netdev - 答复: [PATCH] page_pool: mark unbound node page as reusable pages

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Message-ID: <656e11b6605740b18ac7bb8e3b67ed93@baidu.com>
Date:   Thu, 5 Dec 2019 01:08:56 +0000
From:   "Li,Rongqing" <lirongqing@...du.com>
To:     Yunsheng Lin <linyunsheng@...wei.com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "saeedm@...lanox.com" <saeedm@...lanox.com>
Subject: 答复: [PATCH] page_pool: mark unbound node page as reusable pages



> -----邮件原件-----
> 发件人: Yunsheng Lin [mailto:linyunsheng@...wei.com]
> 发送时间: 2019年12月5日 8:55
> 收件人: Li,Rongqing <lirongqing@...du.com>; netdev@...r.kernel.org;
> saeedm@...lanox.com
> 主题: Re: [PATCH] page_pool: mark unbound node page as reusable pages
> 
> On 2019/12/4 18:14, Li RongQing wrote:
> > some drivers uses page pool, but not require to allocate page from
> > bound node, so pool.p.nid is NUMA_NO_NODE, and this fixed patch will
> > block this kind of driver to recycle
> >
> > Fixes: d5394610b1ba ("page_pool: Don't recycle non-reusable pages")
> > Signed-off-by: Li RongQing <lirongqing@...du.com>
> > Cc: Saeed Mahameed <saeedm@...lanox.com>
> > ---
> >  net/core/page_pool.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/net/core/page_pool.c b/net/core/page_pool.c index
> > a6aefe989043..4054db683178 100644
> > --- a/net/core/page_pool.c
> > +++ b/net/core/page_pool.c
> > @@ -317,7 +317,9 @@ static bool __page_pool_recycle_direct(struct page
> *page,
> >   */
> >  static bool pool_page_reusable(struct page_pool *pool, struct page
> > *page)  {
> > -	return !page_is_pfmemalloc(page) && page_to_nid(page) == pool->p.nid;
> > +	return !page_is_pfmemalloc(page) &&
> > +		(page_to_nid(page) == pool->p.nid ||
> > +		 pool->p.nid == NUMA_NO_NODE);
> 
> If I understand it correctly, you are allowing recycling when
> pool->p.nid is NUMA_NO_NODE, which does not seems match the commit
> log: "this fixed patch will block this kind of driver to recycle".
> 
> Maybe you mean "commit d5394610b1ba" by this fixed patch?

yes

> 
> Also, maybe it is better to allow recycling if the below condition is matched:
> 
> 	pool->p.nid == NUMA_NO_NODE && page_to_nid(page) ==
> numa_mem_id()

If driver uses NUMA_NO_NODE, it does not care numa node, and maybe its platform
Only has a node, so not need to compare like "page_to_nid(page) ==  numa_mem_id()"


-RongQing


> 
> >  }
> >
> >  void __page_pool_put_page(struct page_pool *pool, struct page *page,
> >