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[PATCH net-next v19 05/13] page_pool: devmem support

by Mina Almasry

Convert netmem to be a union of struct page and struct netmem. Overload the LSB of struct netmem* to indicate that it's a net_iov, otherwise it's a page. Currently these entries in struct page are rented by the page_pool and used exclusively by the net stack: struct { unsigned long pp_magic; struct page_pool *pp; unsigned long _pp_mapping_pad; unsigned long dma_addr; atomic_long_t pp_ref_count; }; Mirror these (and only these) entries into struct net_iov and implement netmem helpers that can access these common fields regardless of whether the underlying type is page or net_iov. Implement checks for net_iov in netmem helpers which delegate to mm APIs, to ensure net_iov are never passed to the mm stack. Signed-off-by: Mina Almasry <almasrymina(a)google.com> Reviewed-by: Pavel Begunkov <asml.silence(a)gmail.com> --- v19: - Move page_pool_set_dma_addr(_netmem) to page_pool_priv.h - Don't reset niov dma_addr on allocation/free. Instead, it's set once when the binding happens and it never changes (Jakub) v17: - Rename netmem_to_pfn to netmem_pfn_trace (Jakub) - Move some low level netmem helpers to netmem_priv.h (Jakub). v13: - Move NET_IOV dependent changes to this patch. - Fixed comment (Pavel) - Applied Reviewed-by from Pavel. v9: https://lore.kernel.org/netdev/20240403002053.2376017-8-almasrymina@google.… - Remove CONFIG checks in netmem_is_net_iov() (Pavel/David/Jens) v7: - Remove static_branch_unlikely from netmem_to_net_iov(). We're getting better results from the fast path in bench_page_pool_simple tests without the static_branch_unlikely, and the addition of static_branch_unlikely doesn't improve performance of devmem TCP. Additionally only check netmem_to_net_iov() if CONFIG_DMA_SHARED_BUFFER is enabled, otherwise dmabuf net_iovs cannot exist anyway. net-next base: 8 cycle fast path. with static_branch_unlikely: 10 cycle fast path. without static_branch_unlikely: 9 cycle fast path. CONFIG_DMA_SHARED_BUFFER disabled: 8 cycle fast path as baseline. Performance of devmem TCP is at 95% line rate is regardless of static_branch_unlikely or not. v6: - Rebased on top of the merged netmem_ref type. - Rebased on top of the merged skb_pp_frag_ref() changes. v5: - Use netmem instead of page* with LSB set. - Use pp_ref_count for refcounting net_iov. - Removed many of the custom checks for netmem. v1: - Disable fragmentation support for iov properly. - fix napi_pp_put_page() path (Yunsheng). - Use pp_frag_count for devmem refcounting. Cc: linux-mm(a)kvack.org Cc: Matthew Wilcox <willy(a)infradead.org> --- include/net/netmem.h | 128 +++++++++++++++++++++++++++++-- include/net/page_pool/helpers.h | 39 ++-------- include/trace/events/page_pool.h | 12 +-- net/core/devmem.c | 8 ++ net/core/netmem_priv.h | 31 ++++++++ net/core/page_pool.c | 25 +++--- net/core/page_pool_priv.h | 24 ++++++ net/core/skbuff.c | 23 +++--- 8 files changed, 221 insertions(+), 69 deletions(-) create mode 100644 net/core/netmem_priv.h diff --git a/include/net/netmem.h b/include/net/netmem.h index 664df8325ece..284f84a312c2 100644 --- a/include/net/netmem.h +++ b/include/net/netmem.h @@ -9,14 +9,51 @@ #define _NET_NETMEM_H #include <net/devmem.h> +#include <net/net_debug.h> /* net_iov */ +DECLARE_STATIC_KEY_FALSE(page_pool_mem_providers); + +/* We overload the LSB of the struct page pointer to indicate whether it's + * a page or net_iov. + */ +#define NET_IOV 0x01UL + struct net_iov { + unsigned long __unused_padding; + unsigned long pp_magic; + struct page_pool *pp; struct dmabuf_genpool_chunk_owner *owner; unsigned long dma_addr; + atomic_long_t pp_ref_count; }; +/* These fields in struct page are used by the page_pool and net stack: + * + * struct { + * unsigned long pp_magic; + * struct page_pool *pp; + * unsigned long _pp_mapping_pad; + * unsigned long dma_addr; + * atomic_long_t pp_ref_count; + * }; + * + * We mirror the page_pool fields here so the page_pool can access these fields + * without worrying whether the underlying fields belong to a page or net_iov. + * + * The non-net stack fields of struct page are private to the mm stack and must + * never be mirrored to net_iov. + */ +#define NET_IOV_ASSERT_OFFSET(pg, iov) \ + static_assert(offsetof(struct page, pg) == \ + offsetof(struct net_iov, iov)) +NET_IOV_ASSERT_OFFSET(pp_magic, pp_magic); +NET_IOV_ASSERT_OFFSET(pp, pp); +NET_IOV_ASSERT_OFFSET(dma_addr, dma_addr); +NET_IOV_ASSERT_OFFSET(pp_ref_count, pp_ref_count); +#undef NET_IOV_ASSERT_OFFSET + static inline struct dmabuf_genpool_chunk_owner * net_iov_owner(const struct net_iov *niov) { @@ -47,20 +84,37 @@ net_iov_binding(const struct net_iov *niov) */ typedef unsigned long __bitwise netmem_ref; +static inline bool netmem_is_net_iov(const netmem_ref netmem) +{ + return (__force unsigned long)netmem & NET_IOV; +} + /* This conversion fails (returns NULL) if the netmem_ref is not struct page * backed. - * - * Currently struct page is the only possible netmem, and this helper never - * fails. */ static inline struct page *netmem_to_page(netmem_ref netmem) { + if (WARN_ON_ONCE(netmem_is_net_iov(netmem))) + return NULL; + return (__force struct page *)netmem; } -/* Converting from page to netmem is always safe, because a page can always be - * a netmem. - */ +static inline struct net_iov *netmem_to_net_iov(netmem_ref netmem) +{ + if (netmem_is_net_iov(netmem)) + return (struct net_iov *)((__force unsigned long)netmem & + ~NET_IOV); + + DEBUG_NET_WARN_ON_ONCE(true); + return NULL; +} + +static inline netmem_ref net_iov_to_netmem(struct net_iov *niov) +{ + return (__force netmem_ref)((unsigned long)niov | NET_IOV); +} + static inline netmem_ref page_to_netmem(struct page *page) { return (__force netmem_ref)page; @@ -68,17 +122,77 @@ static inline netmem_ref page_to_netmem(struct page *page) static inline int netmem_ref_count(netmem_ref netmem) { + /* The non-pp refcount of net_iov is always 1. On net_iov, we only + * support pp refcounting which uses the pp_ref_count field. + */ + if (netmem_is_net_iov(netmem)) + return 1; + return page_ref_count(netmem_to_page(netmem)); } -static inline unsigned long netmem_to_pfn(netmem_ref netmem) +static inline unsigned long netmem_pfn_trace(netmem_ref netmem) { + if (netmem_is_net_iov(netmem)) + return 0; + return page_to_pfn(netmem_to_page(netmem)); } +static inline struct net_iov *__netmem_clear_lsb(netmem_ref netmem) +{ + return (struct net_iov *)((__force unsigned long)netmem & ~NET_IOV); +} + +static inline struct page_pool *netmem_get_pp(netmem_ref netmem) +{ + return __netmem_clear_lsb(netmem)->pp; +} + +static inline atomic_long_t *netmem_get_pp_ref_count_ref(netmem_ref netmem) +{ + return &__netmem_clear_lsb(netmem)->pp_ref_count; +} + +static inline bool netmem_is_pref_nid(netmem_ref netmem, int pref_nid) +{ + /* Assume net_iov are on the preferred node without actually + * checking... + * + * This check is only used to check for recycling memory in the page + * pool's fast paths. Currently the only implementation of net_iov + * is dmabuf device memory. It's a deliberate decision by the user to + * bind a certain dmabuf to a certain netdev, and the netdev rx queue + * would not be able to reallocate memory from another dmabuf that + * exists on the preferred node, so, this check doesn't make much sense + * in this case. Assume all net_iovs can be recycled for now. + */ + if (netmem_is_net_iov(netmem)) + return true; + + return page_to_nid(netmem_to_page(netmem)) == pref_nid; +} + static inline netmem_ref netmem_compound_head(netmem_ref netmem) { + /* niov are never compounded */ + if (netmem_is_net_iov(netmem)) + return netmem; + return page_to_netmem(compound_head(netmem_to_page(netmem))); } +static inline void *netmem_address(netmem_ref netmem) +{ + if (netmem_is_net_iov(netmem)) + return NULL; + + return page_address(netmem_to_page(netmem)); +} + +static inline unsigned long netmem_get_dma_addr(netmem_ref netmem) +{ + return __netmem_clear_lsb(netmem)->dma_addr; +} + #endif /* _NET_NETMEM_H */ diff --git a/include/net/page_pool/helpers.h b/include/net/page_pool/helpers.h index 2b43a893c619..793e6fd78bc5 100644 --- a/include/net/page_pool/helpers.h +++ b/include/net/page_pool/helpers.h @@ -216,7 +216,7 @@ page_pool_get_dma_dir(const struct page_pool *pool) static inline void page_pool_fragment_netmem(netmem_ref netmem, long nr) { - atomic_long_set(&netmem_to_page(netmem)->pp_ref_count, nr); + atomic_long_set(netmem_get_pp_ref_count_ref(netmem), nr); } /** @@ -244,7 +244,7 @@ static inline void page_pool_fragment_page(struct page *page, long nr) static inline long page_pool_unref_netmem(netmem_ref netmem, long nr) { - struct page *page = netmem_to_page(netmem); + atomic_long_t *pp_ref_count = netmem_get_pp_ref_count_ref(netmem); long ret; /* If nr == pp_ref_count then we have cleared all remaining @@ -261,19 +261,19 @@ static inline long page_pool_unref_netmem(netmem_ref netmem, long nr) * initially, and only overwrite it when the page is partitioned into * more than one piece. */ - if (atomic_long_read(&page->pp_ref_count) == nr) { + if (atomic_long_read(pp_ref_count) == nr) { /* As we have ensured nr is always one for constant case using * the BUILD_BUG_ON(), only need to handle the non-constant case * here for pp_ref_count draining, which is a rare case. */ BUILD_BUG_ON(__builtin_constant_p(nr) && nr != 1); if (!