From: Ilias Apalodimas <ilias.apalodimas@linaro.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: Matteo Croce <mcroce@linux.microsoft.com>,
netdev@vger.kernel.org, linux-mm@kvack.org,
Ayush Sawal <ayush.sawal@chelsio.com>,
Vinay Kumar Yadav <vinay.yadav@chelsio.com>,
Rohit Maheshwari <rohitm@chelsio.com>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
Marcin Wojtas <mw@semihalf.com>,
Russell King <linux@armlinux.org.uk>,
Mirko Lindner <mlindner@marvell.com>,
Stephen Hemminger <stephen@networkplumber.org>,
Tariq Toukan <tariqt@nvidia.com>,
Jesper Dangaard Brouer <hawk@kernel.org>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
John Fastabend <john.fastabend@gmail.com>,
Boris Pismenny <borisp@nvidia.com>, Arnd Bergmann <arnd@arndb.de>,
Andrew Morton <akpm@linux-foundation.org>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Vlastimil Babka <vbabka@suse.cz>, Yu Zhao <yuzhao@google.com>,
Will Deacon <will@kernel.org>,
Michel Lespinasse <walken@google.com>,
Fenghua Yu <fenghua.yu@intel.com>, Roman Gushchin <guro@fb.com>,
Hugh Dickins <hughd@google.com>, Peter Xu <peterx@redhat.com>,
Jason Gunthorpe <jgg@ziepe.ca>,
Guoqing Jiang <guoqing.jiang@cloud.ionos.com>,
Jonathan Lemon <jonathan.lemon@gmail.com>,
Alexander Lobakin <alobakin@pm.me>,
Cong Wang <cong.wang@bytedance.com>, wenxu <wenxu@ucloud.cn>,
Kevin Hao <haokexin@gmail.com>,
Aleksandr Nogikh <nogikh@google.com>,
Jakub Sitnicki <jakub@cloudflare.com>,
Marco Elver <elver@google.com>,
Willem de Bruijn <willemb@google.com>,
Miaohe Lin <linmiaohe@huawei.com>,
Yunsheng Lin <linyunsheng@huawei.com>,
Guillaume Nault <gnault@redhat.com>,
linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org,
bpf@vger.kernel.org, Eric Dumazet <edumazet@google.com>,
David Ahern <dsahern@gmail.com>,
Lorenzo Bianconi <lorenzo@kernel.org>,
Saeed Mahameed <saeedm@nvidia.com>, Andrew Lunn <andrew@lunn.ch>,
Paolo Abeni <pabeni@redhat.com>
Subject: Re: [PATCH net-next v3 2/5] mm: add a signature in struct page
Date: Sat, 10 Apr 2021 19:16:45 +0300 [thread overview]
Message-ID: <YHHPbQm2pn2ysth0@enceladus> (raw)
In-Reply-To: <20210410154824.GZ2531743@casper.infradead.org>
Hi Matthew
On Sat, Apr 10, 2021 at 04:48:24PM +0100, Matthew Wilcox wrote:
> On Sat, Apr 10, 2021 at 12:37:58AM +0200, Matteo Croce wrote:
> > This is needed by the page_pool to avoid recycling a page not allocated
> > via page_pool.
>
> Is the PageType mechanism more appropriate to your needs? It wouldn't
> be if you use page->_mapcount (ie mapping it to userspace).
Interesting!
Please keep in mind this was written ~2018 and was stale on my branches for
quite some time. So back then I did try to use PageType, but had not free
bits. Looking at it again though, it's cleaned up. So yes I think this can
be much much cleaner. Should we go and define a new PG_pagepool?
Thanks!
/Ilias
>
> > Signed-off-by: Matteo Croce <mcroce@microsoft.com>
> > ---
> > include/linux/mm_types.h | 1 +
> > include/net/page_pool.h | 2 ++
> > net/core/page_pool.c | 4 ++++
> > 3 files changed, 7 insertions(+)
> >
> > diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
> > index 6613b26a8894..ef2d0d5f62e4 100644
> > --- a/include/linux/mm_types.h
> > +++ b/include/linux/mm_types.h
> > @@ -101,6 +101,7 @@ struct page {
> > * 32-bit architectures.
