From f8cbf6bde4c8d5d32330bcceafa7b139fec89f97 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sat, 24 Feb 2024 09:06:30 +0000 Subject: netlink: use kvmalloc() in netlink_alloc_large_skb() This is a followup of commit 234ec0b6034b ("netlink: fix potential sleeping issue in mqueue_flush_file"), because vfree_atomic() overhead is unfortunate for medium sized allocations. 1) If the allocation is smaller than PAGE_SIZE, do not bother with vmalloc() at all. Some arches have 64KB PAGE_SIZE, while NLMSG_GOODSIZE is smaller than 8KB. 2) Use kvmalloc(), which might allocate one high order page instead of vmalloc if memory is not too fragmented. Signed-off-by: Eric Dumazet Reviewed-by: Zhengchao Shao Link: https://lore.kernel.org/r/20240224090630.605917-1-edumazet@google.com Signed-off-by: Jakub Kicinski --- net/netlink/af_netlink.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-) diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index be5792b638aa..765921cf1194 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -1202,23 +1202,21 @@ struct sock *netlink_getsockbyfilp(struct file *filp) struct sk_buff *netlink_alloc_large_skb(unsigned int size, int broadcast) { + size_t head_size = SKB_HEAD_ALIGN(size); struct sk_buff *skb; void *data; - if (size <= NLMSG_GOODSIZE || broadcast) + if (head_size <= PAGE_SIZE || broadcast) return alloc_skb(size, GFP_KERNEL); - size = SKB_DATA_ALIGN(size) + - SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); - - data = vmalloc(size); - if (data == NULL) + data = kvmalloc(head_size, GFP_KERNEL); + if (!data) return NULL; - skb = __build_skb(data, size); - if (skb == NULL) - vfree(data); - else + skb = __build_skb(data, head_size); + if (!skb) + kvfree(data); + else if (is_vmalloc_addr(data)) skb->destructor = netlink_skb_destructor; return skb; -- cgit