On Fri, May 08, 2020 at 01:10:00PM +0530, Sunil Kovvuri wrote:
> On Fri, May 8, 2020 at 9:43 AM Kevin Hao <haoke...@gmail.com> wrote:
> >
> > In the current codes, the octeontx2 uses its own method to allocate
> > the pool buffers, but there are some issues in this implementation.
> > 1. We have to run the otx2_get_page() for each allocation cycle and
> > this is pretty error prone. As I can see there is no invocation
> > of the otx2_get_page() in otx2_pool_refill_task(), this will leave
> > the allocated pages have the wrong refcount and may be freed wrongly.
> > 2. It wastes memory. For example, if we only receive one packet in a
> > NAPI RX cycle, and then allocate a 2K buffer with otx2_alloc_rbuf()
> > to refill the pool buffers and leave the remain area of the allocated
> > page wasted. On a kernel with 64K page, 62K area is wasted.
> >
> > IMHO it is really unnecessary to implement our own method for the
> > buffers allocate, we can reuse the napi_alloc_frag() to simplify
> > our code.
> >
> > Signed-off-by: Kevin Hao <haoke...@gmail.com>
> > ---
> > .../marvell/octeontx2/nic/otx2_common.c | 51 ++++++++-----------
> > .../marvell/octeontx2/nic/otx2_common.h | 15 +-----
> > .../marvell/octeontx2/nic/otx2_txrx.c | 3 +-
> > .../marvell/octeontx2/nic/otx2_txrx.h | 4 --
> > 4 files changed, 22 insertions(+), 51 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
> > b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
> > index f1d2dea90a8c..15fa1ad57f88 100644
> > --- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
> > +++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
> > @@ -379,40 +379,32 @@ void otx2_config_irq_coalescing(struct otx2_nic
> > *pfvf, int qidx)
> > (pfvf->hw.cq_ecount_wait - 1));
> > }
> >
> > -dma_addr_t otx2_alloc_rbuf(struct otx2_nic *pfvf, struct otx2_pool *pool,
> > - gfp_t gfp)
> > +dma_addr_t _otx2_alloc_rbuf(struct otx2_nic *pfvf, struct otx2_pool *pool)
> > {
> > dma_addr_t iova;
> > + u8 *buf;
> >
> > - /* Check if request can be accommodated in previous allocated page
> > */
> > - if (pool->page && ((pool->page_offset + pool->rbsize) <=
> > - (PAGE_SIZE << pool->rbpage_order))) {
> > - pool->pageref++;
> > - goto ret;
> > - }
> > -
> > - otx2_get_page(pool);
> > -
> > - /* Allocate a new page */
> > - pool->page = alloc_pages(gfp | __GFP_COMP | __GFP_NOWARN,
> > - pool->rbpage_order);
> > - if (unlikely(!pool->page))
> > + buf = napi_alloc_frag(pool->rbsize);
> > + if (unlikely(!buf))
> > return -ENOMEM;
> >
> > - pool->page_offset = 0;
> > -ret:
> > - iova = (u64)otx2_dma_map_page(pfvf, pool->page, pool->page_offset,
> > - pool->rbsize, DMA_FROM_DEVICE);
> > - if (!iova) {
> > - if (!pool->page_offset)
> > - __free_pages(pool->page, pool->rbpage_order);
> > - pool->page = NULL;
> > + iova = dma_map_single(pfvf->dev, buf, pool->rbsize,
> > DMA_FROM_DEVICE);
> > + if (unlikely(dma_mapping_error(pfvf->dev, iova)))
> > return -ENOMEM;
>
> Use DMA_ATTR_SKIP_CPU_SYNC while mapping the buffer.Sure. V2 is coming. Thanks, Kevin > > Thanks, > Sunil.
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