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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Willem de Bruijn , David Ahern , Matthew Wilcox , Al Viro , Christoph Hellwig , Jens Axboe , Jeff Layton , Christian Brauner , Chuck Lever III , Linus Torvalds , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Jeroen de Borst , Catherine Sullivan , Shailend Chand , Felix Fietkau , John Crispin , Sean Wang , Mark Lee , Lorenzo Bianconi , Matthias Brugger , AngeloGioacchino Del Regno , Keith Busch , Jens Axboe , Christoph Hellwig , Sagi Grimberg , Chaitanya Kulkarni , Andrew Morton , linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-nvme@lists.infradead.org Subject: [PATCH net-next v6 04/18] mm: Make the page_frag_cache allocator use per-cpu Date: Tue, 11 Apr 2023 17:08:48 +0100 Message-Id: <20230411160902.4134381-5-dhowells@redhat.com> In-Reply-To: <20230411160902.4134381-1-dhowells@redhat.com> References: <20230411160902.4134381-1-dhowells@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.1 X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: C195D2002B X-Stat-Signature: m5xs6qg3xrtyboxdc13zfyuonb7dumss X-Rspam-User: X-HE-Tag: 1681229368-32334 X-HE-Meta: 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 g8WZxEfB 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Make the page_frag_cache allocator have a separate allocation bucket for each cpu to avoid racing. This means that no lock is required, other than preempt disablement, to allocate from it, though if a softirq wants to access it, then softirq disablement will need to be added. Make the NVMe, mediatek and GVE drivers pass in NULL to page_frag_cache() and use the default allocation buckets rather than defining their own. Signed-off-by: David Howells cc: "David S. Miller" cc: Eric Dumazet cc: Jakub Kicinski cc: Paolo Abeni cc: Jens Axboe cc: Jeroen de Borst cc: Catherine Sullivan cc: Shailend Chand cc: Felix Fietkau cc: John Crispin cc: Sean Wang cc: Mark Lee cc: Lorenzo Bianconi cc: Matthias Brugger cc: AngeloGioacchino Del Regno cc: Keith Busch cc: Jens Axboe cc: Christoph Hellwig cc: Sagi Grimberg cc: Chaitanya Kulkarni cc: Andrew Morton cc: Matthew Wilcox cc: netdev@vger.kernel.org cc: linux-arm-kernel@lists.infradead.org cc: linux-mediatek@lists.infradead.org cc: linux-nvme@lists.infradead.org cc: linux-mm@kvack.org --- drivers/net/ethernet/google/gve/gve.h | 1 - drivers/net/ethernet/google/gve/gve_main.c | 9 - drivers/net/ethernet/google/gve/gve_rx.c | 2 +- drivers/net/ethernet/mediatek/mtk_wed_wo.c | 6 +- drivers/net/ethernet/mediatek/mtk_wed_wo.h | 2 - drivers/nvme/host/tcp.c | 13 +- drivers/nvme/target/tcp.c | 19 +- include/linux/gfp.h | 19 +- mm/page_frag_alloc.c | 196 ++++++++++++++------- net/core/skbuff.c | 32 ++-- 10 files changed, 165 insertions(+), 134 deletions(-) diff --git a/drivers/net/ethernet/google/gve/gve.h b/drivers/net/ethernet/google/gve/gve.h index e214b51d3c8b..5864d723210a 100644 --- a/drivers/net/ethernet/google/gve/gve.h +++ b/drivers/net/ethernet/google/gve/gve.h @@ -250,7 +250,6 @@ struct gve_rx_ring { struct xdp_rxq_info xdp_rxq; struct xdp_rxq_info xsk_rxq; struct xsk_buff_pool *xsk_pool; - struct page_frag_cache page_cache; /* Page cache to allocate XDP frames */ }; /* A TX desc ring entry */ diff --git a/drivers/net/ethernet/google/gve/gve_main.c b/drivers/net/ethernet/google/gve/gve_main.c index b2fc1a3e6340..6c835038a8eb 100644 --- a/drivers/net/ethernet/google/gve/gve_main.c +++ b/drivers/net/ethernet/google/gve/gve_main.c @@ -1261,14 +1261,6 @@ static void gve_unreg_xdp_info(struct gve_priv *priv) } } -static void gve_drain_page_cache(struct gve_priv *priv) -{ - int i; - - for (i = 0; i < priv->rx_cfg.num_queues; i++) - page_frag_cache_clear(&priv->rx[i].page_cache); -} - static int gve_open(struct net_device *dev) { struct gve_priv *priv = netdev_priv(dev); @@ -1352,7 +1344,6 @@ static int gve_close(struct net_device *dev) netif_carrier_off(dev); if (gve_get_device_rings_ok(priv)) { gve_turndown(priv); - gve_drain_page_cache(priv); err = gve_destroy_rings(priv); if (err) goto err; diff --git a/drivers/net/ethernet/google/gve/gve_rx.c b/drivers/net/ethernet/google/gve/gve_rx.c index d1da7413dc4d..7ae8377c394f 100644 --- a/drivers/net/ethernet/google/gve/gve_rx.c +++ b/drivers/net/ethernet/google/gve/gve_rx.c @@ -634,7 +634,7 @@ static int gve_xdp_redirect(struct net_device *dev, struct gve_rx_ring *rx, total_len = headroom + SKB_DATA_ALIGN(len) + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); - frame = page_frag_alloc(&rx->page_cache, total_len, GFP_ATOMIC); + frame = page_frag_alloc(NULL, total_len, GFP_ATOMIC); if (!frame) { u64_stats_update_begin(&rx->statss); rx->xdp_alloc_fails++; diff --git a/drivers/net/ethernet/mediatek/mtk_wed_wo.c b/drivers/net/ethernet/mediatek/mtk_wed_wo.c index d90fea2c7d04..859f34447f2f 100644 --- a/drivers/net/ethernet/mediatek/mtk_wed_wo.c +++ b/drivers/net/ethernet/mediatek/mtk_wed_wo.c @@ -143,7 +143,7 @@ mtk_wed_wo_queue_refill(struct mtk_wed_wo *wo, struct mtk_wed_wo_queue *q, dma_addr_t addr; void *buf; - buf = page_frag_alloc(&q->cache, q->buf_size, GFP_ATOMIC); + buf = page_frag_alloc(NULL, q->buf_size, GFP_ATOMIC); if (!buf) break; @@ -296,8 +296,6 @@ mtk_wed_wo_queue_tx_clean(struct mtk_wed_wo *wo, struct mtk_wed_wo_queue *q) skb_free_frag(entry->buf); entry->buf = NULL; } - - page_frag_cache_clear(&q->cache); } static void @@ -311,8 +309,6 @@ mtk_wed_wo_queue_rx_clean(struct mtk_wed_wo *wo, struct mtk_wed_wo_queue *q) skb_free_frag(buf); } - - page_frag_cache_clear(&q->cache); } static void diff --git a/drivers/net/ethernet/mediatek/mtk_wed_wo.h b/drivers/net/ethernet/mediatek/mtk_wed_wo.h index dbcf42ce9173..6f940db67fb8 100644 --- a/drivers/net/ethernet/mediatek/mtk_wed_wo.h +++ b/drivers/net/ethernet/mediatek/mtk_wed_wo.h @@ -210,8 +210,6 @@ struct mtk_wed_wo_queue_entry { struct mtk_wed_wo_queue { struct mtk_wed_wo_queue_regs regs; - struct page_frag_cache cache; - struct mtk_wed_wo_queue_desc *desc; dma_addr_t desc_dma; diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c index 05629e83b41d..5a92236db92a 100644 --- a/drivers/nvme/host/tcp.c +++ b/drivers/nvme/host/tcp.c @@ -147,8 +147,6 @@ struct nvme_tcp_queue { __le32 exp_ddgst; __le32 recv_ddgst; - struct page_frag_cache pf_cache; - void (*state_change)(struct sock *); void (*data_ready)(struct sock *); void (*write_space)(struct sock *); @@ -482,9 +480,8 @@ static int nvme_tcp_init_request(struct blk_mq_tag_set *set, struct nvme_tcp_queue *queue = &ctrl->queues[queue_idx]; u8 hdgst = nvme_tcp_hdgst_len(queue); - req->pdu = page_frag_alloc(&queue->pf_cache, - sizeof(struct nvme_tcp_cmd_pdu) + hdgst, - GFP_KERNEL | __GFP_ZERO); + req->pdu = page_frag_alloc(NULL, sizeof(struct nvme_tcp_cmd_pdu) + hdgst, + GFP_KERNEL | __GFP_ZERO); if (!req->pdu) return -ENOMEM; @@ -1300,9 +1297,8 @@ static int nvme_tcp_alloc_async_req(struct nvme_tcp_ctrl *ctrl) struct nvme_tcp_request *async = &ctrl->async_req; u8 hdgst = nvme_tcp_hdgst_len(queue); - async->pdu = page_frag_alloc(&queue->pf_cache, - sizeof(struct nvme_tcp_cmd_pdu) + hdgst, - GFP_KERNEL | __GFP_ZERO); + async->pdu = page_frag_alloc(NULL, sizeof(struct nvme_tcp_cmd_pdu) + hdgst, + GFP_KERNEL | __GFP_ZERO); if (!async->pdu) return -ENOMEM; @@ -1322,7 +1318,6 @@ static void nvme_tcp_free_queue(struct nvme_ctrl *nctrl, int qid) if (queue->hdr_digest || queue->data_digest) nvme_tcp_free_crypto(queue); - page_frag_cache_clear(&queue->pf_cache); noreclaim_flag = memalloc_noreclaim_save(); sock_release(queue->sock); memalloc_noreclaim_restore(noreclaim_flag); diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c index ae871c31cf00..d6cc557cc539 100644 --- a/drivers/nvme/target/tcp.c +++ b/drivers/nvme/target/tcp.c @@ -143,8 +143,6 @@ struct nvmet_tcp_queue { struct nvmet_tcp_cmd connect; - struct page_frag_cache pf_cache; - void (*data_ready)(struct sock *); void (*state_change)(struct sock *); void (*write_space)(struct sock *); @@ -1312,25 +1310,25 @@ static int nvmet_tcp_alloc_cmd(struct nvmet_tcp_queue *queue, c->queue = queue; c->req.port = queue->port->nport; - c->cmd_pdu = page_frag_alloc(&queue->pf_cache, - sizeof(*c->cmd_pdu) + hdgst, GFP_KERNEL | __GFP_ZERO); + c->cmd_pdu = page_frag_alloc(NULL, sizeof(*c->cmd_pdu) + hdgst, + GFP_KERNEL | __GFP_ZERO); if (!c->cmd_pdu) return -ENOMEM; c->req.cmd = &c->cmd_pdu->cmd; - c->rsp_pdu = page_frag_alloc(&queue->pf_cache, - sizeof(*c->rsp_pdu) + hdgst, GFP_KERNEL | __GFP_ZERO); + c->rsp_pdu = page_frag_alloc(NULL, sizeof(*c->rsp_pdu) + hdgst, + GFP_KERNEL | __GFP_ZERO); if (!c->rsp_pdu) goto out_free_cmd; c->req.cqe = &c->rsp_pdu->cqe; - c->data_pdu = page_frag_alloc(&queue->pf_cache, - sizeof(*c->data_pdu) + hdgst, GFP_KERNEL | __GFP_ZERO); + c->data_pdu = page_frag_alloc(NULL, sizeof(*c->data_pdu) + hdgst, + GFP_KERNEL | __GFP_ZERO); if (!c->data_pdu) goto out_free_rsp; - c->r2t_pdu = page_frag_alloc(&queue->pf_cache, - sizeof(*c->r2t_pdu) + hdgst, GFP_KERNEL | __GFP_ZERO); + c->r2t_pdu = page_frag_alloc(NULL, sizeof(*c->r2t_pdu) + hdgst, + GFP_KERNEL | __GFP_ZERO); if (!c->r2t_pdu) goto out_free_data; @@ -1459,7 +1457,6 @@ static void nvmet_tcp_release_queue_work(struct work_struct *w) if (queue->hdr_digest || queue->data_digest) nvmet_tcp_free_crypto(queue); ida_free(&nvmet_tcp_queue_ida, queue->idx); - page_frag_cache_clear(&queue->pf_cache); kfree(queue); } diff --git a/include/linux/gfp.h b/include/linux/gfp.h index 9f77ba6af361..b208ca315882 100644 --- a/include/linux/gfp.h +++ b/include/linux/gfp.h @@ -304,18 +304,19 @@ extern void free_pages(unsigned long addr, unsigned int order); struct page_frag_cache; extern void __page_frag_cache_drain(struct page *page, unsigned int count); -extern void *page_frag_alloc_align(struct page_frag_cache *nc, - unsigned int fragsz, gfp_t gfp_mask, - unsigned int align_mask); - -static inline void *page_frag_alloc(struct page_frag_cache *nc, - unsigned int fragsz, gfp_t gfp_mask) +extern void *page_frag_alloc_align(struct page_frag_cache __percpu *frag_cache, + size_t fragsz, gfp_t gfp, + unsigned long align_mask); +extern void *page_frag_memdup(struct page_frag_cache __percpu *frag_cache, + const void *p, size_t fragsz, gfp_t gfp, + unsigned long align_mask); + +static inline void *page_frag_alloc(struct page_frag_cache __percpu *frag_cache, + size_t fragsz, gfp_t gfp) { - return page_frag_alloc_align(nc, fragsz, gfp_mask, ~0u); + return