__builtin_constant_p(nr)) - atomic_long_set(&page->pp_ref_count, 1); + atomic_long_set(pp_ref_count, 1); return 0; } - ret = atomic_long_sub_return(nr, &page->pp_ref_count); + ret = atomic_long_sub_return(nr, pp_ref_count); WARN_ON(ret < 0); /* We are the last user here too, reset pp_ref_count back to 1 to @@ -282,7 +282,7 @@ static inline long page_pool_unref_netmem(netmem_ref netmem, long nr) * page_pool_unref_page() currently. */ if (unlikely(!ret)) - atomic_long_set(&page->pp_ref_count, 1); + atomic_long_set(pp_ref_count, 1); return ret; } @@ -401,9 +401,7 @@ static inline void page_pool_free_va(struct page_pool *pool, void *va, static inline dma_addr_t page_pool_get_dma_addr_netmem(netmem_ref netmem) { - struct page *page = netmem_to_page(netmem); - - dma_addr_t ret = page->dma_addr; + dma_addr_t ret = netmem_get_dma_addr(netmem); if (PAGE_POOL_32BIT_ARCH_WITH_64BIT_DMA) ret <<= PAGE_SHIFT; @@ -423,24 +421,6 @@ static inline dma_addr_t page_pool_get_dma_addr(const struct page *page) return page_pool_get_dma_addr_netmem(page_to_netmem((struct page *)page)); } -static inline bool page_pool_set_dma_addr_netmem(netmem_ref netmem, - dma_addr_t addr) -{ - struct page *page = netmem_to_page(netmem); - - if (PAGE_POOL_32BIT_ARCH_WITH_64BIT_DMA) { - page->dma_addr = addr >> PAGE_SHIFT; - - /* We assume page alignment to shave off bottom bits, - * if this "compression" doesn't work we need to drop. - */ - return addr != (dma_addr_t)page->dma_addr << PAGE_SHIFT; - } - - page->dma_addr = addr; - return false; -} - /** * page_pool_dma_sync_for_cpu - sync Rx page for CPU after it's written by HW * @pool: &page_pool the @page belongs to @@ -463,11 +443,6 @@ static inline void page_pool_dma_sync_for_cpu(const struct page_pool *pool, page_pool_get_dma_dir(pool)); } -static inline bool page_pool_set_dma_addr(struct page *page, dma_addr_t addr) -{ - return page_pool_set_dma_addr_netmem(page_to_netmem(page), addr); -} - static inline bool page_pool_put(struct page_pool *pool) { return refcount_dec_and_test(&pool->user_cnt); diff --git a/include/trace/events/page_pool.h b/include/trace/events/page_pool.h index 543e54e432a1..31825ed30032 100644 --- a/include/trace/events/page_pool.h +++ b/include/trace/events/page_pool.h @@ -57,12 +57,12 @@ TRACE_EVENT(page_pool_state_release, __entry->pool = pool; __entry->netmem = (__force unsigned long)netmem; __entry->release = release; - __entry->pfn = netmem_to_pfn(netmem); + __entry->pfn = netmem_pfn_trace(netmem); ), - TP_printk("page_pool=%p netmem=%p pfn=0x%lx release=%u", + TP_printk("page_pool=%p netmem=%p is_net_iov=%lu pfn=0x%lx release=%u", __entry->pool, (void *)__entry->netmem, - __entry->pfn, __entry->release) + __entry->netmem & NET_IOV, __entry->pfn, __entry->release) ); TRACE_EVENT(page_pool_state_hold, @@ -83,12 +83,12 @@ TRACE_EVENT(page_pool_state_hold, __entry->pool = pool; __entry->netmem = (__force unsigned long)netmem; __entry->hold = hold; - __entry->pfn = netmem_to_pfn(netmem); + __entry->pfn = netmem_pfn_trace(netmem); ), - TP_printk("page_pool=%p netmem=%p pfn=0x%lx hold=%u", + TP_printk("page_pool=%p netmem=%p is_net_iov=%lu, pfn=0x%lx hold=%u", __entry->pool, (void *)__entry->netmem, - __entry->pfn, __entry->hold) + __entry->netmem & NET_IOV, __entry->pfn, __entry->hold) ); TRACE_EVENT(page_pool_update_nid, diff --git a/net/core/devmem.c b/net/core/devmem.c index 88d188149148..301f4250ca82 100644 --- a/net/core/devmem.c +++ b/net/core/devmem.c @@ -19,6 +19,8 @@ #include <net/devmem.h> #include <net/netdev_queues.h> +#include "page_pool_priv.h" + /* Device memory support */ /* Protected by rtnl_lock() */ @@ -83,6 +85,10 @@ net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding) index = offset / PAGE_SIZE; niov = &owner->niovs[index]; + niov->pp_magic = 0; + niov->pp = NULL; + atomic_long_set(&niov->pp_ref_count, 0); + return niov; } @@ -255,6 +261,8 @@ struct net_devmem_dmabuf_binding *net_devmem_bind_dmabuf(struct net_device *dev, for (i = 0; i < owner->num_niovs; i++) { niov = &owner->niovs[i]; niov->owner = owner; + page_pool_set_dma_addr_netmem(net_iov_to_netmem(niov), + net_devmem_get_dma_addr(niov)); } virtual += len; diff --git a/net/core/netmem_priv.h b/net/core/netmem_priv.h new file mode 100644 index 000000000000..7eadb8393e00 --- /dev/null +++ b/net/core/netmem_priv.h @@ -0,0 +1,31 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef __NETMEM_PRIV_H +#define __NETMEM_PRIV_H + +static inline unsigned long netmem_get_pp_magic(netmem_ref netmem) +{ + return __netmem_clear_lsb(netmem)->pp_magic; +} + +static inline void netmem_or_pp_magic(netmem_ref netmem, unsigned long pp_magic) +{ + __netmem_clear_lsb(netmem)->pp_magic |= pp_magic; +} + +static inline void netmem_clear_pp_magic(netmem_ref netmem) +{ + __netmem_clear_lsb(netmem)->pp_magic = 0; +} + +static inline void netmem_set_pp(netmem_ref netmem, struct page_pool *pool) +{ + __netmem_clear_lsb(netmem)->pp = pool; +} + +static inline void netmem_set_dma_addr(netmem_ref netmem, + unsigned long dma_addr) +{ + __netmem_clear_lsb(netmem)->dma_addr = dma_addr; +} +#endif diff --git a/net/core/page_pool.c b/net/core/page_pool.c index 2abe6e919224..13277f05aebd 100644 --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -25,6 +25,9 @@ #include <trace/events/page_pool.h> #include "page_pool_priv.h" +#include "netmem_priv.h" + +DEFINE_STATIC_KEY_FALSE(page_pool_mem_providers); #define DEFER_TIME (msecs_to_jiffies(1000)) #define DEFER_WARN_INTERVAL (60 * HZ) @@ -358,7 +361,7 @@ static noinline netmem_ref page_pool_refill_alloc_cache(struct page_pool *pool) if (unlikely(!netmem)) break; - if (likely(page_to_nid(netmem_to_page(netmem)) == pref_nid)) { + if (likely(netmem_is_pref_nid(netmem, pref_nid))) { pool->alloc.cache[pool->alloc.count++] = netmem; } else { /* NUMA mismatch; @@ -454,10 +457,8 @@ static bool page_pool_dma_map(struct page_pool *pool, netmem_ref netmem) static void page_pool_set_pp_info(struct page_pool *pool, netmem_ref netmem) { - struct page *page = netmem_to_page(netmem); - - page->pp = pool; - page->pp_magic |= PP_SIGNATURE; + netmem_set_pp(netmem, pool); + netmem_or_pp_magic(netmem, PP_SIGNATURE); /* Ensuring all pages have been split into one fragment initially: * page_pool_set_pp_info() is only called once for every page when it @@ -472,10 +473,8 @@ static void page_pool_set_pp_info(struct page_pool *pool, netmem_ref netmem) static void page_pool_clear_pp_info(netmem_ref netmem) { - struct page *page = netmem_to_page(netmem); - - page->pp_magic = 0; - page->pp = NULL; + netmem_clear_pp_magic(netmem); + netmem_set_pp(netmem, NULL); } static struct page *__page_pool_alloc_page_order(struct page_pool *pool, @@ -692,8 +691,9 @@ static bool page_pool_recycle_in_cache(netmem_ref netmem, static bool __page_pool_page_can_be_recycled(netmem_ref netmem) { - return page_ref_count(netmem_to_page(netmem)) == 1 && - !page_is_pfmemalloc(netmem_to_page(netmem)); + return netmem_is_net_iov(netmem) || + (page_ref_count(netmem_to_page(netmem)) == 1 && + !page_is_pfmemalloc(netmem_to_page(netmem))); } /* If the page refcnt == 1, this will try to recycle the page. @@ -728,6 +728,7 @@ __page_pool_put_page(struct page_pool *pool, netmem_ref netmem, /* Page found as candidate for recycling */ return netmem; } + /* Fallback/non-XDP mode: API user have elevated refcnt. * * Many drivers split up the page into fragments, and some @@ -949,7 +950,7 @@ static void page_pool_empty_ring(struct page_pool *pool) /* Empty recycle ring */ while ((netmem = (__force netmem_ref)ptr_ring_consume_bh(&pool->ring))) { /* Verify the refcnt invariant of cached pages */ - if (!(page_ref_count(netmem_to_page(netmem)) == 1)) + if (!(netmem_ref_count(netmem) == 1)) pr_crit("%s() page_pool refcnt %d violation\n", __func__, netmem_ref_count(netmem)); diff --git a/net/core/page_pool_priv.h b/net/core/page_pool_priv.h index 90665d40f1eb..581501b5cd8c 100644 --- a/net/core/page_pool_priv.h +++ b/net/core/page_pool_priv.h @@ -3,10 +3,34 @@ #ifndef __PAGE_POOL_PRIV_H #define __PAGE_POOL_PRIV_H +#include "netmem_priv.h" + s32 page_pool_inflight(const struct page_pool *pool, bool strict); int page_pool_list(struct page_pool *pool); void page_pool_detached(struct page_pool *pool); void page_pool_unlist(struct page_pool *pool); +static inline bool page_pool_set_dma_addr_netmem(netmem_ref netmem, + dma_addr_t addr) +{ + if (PAGE_POOL_32BIT_ARCH_WITH_64BIT_DMA) { + netmem_set_dma_addr(netmem, addr >> PAGE_SHIFT); + + /* We assume page alignment to shave off bottom bits, + * if this "compression" doesn't work we need to drop. + */ + return addr != (dma_addr_t)netmem_get_dma_addr(netmem) + << PAGE_SHIFT; + } + + netmem_set_dma_addr(netmem, addr); + return false; +} + +static inline bool page_pool_set_dma_addr(struct page *page, dma_addr_t addr) +{ + return page_pool_set_dma_addr_netmem(page_to_netmem(page), addr); +} + #endif diff --git a/net/core/skbuff.c b/net/core/skbuff.c index de2a044cc665..9e2b28342793 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -89,6 +89,7 @@ #include "dev.h" #include "sock_destructor.h" +#include "netmem_priv.h" #ifdef CONFIG_SKB_EXTENSIONS static struct kmem_cache *skbuff_ext_cache __ro_after_init; @@ -920,9 +921,9 @@ static void skb_clone_fraglist(struct sk_buff *skb) skb_get(list); } -static bool is_pp_page(struct page *page) +static bool is_pp_netmem(netmem_ref netmem) { - return (page->pp_magic & ~0x3UL) == PP_SIGNATURE; + return (netmem_get_pp_magic(netmem) & ~0x3UL) == PP_SIGNATURE; } int skb_pp_cow_data(struct page_pool *pool, struct sk_buff **pskb, @@ -1020,9 +1021,7 @@ EXPORT_SYMBOL(skb_cow_data_for_xdp); #if IS_ENABLED(CONFIG_PAGE_POOL) bool napi_pp_put_page(netmem_ref netmem) { - struct page *page = netmem_to_page(netmem); - - page = compound_head(page); + netmem = netmem_compound_head(netmem); /* page->pp_magic is OR'ed with PP_SIGNATURE after the allocation * in order to preserve any existing bits, such as bit 0 for the @@ -1031,10 +1030,10 @@ bool napi_pp_put_page(netmem_ref netmem) * and page_is_pfmemalloc() is checked in __page_pool_put_page() * to avoid recycling the pfmemalloc page. */ - if (unlikely(!is_pp_page(page))) + if (unlikely(!is_pp_netmem(netmem))) return false; - page_pool_put_full_netmem(page->pp, page_to_netmem(page), false); + page_pool_put_full_netmem(netmem_get_pp(netmem), netmem, false); return true; } @@ -1061,7 +1060,7 @@ static bool skb_pp_recycle(struct sk_buff *skb, void *data) static int skb_pp_frag_ref(struct sk_buff *skb) { struct skb_shared_info *shinfo; - struct page *head_page; + netmem_ref head_netmem; int i; if (!skb->pp_recycle) @@ -1070,11 +1069,11 @@ static int skb_pp_frag_ref(struct sk_buff *skb) shinfo = skb_shinfo(skb); for (i = 0; i < shinfo->nr_frags; i++) { - head_page = compound_head(skb_frag_page(&shinfo->frags[i])); - if (likely(is_pp_page(head_page))) - page_pool_ref_page(head_page); + head_netmem = netmem_compound_head(shinfo->frags[i].netmem); + if (likely(is_pp_netmem(head_netmem))) + page_pool_ref_netmem(head_netmem); else - page_ref_inc(head_page); + page_ref_inc(netmem_to_page(head_netmem)); } return 0; } -- 2.46.0.76.ge559c4bf1a-goog

