D (rb->page_size =3D=3D qemu_host_page_size) && + (rb->fd =3D=3D -1 || !(rb->flags & RAM_SHARED)); + need_fallocate =3D rb->fd !=3D -1; + if (ret =3D=3D -1 && need_fallocate) { #ifdef CONFIG_FALLOCATE_PUNCH_HOLE ret =3D fallocate(rb->fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEE= P_SIZE, start, length); #endif } + if (need_madvise && (!need_fallocate || (ret =3D=3D 0))) { +#if defined(CONFIG_MADVISE) + ret =3D madvise(host_startaddr, length, MADV_DONTNEED); +#endif + } + trace_ram_block_discard_range(rb->idstr, host_startaddr, + need_madvise, need_fallocate, ret); if (ret) { ret =3D -errno; error_report("ram_block_discard_range: Failed to discard range= " diff --git a/trace-events b/trace-events index bae63fdb1d..2c6e8d2160 100644 --- a/trace-events +++ b/trace-events @@ -55,6 +55,9 @@ dma_complete(void *dbs, int ret, void *cb) "dbs=3D%p ret= =3D%d cb=3D%p" dma_blk_cb(void *dbs, int ret) "dbs=3D%p ret=3D%d" dma_map_wait(void *dbs) "dbs=3D%p" =20 +# exec.c +ram_block_discard_range(const char *rbname, void *hva, bool need_madvise, = bool need_fallocate, int ret) "%s@%p: madvise: %d fallocate: %d ret: %d" + # memory.c memory_region_ops_read(int cpu_index, void *mr, uint64_t addr, uint64_t va= lue, unsigned size) "cpu %d mr %p addr %#"PRIx64" value %#"PRIx64" size %u" memory_region_ops_write(int cpu_index, void *mr, uint64_t addr, uint64_t v= alue, unsigned size) "cpu %d mr %p addr %#"PRIx64" value %#"PRIx64" size %u" --=20 2.13.0