Re: [PATCH 1/2] net: Export __netdev_alloc_frag() to allow gfp_mask flags

From: Eric Dumazet
Date: Wed Jul 29 2015 - 12:32:06 EST


On Wed, 2015-07-29 at 11:10 -0400, WingMan Kwok wrote:
> This patch makes the function __netdev_alloc_frag() non-static and
> exports it so that drivers that need to specify additional flags,
> such as __GFP_DMA, can use it. The currently exported function,
> netdev_alloc_frag() doesn't allow passing in gfp_mask flags.
>
> Signed-off-by: WingMan Kwok <w-kwok2@xxxxxx>
> Signed-off-by: Reece R. Pollack <x0183204@xxxxxx>
> ---
> include/linux/skbuff.h | 1 +
> net/core/skbuff.c | 3 ++-
> 2 files changed, 3 insertions(+), 1 deletion(-)

You can not do this.

__napi_alloc_frag() uses __alloc_page_frag() using a per cpu reserve.

This per cpu reserve would be shared by regular GFP_ATOMIC and your
__GFP_DMA allocations.



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