From: Puranjay Mohan <puranjay@kernel.org>
To: bpf@vger.kernel.org
Cc: Puranjay Mohan <puranjay@kernel.org>,
Puranjay Mohan <puranjay12@gmail.com>,
Alexei Starovoitov <ast@kernel.org>,
Andrii Nakryiko <andrii@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Martin KaFai Lau <martin.lau@kernel.org>,
Eduard Zingerman <eddyz87@gmail.com>,
Kumar Kartikeya Dwivedi <memxor@gmail.com>,
kernel-team@meta.com
Subject: [PATCH bpf-next v2 2/2] bpf: arena: Reintroduce memcg accounting
Date: Wed, 31 Dec 2025 06:14:33 -0800 [thread overview]
Message-ID: <20251231141434.3416822-3-puranjay@kernel.org> (raw)
In-Reply-To: <20251231141434.3416822-1-puranjay@kernel.org>
When arena allocations were converted from bpf_map_alloc_pages() to
kmalloc_nolock() to support non-sleepable contexts, memcg accounting was
inadvertently lost. This commit restores proper memory accounting for
all arena-related allocations.
All arena related allocations are accounted into memcg of the process
that created bpf_arena.
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
---
kernel/bpf/arena.c | 44 ++++++++++++++++++++++++++++++++++++-----
kernel/bpf/range_tree.c | 5 +++--
2 files changed, 42 insertions(+), 7 deletions(-)
diff --git a/kernel/bpf/arena.c b/kernel/bpf/arena.c
index 456ac989269d..45b55961683f 100644
--- a/kernel/bpf/arena.c
+++ b/kernel/bpf/arena.c
@@ -360,6 +360,7 @@ static vm_fault_t arena_vm_fault(struct vm_fault *vmf)
{
struct bpf_map *map = vmf->vma->vm_file->private_data;
struct bpf_arena *arena = container_of(map, struct bpf_arena, map);
+ struct mem_cgroup *new_memcg, *old_memcg;
struct page *page;
long kbase, kaddr;
unsigned long flags;
@@ -377,6 +378,8 @@ static vm_fault_t arena_vm_fault(struct vm_fault *vmf)
/* already have a page vmap-ed */
goto out;
+ bpf_map_memcg_enter(map, &old_memcg, &new_memcg);
+
if (arena->map.map_flags & BPF_F_SEGV_ON_FAULT)
/* User space requested to segfault when page is not allocated by bpf prog */
goto out_unlock_sigsegv;
@@ -400,12 +403,14 @@ static vm_fault_t arena_vm_fault(struct vm_fault *vmf)
goto out_unlock_sigsegv;
}
flush_vmap_cache(kaddr, PAGE_SIZE);
+ bpf_map_memcg_exit(old_memcg, new_memcg);
out:
page_ref_add(page, 1);
raw_res_spin_unlock_irqrestore(&arena->spinlock, flags);
vmf->page = page;
return 0;
out_unlock_sigsegv:
+ bpf_map_memcg_exit(old_memcg, new_memcg);
raw_res_spin_unlock_irqrestore(&arena->spinlock, flags);
return VM_FAULT_SIGSEGV;
}
@@ -557,7 +562,7 @@ static long arena_alloc_pages(struct bpf_arena *arena, long uaddr, long page_cnt
/* Cap allocation size to KMALLOC_MAX_CACHE_SIZE so kmalloc_nolock() can succeed. */
alloc_pages = min(page_cnt, KMALLOC_MAX_CACHE_SIZE / sizeof(struct page *));
- pages = kmalloc_nolock(alloc_pages * sizeof(struct page *), 0, NUMA_NO_NODE);
+ pages = kmalloc_nolock(alloc_pages * sizeof(struct page *), __GFP_ACCOUNT, NUMA_NO_NODE);
if (!pages)
return 0;
data.pages = pages;
@@ -713,7 +718,7 @@ static void arena_free_pages(struct bpf_arena *arena, long uaddr, long page_cnt,
return;
defer:
- s = kmalloc_nolock(sizeof(struct arena_free_span), 0, -1);
+ s = kmalloc_nolock(sizeof(struct arena_free_span), __GFP_ACCOUNT, -1);
if (!s)
/*
* If allocation fails in non-sleepable context, pages are intentionally left
@@ -766,6 +771,7 @@ static int arena_reserve_pages(struct bpf_arena *arena, long uaddr, u32 page_cnt
static void arena_free_worker(struct work_struct *work)
{
struct bpf_arena *arena = container_of(work, struct bpf_arena, free_work);
+ struct mem_cgroup *new_memcg, *old_memcg;
struct llist_node *list, *pos, *t;
struct arena_free_span *s;
u64 arena_vm_start, user_vm_start;
@@ -780,6 +786,8 @@ static void arena_free_worker(struct work_struct *work)
return;
}
+ bpf_map_memcg_enter(&arena->map, &old_memcg, &new_memcg);
+
init_llist_head(&free_pages);
arena_vm_start = bpf_arena_get_kern_vm_start(arena);
user_vm_start = bpf_arena_get_user_vm_start(arena);
@@ -820,6 +828,8 @@ static void arena_free_worker(struct work_struct *work)
page = llist_entry(pos, struct page, pcp_llist);
__free_page(page);
}
+
+ bpf_map_memcg_exit(old_memcg, new_memcg);
}
static void arena_free_irq(struct irq_work *iw)
@@ -834,49 +844,69 @@ __bpf_kfunc_start_defs();
