Re: can a kmalloc be both GFP_ATOMIC and GFP_KERNEL at the sametime?

From: Christoph Lameter
Date: Mon Apr 30 2007 - 01:59:15 EST


On Sat, 28 Apr 2007, Alan Cox wrote:

> > > drivers/scsi/aic7xxx_old.c: aic_dev = kmalloc(sizeof(struct aic_dev_data), GFP_ATOMIC | GFP_KERNEL);
> > > drivers/message/i2o/device.c: resblk = kmalloc(buflen + 8, GFP_KERNEL | GFP_ATOMIC);
> > >
> > > clarification?
> >
> > oh, i'm *aware* of the definitions of those flags, but every single
> > source i've ever read has *strongly* suggested that you don't use
>
> I don't believe either of those is doing what the author intended 8).

Well sortof. First of all kmalloc may not even allocate a page to
satisfy the request. If it does then we do essentially GFP_KERNEL |
__GFP_HIGH meaning a allocation where we can sleep etc but are allowed to
dip into the reserves.

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