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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,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 E22C2C2D0DC for ; Thu, 2 Jan 2020 16:57:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B205A2072C for ; Thu, 2 Jan 2020 16:57:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577984257; bh=uW8jGUr138pGm3jI/CFcv9YGrafX9pkUNwRhPXAL3Lg=; h=Date:From:To:Subject:References:In-Reply-To:List-ID:From; b=biCF1ywStb4D7wBWliXn5VZdgvhCE8CbkRUE+lD/MasrgRCDYkCb0wP3aMsJri8Fq 7BDykydV3Tj4WAklfM7CuMGP/PenZebqUZmHKPTW/TxkclT36UDmkVPhG8j1tSmT01 9YIsm3L5LMAI1Hm5JWNQbwYXcPnoeBKNK2PVCJKo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728879AbgABQ5h (ORCPT ); Thu, 2 Jan 2020 11:57:37 -0500 Received: from mail-qv1-f68.google.com ([209.85.219.68]:33780 "EHLO mail-qv1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728847AbgABQ5g (ORCPT ); Thu, 2 Jan 2020 11:57:36 -0500 Received: by mail-qv1-f68.google.com with SMTP id z3so15239427qvn.0 for ; Thu, 02 Jan 2020 08:57:36 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=oE57YWQpxhB8KxbcsvfbeP4c6czknQZnNzFlx1WhT2A=; b=GZ6isAiq18Dwmfa5Srqx84RRnWa+oau8rduQ1HBU88dIavlk4hDPojlB0nn4k4gw3o R58qopyt/kHkQ82ULzk9Dcwos0sGjKtKdsa/f0H7LuXrhYQ86putAJoz9QN199G0mtPH Xup0458Gx2IaBv7s2S7zTQqJDV4FU9pw2HWou+Q/1fa5P8zantW8NC5wCAVuj1MwdG/i 3JzZt6bAlFPx1WxGVvboXzBPdiiooGMhlTUxcOYa4zd082OUViXkcZInW431ClG3xa8V BlJyUhCAypHYp5xQU6gr+TI9cTegYQpFg9VJjFzR+Gkj1LnKp1BOorgSTOOpwjSq7nkz KKnw== X-Gm-Message-State: APjAAAVdopZG+Q/d1KyQvfd0IuYtxjeIKESsn5Xml1ZeTCs+TpbdlqCu c7tyRSONoO7z0xrepsynPrs= X-Google-Smtp-Source: APXvYqzU73Hp3SjlnpdUWofWxyEXDESM/nkY/6OAdKM/AHleE+pqsK+pEZmfEO+kZpvKNv8iulGlOg== X-Received: by 2002:a05:6214:1907:: with SMTP id er7mr64002382qvb.199.1577984255647; Thu, 02 Jan 2020 08:57:35 -0800 (PST) Received: from dennisz-mbp.dhcp.thefacebook.com ([2620:10d:c091:500::1:29bb]) by smtp.gmail.com with ESMTPSA id t2sm16982119qtn.22.2020.01.02.08.57.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 02 Jan 2020 08:57:34 -0800 (PST) Date: Thu, 2 Jan 2020 11:57:31 -0500 From: Dennis Zhou To: dsterba@suse.cz, David Sterba , Chris Mason , Josef Bacik , Omar Sandoval , kernel-team@fb.com, linux-btrfs@vger.kernel.org Subject: Re: [PATCH 19/22] btrfs: keep track of discard reuse stats Message-ID: <20200102165731.GF86832@dennisz-mbp.dhcp.thefacebook.com> References: <20191230173352.GW3929@twin.jikos.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191230173352.GW3929@twin.jikos.cz> User-Agent: Mutt/1.12.2 (2019-09-21) Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org Archived-At: List-Archive: List-Post: On Mon, Dec 30, 2019 at 06:33:52PM +0100, David Sterba wrote: > On Fri, Dec 13, 2019 at 04:22:28PM -0800, Dennis Zhou wrote: > > Keep track of how much we are discarding and how often we are reusing > > with async discard. > > > > Signed-off-by: Dennis Zhou > > Reviewed-by: Josef Bacik > > --- > > fs/btrfs/ctree.h | 3 +++ > > fs/btrfs/discard.c | 7 +++++++ > > fs/btrfs/free-space-cache.c | 14 ++++++++++++++ > > fs/btrfs/sysfs.c | 36 ++++++++++++++++++++++++++++++++++++ > > 4 files changed, 60 insertions(+) > > > > diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h > > index dddf51e27bed..edfbe6060e8d 100644 > > --- a/fs/btrfs/ctree.h > > +++ b/fs/btrfs/ctree.h > > @@ -474,6 +474,9 @@ struct btrfs_discard_ctl { > > u32 delay; > > u32 iops_limit; > > u64 bps_limit; > > + u64 discard_extent_bytes; > > + u64 discard_bitmap_bytes; > > + atomic64_t discard_bytes_saved; > > }; > > > > /* delayed seq elem */ > > diff --git a/fs/btrfs/discard.c b/fs/btrfs/discard.c > > index 55ad357e65f3..fe73814526ef 100644 > > --- a/fs/btrfs/discard.c > > +++ b/fs/btrfs/discard.c > > @@ -419,11 +419,15 @@ static void btrfs_discard_workfn(struct work_struct *work) > > block_group->discard_cursor, > > btrfs_block_group_end(block_group), > > minlen, maxlen, true); > > + WRITE_ONCE(discard_ctl->discard_bitmap_bytes, > > + discard_ctl->discard_bitmap_bytes + trimmed); > > The same argument is used for read and write, this does not seem to be a > clear usage pattern for WRITE_ONCE, is there are cleaner way to do that? > Yeah that doesn't really make any sense. I think we are okay here anyway as btrfs_discard_workfn() provides synchronization by being a single work item. So, I've removed the WRITE_ONCE. > > } else { > > btrfs_trim_block_group_extents(block_group, &trimmed, > > block_group->discard_cursor, > > btrfs_block_group_end(block_group), > > minlen, true); > > + WRITE_ONCE(discard_ctl->discard_extent_bytes, > > + discard_ctl->discard_extent_bytes + trimmed);