__bpf_kfunc void *bpf_arena_alloc_pages(void *p__map, void *addr__ign, u32 page_cnt,
int node_id, u64 flags)
{
+ void *ret;
struct bpf_map *map = p__map;
+ struct mem_cgroup *new_memcg, *old_memcg;
struct bpf_arena *arena = container_of(map, struct bpf_arena, map);
if (map->map_type != BPF_MAP_TYPE_ARENA || flags || !page_cnt)
return NULL;
- return (void *)arena_alloc_pages(arena, (long)addr__ign, page_cnt, node_id, true);
+ bpf_map_memcg_enter(map, &old_memcg, &new_memcg);
+ ret = (void *)arena_alloc_pages(arena, (long)addr__ign, page_cnt, node_id, true);
+ bpf_map_memcg_exit(old_memcg, new_memcg);
+
+ return ret;
}
void *bpf_arena_alloc_pages_non_sleepable(void *p__map, void *addr__ign, u32 page_cnt,
int node_id, u64 flags)
{
+ void *ret;
struct bpf_map *map = p__map;
+ struct mem_cgroup *new_memcg, *old_memcg;
struct bpf_arena *arena = container_of(map, struct bpf_arena, map);
if (map->map_type != BPF_MAP_TYPE_ARENA || flags || !page_cnt)
return NULL;
- return (void *)arena_alloc_pages(arena, (long)addr__ign, page_cnt, node_id, false);
+ bpf_map_memcg_enter(map, &old_memcg, &new_memcg);
+ ret = (void *)arena_alloc_pages(arena, (long)addr__ign, page_cnt, node_id, false);
+ bpf_map_memcg_exit(old_memcg, new_memcg);
+
+ return ret;
}
__bpf_kfunc void bpf_arena_free_pages(void *p__map, void *ptr__ign, u32 page_cnt)
{
struct bpf_map *map = p__map;
+ struct mem_cgroup *new_memcg, *old_memcg;
struct bpf_arena *arena = container_of(map, struct bpf_arena, map);
if (map->map_type != BPF_MAP_TYPE_ARENA || !page_cnt || !ptr__ign)
return;
+ bpf_map_memcg_enter(map, &old_memcg, &new_memcg);
arena_free_pages(arena, (long)ptr__ign, page_cnt, true);
+ bpf_map_memcg_exit(old_memcg, new_memcg);
}
void bpf_arena_free_pages_non_sleepable(void *p__map, void *ptr__ign, u32 page_cnt)
{
struct bpf_map *map = p__map;
+ struct mem_cgroup *new_memcg, *old_memcg;
struct bpf_arena *arena = container_of(map, struct bpf_arena, map);
if (map->map_type != BPF_MAP_TYPE_ARENA || !page_cnt || !ptr__ign)
return;
+ bpf_map_memcg_enter(map, &old_memcg, &new_memcg);
arena_free_pages(arena, (long)ptr__ign, page_cnt, false);
+ bpf_map_memcg_exit(old_memcg, new_memcg);
}
__bpf_kfunc int bpf_arena_reserve_pages(void *p__map, void *ptr__ign, u32 page_cnt)
{
+ int ret;
struct bpf_map *map = p__map;
+ struct mem_cgroup *new_memcg, *old_memcg;
struct bpf_arena *arena = container_of(map, struct bpf_arena, map);
if (map->map_type != BPF_MAP_TYPE_ARENA)
@@ -885,7 +915,11 @@ __bpf_kfunc int bpf_arena_reserve_pages(void *p__map, void *ptr__ign, u32 page_c
if (!page_cnt)
return 0;
- return arena_reserve_pages(arena, (long)ptr__ign, page_cnt);
+ bpf_map_memcg_enter(map, &old_memcg, &new_memcg);
+ ret = arena_reserve_pages(arena, (long)ptr__ign, page_cnt);
+ bpf_map_memcg_exit(old_memcg, new_memcg);
+
+ return ret;
}
__bpf_kfunc_end_defs();
diff --git a/kernel/bpf/range_tree.c b/kernel/bpf/range_tree.c
index 99c63d982c5d..2f28886f3ff7 100644
--- a/kernel/bpf/range_tree.c
+++ b/kernel/bpf/range_tree.c
@@ -149,7 +149,8 @@ int range_tree_clear(struct range_tree *rt, u32 start, u32 len)
range_it_insert(rn, rt);
/* Add a range */
- new_rn = kmalloc_nolock(sizeof(struct range_node), 0, NUMA_NO_NODE);
+ new_rn = kmalloc_nolock(sizeof(struct range_node), __GFP_ACCOUNT,
+ NUMA_NO_NODE);
if (!new_rn)
return -ENOMEM;
new_rn->rn_start = last + 1;
@@ -234,7 +235,7 @@ int range_tree_set(struct range_tree *rt, u32 start, u32 len)
right->rn_start = start;
range_it_insert(right, rt);
} else {
- left = kmalloc_nolock(sizeof(struct range_node), 0, NUMA_NO_NODE);
+ left = kmalloc_nolock(sizeof(struct range_node), __GFP_ACCOUNT, NUMA_NO_NODE);
if (!left)
return -ENOMEM;
left->rn_start = start;
--
2.47.3
next prev parent reply other threads:[~2025-12-31 14:14 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-31 14:14 [PATCH bpf-next v2 0/2] memcg accounting for BPF arena Puranjay Mohan
2025-12-31 14:14 ` [PATCH bpf-next v2 1/2] bpf: syscall: Introduce memcg enter/exit helpers Puranjay Mohan
2025-12-31 14:14 ` Puranjay Mohan [this message]
2025-12-31 17:25 ` [PATCH bpf-next v2 2/2] bpf: arena: Reintroduce memcg accounting Alexei Starovoitov
2025-12-31 17:30 ` Puranjay Mohan
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