lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Wed, 7 Mar 2012 12:22:20 -0500
From:	Ted Ts'o <>
To:	Lukas Czerner <>
Subject: Re: [PATCH 4/4 v2] ext4: Do not discard group with BLOCK_UNINIT set

On Wed, Mar 07, 2012 at 08:10:00AM +0100, Lukas Czerner wrote:
> Ok, if there is a plan to implement that, I am fine with dropping th
> patches. But since this optimization would be helpful for discard, we
> can introduce BLOCK_DISCARDED/UNPROVISIONED flag maybe ? Which would be
> sen only after discard and cleared with the first allocation ?

Heh, great minds think alike.  I was thinking about a the possibility
of having a BLOCK_DISCARDED flag this morning, with exactly the
semantics that you are suggesting.  There may be devices in the future
that have fast trims which will prefer to always get the duplicate
trim requests, but there is no question there are a lot of crappy
devices out there right now where trims are extremely expensive, so
that seems fair.

Something else to think about for the future, for battery driven
devices (such as handsets) automatically sending tirm commands might
not be a good idea when the device is sleeping/has the screen turned
off.  Given that we don't have an easy way of determining whether or
not the device is in a low powered state (ideally we only send the
trims right after work has been queued to the device, so it's woken up
already, but when there isn't anything else that needs to be sent to
the device).

					- Ted
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to
More majordomo info at

Powered by blists - more mailing lists