Re: [PATCH v6 net-next 1/5] net: add generic per-cpu page_pool allocator

[Lorenzo Bianconi <lorenzo@kernel.org>]

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> 
> 
> On 28/01/2024 15.20, Lorenzo Bianconi wrote:
> > Introduce generic percpu page_pools allocator.
> > Moreover add page_pool_create_percpu() and cpuid filed in page_pool struct
> > in order to recycle the page in the page_pool "hot" cache if
> > napi_pp_put_page() is running on the same cpu.
> > This is a preliminary patch to add xdp multi-buff support for xdp running
> > in generic mode.
> > 
> > Signed-off-by: Lorenzo Bianconi<lorenzo@kernel.org>
> > ---
> >   include/net/page_pool/types.h |  3 +++
> >   net/core/dev.c                | 40 +++++++++++++++++++++++++++++++++++
> >   net/core/page_pool.c          | 23 ++++++++++++++++----
> >   net/core/skbuff.c             |  5 +++--
> >   4 files changed, 65 insertions(+), 6 deletions(-)
> > 
> [...]
> > diff --git a/net/core/dev.c b/net/core/dev.c
> > index cb2dab0feee0..bf9ec740b09a 100644
> > --- a/net/core/dev.c
> > +++ b/net/core/dev.c
> [...]
> > @@ -11686,6 +11690,27 @@ static void __init net_dev_struct_check(void)
> >    *
> >    */
> > +#define SD_PAGE_POOL_RING_SIZE	256
> > +static int net_page_pool_alloc(int cpuid)
> 
> I don't like the name net_page_pool_alloc().
> It uses the page_pool_create APIs.
> 
> Let us renamed to net_page_pool_create() ?

ack, I will fix it.

Regards,
Lorenzo

> 
> 
> > +{
> > +#if IS_ENABLED(CONFIG_PAGE_POOL)
> > +	struct page_pool_params page_pool_params = {
> > +		.pool_size = SD_PAGE_POOL_RING_SIZE,
> > +		.nid = NUMA_NO_NODE,
> > +	};
> > +	struct page_pool *pp_ptr;
> > +
> > +	pp_ptr = page_pool_create_percpu(&page_pool_params, cpuid);
> > +	if (IS_ERR(pp_ptr)) {
> > +		pp_ptr = NULL;
> > +		return -ENOMEM;
> > +	}
> > +
> > +	per_cpu(page_pool, cpuid) = pp_ptr;
> > +#endif
> > +	return 0;
> > +}
> > +
> >   /*
> >    *       This is called single threaded during boot, so no need
> >    *       to take the rtnl semaphore.
> > @@ -11738,6 +11763,9 @@ static int __init net_dev_init(void)
> >   		init_gro_hash(&sd->backlog);
> >   		sd->backlog.poll = process_backlog;
> >   		sd->backlog.weight = weight_p;
> > +
> > +		if (net_page_pool_alloc(i))
> > +			goto out;
> >   	}
> >   	dev_boot_phase = 0;
> > @@ -11765,6 +11793,18 @@ static int __init net_dev_init(void)
> >   	WARN_ON(rc < 0);
> >   	rc = 0;
> >   out:
> > +	if (rc < 0) {
> > +		for_each_possible_cpu(i) {
> > +			struct page_pool *pp_ptr = this_cpu_read(page_pool);
> > +
> > +			if (!pp_ptr)
> > +				continue;
> > +
> > +			page_pool_destroy(pp_ptr);
> > +			per_cpu(page_pool, i) = NULL;
> > +		}
> > +	}
> > +
> >   	return rc;
> >   }

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