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[PATCH net-next v19 04/13] netdev: netdevice devmem allocator

by Mina Almasry

Implement netdev devmem allocator. The allocator takes a given struct netdev_dmabuf_binding as input and allocates net_iov from that binding. The allocation simply delegates to the binding's genpool for the allocation logic and wraps the returned memory region in a net_iov struct. Signed-off-by: Willem de Bruijn <willemb(a)google.com> Signed-off-by: Kaiyuan Zhang <kaiyuanz(a)google.com> Signed-off-by: Mina Almasry <almasrymina(a)google.com> Reviewed-by: Pavel Begunkov <asml.silence(a)gmail.com> --- v19: - Don't reset dma_addr on allocation/free (Jakub) v17: - Don't acquire a binding ref for every allocation (Jakub). v11: - Fix extraneous inline directive (Paolo) v8: - Rename netdev_dmabuf_binding -> net_devmem_dmabuf_binding to avoid patch-by-patch build error. - Move niov->pp_magic/pp/pp_ref_counter usage to later patch to avoid patch-by-patch build error. v7: - netdev_ -> net_devmem_* naming (Yunsheng). v6: - Add comment on net_iov_dma_addr to explain why we don't use niov->dma_addr (Pavel) - Refactor new functions into net/core/devmem.c (Pavel) v1: - Rename devmem -> dmabuf (David). --- include/net/devmem.h | 13 +++++++++++++ include/net/netmem.h | 18 ++++++++++++++++++ net/core/devmem.c | 38 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 69 insertions(+) diff --git a/include/net/devmem.h b/include/net/devmem.h index c7bd6a0a6b9e..2e7cc46d4d3c 100644 --- a/include/net/devmem.h +++ b/include/net/devmem.h @@ -69,7 +69,20 @@ void net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding); int net_devmem_bind_dmabuf_to_queue(struct net_device *dev, u32 rxq_idx, struct net_devmem_dmabuf_binding *binding); void dev_dmabuf_uninstall(struct net_device *dev); +struct net_iov * +net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding); +void net_devmem_free_dmabuf(struct net_iov *ppiov); #else +static inline struct net_iov * +net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding) +{ + return NULL; +} + +static inline void net_devmem_free_dmabuf(struct net_iov *ppiov) +{ +} + static inline void __net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding) { diff --git a/include/net/netmem.h b/include/net/netmem.h index 41e96c2f94b5..664df8325ece 100644 --- a/include/net/netmem.h +++ b/include/net/netmem.h @@ -14,8 +14,26 @@ struct net_iov { struct dmabuf_genpool_chunk_owner *owner; + unsigned long dma_addr; }; +static inline struct dmabuf_genpool_chunk_owner * +net_iov_owner(const struct net_iov *niov) +{ + return niov->owner; +} + +static inline unsigned int net_iov_idx(const struct net_iov *niov) +{ + return niov - net_iov_owner(niov)->niovs; +} + +static inline struct net_devmem_dmabuf_binding * +net_iov_binding(const struct net_iov *niov) +{ + return net_iov_owner(niov)->binding; +} + /* netmem */ /** diff --git a/net/core/devmem.c b/net/core/devmem.c index 1b693424c17d..88d188149148 100644 --- a/net/core/devmem.c +++ b/net/core/devmem.c @@ -35,6 +35,14 @@ static void net_devmem_dmabuf_free_chunk_owner(struct gen_pool *genpool, kfree(owner); } +static dma_addr_t net_devmem_get_dma_addr(const struct net_iov *niov) +{ + struct dmabuf_genpool_chunk_owner *owner = net_iov_owner(niov); + + return owner->base_dma_addr + + ((dma_addr_t)net_iov_idx(niov) << PAGE_SHIFT); +} + void __net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding) { size_t size, avail; @@ -57,6 +65,36 @@ void __net_devmem_dmabuf_binding_free(struct net_devmem_dmabuf_binding *binding) kfree(binding); } +struct net_iov * +net_devmem_alloc_dmabuf(struct net_devmem_dmabuf_binding *binding) +{ + struct dmabuf_genpool_chunk_owner *owner; + unsigned long dma_addr; + struct net_iov *niov; + ssize_t offset; + ssize_t index; + + dma_addr = gen_pool_alloc_owner(binding->chunk_pool, PAGE_SIZE, + (void **)&owner); + if (!dma_addr) + return NULL; + + offset = dma_addr - owner->base_dma_addr; + index = offset / PAGE_SIZE; + niov = &owner->niovs[index]; + + return niov; +} + +void net_devmem_free_dmabuf(struct net_iov *niov) +{ + struct net_devmem_dmabuf_binding *binding = net_iov_binding(niov); + unsigned long dma_addr = net_devmem_get_dma_addr(niov); + + if (gen_pool_has_addr(binding->chunk_pool, dma_addr, PAGE_SIZE)) + gen_pool_free(binding->chunk_pool, dma_addr, PAGE_SIZE); +} + void net_devmem_unbind_dmabuf(struct net_devmem_dmabuf_binding *binding) { struct netdev_rx_queue *rxq; -- 2.46.0.76.ge559c4bf1a-goog

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[PATCH net-next v19 02/13] net: netdev netlink api to bind dma-buf to a net device

