From patchwork Thu Jun 24 18:04:17 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Paolo Bonzini X-Patchwork-Id: 12342725 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=-16.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 0D831C49EA6 for ; Thu, 24 Jun 2021 18:12:16 +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 825C460FD8 for ; Thu, 24 Jun 2021 18:12:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 825C460FD8 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 ([::1]:60746 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lwTpk-0003of-KD for qemu-devel@archiver.kernel.org; Thu, 24 Jun 2021 14:12:12 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51678) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lwTiQ-00081B-8D; Thu, 24 Jun 2021 14:04:39 -0400 Received: from mail-ej1-x629.google.com ([2a00:1450:4864:20::629]:35808) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1lwTiJ-0001SJ-Rs; Thu, 24 Jun 2021 14:04:37 -0400 Received: by mail-ej1-x629.google.com with SMTP id gn32so10930876ejc.2; Thu, 24 Jun 2021 11:04:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=XzrbbkEGL9DUDKoP6G9+FXKiRtPajUq/O5vyZRD1tS4=; b=awr+BAkN5scwFViKHAvpUqN8lx1NSYBZguAnrGrHj/s7Sgqvy7Ee2AHhFCQHQDP80E EuUrIf9pP9Tv8QFWBPTMZXaPGTxjrdSCpirJCdz6mOh+PfJiFVDK3nV9ccoZlS5uiu0a lTmpjEwzAnqgK4W6AEK6sJecYa9zxrmct54QjwVNQxdVBDbyC1+fh9JYzU5wTeJSARvt fHaNljZwOKRrDRamzBgeyN935i6IAwgQOS/CWUcx6ThCxG34FiaoBikDuPmkWwQxz5+c haTRcXGS4vg1iTcyQP/HUbYNIeDuLpDPd0TN3And693SlzHQoUHE7x1DDIZLVCxDhrNE jJxg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-transfer-encoding; bh=XzrbbkEGL9DUDKoP6G9+FXKiRtPajUq/O5vyZRD1tS4=; b=WRLnyoSIlbxeXi/eZQxP14i4C6pgZck8fq4vwvlT9n4sjrQH0wFppFw2IAHzM92r1a zq4EIymAb8ln3ywdFxluy2d5YFhrT6IIXfvn0JKrmEVDu1qyo2phsV+rDtKqPn2FGvQ0 HfpF8YjmKcTTjfpuWNOLpSZRAib/CpQAtm8V6X6Pla5dUS+zN5S+3nn7hkVUnVSKA54q KXkB2YFjWhiE6vP9IL+vNNbweYUv/Hz/zvX9/iwTBvWuCS5nuyvcFTqi5ImpFc+UvFQe BQOP+i13NAUzMY7fyojze1rgfk7vIOEkXYYwGQoYG3e+OvVowUnlllwCHcQjP3Uwz0uG gDrQ== X-Gm-Message-State: AOAM531EdWneWpffvwd2ulp23ZlvlcuPKULbkVDMfhbhHIlCZrdajEOW 8+pGKupkTm0FOW7VzFW3nCRWImQKPqA= X-Google-Smtp-Source: ABdhPJwZUIdViLfA/75syoYpnk2qvGt6zidPycs/wJ/swekmSGCMw0AmdMsjPNsB8rZa4oHiB7ft9w== X-Received: by 2002:a17:906:fc6:: with SMTP id c6mr6436973ejk.65.1624557869633; Thu, 24 Jun 2021 11:04:29 -0700 (PDT) Received: from avogadro.lan ([2001:b07:6468:f312:c8dd:75d4:99ab:290a]) by smtp.gmail.com with ESMTPSA id a1sm2436466edt.16.2021.06.24.11.04.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 24 Jun 2021 11:04:29 -0700 (PDT) From: Paolo Bonzini To: qemu-devel@nongnu.org Subject: [PATCH 05/11] block: add max_hw_transfer to BlockLimits Date: Thu, 24 Jun 2021 20:04:17 +0200 Message-Id: <20210624180423.1322165-6-pbonzini@redhat.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210624180423.1322165-1-pbonzini@redhat.com> References: <20210624180423.1322165-1-pbonzini@redhat.com> MIME-Version: 1.0 Received-SPF: pass client-ip=2a00:1450:4864:20::629; envelope-from=paolo.bonzini@gmail.com; helo=mail-ej1-x629.google.com X-Spam_score_int: -14 X-Spam_score: -1.5 X-Spam_bar: - X-Spam_report: (-1.5 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FORGED_FROMDOMAIN=0.25, FREEMAIL_FROM=0.001, HEADER_FROM_DIFFERENT_DOMAINS=0.25, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no 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: mreitz@redhat.com, qemu-block@nongnu.org, mlevitsk@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" For block host devices, I/O can happen through either the kernel file descriptor I/O system calls (preadv/pwritev, io_submit, io_uring) or the SCSI passthrough ioctl SG_IO. In the latter case, the size of each transfer can be limited by the HBA, while for file descriptor I/O the kernel is able to split and merge I/O in smaller pieces as needed. Applying the HBA limits to file descriptor I/O results in more system calls and suboptimal performance, so this patch splits the max_transfer limit in two: max_transfer remains valid and is used