From: Alexei Starovoitov Date: Wed, 19 Nov 2025 00:20:25 +0000 (-0800) Subject: Merge branch 'replace-bpf-memory-allocator-with-kmalloc_nolock-in-local-storage' X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d6ec0906d6c40435a6a79e4981342161c5d82ef1;p=thirdparty%2Flinux.git Merge branch 'replace-bpf-memory-allocator-with-kmalloc_nolock-in-local-storage' Amery Hung says: ==================== Replace BPF memory allocator with kmalloc_nolock() in local storage This patchset tries to simplify bpf_local_storage.c by adopting kmalloc_nolock(). This removes memory preallocation and reduces the dependency of smap in bpf_selem_free() and bpf_local_storage_free(). The later will simplify a future refactor that replaces local_storage->lock and b->lock [1]. RFC v1 tried to switch to kmalloc_nolock() unconditionally. However, as there is substantial performance loss in socket local storage due to 1) defer_free() in kfree_nolock() and 2) no kfree_rcu() batching, replacing kzalloc() is postponed until necessary improvements in mm land. Benchmark ./bench -p 1 local-storage-create --storage-type \ --batch-size <16,32,64> The benchmark is a microbenchmark stress-testing how fast local storage can be created. For task local storage, switching from BPF memory allocator to kmalloc_nolock() yields a small amount of improvement. For socket local storage, it remains roughly the same as nothing has changed. Socket local storage memory alloc batch creation speed creation speed diff --------------- ---- ------------------ ---- kzalloc 16 144.149 ± 0.642k/s 3.10 kmallocs/create (before) 32 144.379 ± 1.070k/s 3.08 kmallocs/create 64 144.491 ± 0.818k/s 3.13 kmallocs/create kzalloc 16 146.180 ± 1.403k/s 3.10 kmallocs/create +1.4% (not changed) 32 146.245 ± 1.272k/s 3.10 kmallocs/create +1.3% 64 145.012 ± 1.545k/s 3.10 kmallocs/create +0.4% Task local storage memory alloc batch creation speed creation speed diff --------------- ---- ------------------ ---- BPF memory 16 24.668 ± 0.121k/s 2.54 kmallocs/create allocator 32 22.899 ± 0.097k/s 2.67 kmallocs/create (before) 64 22.559 ± 0.076k/s 2.56 kmallocs/create kmalloc_nolock 16 25.796 ± 0.059k/s 2.52 kmallocs/create +4.6% (after) 32 23.412 ± 0.069k/s 2.50 kmallocs/create +2.2% 64 23.717 ± 0.108k/s 2.60 kmallocs/create +5.1% [1] https://lore.kernel.org/bpf/20251002225356.1505480-1-ameryhung@gmail.com/ v1 -> v2 - Only replace BPF memory allocator with kmalloc_nolock() Link: https://lore.kernel.org/bpf/20251112175939.2365295-1-ameryhung@gmail.com/ ==================== Link: https://patch.msgid.link/20251114201329.3275875-1-ameryhung@gmail.com Signed-off-by: Alexei Starovoitov --- d6ec0906d6c40435a6a79e4981342161c5d82ef1