mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-12 05:48:40 +00:00
![Jesper Dangaard Brouer](/assets/img/avatar_default.png)
When Jonathan change the page_pool to become responsible to its own shutdown via deferred work queue, then the disconnect_cnt counter was removed from xdp memory model tracepoint. This patch change the page_pool_inflight tracepoint name to page_pool_release, because it reflects the new responsability better. And it reintroduces a counter that reflect the number of times page_pool_release have been tried. The counter is also used by the code, to only empty the alloc cache once. With a stuck work queue running every second and counter being 64-bit, it will overrun in approx 584 billion years. For comparison, Earth lifetime expectancy is 7.5 billion years, before the Sun will engulf, and destroy, the Earth. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
207 lines
6.2 KiB
C
207 lines
6.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0
|
|
*
|
|
* page_pool.h
|
|
* Author: Jesper Dangaard Brouer <netoptimizer@brouer.com>
|
|
* Copyright (C) 2016 Red Hat, Inc.
|
|
*/
|
|
|
|
/**
|
|
* DOC: page_pool allocator
|
|
*
|
|
* This page_pool allocator is optimized for the XDP mode that
|
|
* uses one-frame-per-page, but have fallbacks that act like the
|
|
* regular page allocator APIs.
|
|
*
|
|
* Basic use involve replacing alloc_pages() calls with the
|
|
* page_pool_alloc_pages() call. Drivers should likely use
|
|
* page_pool_dev_alloc_pages() replacing dev_alloc_pages().
|
|
*
|
|
* API keeps track of in-flight pages, in-order to let API user know
|
|
* when it is safe to dealloactor page_pool object. Thus, API users
|
|
* must make sure to call page_pool_release_page() when a page is
|
|
* "leaving" the page_pool. Or call page_pool_put_page() where
|
|
* appropiate. For maintaining correct accounting.
|
|
*
|
|
* API user must only call page_pool_put_page() once on a page, as it
|
|
* will either recycle the page, or in case of elevated refcnt, it
|
|
* will release the DMA mapping and in-flight state accounting. We
|
|
* hope to lift this requirement in the future.
|
|
*/
|
|
#ifndef _NET_PAGE_POOL_H
|
|
#define _NET_PAGE_POOL_H
|
|
|
|
#include <linux/mm.h> /* Needed by ptr_ring */
|
|
#include <linux/ptr_ring.h>
|
|
#include <linux/dma-direction.h>
|
|
|
|
#define PP_FLAG_DMA_MAP 1 /* Should page_pool do the DMA map/unmap */
|
|
#define PP_FLAG_ALL PP_FLAG_DMA_MAP
|
|
|
|
/*
|
|
* Fast allocation side cache array/stack
|
|
*
|
|
* The cache size and refill watermark is related to the network
|
|
* use-case. The NAPI budget is 64 packets. After a NAPI poll the RX
|
|
* ring is usually refilled and the max consumed elements will be 64,
|
|
* thus a natural max size of objects needed in the cache.
|
|
*
|
|
* Keeping room for more objects, is due to XDP_DROP use-case. As
|
|
* XDP_DROP allows the opportunity to recycle objects directly into
|
|
* this array, as it shares the same softirq/NAPI protection. If
|
|
* cache is already full (or partly full) then the XDP_DROP recycles
|
|
* would have to take a slower code path.
|
|
*/
|
|
#define PP_ALLOC_CACHE_SIZE 128
|
|
#define PP_ALLOC_CACHE_REFILL 64
|
|
struct pp_alloc_cache {
|
|
u32 count;
|
|
void *cache[PP_ALLOC_CACHE_SIZE];
|
|
};
|
|
|
|
struct page_pool_params {
|
|
unsigned int flags;
|
|
unsigned int order;
|
|
unsigned int pool_size;
|
|
int nid; /* Numa node id to allocate from pages from */
|
|
struct device *dev; /* device, for DMA pre-mapping purposes */
|
|
enum dma_data_direction dma_dir; /* DMA mapping direction */
|
|
};
|
|
|
|
struct page_pool {
|
|
struct page_pool_params p;
|
|
|
|
struct delayed_work release_dw;
|
|
void (*disconnect)(void *);
|
|
unsigned long defer_start;
|
|
unsigned long defer_warn;
|
|
|
|
u32 pages_state_hold_cnt;
|
|
|
|
/*
|
|
* Data structure for allocation side
|
|
*
|
|
* Drivers allocation side usually already perform some kind
|
|
* of resource protection. Piggyback on this protection, and
|
|
* require driver to protect allocation side.
