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From: Peter Zijlstra <peterz@infradead.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: mingo@kernel.org, rusty@rustcorp.com.au,
	mathieu.desnoyers@efficios.com, oleg@redhat.com,
	paulmck@linux.vnet.ibm.com, torvalds@linux-foundation.org,
	linux-kernel@vger.kernel.org, andi@firstfloor.org,
	rostedt@goodmis.org, tglx@linutronix.de,
	Michel Lespinasse <walken@google.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	David Woodhouse <David.Woodhouse@intel.com>,
	Rik van Riel <riel@redhat.com>
Subject: Re: [PATCH 6/8] rbtree: Implement generic latch_tree
Date: Thu, 19 Mar 2015 23:04:33 +0100	[thread overview]
Message-ID: <20150319220433.GS2896@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <20150319135833.5a844744936bd8fdafea7ed5@linux-foundation.org>

On Thu, Mar 19, 2015 at 01:58:33PM -0700, Andrew Morton wrote:
> OK.  This code is basically required to support perf/ftrace and
> modules, yes?  Presumably small and space-constrained systems aren't
> using either, so they don't take the hit.
> 
> However CONFIG_MODULES systems which aren't using perf/ftrace _do_ take
> a hit.  How many systems are we talking here?  All non-x86?

No, there's plenty !x86 systems that have NMI and perf/ftrace, in fact,
ARM has them (FIQ) and there's event some ARM chips that use them for
perf (i.MX6 is one).

But sure, we could make this depend on CONFIG_PERF_EVENTS ||
CONFIG_TRACING.

  parent reply	other threads:[~2015-03-19 22:04 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-18 13:36 [PATCH 0/8] latched RB-trees and __module_address() Peter Zijlstra
2015-03-18 13:36 ` [PATCH 1/8] module: Sanitize RCU usage and locking Peter Zijlstra
2015-03-20  3:36   ` Rusty Russell
2015-03-18 13:36 ` [PATCH 2/8] module: Annotate module version magic Peter Zijlstra
2015-03-18 13:36 ` [PATCH 3/8] module, jump_label: Fix module locking Peter Zijlstra
2015-03-20  4:26   ` Rusty Russell
2015-03-20  9:11     ` Peter Zijlstra
2015-03-18 13:36 ` [PATCH 4/8] rbtree: Make lockless searches non-fatal Peter Zijlstra
2015-03-18 13:36 ` [PATCH 5/8] seqlock: Better document raw_write_seqcount_latch() Peter Zijlstra
2015-03-18 14:29   ` Mathieu Desnoyers
2015-03-18 14:50     ` Peter Zijlstra
2015-03-18 13:36 ` [PATCH 6/8] rbtree: Implement generic latch_tree Peter Zijlstra
2015-03-18 16:20   ` Ingo Molnar
2015-03-19  5:14   ` Andrew Morton
2015-03-19  7:25     ` Peter Zijlstra
2015-03-19 20:58       ` Andrew Morton
2015-03-19 21:36         ` Steven Rostedt
2015-03-19 21:38           ` Steven Rostedt
2015-03-19 21:47           ` Andrew Morton
2015-03-19 21:54             ` Steven Rostedt
2015-03-19 22:12           ` Peter Zijlstra
2015-03-19 22:04         ` Peter Zijlstra [this message]
2015-03-20  9:50           ` Peter Zijlstra
2015-03-19 22:10         ` Peter Zijlstra
2015-03-18 13:36 ` [PATCH 7/8] module: Optimize __module_address() using a latched RB-tree Peter Zijlstra
2015-03-18 13:36 ` [PATCH 8/8] module: Use __module_address() for module_address_lookup() Peter Zijlstra
2015-03-18 14:21 ` [PATCH 0/8] latched RB-trees and __module_address() Christoph Hellwig
2015-03-18 14:38   ` Peter Zijlstra

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