Re: [PATCH] Allow __vmalloc with GFP_ATOMIC

From: Nick Piggin
Date: Sat Apr 28 2007 - 00:14:22 EST


Giridhar Pemmasani wrote:
Until 2.6.19, __vmalloc with GFP_ATOMIC was possible, but __get_vm_area_node
would allocate the node itself with GFP_KERNEL, causing a warning. In 2.6.19,
this was "fixed" by using the same flags that were passed to __vmalloc also
in __get_vm_area_node. However, __get_vm_area_node does
BUG_ON(in_interrupt()) now, since vmlist_lock is obtained without disabling
bottom-half's. The patch below uses bh disabled lock for vmlist_lock, so that
__vmalloc can be used in interrupt context.

In 2.6.21, __vmalloc with GFP_ATOMIC is used by arch/um/kernel/process.c;
__vmalloc is also used in ntfs, xfs, but it is not clear to me if they use it
with GFP_ATOMIC or GFP_KERNEL.

Thanks,
Giri

Hi Giri,

I'm sure I've read the reason for this one before, but when you do patches
like these, can you include that reason in the changelog please?

Thanks,
Nick

--
SUSE Labs, Novell Inc.
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