Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > linux.kernel > #1413550

Re: [RFC 10/12] x86, rwsem: simplify __down_write

From Peter Zijlstra <peterz@infradead.org>
Newsgroups linux.kernel
Subject Re: [RFC 10/12] x86, rwsem: simplify __down_write
Date 2016-06-04 00:40 +0200
Message-ID <rG5UZ-Ei-13@gated-at.bofh.it> (permalink)
References <qXPKi-8sh-3@gated-at.bofh.it> <qXPKj-8sh-35@gated-at.bofh.it> <qY0Po-7NH-11@gated-at.bofh.it> <rFZZf-5w1-7@gated-at.bofh.it>
Organization linux.* mail to news gateway

Show all headers | View raw


On Fri, Jun 03, 2016 at 06:13:39PM +0200, Peter Zijlstra wrote:
> So I've been playing with this again because Jason's atomic_long_t
> patches made a mess of things.
> 
> (similar findings for both ia64 and s390, suggesting killing all
> arch/*/include/asm/rwsem.h might actuyally be an option).
> 

Blergh; so looking at more asm there's still a few tricks we cannot do.
So while overall size is down, some paths do end up more expensive. (It
typically boils down to creative use of condition flags, which is very
hard in C)

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread


Thread

Re: [RFC 10/12] x86, rwsem: simplify __down_write Peter Zijlstra <peterz@infradead.org> - 2016-06-03 18:20 +0200
  Re: [RFC 10/12] x86, rwsem: simplify __down_write Peter Zijlstra <peterz@infradead.org> - 2016-06-04 00:40 +0200
    Re: [RFC 10/12] x86, rwsem: simplify __down_write David Howells <dhowells@redhat.com> - 2016-06-09 16:50 +0200
      Re: [RFC 10/12] x86, rwsem: simplify __down_write Peter Zijlstra <peterz@infradead.org> - 2016-06-09 19:40 +0200
        Re: [RFC 10/12] x86, rwsem: simplify __down_write "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-06-10 20:00 +0200

csiph-web