From: Eric Dumazet edumazet@google.com
[ Upstream commit f8ece40786c9342249aa0a1b55e148ee23b2a746 ]
We have platforms with 6 NUMA nodes and 480 cpus.
inet_ehash_locks_alloc() currently allocates a single 64KB page to hold all ehash spinlocks. This adds more pressure on a single node.
Change inet_ehash_locks_alloc() to use vmalloc() to spread the spinlocks on all online nodes, driven by NUMA policies.
At boot time, NUMA policy is interleave=all, meaning that tcp_hashinfo.ehash_locks gets hash dispersion on all nodes.
Tested:
lack5:~# grep inet_ehash_locks_alloc /proc/vmallocinfo 0x00000000d9aec4d1-0x00000000a828b652 69632 inet_ehash_locks_alloc+0x90/0x100 pages=16 vmalloc N0=2 N1=3 N2=3 N3=3 N4=3 N5=2
lack5:~# echo 8192 >/proc/sys/net/ipv4/tcp_child_ehash_entries lack5:~# numactl --interleave=all unshare -n bash -c "grep inet_ehash_locks_alloc /proc/vmallocinfo" 0x000000004e99d30c-0x00000000763f3279 36864 inet_ehash_locks_alloc+0x90/0x100 pages=8 vmalloc N0=1 N1=2 N2=2 N3=1 N4=1 N5=1 0x00000000d9aec4d1-0x00000000a828b652 69632 inet_ehash_locks_alloc+0x90/0x100 pages=16 vmalloc N0=2 N1=3 N2=3 N3=3 N4=3 N5=2
lack5:~# numactl --interleave=0,5 unshare -n bash -c "grep inet_ehash_locks_alloc /proc/vmallocinfo" 0x00000000fd73a33e-0x0000000004b9a177 36864 inet_ehash_locks_alloc+0x90/0x100 pages=8 vmalloc N0=4 N5=4 0x00000000d9aec4d1-0x00000000a828b652 69632 inet_ehash_locks_alloc+0x90/0x100 pages=16 vmalloc N0=2 N1=3 N2=3 N3=3 N4=3 N5=2
lack5:~# echo 1024 >/proc/sys/net/ipv4/tcp_child_ehash_entries lack5:~# numactl --interleave=all unshare -n bash -c "grep inet_ehash_locks_alloc /proc/vmallocinfo" 0x00000000db07d7a2-0x00000000ad697d29 8192 inet_ehash_locks_alloc+0x90/0x100 pages=1 vmalloc N2=1 0x00000000d9aec4d1-0x00000000a828b652 69632 inet_ehash_locks_alloc+0x90/0x100 pages=16 vmalloc N0=2 N1=3 N2=3 N3=3 N4=3 N5=2
Signed-off-by: Eric Dumazet edumazet@google.com Tested-by: Jason Xing kerneljasonxing@gmail.com Reviewed-by: Kuniyuki Iwashima kuniyu@amazon.com Link: https://patch.msgid.link/20250305130550.1865988-1-edumazet@google.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/ipv4/inet_hashtables.c | 37 ++++++++++++++++++++++++++----------- 1 file changed, 26 insertions(+), 11 deletions(-)
diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c index 0fb5d758264fe..fea74ab2a4bec 100644 --- a/net/ipv4/inet_hashtables.c +++ b/net/ipv4/inet_hashtables.c @@ -934,22 +934,37 @@ int inet_ehash_locks_alloc(struct inet_hashinfo *hashinfo) { unsigned int locksz = sizeof(spinlock_t); unsigned int i, nblocks = 1; + spinlock_t *ptr = NULL;
- if (locksz != 0) { - /* allocate 2 cache lines or at least one spinlock per cpu */ - nblocks = max(2U * L1_CACHE_BYTES / locksz, 1U); - nblocks = roundup_pow_of_two(nblocks * num_possible_cpus()); + if (locksz == 0) + goto set_mask;
- /* no more locks than number of hash buckets */ - nblocks = min(nblocks, hashinfo->ehash_mask + 1); + /* Allocate 2 cache lines or at least one spinlock per cpu. */ + nblocks = max(2U * L1_CACHE_BYTES / locksz, 1U) * num_possible_cpus();
- hashinfo->ehash_locks = kvmalloc_array(nblocks, locksz, GFP_KERNEL); - if (!hashinfo->ehash_locks) - return -ENOMEM; + /* At least one page per NUMA node. */ + nblocks = max(nblocks, num_online_nodes() * PAGE_SIZE / locksz); + + nblocks = roundup_pow_of_two(nblocks); + + /* No more locks than number of hash buckets. */ + nblocks = min(nblocks, hashinfo->ehash_mask + 1);
- for (i = 0; i < nblocks; i++) - spin_lock_init(&hashinfo->ehash_locks[i]); + if (num_online_nodes() > 1) { + /* Use vmalloc() to allow NUMA policy to spread pages + * on all available nodes if desired. + */ + ptr = vmalloc_array(nblocks, locksz); + } + if (!ptr) { + ptr = kvmalloc_array(nblocks, locksz, GFP_KERNEL); + if (!ptr) + return -ENOMEM; } + for (i = 0; i < nblocks; i++) + spin_lock_init(&ptr[i]); + hashinfo->ehash_locks = ptr; +set_mask: hashinfo->ehash_locks_mask = nblocks - 1; return 0; }