page_frag_alloc_align(frag_cache, fragsz, gfp, ULONG_MAX); } -void page_frag_cache_clear(struct page_frag_cache *nc); - extern void page_frag_free(void *addr); #define __free_page(page) __free_pages((page), 0) diff --git a/mm/page_frag_alloc.c b/mm/page_frag_alloc.c index ac4cf1eac8ea..7844398afe26 100644 --- a/mm/page_frag_alloc.c +++ b/mm/page_frag_alloc.c @@ -16,25 +16,23 @@ #include #include +static DEFINE_PER_CPU(struct page_frag_cache, page_frag_default_allocator); + /* * Allocate a new folio for the frag cache. */ -static struct folio *page_frag_cache_refill(struct page_frag_cache *nc, - gfp_t gfp_mask) +static struct folio *page_frag_cache_refill(gfp_t gfp) { - struct folio *folio = NULL; - gfp_t gfp = gfp_mask; + struct folio *folio; #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE) - gfp_mask |= __GFP_NOWARN | __GFP_NORETRY | __GFP_NOMEMALLOC; - folio = folio_alloc(gfp_mask, PAGE_FRAG_CACHE_MAX_ORDER); + folio = folio_alloc(gfp | __GFP_NOWARN | __GFP_NORETRY | __GFP_NOMEMALLOC, + PAGE_FRAG_CACHE_MAX_ORDER); + if (folio) + return folio; #endif - if (unlikely(!folio)) - folio = folio_alloc(gfp, 0); - if (folio) - nc->folio = folio; - return folio; + return folio_alloc(gfp, 0); } void __page_frag_cache_drain(struct page *page, unsigned int count) @@ -47,55 +45,68 @@ void __page_frag_cache_drain(struct page *page, unsigned int count) } EXPORT_SYMBOL(__page_frag_cache_drain); -void page_frag_cache_clear(struct page_frag_cache *nc) -{ - struct folio *folio = nc->folio; - - if (folio) { - VM_BUG_ON_FOLIO(folio_ref_count(folio) == 0, folio); - folio_put_refs(folio, nc->pagecnt_bias); - nc->folio = NULL; - } -} -EXPORT_SYMBOL(page_frag_cache_clear); - -void *page_frag_alloc_align(struct page_frag_cache *nc, - unsigned int fragsz, gfp_t gfp_mask, - unsigned int align_mask) +/** + * page_frag_alloc_align - Allocate some memory for use in zerocopy + * @frag_cache: The frag cache to use (or NULL for the default) + * @fragsz: The size of the fragment desired + * @gfp: Allocation flags under which to make an allocation + * @align_mask: The required alignment + * + * Allocate some memory for use with zerocopy where protocol bits have to be + * mixed in with spliced/zerocopied data. Unlike memory allocated from the + * slab, this memory's lifetime is purely dependent on the folio's refcount. + * + * The way it works is that a folio is allocated and fragments are broken off + * sequentially and returned to the caller with a ref until the folio no longer + * has enough spare space - at which point the allocator's ref is dropped and a + * new folio is allocated. The folio remains in existence until the last ref + * held by, say, an sk_buff is discarded and then the page is returned to the + * page allocator. + * + * Returns a pointer to the memory on success and -ENOMEM on allocation + * failure. + * + * The allocated memory should be disposed of with folio_put(). + */ +void *page_frag_alloc_align(struct page_frag_cache __percpu *frag_cache, + size_t fragsz, gfp_t gfp, unsigned long align_mask) { - struct folio *folio = nc->folio; + struct page_frag_cache *nc; + struct folio *folio, *spare = NULL; size_t offset; + void *p; - if (unlikely(!folio)) { -refill: - folio = page_frag_cache_refill(nc, gfp_mask); - if (!folio) - return NULL; - - /* Even if we own the page, we do not use atomic_set(). - * This would break get_page_unless_zero() users. - */ - folio_ref_add(folio, PAGE_FRAG_CACHE_MAX_SIZE); + if (!frag_cache) + frag_cache = &page_frag_default_allocator; + if (WARN_ON_ONCE(fragsz == 0)) + fragsz = 1; + align_mask &= ~3UL; - /* reset page count bias and offset to start of new frag */ - nc->pfmemalloc = folio_is_pfmemalloc(folio); - nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1; - nc->offset = folio_size(folio); + nc = get_cpu_ptr(frag_cache); +reload: + folio = nc->folio; + offset = nc->offset; +try_again: + + /* Make the allocation if there's sufficient space. */ + if (fragsz <= offset) { + nc->pagecnt_bias--; + offset = (offset - fragsz) & align_mask; + nc->offset = offset; + p = folio_address(folio) + offset; + put_cpu_ptr(frag_cache); + if (spare) + folio_put(spare); + return p; } - offset = nc->offset; - if (unlikely(fragsz > offset)) { - /* Reuse the folio if everyone we gave it to has finished with - * it. - */ - if (!folio_ref_sub_and_test(folio, nc->pagecnt_bias)) { - nc->folio = NULL; + /* Insufficient space - see if we can refurbish the current folio. */ + if (folio) { + if (!folio_ref_sub_and_test(folio, nc->pagecnt_bias)) goto refill; - } if (unlikely(nc->pfmemalloc)) { __folio_put(folio); - nc->folio = NULL; goto refill; } @@ -105,27 +116,56 @@ void *page_frag_alloc_align(struct page_frag_cache *nc, /* reset page count bias and offset to start of new frag */ nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1; offset = folio_size(folio); - if (unlikely(fragsz > offset)) { - /* - * The caller is trying to allocate a fragment - * with fragsz > PAGE_SIZE but the cache isn't big - * enough to satisfy the request, this may - * happen in low memory conditions. - * We don't release the cache page because - * it could make memory pressure worse - * so we simply return NULL here. - */ - nc->offset = offset; + if (unlikely(fragsz > offset)) + goto frag_too_big; + goto try_again; + } + +refill: + if (!spare) { + nc->folio = NULL; + put_cpu_ptr(frag_cache); + + spare = page_frag_cache_refill(gfp); + if (!spare) return NULL; - } + + nc = get_cpu_ptr(frag_cache); + /* We may now be on a different cpu and/or someone else may + * have refilled it + */ + nc->pfmemalloc = folio_is_pfmemalloc(spare); + if (nc->folio) + goto reload; } - nc->pagecnt_bias--; - offset -= fragsz; - offset &= align_mask; + nc->folio = spare; + folio = spare; + spare = NULL; + + /* Even if we own the page, we do not use atomic_set(). This would + * break get_page_unless_zero() users. + */ + folio_ref_add(folio, PAGE_FRAG_CACHE_MAX_SIZE); + + /* Reset page count bias and offset to start of new frag */ + nc->pagecnt_bias = PAGE_FRAG_CACHE_MAX_SIZE + 1; + offset = folio_size(folio); + goto try_again; + +frag_too_big: + /* + * The caller is trying to allocate a fragment with fragsz > PAGE_SIZE + * but the cache isn't big enough to satisfy the request, this may + * happen in low memory conditions. We don't release the cache page + * because it could make memory pressure worse so we simply return NULL + * here. + */ nc->offset = offset; - - return folio_address(folio) + offset; + put_cpu_ptr(frag_cache); + if (spare) + folio_put(spare); + return NULL; } EXPORT_SYMBOL(page_frag_alloc_align); @@ -137,3 +177,25 @@ void page_frag_free(void *addr) folio_put(virt_to_folio(addr)); } EXPORT_SYMBOL(page_frag_free); + +/** + * page_frag_memdup - Allocate a page fragment and duplicate some data into it + * @frag_cache: The frag cache to use (or NULL for the default) + * @fragsz: The amount of memory to copy (maximum 1/2 page). + * @p: The source data to