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Date:   Thu, 27 Jun 2019 17:28:54 +0200
From:   David Sterba <dsterba@suse.cz>
To:     Naohiro Aota <Naohiro.Aota@wdc.com>
Cc:     "dsterba@suse.cz" <dsterba@suse.cz>,
        "linux-btrfs@vger.kernel.org" <linux-btrfs@vger.kernel.org>,
        David Sterba <dsterba@suse.com>, Chris Mason <clm@fb.com>,
        Josef Bacik <josef@toxicpanda.com>, Qu Wenruo <wqu@suse.com>,
        Nikolay Borisov <nborisov@suse.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Hannes Reinecke <hare@suse.com>,
        "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
        Damien Le Moal <Damien.LeMoal@wdc.com>,
        Matias =?iso-8859-1?Q?Bj=F8rling?= <mb@lightnvm.io>,
        Johannes Thumshirn <jthumshirn@suse.de>,
        Bart Van Assche <bvanassche@acm.org>
Subject: Re: [PATCH 07/19] btrfs: do sequential extent allocation in HMZONED
 mode
Message-ID: <20190627152854.GC20977@twin.jikos.cz>
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On Tue, Jun 18, 2019 at 08:49:00AM +0000, Naohiro Aota wrote:
> On 2019/06/18 7:29, David Sterba wrote:
> > On Fri, Jun 07, 2019 at 10:10:13PM +0900, Naohiro Aota wrote:
> >> +	u64 unusable;
> > 
> > 'unusable' is specific to the zones, so 'zone_unusable' would make it
> > clear. The terminilogy around space is confusing already (we have
> > unused, free, reserved, allocated, slack).
> 
> Sure. I will change the name.
> 
> Or, is it better toadd new struct "btrfs_seq_alloc_info" and move all
> these variable there? Then, I can just add one pointer to the struct here.

There are 4 new members, but the block group structure is large already
(528 bytes) so adding a few more will not make the allocations worse.
There are also holes or inefficient types used so the size can be
squeezed a bit, but this is unrelated to this patchset.