Jens Axboe [jaxboe@xxxxxxxxxxxx] wrote:
> > This patch also _fixed_ our problem. So we are fine with either patch,
> > but this patch is preferred as it enables more request merges. Also,
> > both patches maybe needed for some configurations.
>
> Plus it doesn't needlessly bounce, that's the real problem you want to
> fix. I have applied this thread patch to for-2.6.37/core, thanks.
There is a shortcut check in blk_queue_bounce() that uses blk_max_pfn to
return without doing anything. blk_max_pfn is not updated when we do
hot-plug memory add, so bounce buffers are NOT really used in our case
(thankfully)!
Here is the code that may need some fix in future:
if (!(q->limits.bounce_gfp & GFP_DMA)) {
if (queue_bounce_pfn(q) >= blk_max_pfn)
return;
Thank you so much for applying this patch.
Thanks, Malahal.
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