copy + * @gfp: Allocation flags under which to make an allocation + * @align_mask: The required alignment + */ +void *page_frag_memdup(struct page_frag_cache __percpu *frag_cache, + const void *p, size_t fragsz, gfp_t gfp, + unsigned long align_mask) +{ + void *q; + + q = page_frag_alloc_align(frag_cache, fragsz, gfp, align_mask); + if (!q) + return q; + + return memcpy(q, p, fragsz); +} +EXPORT_SYMBOL(page_frag_memdup); diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 050a875d09c5..3d05ed64b606 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -222,13 +222,13 @@ static void *page_frag_alloc_1k(struct page_frag_1k *nc, gfp_t gfp_mask) #endif struct napi_alloc_cache { - struct page_frag_cache page; struct page_frag_1k page_small; unsigned int skb_count; void *skb_cache[NAPI_SKB_CACHE_SIZE]; }; static DEFINE_PER_CPU(struct page_frag_cache, netdev_alloc_cache); +static DEFINE_PER_CPU(struct page_frag_cache, napi_frag_cache); static DEFINE_PER_CPU(struct napi_alloc_cache, napi_alloc_cache); /* Double check that napi_get_frags() allocates skbs with @@ -250,11 +250,9 @@ void napi_get_frags_check(struct napi_struct *napi) void *__napi_alloc_frag_align(unsigned int fragsz, unsigned int align_mask) { - struct napi_alloc_cache *nc = this_cpu_ptr(&napi_alloc_cache); - fragsz = SKB_DATA_ALIGN(fragsz); - return page_frag_alloc_align(&nc->page, fragsz, GFP_ATOMIC, align_mask); + return page_frag_alloc_align(&napi_frag_cache, fragsz, GFP_ATOMIC, align_mask); } EXPORT_SYMBOL(__napi_alloc_frag_align); @@ -264,15 +262,12 @@ void *__netdev_alloc_frag_align(unsigned int fragsz, unsigned int align_mask) fragsz = SKB_DATA_ALIGN(fragsz); if (in_hardirq() || irqs_disabled()) { - struct page_frag_cache *nc = this_cpu_ptr(&netdev_alloc_cache); - - data = page_frag_alloc_align(nc, fragsz, GFP_ATOMIC, align_mask); + data = page_frag_alloc_align(&netdev_alloc_cache, + fragsz, GFP_ATOMIC, align_mask); } else { - struct napi_alloc_cache *nc; - local_bh_disable(); - nc = this_cpu_ptr(&napi_alloc_cache); - data = page_frag_alloc_align(&nc->page, fragsz, GFP_ATOMIC, align_mask); + data = page_frag_alloc_align(&napi_frag_cache, + fragsz, GFP_ATOMIC, align_mask); local_bh_enable(); } return data; @@ -652,7 +647,6 @@ EXPORT_SYMBOL(__alloc_skb); struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int len, gfp_t gfp_mask) { - struct page_frag_cache *nc; struct sk_buff *skb; bool pfmemalloc; void *data; @@ -677,14 +671,12 @@ struct sk_buff *__netdev_alloc_skb(struct net_device *dev, unsigned int len, gfp_mask |= __GFP_MEMALLOC; if (in_hardirq() || irqs_disabled()) { - nc = this_cpu_ptr(&netdev_alloc_cache); - data = page_frag_alloc(nc, len, gfp_mask); - pfmemalloc = nc->pfmemalloc; + data = page_frag_alloc(&netdev_alloc_cache, len, gfp_mask); + pfmemalloc = folio_is_pfmemalloc(virt_to_folio(data)); } else { local_bh_disable(); - nc = this_cpu_ptr(&napi_alloc_cache.page); - data = page_frag_alloc(nc, len, gfp_mask); - pfmemalloc = nc->pfmemalloc; + data = page_frag_alloc(&napi_frag_cache, len, gfp_mask); + pfmemalloc = folio_is_pfmemalloc(virt_to_folio(data)); local_bh_enable(); } @@ -772,8 +764,8 @@ struct sk_buff *__napi_alloc_skb(struct napi_struct *napi, unsigned int len, } else { len = SKB_HEAD_ALIGN(len); - data = page_frag_alloc(&nc->page, len, gfp_mask); - pfmemalloc = nc->page.pfmemalloc; + data = page_frag_alloc(&napi_frag_cache, len, gfp_mask); + pfmemalloc = folio_is_pfmemalloc(virt_to_folio(data)); } if (unlikely(!data))