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[209.51.188.17]) by mx.google.com with ESMTPS id i23si16498606yba.272.2020.06.16.02.37.45 for (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Tue, 16 Jun 2020 02:37:45 -0700 (PDT) Received-SPF: pass (google.com: domain of qemu-devel-bounces+alex.bennee=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; Authentication-Results: mx.google.com; dkim=fail header.i=@redhat.com header.s=mimecast20190719 header.b=QdRYHoG5; spf=pass (google.com: domain of qemu-devel-bounces+alex.bennee=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom="qemu-devel-bounces+alex.bennee=linaro.org@nongnu.org"; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from localhost ([::1]:43252 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jl82K-0003PY-P9 for alex.bennee@linaro.org; Tue, 16 Jun 2020 05:37:44 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:46138) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jl80g-0001em-N0 for qemu-devel@nongnu.org; Tue, 16 Jun 2020 05:36:03 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:42771 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jl80f-0000No-A0 for qemu-devel@nongnu.org; Tue, 16 Jun 2020 05:36:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1592300160; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=VYHHWc9u8FwNYjbF4kyrTR113dbvf8NpChpRI0AbqT8=; b=QdRYHoG5WEvGcjcWB1v2HUJ4kZJGFIF+K2OZaE/nETSJnHakNUQDIAhVJc+Fl1giX13X0b SUWM3ZzrtIhw9Mi5SCElwvzLeLdKx7X9UhxipPLy9xxw4r0CCs43qbciumrvV3CTs96SOJ TKVCUnBnDBIh2+fnR/HDL8Yv9oNzJkI= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-63-xwkLMQcSOZ-YBlyV9u07QA-1; Tue, 16 Jun 2020 05:35:57 -0400 X-MC-Unique: xwkLMQcSOZ-YBlyV9u07QA-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C12B51937FC4; Tue, 16 Jun 2020 09:35:55 +0000 (UTC) Received: from work-vm (ovpn-112-42.ams2.redhat.com [10.36.112.42]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E6DEB7BA14; Tue, 16 Jun 2020 09:35:53 +0000 (UTC) Date: Tue, 16 Jun 2020 10:35:51 +0100 From: "Dr. David Alan Gilbert" To: Keqian Zhu Subject: Re: [PATCH v2] migration: Count new_dirty instead of real_dirty Message-ID: <20200616093551.GA2790@work-vm> References: <20200616021059.25984-1-zhukeqian1@huawei.com> MIME-Version: 1.0 In-Reply-To: <20200616021059.25984-1-zhukeqian1@huawei.com> User-Agent: Mutt/1.14.0 (2020-05-02) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=207.211.31.120; envelope-from=dgilbert@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/06/16 02:46:07 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN X-Spam_action: no action 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: zhang.zhanghailiang@huawei.com, Paolo Bonzini , Juan Quintela , Chao Fan , qemu-devel@nongnu.org, qemu-arm@nongnu.org, jianjay.zhou@huawei.com, wanghaibin.wang@huawei.com Errors-To: qemu-devel-bounces+alex.bennee=linaro.org@nongnu.org Sender: "Qemu-devel" X-TUID: GFiAPJhSBHf/ * Keqian Zhu (zhukeqian1@huawei.com) wrote: > real_dirty_pages becomes equal to total ram size after dirty log sync > in ram_init_bitmaps, the reason is that the bitmap of ramblock is > initialized to be all set, so old path counts them as "real dirty" at > beginning. > > This causes wrong dirty rate and false positive throttling at the end > of first ram save iteration. > > Signed-off-by: Keqian Zhu Since this function already returns num_dirty, why not just change the caller to increment a counter based off the return value? Can you point to the code which is using this value that triggers the throttle? Dave > --- > Changelog: > > v2: > - use new_dirty_pages instead of accu_dirty_pages. > - adjust commit messages. > > --- > include/exec/ram_addr.h | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h > index 7b5c24e928..a95e2e7c25 100644 > --- a/include/exec/ram_addr.h > +++ b/include/exec/ram_addr.h > @@ -443,7 +443,7 @@ 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) > + uint64_t *new_dirty_pages) > { > ram_addr_t addr; > unsigned long word = BIT_WORD((start + rb->offset) >> TARGET_PAGE_BITS); > @@ -469,7 +469,6 @@ uint64_t cpu_physical_memory_sync_dirty_bitmap(RAMBlock *rb, > if (src[idx][offset]) { > unsigned long bits = atomic_xchg(&src[idx][offset], 0); > unsigned long new_dirty; > - *real_dirty_pages += ctpopl(bits); > new_dirty = ~dest[k]; > dest[k] |= bits; > new_dirty &= bits; > @@ -502,7 +501,6 @@ uint64_t cpu_physical_memory_sync_dirty_bitmap(RAMBlock *rb, > start + addr + offset, > TARGET_PAGE_SIZE, > DIRTY_MEMORY_MIGRATION)) { > - *real_dirty_pages += 1; > long k = (start + addr) >> TARGET_PAGE_BITS; > if (!test_and_set_bit(k, dest)) { > num_dirty++; > @@ -511,6 +509,7 @@ uint64_t cpu_physical_memory_sync_dirty_bitmap(RAMBlock *rb, > } > } > > + *new_dirty_pages += num_dirty; > return num_dirty; > } > #endif > -- > 2.19.1 > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK