Netdev Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Yunsheng Lin <linyunsheng@huawei.com>
To: <davem@davemloft.net>, <kuba@kernel.org>
Cc: <alexander.duyck@gmail.com>, <linux@armlinux.org.uk>,
	<mw@semihalf.com>, <linuxarm@openeuler.org>,
	<yisen.zhuang@huawei.com>, <salil.mehta@huawei.com>,
	<thomas.petazzoni@bootlin.com>, <hawk@kernel.org>,
	<ilias.apalodimas@linaro.org>, <ast@kernel.org>,
	<daniel@iogearbox.net>, <john.fastabend@gmail.com>,
	<akpm@linux-foundation.org>, <peterz@infradead.org>,
	<will@kernel.org>, <willy@infradead.org>, <vbabka@suse.cz>,
	<fenghua.yu@intel.com>, <guro@fb.com>, <peterx@redhat.com>,
	<feng.tang@intel.com>, <jgg@ziepe.ca>, <mcroce@microsoft.com>,
	<hughd@google.com>, <jonathan.lemon@gmail.com>, <alobakin@pm.me>,
	<willemb@google.com>, <wenxu@ucloud.cn>,
	<cong.wang@bytedance.com>, <haokexin@gmail.com>,
	<nogikh@google.com>, <elver@google.com>, <netdev@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, <bpf@vger.kernel.org>
Subject: [PATCH rfc v2 4/5] page_pool: support page frag API for page pool
Date: Sat, 10 Jul 2021 15:43:21 +0800	[thread overview]
Message-ID: <1625903002-31619-5-git-send-email-linyunsheng@huawei.com> (raw)
In-Reply-To: <1625903002-31619-1-git-send-email-linyunsheng@huawei.com>

Currently each desc use a whole page to do ping-pong page
reusing in most driver. As the page pool has support page
recycling based on elevated refcnt, it makes sense to add
a page frag API in page pool to split a page to different
frag to serve multi descriptions.

This means a huge memory saving for kernel with page size of
64K, as a page can be used by 32 descriptions with 2k buffer
size, comparing to each desc using one page currently.

Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
---
 include/net/page_pool.h | 14 ++++++++++++++
 net/core/page_pool.c    | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+)

diff --git a/include/net/page_pool.h b/include/net/page_pool.h
index f0e708d..06a5e43 100644
--- a/include/net/page_pool.h
+++ b/include/net/page_pool.h
@@ -80,6 +80,7 @@ struct page_pool_params {
 	enum dma_data_direction dma_dir; /* DMA mapping direction */
 	unsigned int	max_len; /* max DMA sync memory size */
 	unsigned int	offset;  /* DMA addr offset */
+	unsigned int	frag_size;
 };
 
 struct page_pool {
@@ -91,6 +92,8 @@ struct page_pool {
 	unsigned long defer_warn;
 
 	u32 pages_state_hold_cnt;
+	unsigned int frag_offset;
+	struct page *frag_page;
 
 	/*
 	 * Data structure for allocation side
@@ -140,6 +143,17 @@ static inline struct page *page_pool_dev_alloc_pages(struct page_pool *pool)
 	return page_pool_alloc_pages(pool, gfp);
 }
 
+struct page *page_pool_alloc_frag(struct page_pool *pool,
+				  unsigned int *offset, gfp_t gfp);
+
+static inline struct page *page_pool_dev_alloc_frag(struct page_pool *pool,
+						    unsigned int *offset)
+{
+	gfp_t gfp = (GFP_ATOMIC | __GFP_NOWARN);
+
+	return page_pool_alloc_frag(pool, offset, gfp);
+}
+
 /* get the stored dma direction. A driver might decide to treat this locally and
  * avoid the extra cache line from page_pool to determine the direction
  */
diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index a87cbe1..b787033 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
@@ -350,6 +350,53 @@ struct page *page_pool_alloc_pages(struct page_pool *pool, gfp_t gfp)
 }
 EXPORT_SYMBOL(page_pool_alloc_pages);
 