by Mina Almasry

API takes the dma-buf fd as input, and binds it to the netdevice. The user can specify the rx queues to bind the dma-buf to. Suggested-by: Stanislav Fomichev <sdf(a)google.com> Signed-off-by: Mina Almasry <almasrymina(a)google.com> Reviewed-by: Donald Hunter <donald.hunter(a)gmail.com> Reviewed-by: Jakub Kicinski <kuba(a)kernel.org> --- v16: - Use subset-of: queue queue-id instead of queue-dmabuf (Jakub). - Rename attribute 'bind-dmabuf' to more generic 'dmabuf' (Jakub). - Use 'dmabuf' everywhere instead of mix of 'dma-buf' and 'dmabuf' (Donald). - Remove repetitive 'dmabuf' naming that appeared in some places (Jakub). - Reordered where the new operations went so I don't break the enum UAPI (Jakub). v7: - Use flags: [ admin-perm ] instead of a CAP_NET_ADMIN check. Changes in v1: - Add rx-queue-type to distingish rx from tx (Jakub) - Return dma-buf ID from netlink API (David, Stan) Changes in RFC-v3: - Support binding multiple rx rx-queues --- Documentation/netlink/specs/netdev.yaml | 47 +++++++++++++++++++++++++ include/uapi/linux/netdev.h | 11 ++++++ net/core/netdev-genl-gen.c | 19 ++++++++++ net/core/netdev-genl-gen.h | 2 ++ net/core/netdev-genl.c | 6 ++++ tools/include/uapi/linux/netdev.h | 11 ++++++ 6 files changed, 96 insertions(+) diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml index 959755be4d7f..4930e8142aa6 100644 --- a/Documentation/netlink/specs/netdev.yaml +++ b/Documentation/netlink/specs/netdev.yaml @@ -457,6 +457,39 @@ attribute-sets: Number of times driver re-started accepting send requests to this queue from the stack. type: uint + - + name: queue-id + subset-of: queue + attributes: + - + name: id + - + name: type + - + name: dmabuf + attributes: + - + name: ifindex + doc: netdev ifindex to bind the dmabuf to. + type: u32 + checks: + min: 1 + - + name: queues + doc: receive queues to bind the dmabuf to. + type: nest + nested-attributes: queue-id + multi-attr: true + - + name: fd + doc: dmabuf file descriptor to bind. + type: u32 + - + name: id + doc: id of the dmabuf binding + type: u32 + checks: + min: 1 operations: list: @@ -619,6 +652,20 @@ operations: - rx-bytes - tx-packets - tx-bytes + - + name: bind-rx + doc: Bind dmabuf to netdev + attribute-set: dmabuf + flags: [ admin-perm ] + do: + request: + attributes: + - ifindex + - fd + - queues + reply: + attributes: + - id mcast-groups: list: diff --git a/include/uapi/linux/netdev.h b/include/uapi/linux/netdev.h index 43742ac5b00d..91bf3ecc5f1d 100644 --- a/include/uapi/linux/netdev.h +++ b/include/uapi/linux/netdev.h @@ -173,6 +173,16 @@ enum { NETDEV_A_QSTATS_MAX = (__NETDEV_A_QSTATS_MAX - 1) }; +enum { + NETDEV_A_DMABUF_IFINDEX = 1, + NETDEV_A_DMABUF_QUEUES, + NETDEV_A_DMABUF_FD, + NETDEV_A_DMABUF_ID, + + __NETDEV_A_DMABUF_MAX, + NETDEV_A_DMABUF_MAX = (__NETDEV_A_DMABUF_MAX - 1) +}; + enum { NETDEV_CMD_DEV_GET = 1, NETDEV_CMD_DEV_ADD_NTF, @@ -186,6 +196,7 @@ enum { NETDEV_CMD_QUEUE_GET, NETDEV_CMD_NAPI_GET, NETDEV_CMD_QSTATS_GET, + NETDEV_CMD_BIND_RX, __NETDEV_CMD_MAX, NETDEV_CMD_MAX = (__NETDEV_CMD_MAX - 1) diff --git a/net/core/netdev-genl-gen.c b/net/core/netdev-genl-gen.c index 8350a0afa9ec..6b7fe6035067 100644 --- a/net/core/netdev-genl-gen.c +++ b/net/core/netdev-genl-gen.c @@ -27,6 +27,11 @@ const struct nla_policy netdev_page_pool_info_nl_policy[NETDEV_A_PAGE_POOL_IFIND [NETDEV_A_PAGE_POOL_IFINDEX] = NLA_POLICY_FULL_RANGE(NLA_U32, &netdev_a_page_pool_ifindex_range), }; +const struct nla_policy netdev_queue_id_nl_policy[NETDEV_A_QUEUE_TYPE + 1] = { + [NETDEV_A_QUEUE_ID] = { .type = NLA_U32, }, + [NETDEV_A_QUEUE_TYPE] = NLA_POLICY_MAX(NLA_U32, 1), +}; + /* NETDEV_CMD_DEV_GET - do */ static const struct nla_policy netdev_dev_get_nl_policy[NETDEV_A_DEV_IFINDEX + 1] = { [NETDEV_A_DEV_IFINDEX] = NLA_POLICY_MIN(NLA_U32, 1), @@ -74,6 +79,13 @@ static const struct nla_policy netdev_qstats_get_nl_policy[NETDEV_A_QSTATS_SCOPE [NETDEV_A_QSTATS_SCOPE] = NLA_POLICY_MASK(NLA_UINT, 0x1), }; +/* NETDEV_CMD_BIND_RX - do */ +static const struct nla_policy netdev_bind_rx_nl_policy[NETDEV_A_DMABUF_FD + 1] = { + [NETDEV_A_DMABUF_IFINDEX] = NLA_POLICY_MIN(NLA_U32, 1), + [NETDEV_A_DMABUF_FD] = { .type = NLA_U32, }, + [NETDEV_A_DMABUF_QUEUES] = NLA_POLICY_NESTED(netdev_queue_id_nl_policy), +}; + /* Ops table for netdev */ static const struct genl_split_ops netdev_nl_ops[] = { { @@ -151,6 +163,13 @@ static const struct genl_split_ops netdev_nl_ops[] = { .maxattr = NETDEV_A_QSTATS_SCOPE, .flags = GENL_CMD_CAP_DUMP, }, + { + .cmd = NETDEV_CMD_BIND_RX, + .doit = netdev_nl_bind_rx_doit, + .policy = netdev_bind_rx_nl_policy, + .maxattr = NETDEV_A_DMABUF_FD, + .flags = GENL_ADMIN_PERM | GENL_CMD_CAP_DO, + }, }; static const struct genl_multicast_group netdev_nl_mcgrps[] = { diff --git a/net/core/netdev-genl-gen.h b/net/core/netdev-genl-gen.h index 4db40fd5b4a9..67c34005750c 100644 --- a/net/core/netdev-genl-gen.h +++ b/net/core/netdev-genl-gen.h @@ -13,6 +13,7 @@ /* Common nested types */ extern const struct nla_policy netdev_page_pool_info_nl_policy[NETDEV_A_PAGE_POOL_IFINDEX + 1]; +extern const struct nla_policy netdev_queue_id_nl_policy[NETDEV_A_QUEUE_TYPE + 1]; int netdev_nl_dev_get_doit(struct sk_buff *skb, struct genl_info *info); int netdev_nl_dev_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb); @@ -30,6 +31,7 @@ int netdev_nl_napi_get_doit(struct sk_buff *skb, struct genl_info *info); int netdev_nl_napi_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb); int netdev_nl_qstats_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb); +int netdev_nl_bind_rx_doit(struct sk_buff *skb, struct genl_info *info); enum { NETDEV_NLGRP_MGMT, diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c index 05f9515d2c05..2d726e65211d 100644 --- a/net/core/netdev-genl.c +++ b/net/core/netdev-genl.c @@ -721,6 +721,12 @@ int netdev_nl_qstats_get_dumpit(struct sk_buff *skb, return err; } +/* Stub */ +int netdev_nl_bind_rx_doit(struct sk_buff *skb, struct genl_info *info) +{ + return 0; +} + static int netdev_genl_netdevice_event(struct notifier_block *nb, unsigned long event, void *ptr) { diff --git a/tools/include/uapi/linux/netdev.h b/tools/include/uapi/linux/netdev.h index 43742ac5b00d..91bf3ecc5f1d 100644 --- a/tools/include/uapi/linux/netdev.h +++ b/tools/include/uapi/linux/netdev.h @@ -173,6 +173,16 @@ enum { NETDEV_A_QSTATS_MAX = (__NETDEV_A_QSTATS_MAX - 1) }; +enum { + NETDEV_A_DMABUF_IFINDEX = 1, + NETDEV_A_DMABUF_QUEUES, + NETDEV_A_DMABUF_FD, + NETDEV_A_DMABUF_ID, + + __NETDEV_A_DMABUF_MAX, + NETDEV_A_DMABUF_MAX = (__NETDEV_A_DMABUF_MAX - 1) +}; + enum { NETDEV_CMD_DEV_GET = 1, NETDEV_CMD_DEV_ADD_NTF, @@ -186,6 +196,7 @@ enum { NETDEV_CMD_QUEUE_GET, NETDEV_CMD_NAPI_GET, NETDEV_CMD_QSTATS_GET, + NETDEV_CMD_BIND_RX, __NETDEV_CMD_MAX, NETDEV_CMD_MAX = (__NETDEV_CMD_MAX - 1) -- 2.46.0.76.ge559c4bf1a-goog

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[PATCH net-next v19 01/13] netdev: add netdev_rx_queue_restart()

by Mina Almasry

Add netdev_rx_queue_restart(), which resets an rx queue using the queue API recently merged[1]. The queue API was merged to enable the core net stack to reset individual rx queues to actuate changes in the rx queue's configuration. In later patches in this series, we will use netdev_rx_queue_restart() to reset rx queues after binding or unbinding dmabuf configuration, which will cause reallocation of the page_pool to repopulate its memory using the new configuration. [1] https://lore.kernel.org/netdev/20240430231420.699177-1-shailend@google.com/… Signed-off-by: David Wei <dw(a)davidwei.uk> Signed-off-by: Mina Almasry <almasrymina(a)google.com> Reviewed-by: Pavel Begunkov <asml.silence(a)gmail.com> Reviewed-by: Jakub Kicinski <kuba(a)kernel.org> --- v18: - Add more color to commit message (Xuan Zhuo). v17: - Use ASSERT_RTNL() (Jakub). v13: - Add reviewed-by from Pavel (thanks!) - Fixed comment (Pavel) v11: - Fix not checking dev->queue_mgmt_ops (Pavel). - Fix ndo_queue_mem_free call that passed the wrong pointer (David). v9: https://lore.kernel.org/all/20240502045410.3524155-4-dw@davidwei.uk/ (submitted by David). - fixed SPDX license identifier (Simon). - Rebased on top of merged queue API definition, and changed implementation to match that. - Replace rtnl_lock() with rtnl_is_locked() to make it useable from my netlink code where rtnl is already locked. --- include/net/netdev_rx_queue.h | 3 ++ net/core/Makefile | 1 + net/core/netdev_rx_queue.c | 74 +++++++++++++++++++++++++++++++++++ 3 files changed, 78 insertions(+) create mode 100644 net/core/netdev_rx_queue.c diff --git a/include/net/netdev_rx_queue.h b/include/net/netdev_rx_queue.h index aa1716fb0e53..e78ca52d67fb 100644 --- a/include/net/netdev_rx_queue.h +++ b/include/net/netdev_rx_queue.h @@ -54,4 +54,7 @@ get_netdev_rx_queue_index(struct netdev_rx_queue *queue) return index; } #endif + +int netdev_rx_queue_restart(struct net_device *dev, unsigned int rxq); + #endif diff --git a/net/core/Makefile b/net/core/Makefile index 62be9aef2528..f82232b358a2 100644 --- a/net/core/Makefile +++ b/net/core/Makefile @@ -19,6 +19,7 @@ obj-$(CONFIG_NETDEV_ADDR_LIST_TEST) += dev_addr_lists_test.o obj-y += net-sysfs.o obj-y += hotdata.o +obj-y += netdev_rx_queue.o obj-$(CONFIG_PAGE_POOL) += page_pool.o page_pool_user.o obj-$(CONFIG_PROC_FS) += net-procfs.o obj-$(CONFIG_NET_PKTGEN) += pktgen.o diff --git a/net/core/netdev_rx_queue.c b/net/core/netdev_rx_queue.c new file mode 100644 index 000000000000..da11720a5983 --- /dev/null +++ b/net/core/netdev_rx_queue.c @@ -0,0 +1,74 @@ +// SPDX-License-Identifier: GPL-2.0-or-later + +#include <linux/netdevice.h> +#include <net/netdev_queues.h> +#include <net/netdev_rx_queue.h> + +int netdev_rx_queue_restart(struct net_device *dev, unsigned int rxq_idx) +{ + void *new_mem, *old_mem; + int err; + + if (!dev->queue_mgmt_ops || !dev->queue_mgmt_ops->ndo_queue_stop || + !dev->queue_mgmt_ops->ndo_queue_mem_free || + !dev->queue_mgmt_ops->ndo_queue_mem_alloc || + !dev->queue_mgmt_ops->ndo_queue_start) + return -EOPNOTSUPP; + + ASSERT_RTNL(); + + new_mem = kvzalloc(dev->queue_mgmt_ops->ndo_queue_mem_size, GFP_KERNEL); + if (!new_mem) + return -ENOMEM; + + old_mem = kvzalloc(dev->queue_mgmt_ops->ndo_queue_mem_size, GFP_KERNEL); + if (!old_mem) { + err = -ENOMEM; + goto err_free_new_mem; + } + + err = dev->queue_mgmt_ops->ndo_queue_mem_alloc(dev, new_mem, rxq_idx); + if (err) + goto err_free_old_mem; + + err = dev->queue_mgmt_ops->ndo_queue_stop(dev, old_mem, rxq_idx); + if (err) + goto err_free_new_queue_mem; + + err = dev->queue_mgmt_ops->ndo_queue_start(dev, new_mem, rxq_idx); + if (err) + goto err_start_queue; + + dev->queue_mgmt_ops->ndo_queue_mem_free(dev, old_mem); + + kvfree(old_mem); + kvfree(new_mem); + + return 0; + +err_start_queue: + /* Restarting the queue with old_mem should be successful as we haven't + * changed any of the queue configuration, and there is not much we can + * do to recover from a failure here. + * + * WARN if we fail to recover the old rx queue, and at least free + * old_mem so we don't also leak that. + */ + if (dev->queue_mgmt_ops->ndo_queue_start(dev, old_mem, rxq_idx)) { + WARN(1, + "Failed to restart old queue in error path. RX queue %d may be unhealthy.", + rxq_idx); + dev->queue_mgmt_ops->ndo_queue_mem_free(dev, old_mem); + } + +err_free_new_queue_mem: + dev->queue_mgmt_ops->ndo_queue_mem_free(dev, new_mem); + +err_free_old_mem: + kvfree(old_mem); + +err_free_new_mem: + kvfree(new_mem); + + return err; +} -- 2.46.0.76.ge559c4bf1a-goog

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[PATCH] Kselftest: msg_oob.c: Fix warning for Incorrect Specifier

by David Hunter

Change specifier to %p to correctly substitute type 'const void *'. A specifer involved with a macro is causing a misleading warning to occur: In file included from msg_oob.c:14: msg_oob.c: In function ��__recvpair��: ../../kselftest_harness.h:106:40: warning: format ��%s�� expects argument of type ��char *��, but argument 6 has type ��const void *�� [-Wformat=] 106 | fprintf(TH_LOG_STREAM, "# %s:%d:%s:" fmt "\n", \ | ^~~~~~~~~~~~~ ../../kselftest_harness.h:101:17: note: in expansion of macro ��__TH_LOG�� 101 | __TH_LOG(fmt, ##__VA_ARGS__); \ | ^~~~~~~~ msg_oob.c:235:17: note: in expansion of macro ��TH_LOG�� 235 | TH_LOG("Expected:%s", expected_errno ? strerror(expected_errno) : expected_buf); | ^~~~~~ A second set of these three warnings occur later for the incorrect specifier at msg_oob.c:256. By tracing the various macros involved, the correct specifier (in msg_oob.c) can be spotted and changed. Signed-off-by: David Hunter <david.hunter.linux(a)gmail.com> --- tools/testing/selftests/net/af_unix/msg_oob.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/net/af_unix/msg_oob.c b/tools/testing/selftests/net/af_unix/msg_oob.c index 16d0c172eaeb..87090ebda2a7 100644 --- a/tools/testing/selftests/net/af_unix/msg_oob.c +++ b/tools/testing/selftests/net/af_unix/msg_oob.c @@ -232,7 +232,7 @@ static void __recvpair(struct __test_metadata *_metadata, if (ret[0] != expected_len || recv_errno[0] != expected_errno) { TH_LOG("AF_UNIX :%s", ret[0] < 0 ? strerror(recv_errno[0]) : recv_buf[0]); - TH_LOG("Expected:%s", expected_errno ? strerror(expected_errno) : expected_buf); + TH_LOG("Expected:%p", expected_errno ? strerror(expected_errno) : expected_buf); ASSERT_EQ(ret[0], expected_len); ASSERT_EQ(recv_errno[0], expected_errno); @@ -256,7 +256,7 @@ static void __recvpair(struct __test_metadata *_metadata, cmp = strncmp(expected_buf, recv_buf[0], expected_len); if (cmp) { TH_LOG("AF_UNIX :%s", ret[0] < 0 ? strerror(recv_errno[0]) : recv_buf[0]); - TH_LOG("Expected:%s", expected_errno ? strerror(expected_errno) : expected_buf); + TH_LOG("Expected:%p", expected_errno ? strerror(expected_errno) : expected_buf); ASSERT_EQ(cmp, 0); } -- 2.43.0

5 months

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[PATCH v2 1/1] selftests: net: af_unix: convert param to const char* in __recvpair() to fix warning

by Mirsad Todorovac

GCC 13.2.0 reported warning about (void *) being used as a param where (char *) is expected: In file included from msg_oob.c:14: msg_oob.c: In function ‘__recvpair’: ../../kselftest_harness.h:106:40: warning: format ‘%s’ expects argument of type ‘char *’, \ but argument 6 has type ‘const void *’ [-Wformat=] 106 | fprintf(TH_LOG_STREAM, "# %s:%d:%s:" fmt "\n", \ | ^~~~~~~~~~~~~ ../../kselftest_harness.h:101:17: note: in expansion of macro ‘__TH_LOG’ 101 | __TH_LOG(fmt, ##__VA_ARGS__); \ | ^~~~~~~~ msg_oob.c:235:17: note: in expansion of macro ‘TH_LOG’ 235 | TH_LOG("Expected:%s", expected_errno ? strerror(expected_errno) : expected_buf); | ^~~~~~ ../../kselftest_harness.h:106:40: warning: format ‘%s’ expects argument of type ‘char *’, \ but argument 6 has type ‘const void *’ [-Wformat=] 106 | fprintf(TH_LOG_STREAM, "# %s:%d:%s:" fmt "\n", \ | ^~~~~~~~~~~~~ ../../kselftest_harness.h:101:17: note: in expansion of macro ‘__TH_LOG’ 101 | __TH_LOG(fmt, ##__VA_ARGS__); \ | ^~~~~~~~ msg_oob.c:259:25: note: in expansion of macro ‘TH_LOG’ 259 | TH_LOG("Expected:%s", expected_errno ? strerror(expected_errno) : expected_buf); | ^~~~~~ As Simon suggested, all calls to __recvpair() have char * as expected_buf param, so it is safe to change param type from (const void *) to (const char *), which silences the warning. Fixes: d098d77232c37 ("selftest: af_unix: Add msg_oob.c.") Reported-by: Mirsad Todorovac <mtodorovac69(a)gmail.com> Cc: "David S. Miller" <davem(a)davemloft.net> Cc: Eric Dumazet <edumazet(a)google.com> Cc: Jakub Kicinski <kuba(a)kernel.org> Cc: Paolo Abeni <pabeni(a)redhat.com> Cc: Shuah Khan <shuah(a)kernel.org> Cc: Kuniyuki Iwashima <kuniyu(a)amazon.com> Cc: netdev(a)vger.kernel.org Cc: linux-kselftest(a)vger.kernel.org Suggested-by: Simon Horman <horms(a)kernel.org> Signed-off-by: Mirsad Todorovac <mtodorovac69(a)gmail.com> --- v1 -> v2: fixed a typo. change funct param type rather than making two casts, as Simon suggested. changed Subject: line to reflect the modification. minor formatting changes. v1: initial version to fix the compiler warning. tools/testing/selftests/net/af_unix/msg_oob.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/net/af_unix/msg_oob.c b/tools/testing/selftests/net/af_unix/msg_oob.c index 16d0c172eaeb..535eb2c3d7d1 100644 --- a/tools/testing/selftests/net/af_unix/msg_oob.c +++ b/tools/testing/selftests/net/af_unix/msg_oob.c @@ -209,7 +209,7 @@ static void __sendpair(struct __test_metadata *_metadata, static void __recvpair(struct __test_metadata *_metadata, FIXTURE_DATA(msg_oob) *self, - const void *expected_buf, int expected_len, + const char *expected_buf, int expected_len, int buf_len, int flags) { int i, ret[2], recv_errno[2], expected_errno = 0; -- 2.43.0

5 months

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[bpf-next 0/3] samples/bpf: Remove obsolete tracing-related tests

by Daniel T. Lee

The BPF tracing infrastructure has undergone significant evolution, leading to the introduction of more robust and efficient APIs. However, some of the existing tests in the samples/bpf directory have not kept pace with these developments. These outdated tests not only create confusion among users but also increase maintenance overhead. For starter, this patchset focuses on cleaning up outdated 'tracing' related tests within the BPF testing framework. The goal is to modernize and streamline selftests by removing obsolete tests and migrating necessaries to more appropriate locations. Daniel T. Lee (3): selftests/bpf: migrate tracepoint overhead test to prog_tests selftests/bpf: add rename tracepoint bench test samples/bpf: remove obsolete tracing related tests samples/bpf/Makefile | 12 - samples/bpf/test_overhead_kprobe.bpf.c | 41 ---- samples/bpf/test_overhead_raw_tp.bpf.c | 17 -- samples/bpf/test_overhead_tp.bpf.c | 23 -- samples/bpf/test_overhead_user.c | 225 ------------------ samples/bpf/test_override_return.sh | 16 -- samples/bpf/test_probe_write_user.bpf.c | 52 ---- samples/bpf/test_probe_write_user_user.c | 108 --------- samples/bpf/tracex7.bpf.c | 15 -- samples/bpf/tracex7_user.c | 56 ----- tools/testing/selftests/bpf/bench.c | 2 + .../selftests/bpf/benchs/bench_rename.c | 16 ++ .../selftests/bpf/benchs/run_bench_rename.sh | 2 +- .../selftests/bpf/prog_tests/test_overhead.c | 14 +- .../selftests/bpf/progs/test_overhead.c | 11 +- 15 files changed, 39 insertions(+), 571 deletions(-) delete mode 100644 samples/bpf/test_overhead_kprobe.bpf.c delete mode 100644 samples/bpf/test_overhead_raw_tp.bpf.c delete mode 100644 samples/bpf/test_overhead_tp.bpf.c delete mode 100644 samples/bpf/test_overhead_user.c delete mode 100755 samples/bpf/test_override_return.sh delete mode 100644 samples/bpf/test_probe_write_user.bpf.c delete mode 100644 samples/bpf/test_probe_write_user_user.c delete mode 100644 samples/bpf/tracex7.bpf.c delete mode 100644 samples/bpf/tracex7_user.c -- 2.43.0

5 months

3
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[PATCH v1 1/1] selftests: net: af_unix: cast void* to char* in call to macro TH_LOG()

by Mirsad Todorovac

GCC 13.2.0 reported warning about (void *) beeing used as a param where (char *) is expected: In file included from msg_oob.c:14: msg_oob.c: In function ‘__recvpair’: ../../kselftest_harness.h:106:40: warning: format ‘%s’ expects argument of type ‘char *’, but argument 6 has type ‘const void *’ [-Wformat=] 106 | fprintf(TH_LOG_STREAM, "# %s:%d:%s:" fmt "\n", \ | ^~~~~~~~~~~~~ ../../kselftest_harness.h:101:17: note: in expansion of macro ‘__TH_LOG’ 101 | __TH_LOG(fmt, ##__VA_ARGS__); \ | ^~~~~~~~ msg_oob.c:235:17: note: in expansion of macro ‘TH_LOG’ 235 | TH_LOG("Expected:%s", expected_errno ? strerror(expected_errno) : expected_buf); | ^~~~~~ ../../kselftest_harness.h:106:40: warning: format ‘%s’ expects argument of type ‘char *’, but argument 6 has type ‘const void *’ [-Wformat=] 106 | fprintf(TH_LOG_STREAM, "# %s:%d:%s:" fmt "\n", \ | ^~~~~~~~~~~~~ ../../kselftest_harness.h:101:17: note: in expansion of macro ‘__TH_LOG’ 101 | __TH_LOG(fmt, ##__VA_ARGS__); \ | ^~~~~~~~ msg_oob.c:259:25: note: in expansion of macro ‘TH_LOG’ 259 | TH_LOG("Expected:%s", expected_errno ? strerror(expected_errno) : expected_buf); | ^~~~~~ Casting param to (char *) silences the warning. Fixes: d098d77232c37 ("selftest: af_unix: Add msg_oob.c.") Cc: "David S. Miller" <davem(a)davemloft.net> Cc: Eric Dumazet <edumazet(a)google.com> Cc: Jakub Kicinski <kuba(a)kernel.org> Cc: Paolo Abeni <pabeni(a)redhat.com> Cc: Shuah Khan <shuah(a)kernel.org> Cc: Kuniyuki Iwashima <kuniyu(a)amazon.com> Cc: netdev(a)vger.kernel.org Cc: linux-kselftest(a)vger.kernel.org Signed-off-by: Mirsad Todorovac <mtodorovac69(a)gmail.com> --- v1: initial version to fix the compiler warning. tools/testing/selftests/net/af_unix/msg_oob.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/net/af_unix/msg_oob.c b/tools/testing/selftests/net/af_unix/msg_oob.c index 16d0c172eaeb..ae2623eea8ae 100644 --- a/tools/testing/selftests/net/af_unix/msg_oob.c +++ b/tools/testing/selftests/net/af_unix/msg_oob.c @@ -232,7 +232,7 @@ static void __recvpair(struct __test_metadata *_metadata, if (ret[0] != expected_len || recv_errno[0] != expected_errno) { TH_LOG("AF_UNIX :%s", ret[0] < 0 ? strerror(recv_errno[0]) : recv_buf[0]); - TH_LOG("Expected:%s", expected_errno ? strerror(expected_errno) : expected_buf); + TH_LOG("Expected:%s", expected_errno ? strerror(expected_errno) : (char *)expected_buf); ASSERT_EQ(ret[0], expected_len); ASSERT_EQ(recv_errno[0], expected_errno); @@ -256,7 +256,7 @@ static void __recvpair(struct __test_metadata *_metadata, cmp = strncmp(expected_buf, recv_buf[0], expected_len); if (cmp) { TH_LOG("AF_UNIX :%s", ret[0] < 0 ? strerror(recv_errno[0]) : recv_buf[0]); - TH_LOG("Expected:%s", expected_errno ? strerror(expected_errno) : expected_buf); + TH_LOG("Expected:%s", expected_errno ? strerror(expected_errno) : (char *)expected_buf); ASSERT_EQ(cmp, 0); } -- 2.43.0

5 months

3
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[RFC 0/5] SEV Kernel Selftests

by Pratik R. Sampat

This patchset introduces SEV-SNP test to the kernel selftest framework. It also adds negative testing of SEV, ES and SNP VM types. Patch 1 - Extend the sev smoke tests to use the SNP specific ioctl calls and sets up memory to boot a SNP guest VM Patch 2 - Cleanup patch that decouples the ioctl calls from the sev selftest library with its test assert and status counterparts. No functional change introduced Patch 3 - Introduce ioctl test for SEV, ES Patch 4 - Introduce positive and negative ioctl test for SEV-SNP Patch 5 - Adds the X86_FEATURE_SEV_SNP vm type test for KVM_SEV_INIT2 Any feedback/review on the approach and design is highly appreciated! Pratik R. Sampat (5): selftests: KVM: Add a basic SNP smoke test selftests: KVM: Decouple SEV ioctls from asserts selftests: KVM: SEV IOCTL test selftests: KVM: SNP IOCTL test selftests: KVM: SEV-SNP test for KVM_SEV_INIT2 .../selftests/kvm/include/x86_64/processor.h | 1 + .../selftests/kvm/include/x86_64/sev.h | 39 ++- tools/testing/selftests/kvm/lib/kvm_util.c | 7 +- .../selftests/kvm/lib/x86_64/processor.c | 6 +- tools/testing/selftests/kvm/lib/x86_64/sev.c | 181 +++++++++++--- .../selftests/kvm/x86_64/sev_init2_tests.c | 13 + .../selftests/kvm/x86_64/sev_smoke_test.c | 223 +++++++++++++++++- 7 files changed, 418 insertions(+), 52 deletions(-) -- 2.34.1

5 months

5
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[PATCH net-next v18 00/14] Device Memory TCP

by Mina Almasry

v18: https://patchwork.kernel.org/project/netdevbpf/list/?series=874848&state=* ==== v17 got minor feedback: (a) to beef up the description on patch 1 and (b) to remove the leading underscores in the header definition. I applied (a). (b) seems to be against current conventions so I did not apply before further discussion. Full devmem TCP changes including the full GVE driver implementation is here: https://github.com/mina/linux/commits/tcpdevmem-v17/ v17: https://patchwork.kernel.org/project/netdevbpf/list/?series=869900&state=* ==== v16 also got a very thorough review and some testing (thanks again!). Thes version addresses all the concerns reported on v15, in terms of feedback and issues reported. Major changes: - Use ASSERT_RTNL. - Moved around some of the page_pool helpers definitions so I can hide some netmem helpers in private files as Jakub suggested. - Don't make every net_iov hold a ref on the binding as Jakub suggested. - Fix issue reported by Taehee where we access queues after they have been freed. Full devmem TCP changes including the full GVE driver implementation is here: https://github.com/mina/linux/commits/tcpdevmem-v17/ v16: https://patchwork.kernel.org/project/netdevbpf/list/?series=866353&state=* ==== v15 got a thorough review and some testing, and this version addresses almost all the feedback. Some more minor comments where the authors said it could be done later, I left out. Major changes: - Addition of dma-buf introspection to page-pool-get and queue-get. - Fixes to selftests suggested by Taehee. - Fixes to documentation suggested by Donald. - A couple of suggestions and fixes to TCP patches by Eric and David. - Fixes to number assignements suggested by Arnd. - Use rtnl_lock()ing to guard against queue reconfiguration while the page_pool initialization is happening. (Jakub). - Fixes to a few warnings reproduced by Taehee. - Fixes to dma-buf binding suggested by Taehee and Jakub. - Fixes to netlink UAPI suggested by Jakub - Applied a number of Reviewed-bys and Acked-bys (including ones I lost from v13+). Full devmem TCP changes including the full GVE driver implementation is here: https://github.com/mina/linux/commits/tcpdevmem-v16/ One caveat: Taehee reproduced a KASAN warning and reported it here: https://lore.kernel.org/netdev/CAMArcTUdCxOBYGF3vpbq=eBvqZfnc44KBaQTN7H-wqd… I estimate the issue to be minor and easily fixable: https://lore.kernel.org/netdev/CAHS8izNgaqC--GGE2xd85QB=utUnOHmioCsDd1TNxJW… I hope to be able to follow up with a fix to net tree as net-next closes imminently, but if this iteration doesn't make it in, I will repost with a fix squashed after net-next reopens, no problem. v15: https://patchwork.kernel.org/project/netdevbpf/list/?series=865481&state=* ==== No material changes in this version, only a fix to linking against libynl.a from the last version. Per Jakub's instructions I've pulled one of his patches into this series, and now use the new libynl.a correctly, I hope. As usual, the full devmem TCP changes including the full GVE driver implementation is here: https://github.com/mina/linux/commits/tcpdevmem-v15/ v14: https://patchwork.kernel.org/project/netdevbpf/list/?series=865135&archive=… ==== No material changes in this version. Only rebase and re-verification on top of net-next. v13, I think, raced with commit ebad6d0334793 ("net/ipv4: Use nested-BH locking for ipv4_tcp_sk.") being merged to net-next that caused a patchwork failure to apply. This series should apply cleanly on commit c4532232fa2a4 ("selftests: net: remove unneeded IP_GRE config"). I did not wait the customary 24hr as Jakub said it's OK to repost as soon as I build test the rebased version: https://lore.kernel.org/netdev/20240625075926.146d769d@kernel.org/ v13: https://patchwork.kernel.org/project/netdevbpf/list/?series=861406&archive=… ==== Major changes: -------------- This iteration addresses Pavel's review comments, applies his reviewed-by's, and seeks to fix the patchwork build error (sorry!). As usual, the full devmem TCP changes including the full GVE driver implementation is here: https://github.com/mina/linux/commits/tcpdevmem-v13/ v12: https://patchwork.kernel.org/project/netdevbpf/list/?series=859747&state=* ==== Major changes: -------------- This iteration only addresses one minor comment from Pavel with regards to the trace printing of netmem, and the patchwork build error introduced in v11 because I missed doing an allmodconfig build, sorry. Other than that v11, AFAICT, received no feedback. There is one discussion about how the specifics of plugging io uring memory through the page pool, but not relevant to content in this particular patchset, AFAICT. As usual, the full devmem TCP changes including the full GVE driver implementation is here: https://github.com/mina/linux/commits/tcpdevmem-v12/ v11: https://patchwork.kernel.org/project/netdevbpf/list/?series=857457&state=* ==== Major Changes: -------------- v11 addresses feedback received in v10. The major change is the removal of the memory provider ops as requested by Christoph. We still accomplish the same thing, but utilizing direct function calls with if statements rather than generic ops. Additionally address sparse warnings, bugs and review comments from folks that reviewed. As usual, the full devmem TCP changes including the full GVE driver implementation is here: https://github.com/mina/linux/commits/tcpdevmem-v11/ Detailed changelog: ------------------- - Fixes in netdev_rx_queue_restart() from Pavel & David. - Remove commit e650e8c3a36f5 ("net: page_pool: create hooks for custom page providers") from the series to address Christoph's feedback and rebased other patches on the series on this change. - Fixed build errors with CONFIG_DMA_SHARED_BUFFER && !CONFIG_GENERIC_ALLOCATOR build. - Fixed sparse warnings pointed out by Paolo. - Drop unnecessary gro_pull_from_frag0 checks. - Added Bagas reviewed-by to docs. Cc: Bagas Sanjaya <bagasdotme(a)gmail.com> Cc: Steven Rostedt <rostedt(a)goodmis.org> Cc: Christoph Hellwig <hch(a)infradead.org> Cc: Nikolay Aleksandrov <razor(a)blackwall.org> Cc: Taehee Yoo <ap420073(a)gmail.com> Cc: Donald Hunter <donald.hunter(a)gmail.com> v10: https://patchwork.kernel.org/project/netdevbpf/list/?series=852422&state=* ==== Major Changes: -------------- v9 was sent right before the merge window closed (sorry!). v10 is almost a re-send of the series now that the merge window re-opened. Only rebased to latest net-next and addressed some minor iterative comments received on v9. As usual, the full devmem TCP changes including the full GVE driver implementation is here: https://github.com/mina/linux/commits/tcpdevmem-v10/ Detailed changelog: ------------------- - Fixed tokens leaking in DONTNEED setsockopt (Nikolay). - Moved net_iov_dma_addr() to devmem.c and made it a devmem specific helpers (David). - Rename hook alloc_pages to alloc_netmems as alloc_pages is now preprocessor macro defined and causes a build error. v9: === Major Changes: -------------- GVE queue API has been merged. Submitting this version as non-RFC after rebasing on top of the merged API, and dropped the out of tree queue API I was carrying on github. Addressed the little feedback v8 has received. Detailed changelog: ------------------ - Added new patch from David Wei to this series for netdev_rx_queue_restart() - Fixed sparse error. - Removed CONFIG_ checks in netmem_is_net_iov() - Flipped skb->readable to skb->unreadable - Minor fixes to selftests & docs. RFC v8: ======= Major Changes: -------------- - Fixed build error generated by patch-by-patch build. - Applied docs suggestions from Randy. RFC v7: ======= Major Changes: -------------- This revision largely rebases on top of net-next and addresses the feedback RFCv6 received from folks, namely Jakub, Yunsheng, Arnd, David, & Pavel. The series remains in RFC because the queue-API ndos defined in this series are not yet implemented. I have a GVE implementation I carry out of tree for my testing. A upstreamable GVE implementation is in the works. Aside from that, in my estimation all the patches are ready for review/merge. Please do take a look. As usual the full devmem TCP changes including the full GVE driver implementation is here: https://github.com/mina/linux/commits/tcpdevmem-v7/ Detailed changelog: - Use admin-perm in netlink API. - Addressed feedback from Jakub with regards to netlink API implementation. - Renamed devmem.c functions to something more appropriate for that file. - Improve the performance seen through the page_pool benchmark. - Fix the value definition of all the SO_DEVMEM_* uapi. - Various fixes to documentation. Perf - page-pool benchmark: --------------------------- Improved performance of bench_page_pool_simple.ko tests compared to v6: https://pastebin.com/raw/v5dYRg8L net-next base: 8 cycle fast path. RFC v6: 10 cycle fast path. RFC v7: 9 cycle fast path. RFC v7 with CONFIG_DMA_SHARED_BUFFER disabled: 8 cycle fast path, same as baseline. Perf - Devmem TCP benchmark: --------------------- Perf is about the same regardless of the changes in v7, namely the removal of the static_branch_unlikely to improve the page_pool benchmark performance: 189/200gbps bi-directional throughput with RX devmem TCP and regular TCP TX i.e. ~95% line rate. RFC v6: ======= Major Changes: -------------- This revision largely rebases on top of net-next and addresses the little feedback RFCv5 received. The series remains in RFC because the queue-API ndos defined in this series are not yet implemented. I have a GVE implementation I carry out of tree for my testing. A upstreamable GVE implementation is in the works. Aside from that, in my estimation all the patches are ready for review/merge. Please do take a look. As usual the full devmem TCP changes including the full GVE driver implementation is here: https://github.com/mina/linux/commits/tcpdevmem-v6/ This version also comes with some performance data recorded in the cover letter (see below changelog). Detailed changelog: - Rebased on top of the merged netmem_ref changes. - Converted skb->dmabuf to skb->readable (Pavel). Pavel's original suggestion was to remove the skb->dmabuf flag entirely, but when I looked into it closely, I found the issue that if we remove the flag we have to dereference the shinfo(skb) pointer to obtain the first frag to tell whether an skb is readable or not. This can cause a performance regression if it dirties the cache line when the shinfo(skb) was not really needed. Instead, I converted the skb->dmabuf flag into a generic skb->readable flag which can be re-used by io_uring 0-copy RX. - Squashed a few locking optimizations from Eric Dumazet in the RX path and the DEVMEM_DONTNEED setsockopt. - Expanded the tests a bit. Added validation for invalid scenarios and added some more coverage. Perf - page-pool benchmark: --------------------------- bench_page_pool_simple.ko tests with and without these changes: https://pastebin.com/raw/ncHDwAbn AFAIK the number that really matters in the perf tests is the 'tasklet_page_pool01_fast_path Per elem'. This one measures at about 8 cycles without the changes but there is some 1 cycle noise in some results. With the patches this regresses to 9 cycles with the changes but there is 1 cycle noise occasionally running this test repeatedly. Lastly I tried disable the static_branch_unlikely() in netmem_is_net_iov() check. To my surprise disabling the static_branch_unlikely() check reduces the fast path back to 8 cycles, but the 1 cycle noise remains. Perf - Devmem TCP benchmark: --------------------- 189/200gbps bi-directional throughput with RX devmem TCP and regular TCP TX i.e. ~95% line rate. Major changes in RFC v5: ======================== 1. Rebased on top of 'Abstract page from net stack' series and used the new netmem type to refer to LSB set pointers instead of re-using struct page. 2. Downgraded this series back to RFC and called it RFC v5. This is because this series is now dependent on 'Abstract page from net stack'[1] and the queue API. Both are removed from the series to reduce the patch # and those bits are fairly independent or pre-requisite work. 3. Reworked the page_pool devmem support to use netmem and for some more unified handling. 