Messages in this thread | | | Date | Mon, 30 Apr 2007 10:02:25 -0700 | From | Andrew Morton <> | Subject | Re: can a kmalloc be both GFP_ATOMIC and GFP_KERNEL at the same time? |
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On Mon, 30 Apr 2007 04:46:54 -0400 (EDT) "Robert P. J. Day" <rpjday@mindspring.com> wrote:
> On Mon, 30 Apr 2007, Andrew Morton wrote: > > > On Sat, 28 Apr 2007 09:40:39 -0400 (EDT) "Robert P. J. Day" <rpjday@mindspring.com> wrote: > > > > > > > > i'd always assumed that the type flags of GFP_ATOMIC and GFP_KERNEL > > > were mutually exclusive when it came to calling kmalloc(), at least > > > based on everything i'd read. so i'm not sure how to interpret the > > > following: > > > > > > 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? > > > > GFP_ATOMIC implies that the memory comes from the zones which > > GFP_KERNEL also uses. So the above usage of GFP_KERNEL is redundant > > and should be removed. > > hang on ... based on an email i just got, is that reference to > GFP_KERNEL "redundant" or "conflicting"? big difference there. and > is the proper fix to remove "GFP_KERNEL" in both cases? >
umm, yeah, oops. GFP_KERNEL|GFP_ATOMIC is not a redundant combination. It's GFP_KERNEL plus "is able to access emergency pools". We'd normally represent that as GFP_KERNEL|__GFP_HIGH.
However it's questionable whether that was the intent in those two drivers. `git-blame' might tell.
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