> > */
> > dma_addr_t dma_addr;
> > + unsigned long signature;
> > };
> > struct { /* slab, slob and slub */
> > union {
> > diff --git a/include/net/page_pool.h b/include/net/page_pool.h
> > index b5b195305346..b30405e84b5e 100644
> > --- a/include/net/page_pool.h
> > +++ b/include/net/page_pool.h
> > @@ -63,6 +63,8 @@
> > */
> > #define PP_ALLOC_CACHE_SIZE 128
> > #define PP_ALLOC_CACHE_REFILL 64
> > +#define PP_SIGNATURE 0x20210303
> > +
> > struct pp_alloc_cache {
> > u32 count;
> > void *cache[PP_ALLOC_CACHE_SIZE];
> > diff --git a/net/core/page_pool.c b/net/core/page_pool.c
> > index ad8b0707af04..2ae9b554ef98 100644
> > --- a/net/core/page_pool.c
> > +++ b/net/core/page_pool.c
> > @@ -232,6 +232,8 @@ static struct page *__page_pool_alloc_pages_slow(struct page_pool *pool,
> > page_pool_dma_sync_for_device(pool, page, pool->p.max_len);
> >
> > skip_dma_map:
> > + page->signature = PP_SIGNATURE;
> > +
> > /* Track how many pages are held 'in-flight' */
> > pool->pages_state_hold_cnt++;
> >
> > @@ -302,6 +304,8 @@ void page_pool_release_page(struct page_pool *pool, struct page *page)
> > DMA_ATTR_SKIP_CPU_SYNC);
> > page->dma_addr = 0;
> > skip_dma_unmap:
> > + page->signature = 0;
> > +
> > /* This may be the last page returned, releasing the pool, so
> > * it is not safe to reference pool afterwards.
> > */
> > --
> > 2.30.2
> >
next prev parent reply other threads:[~2021-04-10 16:16 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-09 22:37 [PATCH net-next v3 0/5] page_pool: recycle buffers Matteo Croce
2021-04-09 22:37 ` [PATCH net-next v3 1/5] xdp: reduce size of struct xdp_mem_info Matteo Croce
2021-04-09 22:37 ` [PATCH net-next v3 2/5] mm: add a signature in struct page Matteo Croce
2021-04-10 15:48 ` Matthew Wilcox
2021-04-10 16:16 ` Ilias Apalodimas [this message]
2021-04-10 17:42 ` Shakeel Butt
2021-04-10 18:27 ` Ilias Apalodimas
2021-04-10 19:39 ` Matthew Wilcox
2021-04-11 10:05 ` Jesper Dangaard Brouer
2021-04-14 19:41 ` Jesper Dangaard Brouer
2021-04-14 20:09 ` Shakeel Butt
2021-04-14 20:51 ` Eric Dumazet
2021-04-19 5:12 ` Ilias Apalodimas
2021-04-19 14:57 ` Shakeel Butt
2021-04-19 15:43 ` Ilias Apalodimas
2021-04-19 16:21 ` Shakeel Butt
2021-04-19 18:41 ` Ilias Apalodimas
2021-04-19 11:22 ` Jesper Dangaard Brouer
2021-04-19 13:01 ` Matthew Wilcox
2021-04-20 8:10 ` Ilias Apalodimas
2021-04-09 22:37 ` [PATCH net-next v3 3/5] page_pool: Allow drivers to hint on SKB recycling Matteo Croce
2021-04-10 0:11 ` Ilias Apalodimas
2021-04-10 0:39 ` Matteo Croce
2021-04-09 22:38 ` [PATCH net-next v3 4/5] mvpp2: recycle buffers Matteo Croce
2021-04-09 22:38 ` [PATCH net-next v3 5/5] mvneta: " Matteo Croce
2021-04-29 8:27 ` [PATCH net-next v3 0/5] page_pool: " Yunsheng Lin
2021-04-29 18:51 ` Ilias Apalodimas
2021-04-30 3:01 ` Yunsheng Lin
2021-04-30 16:24 ` Ilias Apalodimas
2021-04-30 17:32 ` Ilias Apalodimas
2021-05-03 7:29 ` Jesper Dangaard Brouer
2021-05-06 12:34 ` Yunsheng Lin
2021-05-06 12:58 ` Ilias Apalodimas
2021-05-07 3:23 ` Yunsheng Lin
2021-05-07 7:06 ` Ilias Apalodimas
2021-05-07 8:28 ` Yunsheng Lin
2021-05-07 10:19 ` Jesper Dangaard Brouer
2021-05-07 11:31 ` Christoph Hellwig
2021-05-09 5:11 ` Shay Agroskin
2021-05-11 8:41 ` Ilias Apalodimas
2021-05-10 2:20 ` Yunsheng Lin
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