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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,T_HK_NAME_DR, URIBL_BLOCKED,USER_AGENT_MUTT 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 67E1AC04AB4 for ; Tue, 14 May 2019 14:22:42 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 393FB21473 for ; Tue, 14 May 2019 14:22:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 393FB21473 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 ([127.0.0.1]:48932 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hQYKH-00073W-G1 for qemu-devel@archiver.kernel.org; Tue, 14 May 2019 10:22:41 -0400 Received: from eggs.gnu.org ([209.51.188.92]:36728) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hQYJ3-0006bg-Fw for qemu-devel@nongnu.org; Tue, 14 May 2019 10:21:26 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hQYJ2-000801-BY for qemu-devel@nongnu.org; Tue, 14 May 2019 10:21:25 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53680) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hQYJ2-0007xg-3X for qemu-devel@nongnu.org; Tue, 14 May 2019 10:21:24 -0400 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 4CE45301BE65; Tue, 14 May 2019 14:21:13 +0000 (UTC) Received: from work-vm (ovpn-117-232.ams2.redhat.com [10.36.117.232]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 49BBF608AC; Tue, 14 May 2019 14:21:11 +0000 (UTC) Date: Tue, 14 May 2019 15:21:08 +0100 From: "Dr. David Alan Gilbert" To: Wei Yang , pbonzini@redhat.com Message-ID: <20190514142108.GG2753@work-vm> References: <20190430034412.12935-1-richardw.yang@linux.intel.com> <20190430034412.12935-3-richardw.yang@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190430034412.12935-3-richardw.yang@linux.intel.com> User-Agent: Mutt/1.11.4 (2019-03-13) 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 [10.5.110.47]); Tue, 14 May 2019 14:21:18 +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: Re: [Qemu-devel] [PATCH 2/3] migration/ram.c: start of cpu_physical_memory_sync_dirty_bitmap is always 0 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: qemu-devel@nongnu.org, quintela@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Wei Yang (richardw.yang@linux.intel.com) wrote: > Since start of cpu_physical_memory_sync_dirty_bitmap is always 0, we can > remove this parameter and simplify the calculation a bit. > > Signed-off-by: Wei Yang So I think you're right it's currently unused; however, lets ask Paolo: Do we need to keep this parameter for flexiblity? Dave > --- > include/exec/ram_addr.h | 15 ++++++--------- > migration/ram.c | 2 +- > 2 files changed, 7 insertions(+), 10 deletions(-) > > diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h > index 9ecd911c3e..3dfb2d52fb 100644 > --- a/include/exec/ram_addr.h > +++ b/include/exec/ram_addr.h > @@ -409,18 +409,16 @@ static inline void cpu_physical_memory_clear_dirty_range(ram_addr_t start, > > static inline > uint64_t cpu_physical_memory_sync_dirty_bitmap(RAMBlock *rb, > - ram_addr_t start, > ram_addr_t length, > uint64_t *real_dirty_pages) > { > ram_addr_t addr; > - unsigned long word = BIT_WORD((start + rb->offset) >> TARGET_PAGE_BITS); > + unsigned long word = BIT_WORD(rb->offset >> TARGET_PAGE_BITS); > uint64_t num_dirty = 0; > unsigned long *dest = rb->bmap; > > - /* start address and length is aligned at the start of a word? */ > - if (((word * BITS_PER_LONG) << TARGET_PAGE_BITS) == > - (start + rb->offset) && > + /* offset and length is aligned at the start of a word? */ > + if (((word * BITS_PER_LONG) << TARGET_PAGE_BITS) == (rb->offset) && > !(length & ((BITS_PER_LONG << TARGET_PAGE_BITS) - 1))) { > int k; > int nr = BITS_TO_LONGS(length >> TARGET_PAGE_BITS); > @@ -428,14 +426,13 @@ uint64_t cpu_physical_memory_sync_dirty_bitmap(RAMBlock *rb, > unsigned long idx = (word * BITS_PER_LONG) / DIRTY_MEMORY_BLOCK_SIZE; > unsigned long offset = BIT_WORD((word * BITS_PER_LONG) % > DIRTY_MEMORY_BLOCK_SIZE); > - unsigned long page = BIT_WORD(start >> TARGET_PAGE_BITS); > > rcu_read_lock(); > > src = atomic_rcu_read( > &ram_list.dirty_memory[DIRTY_MEMORY_MIGRATION])->blocks; > > - for (k = page; k < page + nr; k++) { > + for (k = 0; k < nr; k++) { > if (src[idx][offset]) { > unsigned long bits = atomic_xchg(&src[idx][offset], 0); > unsigned long new_dirty; > @@ -458,11 +455,11 @@ uint64_t cpu_physical_memory_sync_dirty_bitmap(RAMBlock *rb, > > for (addr = 0; addr < length; addr += TARGET_PAGE_SIZE) { > if (cpu_physical_memory_test_and_clear_dirty( > - start + addr + offset, > + addr + offset, > TARGET_PAGE_SIZE, > DIRTY_MEMORY_MIGRATION)) { > *real_dirty_pages += 1; > - long k = (start + addr) >> TARGET_PAGE_BITS; > + long k = addr >> TARGET_PAGE_BITS; > if (!test_and_set_bit(k, dest)) { > num_dirty++; > } > diff --git a/migration/ram.c b/migration/ram.c > index 9948b2d021..1def8122e9 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -1646,7 +1646,7 @@ static void migration_bitmap_sync_range(RAMState *rs, RAMBlock *rb, > ram_addr_t length) > { > rs->migration_dirty_pages += > - cpu_physical_memory_sync_dirty_bitmap(rb, 0, length, > + cpu_physical_memory_sync_dirty_bitmap(rb, length, > &rs->num_dirty_pages_period); > } > > -- > 2.19.1 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK