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=-13.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 3C104C433E1 for ; Thu, 27 Aug 2020 07:27:04 +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 125D122BEA for ; Thu, 27 Aug 2020 07:27:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 125D122BEA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:58604 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kBCJL-0001KT-7Z for qemu-devel@archiver.kernel.org; Thu, 27 Aug 2020 03:27:03 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:49018) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kBBOa-00023E-8G for qemu-devel@nongnu.org; Thu, 27 Aug 2020 02:28:24 -0400 Received: from szxga06-in.huawei.com ([45.249.212.32]:49270 helo=huawei.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kBBOX-0007BO-4w for qemu-devel@nongnu.org; Thu, 27 Aug 2020 02:28:23 -0400 Received: from DGGEMS405-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id 7C7CD1869C1F422EE26F; Thu, 27 Aug 2020 14:28:13 +0800 (CST) Received: from [127.0.0.1] (10.174.186.4) by DGGEMS405-HUB.china.huawei.com (10.3.19.205) with Microsoft SMTP Server id 14.3.487.0; Thu, 27 Aug 2020 14:28:04 +0800 From: Zheng Chuan Subject: Re: [PATCH v5 06/12] migration/dirtyrate: Record hash results for each sampled page To: "Dr. David Alan Gilbert" , David Edmondson References: <1598260480-64862-1-git-send-email-zhengchuan@huawei.com> <1598260480-64862-7-git-send-email-zhengchuan@huawei.com> <20200826123016.GA2727@work-vm> Message-ID: Date: Thu, 27 Aug 2020 14:28:03 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <20200826123016.GA2727@work-vm> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.186.4] X-CFilter-Loop: Reflected Received-SPF: pass client-ip=45.249.212.32; envelope-from=zhengchuan@huawei.com; helo=huawei.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/27 02:28:14 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] X-Spam_score_int: -63 X-Spam_score: -6.4 X-Spam_bar: ------ X-Spam_report: (-6.4 / 5.0 requ) BAYES_00=-1.9, NICE_REPLY_A=-2.239, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no 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: berrange@redhat.com, zhang.zhanghailiang@huawei.com, quintela@redhat.com, qemu-devel@nongnu.org, xiexiangyou@huawei.com, alex.chen@huawei.com, ann.zhuangyanying@huawei.com, fangying1@huawei.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 2020/8/26 20:30, Dr. David Alan Gilbert wrote: > * David Edmondson (dme@dme.org) wrote: >> On Monday, 2020-08-24 at 17:14:34 +08, Chuan Zheng wrote: >> >>> Record hash results for each sampled page, crc32 is taken to calculate >>> hash results for each sampled 4K-page. >>> >>> Signed-off-by: Chuan Zheng >>> Signed-off-by: YanYing Zhuang >>> --- >>> migration/dirtyrate.c | 136 ++++++++++++++++++++++++++++++++++++++++++++++++++ >>> migration/dirtyrate.h | 15 ++++++ >>> 2 files changed, 151 insertions(+) >>> >>> diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c >>> index f6a94d8..66de426 100644 >>> --- a/migration/dirtyrate.c >>> +++ b/migration/dirtyrate.c >>> @@ -10,6 +10,7 @@ >>> * See the COPYING file in the top-level directory. >>> */ >>> >>> +#include >>> #include "qemu/osdep.h" >>> #include "qapi/error.h" >>> #include "crypto/hash.h" >>> @@ -66,6 +67,141 @@ static void update_dirtyrate(uint64_t msec) >>> DirtyStat.dirty_rate = dirtyrate; >>> } >>> >>> +/* >>> + * get hash result for the sampled memory with length of 4K byte in ramblock, >>> + * which starts from ramblock base address. >>> + */ >>> +static uint32_t get_ramblock_vfn_hash(struct RamblockDirtyInfo *info, >>> + uint64_t vfn) >>> +{ >>> + struct iovec iov_array; >> >> There's no need for an iovec now that crc32() is being used. >> OK, will take two variables instead to represent base address and length. >>> + uint32_t crc; >>> + >>> + iov_array.iov_base = info->ramblock_addr + >>> + vfn * DIRTYRATE_SAMPLE_PAGE_SIZE; >>> + iov_array.iov_len = DIRTYRATE_SAMPLE_PAGE_SIZE; >>> + >>> + crc = crc32(0, iov_array.iov_base, iov_array.iov_len); >>> + >>> + return crc; >>> +} >>> + >>> +static int save_ramblock_hash(struct RamblockDirtyInfo *info) >>> +{ >>> + unsigned int sample_pages_count; >>> + int i; >>> + int ret = -1; >> >> There's no need to initialise "ret". >> >>> + GRand *rand = g_rand_new(); >> >> Calling g_rand_new() when the result may not be used (because of the >> various conditions immediately below) seems as though it might waste >> entropy. Could this be pushed down just above the loop? It would even >> get rid of the gotos ;-) >> OK, i'll try it. >>> + sample_pages_count = info->sample_pages_count; >>> + >>> + /* ramblock size less than one page, return success to skip this ramblock */ >>> + if (unlikely(info->ramblock_pages == 0 || sample_pages_count == 0)) { >>> + ret = 0; >>> + goto out; >>> + } >>> + >>> + info->hash_result = g_try_malloc0_n(sample_pages_count, >>> + sizeof(uint32_t)); >>> + if (!info->hash_result) { >>> + ret = -1; >>> + goto out; >>> + } >>> + >>> + info->sample_page_vfn = g_try_malloc0_n(sample_pages_count, >>> + sizeof(uint64_t)); >>> + if (!info->sample_page_vfn) { >>> + g_free(info->hash_result); >>> + ret = -1; >>> + goto out; >>> + } >>> + >>> + for (i = 0; i < sample_pages_count; i++) { >>> + info->sample_page_vfn[i] = g_rand_int_range(rand, 0, >>> + info->ramblock_pages - 1); >>> + info->hash_result[i] = get_ramblock_vfn_hash(info, >>> + info->sample_page_vfn[i]); >>> + } >>> + ret = 0; >>> + >>> +out: >>> + g_rand_free(rand); >>> + return ret; >>> +} >>> + >>> +static void get_ramblock_dirty_info(RAMBlock *block, >>> + struct RamblockDirtyInfo *info, >>> + struct DirtyRateConfig *config) >>> +{ >>> + uint64_t sample_pages_per_gigabytes = config->sample_pages_per_gigabytes; >>> + >>> + /* Right shift 30 bits to calc block size in GB */ >>> + info->sample_pages_count = (qemu_ram_get_used_length(block) * >>> + sample_pages_per_gigabytes) >> >>> + DIRTYRATE_PAGE_SHIFT_GB; >> >> Doing the calculation this way around seems odd. Why was it not: >> >> info->sample_pages_count = (qemu_ram_get_used_length(block) >> >> DIRTYRATE_PAGE_SHIFT_GB) * >> sample_pages_per_gigabytes; >> >> ? > > Because that would give 0 for a 0.5GB block > > Dave > >>> + >>> + /* Right shift 12 bits to calc page count in 4KB */ >>> + info->ramblock_pages = qemu_ram_get_used_length(block) >> >>> + DIRTYRATE_PAGE_SHIFT_KB; >>> + info->ramblock_addr = qemu_ram_get_host_addr(block); >>> + strcpy(info->idstr, qemu_ram_get_idstr(block)); >>> +} >>> + >>> +static struct RamblockDirtyInfo * >>> +alloc_ramblock_dirty_info(int *block_index, >>> + struct RamblockDirtyInfo *block_dinfo) >>> +{ >>> + struct RamblockDirtyInfo *info = NULL; >>> + int index = *block_index; >>> + >>> + if (!block_dinfo) { >>> + index = 0; >>> + block_dinfo = g_try_new(struct RamblockDirtyInfo, 1); >>> + } else { >>> + index++; >>> + block_dinfo = g_try_realloc(block_dinfo, (index + 1) * >>> + sizeof(struct RamblockDirtyInfo)); >> >> g_try_renew() instead of g_try_realloc()? >> Hi, I am not sure that because there only one place in qemu to use g_try_renew. Could you tell me why, because i think g_try_realloc will also return NULL when error happen:) >>> + } >>> + if (!block_dinfo) { >>> + return NULL; >>> + } >>> + >>> + info = &block_dinfo[index]; >>> + *block_index = index; >>> + memset(info, 0, sizeof(struct RamblockDirtyInfo)); >>> + >>> + return block_dinfo; >>> +} >>> + >>> +static int record_ramblock_hash_info(struct RamblockDirtyInfo **block_dinfo, >>> + struct DirtyRateConfig config, >>> + int *block_index) >>> +{ >>> + struct RamblockDirtyInfo *info = NULL; >>> + struct RamblockDirtyInfo *dinfo = NULL; >>> + RAMBlock *block = NULL; >> >> There's no need to initialise "info" or "block". >> OK, will remove unused initialization in V6. >> The declaration of "info" could be pushed into the loop. >> >>> + int index = 0; >>> + >>> + RAMBLOCK_FOREACH_MIGRATABLE(block) { >>> + dinfo = alloc_ramblock_dirty_info(&index, dinfo); >>> + if (dinfo == NULL) { >>> + return -1; >>> + } >>> + info = &dinfo[index]; >>> + get_ramblock_dirty_info(block, info, &config); >>> + if (save_ramblock_hash(info) < 0) { >>> + *block_dinfo = dinfo; >>> + *block_index = index; >>> + return -1; >>> + } >>> + } >>> + >>> + *block_dinfo = dinfo; >>> + *block_index = index; >>> + >>> + return 0; >>> +} >>> + >>> static void calculate_dirtyrate(struct DirtyRateConfig config) >>> { >>> /* todo */ >>> diff --git a/migration/dirtyrate.h b/migration/dirtyrate.h >>> index 9db269d..5050add 100644 >>> --- a/migration/dirtyrate.h >>> +++ b/migration/dirtyrate.h >>> @@ -24,6 +24,21 @@ >>> */ >>> #define RAMBLOCK_INFO_MAX_LEN 256 >>> >>> +/* >>> + * Sample page size 4K as default. >>> + */ >>> +#define DIRTYRATE_SAMPLE_PAGE_SIZE 4096 >>> + >>> +/* >>> + * Sample page size 4K shift >>> + */ >>> +#define DIRTYRATE_PAGE_SHIFT_KB 12 >>> + >>> +/* >>> + * Sample page size 1G shift >>> + */ >>> +#define DIRTYRATE_PAGE_SHIFT_GB 30 >>> + >>> /* Take 1s as default for calculation duration */ >>> #define DEFAULT_FETCH_DIRTYRATE_TIME_SEC 1 >>> >>> -- >>> 1.8.3.1 >> >> dme. >> -- >> You bring light in. >>