linux-kernel - Re: [PATCH] idr: Document ida tree sections

lists.openwall.net		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 linux-cve-announce 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:	Tue, 13 Aug 2013 15:59:27 -0700
From:	Kent Overstreet <kmo@...erainc.com>
To:	Tejun Heo <tj@...nel.org>
Cc:	akpm@...ux-foundation.org, linux-kernel@...r.kernel.org,
	Stephen Rothwell <sfr@...b.auug.org.au>,
	Fengguang Wu <fengguang.wu@...el.com>
Subject: Re: [PATCH] idr: Document ida tree sections

On Tue, Aug 13, 2013 at 06:44:28PM -0400, Tejun Heo wrote:
> Hello, Kent.
> 
> On Tue, Aug 13, 2013 at 03:27:59PM -0700, Kent Overstreet wrote:
> > It's only naturally a radix tree problem _if_ you require sparseness.
> 
> Well, it's not necessarily about requiring it but more about surviving
> it with some grace when things don't go as expected, which is an
> important characteristic for common library stuff.

The patch I posted should solve the high order allocations stuff, and
sparseness from cyclic allocations was already solved.

> > Otherwise, radix trees require pointer chasing, which we can avoid -
> > which saves us both the cost of chasing pointers (which is significant)
> > and the overhead of storing them.
> 
> Vast majority of which can be avoided with simple caching, right?

Whatever caching optimizations you do with a radix tree version I could
apply to this bitmap tree version, and my bitmap tree code is simpler
and _considerably_ faster than the existing code.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/