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SubjectRe: [ewg] Re: [PATCH 1/3] IB/ehca: Replace vmalloc with kmalloc
Hi Roland,

did you have a chance to take a look at the patchset and will you apply it, or
are there any outstanding issues we need to address?

Regards,
Alex

On Wed, 22 Apr 2009 16:02:28 +0200
Stefan Roscher <ossrosch@linux.vnet.ibm.com> wrote:

> In case of large queue pairs there is the possibillity of allocation failures
> due to memory fragmentationo with kmalloc().To ensure the memory is allocated even
> if kmalloc() can not find chunks which are big enough, we try to allocate the memory
> with vmalloc().
>
> Signed-off-by: Stefan Roscher <stefan.roscher@de.ibm.com>
> ---
>
> On Tuesday 21 April 2009 07:34:30 pm Roland Dreier wrote:
> > > + queue->queue_pages = kmalloc(nr_of_pages * sizeof(void *), GFP_KERNEL);
> >
> > How big might this buffer be? Any chance of allocation failure due to
> > memory fragmentation?
> >
> > - R.
> Hey Roland,
> yes you are right and here is the patch to circumvent the described problem.
> It will apply on top of the patchset.
> regards Stefan
>
>
>
> drivers/infiniband/hw/ehca/ipz_pt_fn.c | 17 +++++++++++++----
> 1 files changed, 13 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/infiniband/hw/ehca/ipz_pt_fn.c b/drivers/infiniband/hw/ehca/ipz_pt_fn.c
> index a260559..1227c59 100644
> --- a/drivers/infiniband/hw/ehca/ipz_pt_fn.c
> +++ b/drivers/infiniband/hw/ehca/ipz_pt_fn.c
> @@ -222,8 +222,11 @@ int ipz_queue_ctor(struct ehca_pd *pd, struct ipz_queue *queue,
> /* allocate queue page pointers */
> queue->queue_pages = kmalloc(nr_of_pages * sizeof(void *), GFP_KERNEL);
> if (!queue->queue_pages) {
> - ehca_gen_err("Couldn't allocate queue page list");
> - return 0;
> + queue->queue_pages = vmalloc(nr_of_pages * sizeof(void *));
> + if (!queue->queue_pages) {
> + ehca_gen_err("Couldn't allocate queue page list");
> + return 0;
> + }
> }
> memset(queue->queue_pages, 0, nr_of_pages * sizeof(void *));
>
> @@ -240,7 +243,10 @@ int ipz_queue_ctor(struct ehca_pd *pd, struct ipz_queue *queue,
> ipz_queue_ctor_exit0:
> ehca_gen_err("Couldn't alloc pages queue=%p "
> "nr_of_pages=%x", queue, nr_of_pages);
> - kfree(queue->queue_pages);
> + if (is_vmalloc_addr(queue->queue_pages))
> + vfree(queue->queue_pages);
> + else
> + kfree(queue->queue_pages);
>
> return 0;
> }
> @@ -262,7 +268,10 @@ int ipz_queue_dtor(struct ehca_pd *pd, struct ipz_queue *queue)
> free_page((unsigned long)queue->queue_pages[i]);
> }
>
> - kfree(queue->queue_pages);
> + if (is_vmalloc_addr(queue->queue_pages))
> + vfree(queue->queue_pages);
> + else
> + kfree(queue->queue_pages);
>
> return 1;
> }


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