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To:     Christoph Hellwig <hch@lst.de>
Cc:     Jens Axboe <axboe@kernel.dk>, Song Liu <song@kernel.org>,
        Hans de Goede <hdegoede@redhat.com>,
        Coly Li <colyli@suse.de>, Richard Weinberger <richard@nod.at>,
        Minchan Kim <minchan@kernel.org>,
        Johannes Thumshirn <Johannes.Thumshirn@wdc.com>,
        Justin Sanders <justin@coraid.com>,
        linux-mtd@lists.infradead.org, dm-devel@redhat.com,
        linux-block@vger.kernel.org, linux-bcache@vger.kernel.org,
        linux-kernel@vger.kernel.org, drbd-dev@tron.linbit.com,
        linux-raid@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-mm@kvack.org, cgroups@vger.kernel.org
Subject: Re: [PATCH 07/13] block: lift setting the readahead size into the
 block layer
From:   "Martin K. Petersen" <martin.petersen@oracle.com>
Organization: Oracle Corporation
Message-ID: <yq1y2kzkw1h.fsf@ca-mkp.ca.oracle.com>
References: <20200924065140.726436-1-hch@lst.de>
        <20200924065140.726436-8-hch@lst.de>
Date:   Thu, 24 Sep 2020 11:57:14 -0400
In-Reply-To: <20200924065140.726436-8-hch@lst.de> (Christoph Hellwig's message
        of "Thu, 24 Sep 2020 08:51:34 +0200")
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk


Christoph,

> Drivers shouldn't really mess with the readahead size, as that is a VM
> concept.  Instead set it based on the optimal I/O size by lifting the
> algorithm from the md driver when registering the disk.  Also set
> bdi->io_pages there as well by applying the same scheme based on
> max_sectors.  To ensure the limits work well for stacking drivers a
> new helper is added to update the readahead limits from the block
> limits, which is also called from disk_stack_limits.

Looks good!

Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>

-- 
Martin K. Petersen	Oracle Linux Engineering