+struct page *page_pool_alloc_frag(struct page_pool *pool,
+				  unsigned int *offset, gfp_t gfp)
+{
+	unsigned int frag_offset = pool->frag_offset;
+	unsigned int frag_size = pool->p.frag_size;
+	struct page *frag_page = pool->frag_page;
+	unsigned int max_len = pool->p.max_len;
+
+	if (!frag_page || frag_offset + frag_size > max_len) {
+		frag_page = page_pool_alloc_pages(pool, gfp);
+		if (unlikely(!frag_page)) {
+			pool->frag_page = NULL;
+			return NULL;
+		}
+
+		pool->frag_page = frag_page;
+		frag_offset = 0;
+
+		page_pool_sub_bias(pool, frag_page,
+				   max_len / frag_size - 1);
+	}
+
+	*offset = frag_offset;
+	pool->frag_offset = frag_offset + frag_size;
+
+	return frag_page;
+}
+EXPORT_SYMBOL(page_pool_alloc_frag);
+
+static void page_pool_empty_frag(struct page_pool *pool)
+{
+	unsigned int frag_offset = pool->frag_offset;
+	unsigned int frag_size = pool->p.frag_size;
+	struct page *frag_page = pool->frag_page;
+	unsigned int max_len = pool->p.max_len;
+
+	if (!frag_page)
+		return;
+
+	while (frag_offset + frag_size <= max_len) {
+		page_pool_put_full_page(pool, frag_page, false);
+		frag_offset += frag_size;
+	}
+
+	pool->frag_page = NULL;
+}
+
 /* Calculate distance between two u32 values, valid if distance is below 2^(31)
  *  https://en.wikipedia.org/wiki/Serial_number_arithmetic#General_Solution
  */
@@ -670,6 +717,8 @@ void page_pool_destroy(struct page_pool *pool)
 	if (!page_pool_put(pool))
 		return;
 
+	page_pool_empty_frag(pool);
+
 	if (!page_pool_release(pool))
 		return;
 
-- 
2.7.4


  parent reply	other threads:[~2021-07-10  7:44 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-10  7:43 [PATCH rfc v2 0/5] add elevated refcnt support " Yunsheng Lin
2021-07-10  7:43 ` [PATCH rfc v2 1/5] page_pool: keep pp info as long as page pool owns the page Yunsheng Lin
2021-07-10  7:43 ` [PATCH rfc v2 2/5] page_pool: add interface for getting and setting pagecnt_bias Yunsheng Lin
2021-07-10 16:55   ` Alexander Duyck
2021-07-12  7:44     ` Yunsheng Lin
2021-07-10  7:43 ` [PATCH rfc v2 3/5] page_pool: add page recycling support based on elevated refcnt Yunsheng Lin
2021-07-10 17:24   ` Alexander Duyck
2021-07-12  7:54     ` Yunsheng Lin
2021-07-10 17:31   ` Alexander Duyck
2021-07-12  2:06     ` Yunsheng Lin
2021-07-12  3:30       ` Alexander Duyck
2021-07-10  7:43 ` Yunsheng Lin [this message]
2021-07-10 17:43   ` [PATCH rfc v2 4/5] page_pool: support page frag API for page pool Alexander Duyck
2021-07-12  7:57     ` Yunsheng Lin
2021-07-10  7:43 ` [PATCH rfc v2 5/5] net: hns3: support skb's frag page recycling based on " Yunsheng Lin
2021-07-10 15:40 ` [PATCH rfc v2 0/5] add elevated refcnt support for " Matteo Croce

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1625903002-31619-5-git-send-email-linyunsheng@huawei.com \
    --to=linyunsheng@huawei.com \
    --cc=akpm@linux-foundation.org \
    --cc=alexander.duyck@gmail.com \
    --cc=alobakin@pm.me \
    --cc=ast@kernel.org \
    --cc=bpf@vger.kernel.org \
    --cc=cong.wang@bytedance.com \
    --cc=daniel@iogearbox.net \
    --cc=davem@davemloft.net \
    --cc=elver@google.com \
    --cc=feng.tang@intel.com \
    --cc=fenghua.yu@intel.com \
    --cc=guro@fb.com \
    --cc=haokexin@gmail.com \
    --cc=hawk@kernel.org \
    --cc=hughd@google.com \
    --cc=ilias.apalodimas@linaro.org \
    --cc=jgg@ziepe.ca \
    --cc=john.fastabend@gmail.com \
    --cc=jonathan.lemon@gmail.com \
    --cc=kuba@kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux@armlinux.org.uk \
    --cc=linuxarm@openeuler.org \
    --cc=mcroce@microsoft.com \
    --cc=mw@semihalf.com \
    --cc=netdev@vger.kernel.org \
    --cc=nogikh@google.com \
    --cc=peterx@redhat.com \
    --cc=peterz@infradead.org \
    --cc=salil.mehta@huawei.com \
    --cc=thomas.petazzoni@bootlin.com \
    --cc=vbabka@suse.cz \
    --cc=wenxu@ucloud.cn \
    --cc=will@kernel.org \
    --cc=willemb@google.com \
    --cc=willy@infradead.org \
    --cc=yisen.zhuang@huawei.com \
    --subject='Re: [PATCH rfc v2 4/5] page_pool: support page frag API for page pool' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).