Commit 6960f7e3 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'page_pool-followup-changes-to-restore-tracepoint-features' 



Jesper Dangaard says:

====================
page_pool: followup changes to restore tracepoint features

This patchset is a followup to Jonathan patch, that do not release
pool until inflight == 0. That changed page_pool to be responsible for
its own delayed destruction instead of relying on xdp memory model.

As the page_pool maintainer, I'm promoting the use of tracepoint to
troubleshoot and help driver developers verify correctness when
converting at driver to use page_pool. The role of xdp:mem_disconnect
have changed, which broke my bpftrace tools for shutdown verification.
With these changes, the same capabilities are regained.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents b95e86d8 832ccf6f

include/net/page_pool.h

+2 −0
Original line number Diff line number Diff line
@@ -112,6 +112,8 @@ struct page_pool { 
	 * refcnt serves purpose is to simplify drivers error handling.

	 */

	refcount_t user_cnt;



	u64 destroy_cnt;

};



struct page *page_pool_alloc_pages(struct page_pool *pool, gfp_t gfp);

include/trace/events/page_pool.h

+15 −7
Original line number Diff line number Diff line
@@ -8,9 +8,10 @@ 
#include <linux/types.h>

#include <linux/tracepoint.h>



#include <trace/events/mmflags.h>

#include <net/page_pool.h>



TRACE_EVENT(page_pool_inflight,

TRACE_EVENT(page_pool_release,



	TP_PROTO(const struct page_pool *pool,

		 s32 inflight, u32 hold, u32 release),
@@ -22,6 +23,7 @@ TRACE_EVENT(page_pool_inflight, 
		__field(s32,	inflight)

		__field(u32,	hold)

		__field(u32,	release)

		__field(u64,	cnt)

	),



	TP_fast_assign(
@@ -29,10 +31,12 @@ TRACE_EVENT(page_pool_inflight, 
		__entry->inflight	= inflight;

		__entry->hold		= hold;

		__entry->release	= release;

		__entry->cnt		= pool->destroy_cnt;

	),



	TP_printk("page_pool=%p inflight=%d hold=%u release=%u",

	  __entry->pool, __entry->inflight, __entry->hold, __entry->release)

	TP_printk("page_pool=%p inflight=%d hold=%u release=%u cnt=%llu",

		__entry->pool, __entry->inflight, __entry->hold,

		__entry->release, __entry->cnt)

);



TRACE_EVENT(page_pool_state_release,
@@ -46,16 +50,18 @@ TRACE_EVENT(page_pool_state_release, 
		__field(const struct page_pool *,	pool)

		__field(const struct page *,		page)

		__field(u32,				release)

		__field(unsigned long,			pfn)

	),



	TP_fast_assign(

		__entry->pool		= pool;

		__entry->page		= page;

		__entry->release	= release;

		__entry->pfn		= page_to_pfn(page);

	),



	TP_printk("page_pool=%p page=%p release=%u",

		  __entry->pool, __entry->page, __entry->release)

	TP_printk("page_pool=%p page=%p pfn=%lu release=%u",

		  __entry->pool, __entry->page, __entry->pfn, __entry->release)

);



TRACE_EVENT(page_pool_state_hold,
@@ -69,16 +75,18 @@ TRACE_EVENT(page_pool_state_hold, 
		__field(const struct page_pool *,	pool)

		__field(const struct page *,		page)

		__field(u32,				hold)

		__field(unsigned long,			pfn)

	),



	TP_fast_assign(

		__entry->pool	= pool;

		__entry->page	= page;

		__entry->hold	= hold;

		__entry->pfn	= page_to_pfn(page);

	),



	TP_printk("page_pool=%p page=%p hold=%u",

		  __entry->pool, __entry->page, __entry->hold)

	TP_printk("page_pool=%p page=%p pfn=%lu hold=%u",

		  __entry->pool, __entry->page, __entry->pfn, __entry->hold)

);



#endif /* _TRACE_PAGE_POOL_H */

net/core/page_pool.c

+11 −2
Original line number Diff line number Diff line
@@ -200,7 +200,7 @@ static s32 page_pool_inflight(struct page_pool *pool) 


	inflight = _distance(hold_cnt, release_cnt);



	trace_page_pool_inflight(pool, inflight, hold_cnt, release_cnt);

	trace_page_pool_release(pool, inflight, hold_cnt, release_cnt);

	WARN(inflight < 0, "Negative(%d) inflight packet-pages", inflight);



	return inflight;
@@ -349,10 +349,13 @@ static void page_pool_free(struct page_pool *pool) 
	kfree(pool);

}



static void page_pool_scrub(struct page_pool *pool)

static void page_pool_empty_alloc_cache_once(struct page_pool *pool)

{

	struct page *page;



	if (pool->destroy_cnt)

		return;



	/* Empty alloc cache, assume caller made sure this is

	 * no-longer in use, and page_pool_alloc_pages() cannot be

	 * call concurrently.
@@ -361,6 +364,12 @@ static void page_pool_scrub(struct page_pool *pool) 
		page = pool->alloc.cache[--pool->alloc.count];

		__page_pool_return_page(pool, page);

	}

}



static void page_pool_scrub(struct page_pool *pool)

{

	page_pool_empty_alloc_cache_once(pool);

	pool->destroy_cnt++;



	/* No more consumers should exist, but producers could still

	 * be in-flight.

net/core/xdp.c

+0 −5
Original line number Diff line number Diff line
@@ -73,11 +73,6 @@ static void __xdp_mem_allocator_rcu_free(struct rcu_head *rcu) 
	/* Allow this ID to be reused */

	ida_simple_remove(&mem_id_pool, xa->mem.id);



	/* Poison memory */

	xa->mem.id = 0xFFFF;

	xa->mem.type = 0xF0F0;

	xa->allocator = (void *)0xDEAD9001;



	kfree(xa);

}