4. Reworked the reference counting of net_iov (renamed from page_pool_iov) to use pp_ref_count for refcounting. The full changes including the dependent series and GVE page pool support is here: https://github.com/mina/linux/commits/tcpdevmem-rfcv5/ [1] https://patchwork.kernel.org/project/netdevbpf/list/?series=810774 Major changes in v1: ==================== 1. Implemented MVP queue API ndos to remove the userspace-visible driver reset. 2. Fixed issues in the napi_pp_put_page() devmem frag unref path. 3. Removed RFC tag. Many smaller addressed comments across all the patches (patches have individual change log). Full tree including the rest of the GVE driver changes: https://github.com/mina/linux/commits/tcpdevmem-v1 Changes in RFC v3: ================== 1. Pulled in the memory-provider dependency from Jakub's RFC[1] to make the series reviewable and mergeable. 2. Implemented multi-rx-queue binding which was a todo in v2. 3. Fix to cmsg handling. The sticking point in RFC v2[2] was the device reset required to refill the device rx-queues after the dmabuf bind/unbind. The solution suggested as I understand is a subset of the per-queue management ops Jakub suggested or similar: https://lore.kernel.org/netdev/20230815171638.4c057dcd@kernel.org/ This is not addressed in this revision, because: 1. This point was discussed at netconf & netdev and there is openness to using the current approach of requiring a device reset. 2. Implementing individual queue resetting seems to be difficult for my test bed with GVE. My prototype to test this ran into issues with the rx-queues not coming back up properly if reset individually. At the moment I'm unsure if it's a mistake in the POC or a genuine issue in the virtualization stack behind GVE, which currently doesn't test individual rx-queue restart. 3. Our usecases are not bothered by requiring a device reset to refill the buffer queues, and we'd like to support NICs that run into this limitation with resetting individual queues. My thought is that drivers that have trouble with per-queue configs can use the support in this series, while drivers that support new netdev ops to reset individual queues can automatically reset the queue as part of the dma-buf bind/unbind. The same approach with device resets is presented again for consideration with other sticking points addressed. This proposal includes the rx devmem path only proposed for merge. For a snapshot of my entire tree which includes the GVE POC page pool support & device memory support: https://github.com/torvalds/linux/compare/master...mina:linux:tcpdevmem-v3 [1] https://lore.kernel.org/netdev/f8270765-a27b-6ccf-33ea-cda097168d79@redhat.… [2] https://lore.kernel.org/netdev/CAHS8izOVJGJH5WF68OsRWFKJid1_huzzUK+hpKbLcL4… Changes in RFC v2: ================== The sticking point in RFC v1[1] was the dma-buf pages approach we used to deliver the device memory to the TCP stack. RFC v2 is a proof-of-concept that attempts to resolve this by implementing scatterlist support in the networking stack, such that we can import the dma-buf scatterlist directly. This is the approach proposed at a high level here[2]. Detailed changes: 1. Replaced dma-buf pages approach with importing scatterlist into the page pool. 2. Replace the dma-buf pages centric API with a netlink API. 3. Removed the TX path implementation - there is no issue with implementing the TX path with scatterlist approach, but leaving out the TX path makes it easier to review. 4. Functionality is tested with this proposal, but I have not conducted perf testing yet. I'm not sure there are regressions, but I removed perf claims from the cover letter until they can be re-confirmed. 5. Added Signed-off-by: contributors to the implementation. 6. Fixed some bugs with the RX path since RFC v1. Any feedback welcome, but specifically the biggest pending questions needing feedback IMO are: 1. Feedback on the scatterlist-based approach in general. 2. Netlink API (Patch 1 & 2). 3. Approach to handle all the drivers that expect to receive pages from the page pool (Patch 6). [1] https://lore.kernel.org/netdev/dfe4bae7-13a0-3c5d-d671-f61b375cb0b4@gmail.c… [2] https://lore.kernel.org/netdev/CAHS8izPm6XRS54LdCDZVd0C75tA1zHSu6jLVO8nzTLX… ================== * TL;DR: Device memory TCP (devmem TCP) is a proposal for transferring data to and/or from device memory efficiently, without bouncing the data to a host memory buffer. * Problem: A large amount of data transfers have device memory as the source and/or destination. Accelerators drastically increased the volume of such transfers. Some examples include: - ML accelerators transferring large amounts of training data from storage into GPU/TPU memory. In some cases ML training setup time can be as long as 50% of TPU compute time, improving data transfer throughput & efficiency can help improving GPU/TPU utilization. - Distributed training, where ML accelerators, such as GPUs on different hosts, exchange data among them. - Distributed raw block storage applications transfer large amounts of data with remote SSDs, much of this data does not require host processing. Today, the majority of the Device-to-Device data transfers the network are implemented as the following low level operations: Device-to-Host copy, Host-to-Host network transfer, and Host-to-Device copy. The implementation is suboptimal, especially for bulk data transfers, and can put significant strains on system resources, such as host memory bandwidth, PCIe bandwidth, etc. One important reason behind the current state is the kernel’s lack of semantics to express device to network transfers. * Proposal: In this patch series we attempt to optimize this use case by implementing socket APIs that enable the user to: 1. send device memory across the network directly, and 2. receive incoming network packets directly into device memory. Packet _payloads_ go directly from the NIC to device memory for receive and from device memory to NIC for transmit. Packet _headers_ go to/from host memory and are processed by the TCP/IP stack normally. The NIC _must_ support header split to achieve this. Advantages: - Alleviate host memory bandwidth pressure, compared to existing network-transfer + device-copy semantics. - Alleviate PCIe BW pressure, by limiting data transfer to the lowest level of the PCIe tree, compared to traditional path which sends data through the root complex. * Patch overview: ** Part 1: netlink API Gives user ability to bind dma-buf to an RX queue. ** Part 2: scatterlist support Currently the standard for device memory sharing is DMABUF, which doesn't generate struct pages. On the other hand, networking stack (skbs, drivers, and page pool) operate on pages. We have 2 options: 1. Generate struct pages for dmabuf device memory, or, 2. Modify the networking stack to process scatterlist. Approach #1 was attempted in RFC v1. RFC v2 implements approach #2. ** part 3: page pool support We piggy back on page pool memory providers proposal: https://github.com/kuba-moo/linux/tree/pp-providers It allows the page pool to define a memory provider that provides the page allocation and freeing. It helps abstract most of the device memory TCP changes from the driver. ** part 4: support for unreadable skb frags Page pool iovs are not accessible by the host; we implement changes throughput the networking stack to correctly handle skbs with unreadable frags. ** Part 5: recvmsg() APIs We define user APIs for the user to send and receive device memory. Not included with this series is the GVE devmem TCP support, just to simplify the review. Code available here if desired: https://github.com/mina/linux/tree/tcpdevmem This series is built on top of net-next with Jakub's pp-providers changes cherry-picked. * NIC dependencies: 1. (strict) Devmem TCP require the NIC to support header split, i.e. the capability to split incoming packets into a header + payload and to put each into a separate buffer. Devmem TCP works by using device memory for the packet payload, and host memory for the packet headers. 2. (optional) Devmem TCP works better with flow steering support & RSS support, i.e. the NIC's ability to steer flows into certain rx queues. This allows the sysadmin to enable devmem TCP on a subset of the rx queues, and steer devmem TCP traffic onto these queues and non devmem TCP elsewhere. The NIC I have access to with these properties is the GVE with DQO support running in Google Cloud, but any NIC that supports these features would suffice. I may be able to help reviewers bring up devmem TCP on their NICs. * Testing: The series includes a udmabuf kselftest that show a simple use case of devmem TCP and validates the entire data path end to end without a dependency on a specific dmabuf provider. ** Test Setup Kernel: net-next with this series and memory provider API cherry-picked locally. Hardware: Google Cloud A3 VMs. NIC: GVE with header split & RSS & flow steering support. Cc: Pavel Begunkov <asml.silence(a)gmail.com> Cc: David Wei <dw(a)davidwei.uk> Cc: Jason Gunthorpe <jgg(a)ziepe.ca> Cc: Yunsheng Lin <linyunsheng(a)huawei.com> Cc: Shailend Chand <shailend(a)google.com> Cc: Harshitha Ramamurthy <hramamurthy(a)google.com> Cc: Shakeel Butt <shakeel.butt(a)linux.dev> Cc: Jeroen de Borst <jeroendb(a)google.com> Cc: Praveen Kaligineedi <pkaligineedi(a)google.com> Mina Almasry (14): netdev: add netdev_rx_queue_restart() net: netdev netlink api to bind dma-buf to a net device netdev: support binding dma-buf to netdevice netdev: netdevice devmem allocator page_pool: move dmaddr helpers to .c file page_pool: devmem support memory-provider: dmabuf devmem memory provider net: support non paged skb frags net: add support for skbs with unreadable frags tcp: RX path for devmem TCP net: add SO_DEVMEM_DONTNEED setsockopt to release RX frags net: add devmem TCP documentation selftests: add ncdevmem, netcat for devmem TCP netdev: add dmabuf introspection Documentation/netlink/specs/netdev.yaml | 61 +++ Documentation/networking/devmem.rst | 269 ++++++++++++ Documentation/networking/index.rst | 1 + arch/alpha/include/uapi/asm/socket.h | 6 + arch/mips/include/uapi/asm/socket.h | 6 + arch/parisc/include/uapi/asm/socket.h | 6 + arch/sparc/include/uapi/asm/socket.h | 6 + include/linux/skbuff.h | 61 ++- include/linux/skbuff_ref.h | 9 +- include/linux/socket.h | 1 + include/net/devmem.h | 128 ++++++ include/net/mp_dmabuf_devmem.h | 44 ++ include/net/netdev_rx_queue.h | 5 + include/net/netmem.h | 164 +++++++- include/net/page_pool/helpers.h | 42 +- include/net/page_pool/types.h | 8 + include/net/sock.h | 2 + include/net/tcp.h | 5 +- include/trace/events/page_pool.h | 12 +- include/uapi/asm-generic/socket.h | 6 + include/uapi/linux/netdev.h | 13 + include/uapi/linux/uio.h | 17 + net/core/Makefile | 3 +- net/core/datagram.c | 6 + net/core/dev.c | 7 +- net/core/devmem.c | 378 +++++++++++++++++ net/core/gro.c | 3 +- net/core/netdev-genl-gen.c | 23 + net/core/netdev-genl-gen.h | 6 + net/core/netdev-genl.c | 111 +++++ net/core/netdev_rx_queue.c | 74 ++++ net/core/netmem_priv.h | 36 ++ net/core/page_pool.c | 147 +++++-- net/core/page_pool_priv.h | 3 + net/core/page_pool_user.c | 4 + net/core/skbuff.c | 77 +++- net/core/sock.c | 68 +++ net/ipv4/esp4.c | 3 +- net/ipv4/tcp.c | 261 +++++++++++- net/ipv4/tcp_input.c | 13 +- net/ipv4/tcp_ipv4.c | 16 + net/ipv4/tcp_minisocks.c | 2 + net/ipv4/tcp_output.c | 5 +- net/ipv6/esp6.c | 3 +- net/packet/af_packet.c | 4 +- tools/include/uapi/linux/netdev.h | 13 + tools/testing/selftests/net/.gitignore | 1 + tools/testing/selftests/net/Makefile | 9 + tools/testing/selftests/net/ncdevmem.c | 536 ++++++++++++++++++++++++ 49 files changed, 2563 insertions(+), 121 deletions(-) create mode 100644 Documentation/networking/devmem.rst create mode 100644 include/net/devmem.h create mode 100644 include/net/mp_dmabuf_devmem.h create mode 100644 net/core/devmem.c create mode 100644 net/core/netdev_rx_queue.c create mode 100644 net/core/netmem_priv.h create mode 100644 tools/testing/selftests/net/ncdevmem.c -- 2.46.0.rc2.264.g509ed76dc8-goog

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