Re: RFC: named anonymous vmas

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Sat, Jun 22, 2013 at 3:31 AM, Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
> On Fri, Jun 21, 2013 at 04:42:41PM -0700, Colin Cross wrote:
>> ranges, which John Stultz has been implementing.  The second is
>> anonymous shareable memory without having a world-writable tmpfs that
>> untrusted apps could fill with files.
>
> I still haven't seen any explanation of what ashmem buys over a shared
> mmap of /dev/zero in that respect, btw.

I believe the difference is that ashmem ties the memory to an fd, so
it can be passed to another process and mmaped to get to the same
memory, but /dev/zero does not.  Passing a /dev/zero fd and mmaping it
would result in a brand new region of zeroed memory.  Opening a tmpfs
file would allow sharing memory by passing the fd, but we don't want a
world-writable tmpfs.

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>




[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Bugtraq]     [Linux]     [Linux OMAP]     [Linux MIPS]     [ECOS]     [Asterisk Internet PBX]     [Linux API]