From nobody Tue Oct 28 04:10:08 2025 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.zohomail.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 151559444963371.79747326032827; Wed, 10 Jan 2018 06:27:29 -0800 (PST) Received: from localhost ([::1]:45058 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eZHLk-0004vR-S2 for importer@patchew.org; Wed, 10 Jan 2018 09:27:28 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53780) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eZHJq-0003j5-GQ for qemu-devel@nongnu.org; Wed, 10 Jan 2018 09:25:31 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eZHJn-0000Zp-2k for qemu-devel@nongnu.org; Wed, 10 Jan 2018 09:25:30 -0500 Received: from mx1.redhat.com ([209.132.183.28]:54149) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eZHJm-0000Z7-LE for qemu-devel@nongnu.org; Wed, 10 Jan 2018 09:25:26 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id BBEA14E907 for ; Wed, 10 Jan 2018 14:25:25 +0000 (UTC) Received: from donizetti.mxp.redhat.com (unknown [10.32.181.235]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2D67F6A96F; Wed, 10 Jan 2018 14:25:20 +0000 (UTC) From: Paolo Bonzini To: qemu-devel@nongnu.org Date: Wed, 10 Jan 2018 15:25:14 +0100 Message-Id: <20180110142515.13242-2-pbonzini@redhat.com> In-Reply-To: <20180110142515.13242-1-pbonzini@redhat.com> References: <20180110142515.13242-1-pbonzini@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Wed, 10 Jan 2018 14:25:25 +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] [PATCH 1/2] find_ram_offset: Add comments and tracing 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: dgilbert@redhat.com, quintela@redhat.com 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" Add some comments and rename the "end" variable so I can understand the various nested loops. Add some tracing so I can see what they're doing. Signed-off-by: Dr. David Alan Gilbert Message-Id: <20180105170138.23357-2-dgilbert@redhat.com> Signed-off-by: Paolo Bonzini --- exec.c | 29 ++++++++++++++++++++++------- trace-events | 4 ++++ 2 files changed, 26 insertions(+), 7 deletions(-) diff --git a/exec.c b/exec.c index ff31e7165f..829f9d8d1a 100644 --- a/exec.c +++ b/exec.c @@ -1661,7 +1661,10 @@ static void *file_ram_alloc(RAMBlock *block, } #endif =20 -/* Called with the ramlist lock held. */ +/* Allocate space within the ram_addr_t space that governs the + * dirty bitmaps. + * Called with the ramlist lock held. + */ static ram_addr_t find_ram_offset(ram_addr_t size) { RAMBlock *block, *next_block; @@ -1674,19 +1677,29 @@ static ram_addr_t find_ram_offset(ram_addr_t size) } =20 RAMBLOCK_FOREACH(block) { - ram_addr_t end, next =3D RAM_ADDR_MAX; + ram_addr_t candidate, next =3D RAM_ADDR_MAX; =20 - end =3D block->offset + block->max_length; + candidate =3D block->offset + block->max_length; =20 + /* Search for the closest following block + * and find the gap. + */ RAMBLOCK_FOREACH(next_block) { - if (next_block->offset >=3D end) { + if (next_block->offset >=3D candidate) { next =3D MIN(next, next_block->offset); } } - if (next - end >=3D size && next - end < mingap) { - offset =3D end; - mingap =3D next - end; + + /* If it fits remember our place and remember the size + * of gap, but keep going so that we might find a smaller + * gap to fill so avoiding fragmentation. + */ + if (next - candidate >=3D size && next - candidate < mingap) { + offset =3D candidate; + mingap =3D next - candidate; } + + trace_find_ram_offset_loop(size, candidate, offset, next, mingap); } =20 if (offset =3D=3D RAM_ADDR_MAX) { @@ -1695,6 +1708,8 @@ static ram_addr_t find_ram_offset(ram_addr_t size) abort(); } =20 + trace_find_ram_offset(size, offset); + return offset; } =20 diff --git a/trace-events b/trace-events index 3695959d0a..a676b02a20 100644 --- a/trace-events +++ b/trace-events @@ -55,6 +55,10 @@ 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 +find_ram_offset(uint64_t size, uint64_t offset) "size: 0x%"PRIx64 " @ 0x%"= PRIx64 +find_ram_offset_loop(uint64_t size, uint64_t candidate, uint64_t offset, u= int64_t next, uint64_t mingap) "trying size: 0x%"PRIx64 " @ 0x%"PRIx64 ," o= ffset: 0x%"PRIx64" next: 0x%"PRIx64 " mingap: 0x%"PRIx64 + # 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 0x%"PRIx64" value 0x%"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 0x%"PRIx64" value 0x%"PRIx64" size = %u" --=20 2.14.3