From b0057c68df711bf6a62033c072ac61c4f9d3cbc1 Mon Sep 17 00:00:00 2001 From: Zihan Xi Date: Fri, 31 Jul 2026 16:46:23 +0000 Subject: [PATCH] xsk: account ring allocations to memcg AF_XDP rings are allocated from setsockopt() and can be mapped into user space. The shared xskq_create() helper allocates the ring backing memory, but the user-controlled and long-lived allocation is not charged as kmem to the allocating memory cgroup. The current implementation uses vmalloc_user(), which allocates the backing pages with GFP_KERNEL | __GFP_ZERO. Use the same VM_USERMAP vmalloc path, but pass GFP_KERNEL_ACCOUNT so the ring backing pages are attributed to memcg/kmem and can be constrained by existing cgroup memory limits. This keeps the existing zeroing and mmap semantics while avoiding AF_XDP-specific optmem or RLIMIT_MEMLOCK accounting. Signed-off-by: Zihan Xi Acked-by: Stanislav Fomichev Link: https://patch.msgid.link/20260731164623.4694-2-zihanx@nebusec.ai Signed-off-by: Jakub Kicinski --- net/xdp/xsk_queue.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/net/xdp/xsk_queue.c b/net/xdp/xsk_queue.c index 4dd01b7d858e..d95b6d0d94aa 100644 --- a/net/xdp/xsk_queue.c +++ b/net/xdp/xsk_queue.c @@ -9,6 +9,8 @@ #include #include +#include + #include "xsk_queue.h" static size_t xskq_get_ring_size(struct xsk_queue *q, bool umem_queue) @@ -21,6 +23,14 @@ static size_t xskq_get_ring_size(struct xsk_queue *q, bool umem_queue) return struct_size(rxtx_ring, desc, q->nentries); } +static void *xskq_vmalloc_user(unsigned long size) +{ + return __vmalloc_node_range(size, SHMLBA, VMALLOC_START, VMALLOC_END, + GFP_KERNEL_ACCOUNT | __GFP_ZERO, PAGE_KERNEL, + VM_USERMAP, NUMA_NO_NODE, + __builtin_return_address(0)); +} + struct xsk_queue *xskq_create(u32 nentries, bool umem_queue) { struct xsk_queue *q; @@ -46,7 +56,7 @@ struct xsk_queue *xskq_create(u32 nentries, bool umem_queue) size = PAGE_ALIGN(size); - q->ring = vmalloc_user(size); + q->ring = xskq_vmalloc_user(size); if (!q->ring) { kfree(q); return NULL;