in general, while max_hw_transfer is limited to the maximum hardware size. max_hw_transfer can then be included by the scsi-generic driver in the block limits page, to ensure that the stricter hardware limit is used. Signed-off-by: Paolo Bonzini Reviewed-by: Max Reitz --- block/block-backend.c | 13 +++++++++++++ block/file-posix.c | 2 +- block/io.c | 2 ++ hw/scsi/scsi-generic.c | 2 +- include/block/block_int.h | 7 +++++++ include/sysemu/block-backend.h | 1 + 6 files changed, 25 insertions(+), 2 deletions(-) diff --git a/block/block-backend.c b/block/block-backend.c index 6e37582740..deb55c272e 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -1953,6 +1953,19 @@ uint32_t blk_get_request_alignment(BlockBackend *blk) return bs ? bs->bl.request_alignment : BDRV_SECTOR_SIZE; } +/* Returns the maximum hardware transfer length, in bytes; guaranteed nonzero */ +uint64_t blk_get_max_hw_transfer(BlockBackend *blk) +{ + BlockDriverState *bs = blk_bs(blk); + uint64_t max = INT_MAX; + + if (bs) { + max = MIN_NON_ZERO(max, bs->bl.max_hw_transfer); + max = MIN_NON_ZERO(max, bs->bl.max_transfer); + } + return ROUND_DOWN(max, blk_get_request_alignment(blk)); +} + /* Returns the maximum transfer length, in bytes; guaranteed nonzero */ uint32_t blk_get_max_transfer(BlockBackend *blk) { diff --git a/block/file-posix.c b/block/file-posix.c index 6db690baf2..88e58d2863 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -1232,7 +1232,7 @@ static void raw_refresh_limits(BlockDriverState *bs, Error **errp) int ret = sg_get_max_transfer_length(s->fd); if (ret > 0 && ret <= BDRV_REQUEST_MAX_BYTES) { - bs->bl.max_transfer = pow2floor(ret); + bs->bl.max_hw_transfer = pow2floor(ret); } ret = sg_get_max_segments(s->fd); diff --git a/block/io.c b/block/io.c index 323854d063..dd93364258 100644 --- a/block/io.c +++ b/block/io.c @@ -127,6 +127,8 @@ static void bdrv_merge_limits(BlockLimits *dst, const BlockLimits *src) { dst->opt_transfer = MAX(dst->opt_transfer, src->opt_transfer); dst->max_transfer = MIN_NON_ZERO(dst->max_transfer, src->max_transfer); + dst->max_hw_transfer = MIN_NON_ZERO(dst->max_hw_transfer, + src->max_hw_transfer); dst->opt_mem_alignment = MAX(dst->opt_mem_alignment, src->opt_mem_alignment); dst->min_mem_alignment = MAX(dst->min_mem_alignment, diff --git a/hw/scsi/scsi-generic.c b/hw/scsi/scsi-generic.c index b6c4143dc7..665baf900e 100644 --- a/hw/scsi/scsi-generic.c +++ b/hw/scsi/scsi-generic.c @@ -179,7 +179,7 @@ static int scsi_handle_inquiry_reply(SCSIGenericReq *r, SCSIDevice *s, int len) (r->req.cmd.buf[1] & 0x01)) { page = r->req.cmd.buf[2]; if (page == 0xb0) { - uint32_t max_transfer = blk_get_max_transfer(s->conf.blk); + uint64_t max_transfer = blk_get_max_hw_transfer(s->conf.blk); uint32_t max_iov = blk_get_max_iov(s->conf.blk); assert(max_transfer); diff --git a/include/block/block_int.h b/include/block/block_int.h index 057d88b1fc..f1a54db0f8 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -695,6 +695,13 @@ typedef struct BlockLimits { * clamped down. */ uint32_t max_transfer; + /* Maximal hardware transfer length in bytes. Applies whenever + * transfers to the device bypass the kernel I/O scheduler, for + * example with SG_IO. If larger than max_transfer or if zero, + * blk_get_max_hw_transfer will fall back to max_transfer. + */ + uint64_t max_hw_transfer; + /* memory alignment, in bytes so that no bounce buffer is needed */ size_t min_mem_alignment; diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h index 5423e3d9c6..9ac5f7bbd3 100644 --- a/include/sysemu/block-backend.h +++ b/include/sysemu/block-backend.h @@ -208,6 +208,7 @@ void blk_eject(BlockBackend *blk, bool eject_flag); int blk_get_flags(BlockBackend *blk); uint32_t blk_get_request_alignment(BlockBackend *blk); uint32_t blk_get_max_transfer(BlockBackend *blk); +uint64_t blk_get_max_hw_transfer(BlockBackend *blk); int blk_get_max_iov(BlockBackend *blk); void blk_set_guest_block_size(BlockBackend *blk, int align); void *blk_try_blockalign(BlockBackend *blk, size_t size);