From: Greg KH <gregkh@linuxfoundation.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH] char_dev: replace cdev_map with an xarray
Date: Mon, 11 Jan 2021 19:11:25 +0100 [thread overview]
Message-ID: <X/yUzVu04TyVuU/f@kroah.com> (raw)
In-Reply-To: <20210111173500.GG35215@casper.infradead.org>
On Mon, Jan 11, 2021 at 05:35:00PM +0000, Matthew Wilcox wrote:
> On Mon, Jan 11, 2021 at 06:05:13PM +0100, Christoph Hellwig wrote:
> > None of the complicated overlapping regions bits of the kobj_map are
> > required for the character device lookup, so just a trivial xarray
> > instead.
>
> Thanks for doing this. We could make it more efficient for chardevs
> that occupy 64 or more consecutive/aligned devices -- is it worth doing?
efficient in what way? Space or faster lookup?
THis shouldn't be on a "fast" lookup path, so I doubt that's worth
optimizing for. Space, maybe, for systems with thousands of scsi
devices, but usually they just stick to the block device, not a char
device from what I remember.
thanks,
greg k-h
next prev parent reply other threads:[~2021-01-11 18:12 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-11 17:05 [PATCH] char_dev: replace cdev_map with an xarray Christoph Hellwig
2021-01-11 17:35 ` Matthew Wilcox
2021-01-11 18:11 ` Greg KH [this message]
2021-01-11 18:20 ` Matthew Wilcox
2021-01-11 18:33 ` Greg KH
2021-01-11 18:51 ` Matthew Wilcox
2021-01-11 18:10 ` Greg KH
2021-01-11 20:58 ` Matthew Wilcox
2021-01-12 9:35 ` Greg KH
2021-01-12 10:00 ` David Laight
2021-01-12 10:25 ` 'Greg KH'
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