From: David Miller <davem@davemloft.net>
To: torvalds@linux-foundation.org
Cc: a.p.zijlstra@chello.nl, avi@redhat.com, mel@csn.ul.ie,
aarcange@redhat.com, tglx@linutronix.de, riel@redhat.com,
mingo@elte.hu, akpm@linux-foundation.org,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
linux-mm@kvack.org, benh@kernel.crashing.org,
hugh.dickins@tiscali.co.uk, npiggin@kernel.dk,
paulmck@linux.vnet.ibm.com, yanmin_zhang@linux.intel.com,
schwidefsky@de.ibm.com, rmk@arm.linux.org.uk,
lethal@linux-sh.org, jdike@addtoit.com, tony.luck@intel.com,
hughd@google.com
Subject: Re: [PATCH 02/17] mm: mmu_gather rework
Date: Fri, 01 Apr 2011 17:07:20 -0700 (PDT) [thread overview]
Message-ID: <20110401.170720.104061844.davem@davemloft.net> (raw)
In-Reply-To: <AANLkTimvHdGZptwmmw73C2jsy=HqgreEAxNurT1Hxbv=@mail.gmail.com>
From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Fri, 1 Apr 2011 09:13:51 -0700
> What's the difference? Integer assignment makes a hell of a difference. Do this:
>
> long long expression = ...
> ...
> bool val = expression;
>
> and depending on implementation it will either just truncate the value
> to a random number of bits, or actually do a compare with zero.
But note that, as you indicate, using int's to store boolean values
have this exact problem.
And most of the time people are converting an "int used as a boolean
value" into a "bool".
At least the "bool" has a chance of giving true boolean semantics in
the case you describe, whereas the 'int' always has the potential
truncation issue.
So, personally, I see it as a net positive to convert int to bool when
the variable is being used to take on true/false values.
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next prev parent reply other threads:[~2011-04-02 0:08 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-17 16:23 [PATCH 00/17] mm: mmu_gather rework Peter Zijlstra
2011-02-17 16:23 ` [PATCH 01/17] tile: Fix __pte_free_tlb Peter Zijlstra
2011-02-17 16:23 ` [PATCH 02/17] mm: mmu_gather rework Peter Zijlstra
2011-03-10 15:50 ` Mel Gorman
2011-03-16 18:55 ` Peter Zijlstra
2011-03-16 20:15 ` Geert Uytterhoeven
2011-03-16 21:08 ` Peter Zijlstra
2011-03-21 8:47 ` Avi Kivity
2011-04-01 12:07 ` Peter Zijlstra
2011-04-01 16:13 ` Linus Torvalds
2011-04-02 0:07 ` David Miller [this message]
2011-02-17 16:23 ` [PATCH 03/17] powerpc: " Peter Zijlstra
2011-02-17 16:23 ` [PATCH 04/17] sparc: " Peter Zijlstra
2011-02-17 16:23 ` [PATCH 05/17] s390: " Peter Zijlstra
2011-02-17 16:23 ` [PATCH 06/17] arm: " Peter Zijlstra
2011-02-24 16:34 ` Peter Zijlstra
2011-02-25 18:04 ` Peter Zijlstra
2011-02-25 19:45 ` Peter Zijlstra
2011-02-25 19:59 ` Hugh Dickins
2011-02-25 21:51 ` Russell King
2011-02-28 11:44 ` Peter Zijlstra
2011-02-28 11:59 ` Russell King
2011-02-28 12:06 ` Russell King
2011-02-28 12:25 ` Peter Zijlstra
2011-02-28 12:06 ` Russell King
2011-02-28 12:20 ` Peter Zijlstra
2011-02-28 12:28 ` Russell King
2011-02-28 12:49 ` Peter Zijlstra
2011-02-28 12:50 ` Russell King
2011-02-28 13:03 ` Peter Zijlstra
2011-02-28 14:18 ` Peter Zijlstra
2011-02-28 14:57 ` Russell King
2011-02-28 15:05 ` Peter Zijlstra
2011-02-28 15:15 ` Russell King
2011-03-01 22:05 ` Chris Metcalf
2011-03-02 10:54 ` Peter Zijlstra
2011-02-17 16:23 ` [PATCH 07/17] sh: " Peter Zijlstra
2011-02-17 16:23 ` [PATCH 08/17] um: " Peter Zijlstra
2011-02-17 16:23 ` [PATCH 09/17] ia64: " Peter Zijlstra
2011-02-17 16:23 ` [PATCH 10/17] mm: Now that all old mmu_gather code is gone, remove the storage Peter Zijlstra
2011-02-17 16:23 ` [PATCH 11/17] mm, powerpc: Move the RCU page-table freeing into generic code Peter Zijlstra
2011-02-17 16:23 ` [PATCH 12/17] s390: use generic RCP page-table freeing Peter Zijlstra
2011-02-17 16:23 ` [PATCH 13/17] mm: Extended batches for generic mmu_gather Peter Zijlstra
2011-02-17 16:23 ` [PATCH 14/17] mm: Provide generic range tracking and flushing Peter Zijlstra
2011-02-17 16:23 ` [PATCH 15/17] arm, mm: Convert arm to generic tlb Peter Zijlstra
2011-02-17 16:23 ` [PATCH 16/17] ia64, mm: Convert ia64 " Peter Zijlstra
2011-02-17 16:23 ` [PATCH 17/17] sh, mm: Convert sh " Peter Zijlstra
2011-02-17 17:36 ` [PATCH 00/17] mm: mmu_gather rework Peter Zijlstra
2011-02-17 17:42 ` Peter Zijlstra
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