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From: Manfred Spraul <manfred@colorfullife.com>
To: William Lee Irwin III <wli@holomorphy.com>
Cc: mpm@selenic.com, linux-kernel@vger.kernel.org
Subject: Re: slab redzoning
Date: Sat, 22 May 2004 10:02:25 +0200	[thread overview]
Message-ID: <40AF0911.6020000@colorfullife.com> (raw)
In-Reply-To: <20040522034902.GB2161@holomorphy.com>

William Lee Irwin III wrote:

>-if ((size < 4096 || fls(size-1) == fls(size-1+3*BYTES_PER_WORD)))
>+if (size + 3*BYTES_PER_WORD <= PAGE_SIZE ||
>
I understand this change: objects between 4082 and 4095 bytes are 
redzoned and cause order==1 allocations, that's wrong.

>+			((size & (size - 1)) &&
>+			(1 << fls(size)) - size > 3*BYTES_PER_WORD))
>
Why this change? I've tested my fls(size-1)==fls(size-1-3*4) approach 
and it always returned the right result: No redzoning between 8181 and 
8192 bytes, between 16373 and 16384, etc.

--
    Manfred


  reply	other threads:[~2004-05-22  8:02 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-05-22  3:49 slab redzoning William Lee Irwin III
2004-05-22  8:02 ` Manfred Spraul [this message]
2004-05-22  8:26   ` William Lee Irwin III
2004-05-22  8:43     ` Manfred Spraul
2004-05-22  8:52       ` William Lee Irwin III
2004-05-22 12:22         ` Manfred Spraul

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