Messages in this thread | | | Date | Tue, 1 Apr 2014 21:27:47 +0400 | Subject | Re: [PATCH RFC] drivers/char/mem: byte generating devices and poisoned mappings | From | Konstantin Khlebnikov <> |
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On Tue, Apr 1, 2014 at 8:59 PM, One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> wrote: > On Tue, 01 Apr 2014 01:16:07 +0400 > Konstantin Khlebnikov <koct9i@gmail.com> wrote: > >> This patch adds 256 virtual character devices: /dev/byte0, ..., /dev/byte255. >> Each works like /dev/zero but generates memory filled with particular byte. > > More kernel code for an ultra-obscure corner case that can be done in > user space > > I don't see the point
True. That was a long-planned joke. But at the final moment I've found practical usage for it and overall design became not such funny.
Currently I'm thinking about single-device model proposed by Kirill.
Let's call it /dev/poison. Application can open it, write a poison (up to a page size) and after that this instance will generate pages filled with this pattern. I don't see how this can be done in userspace without major memory/cpu overhead caused by initial memset.
Default poison might be for example 0xff, so it still will be useful for 'dd'.
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