|
|
*
|
|
* For NIC drivers this means, allocate a page_pool per
|
|
* RX-queue. As the RX-queue is already protected by
|
|
* Softirq/BH scheduling and napi_schedule. NAPI schedule
|
|
* guarantee that a single napi_struct will only be scheduled
|
|
* on a single CPU (see napi_schedule).
|
|
*/
|
|
struct pp_alloc_cache alloc ____cacheline_aligned_in_smp;
|
|
|
|
/* Data structure for storing recycled pages.
|
|
*
|
|
* Returning/freeing pages is more complicated synchronization
|
|
* wise, because free's can happen on remote CPUs, with no
|
|
* association with allocation resource.
|
|
*
|
|
* Use ptr_ring, as it separates consumer and producer
|
|
* effeciently, it a way that doesn't bounce cache-lines.
|
|
*
|
|
* TODO: Implement bulk return pages into this structure.
|
|
*/
|
|
struct ptr_ring ring;
|
|
|
|
atomic_t pages_state_release_cnt;
|
|
|
|
/* A page_pool is strictly tied to a single RX-queue being
|
|
* protected by NAPI, due to above pp_alloc_cache. This
|
|
* 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);
|
|
|
|
static inline struct page *page_pool_dev_alloc_pages(struct page_pool *pool)
|
|
{
|
|
gfp_t gfp = (GFP_ATOMIC | __GFP_NOWARN);
|
|
|
|
return page_pool_alloc_pages(pool, 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
|
|
*/
|
|
static
|
|
inline enum dma_data_direction page_pool_get_dma_dir(struct page_pool *pool)
|
|
{
|
|
return pool->p.dma_dir;
|
|
}
|
|
|
|
struct page_pool *page_pool_create(const struct page_pool_params *params);
|
|
|
|
#ifdef CONFIG_PAGE_POOL
|
|
void page_pool_destroy(struct page_pool *pool);
|
|
void page_pool_use_xdp_mem(struct page_pool *pool, void (*disconnect)(void *));
|
|
#else
|
|
static inline void page_pool_destroy(struct page_pool *pool)
|
|
{
|
|
}
|
|
|
|
static inline void page_pool_use_xdp_mem(struct page_pool *pool,
|
|
void (*disconnect)(void *))
|
|
{
|
|
}
|
|
#endif
|
|
|
|
/* Never call this directly, use helpers below */
|
|
void __page_pool_put_page(struct page_pool *pool,
|
|
struct page *page, bool allow_direct);
|
|
|
|
static inline void page_pool_put_page(struct page_pool *pool,
|
|
struct page *page, bool allow_direct)
|
|
{
|
|
/* When page_pool isn't compiled-in, net/core/xdp.c doesn't
|
|
* allow registering MEM_TYPE_PAGE_POOL, but shield linker.
|
|
*/
|
|
#ifdef CONFIG_PAGE_POOL
|
|
__page_pool_put_page(pool, page, allow_direct);
|
|
#endif
|
|
}
|
|
/* Very limited use-cases allow recycle direct */
|
|
static inline void page_pool_recycle_direct(struct page_pool *pool,
|
|
struct page *page)
|
|
{
|
|
__page_pool_put_page(pool, page, true);
|
|
}
|
|
|
|
/* Disconnects a page (from a page_pool). API users can have a need
|
|
* to disconnect a page (from a page_pool), to allow it to be used as
|
|
* a regular page (that will eventually be returned to the normal
|
|
* page-allocator via put_page).
|
|
*/
|
|
void page_pool_unmap_page(struct page_pool *pool, struct page *page);
|
|
static inline void page_pool_release_page(struct page_pool *pool,
|
|
struct page *page)
|
|
{
|
|
#ifdef CONFIG_PAGE_POOL
|
|
page_pool_unmap_page(pool, page);
|
|
#endif
|
|
}
|
|
|
|
static inline dma_addr_t page_pool_get_dma_addr(struct page *page)
|
|
{
|
|
return page->dma_addr;
|
|
}
|
|
|
|
static inline bool is_page_pool_compiled_in(void)
|
|
{
|
|
#ifdef CONFIG_PAGE_POOL
|
|
return true;
|
|
#else
|
|
return false;
|
|
#endif
|
|
}
|
|
|
|
static inline bool page_pool_put(struct page_pool *pool)
|
|
{
|
|
return refcount_dec_and_test(&pool->user_cnt);
|
|
}
|
|
|
|
#endif /* _NET_PAGE_POOL_H */
|