Re: [PATCH] Time-based RFC 4122 UUID generator

From: Andrew Morton
Date: Sun Nov 18 2007 - 16:06:00 EST


On Sun, 18 Nov 2007 20:38:21 +0100 Helge Deller <deller@xxxxxx> wrote:

> Title: Add time-based RFC 4122 UUID generator
>
> The current Linux kernel currently contains the generate_random_uuid()
> function, which creates - based on RFC 4122 - truly random UUIDs and
> provides them to userspace through /proc/sys/kernel/random/boot_id and
> /proc/sys/kernel/random/uuid.
>
> This patch additionally adds the "Time-based UUID" variant of RFC 4122,
> with which userspace applications can easily get real unique time-based
> UUIDs through /proc/sys/kernel/random/uuid_time.
> A new /proc/sys/kernel/random/uuid_time_clockseq sysfs entry is available,
> so that the clock_seq value can be retained across system bootups (which
> is required by RFC 4122).
>
> The attached implementation uses getnstimeofday() to get very fine-grained
> granularity. This helps, so that userspace tools can get a lot more UUIDs
> (if needed) per time than before.
> A mutex takes care of the proper locking against a mistaken double creation
> of UUIDs for simultanious running processes.

Who will use this feature, and for what?

(In fact, who uses the existing UUID generators, and for what?)

Thanks.
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