Re: SLAB_LEVEL_MASK question

From: Manfred Spraul
Date: Thu Sep 04 2003 - 14:52:45 EST


Hi Henry,

The kernel panics because in the flags variable, I have other flags
(0x1f0) besides SLAB_ATOMIC.


Which flags were set? __GFP_WAIT must not be set [i.e. will panic], the other combinations are invalid. The only legal values for the flags variable are 0 or SLAB_ATOMIC [aka GFP_ATOMIC, aka __GFP_HIGH].

I modified it to:

if (in_interrupt() && (flags & SLAB_ATOMIC) != SLAB_ATOMIC)
BUG();

It seems working fine.

Is this good?


No, it's wrong. Your driver will panic once in a while, especially under memory intensive stress tests.

--
Manfred

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