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| author | Pawan Gupta <pawan.kumar.gupta@linux.intel.com> | 2026-06-29 22:39:29 -0700 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2026-07-01 10:34:41 +0200 |
| commit | b72e29e0f7ee329d89f86db8700c8ea99b4a370a (patch) | |
| tree | ac4ca7ece438c3831892ac9c4d3a9023b615d558 | |
| parent | a9b1f19a6a673ba06820898d0f1ad02883ea1639 (diff) | |
| download | linux-stable-b72e29e0f7ee329d89f86db8700c8ea99b4a370a.tar.gz linux-stable-b72e29e0f7ee329d89f86db8700c8ea99b4a370a.zip | |
bpf: Prefer dirty packs for eBPF allocations
The pack allocator only flushes predictors when reusing a dirty pack for
cBPF, eBPF allocations never trigger a flush. Currently, eBPF picks the
first free pack, which could be a clean pack. As an optimization, leaving
a clean pack for cBPF can avoid flushes.
Prefer dirty packs for eBPF and keep clean packs free for cBPF. This
mirrors the existing cBPF preference for clean packs: each program kind
prefers the pack that avoids an extra flush, and falls back to the other
kind only when no preferred pack has room. eBPF reuse of a dirty pack is
harmless since eBPF being privileged does not flush.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
| -rw-r--r-- | kernel/bpf/core.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 1b32b9f2491f..6e19a030da6f 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -988,10 +988,10 @@ void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns, bool goto found_free_area; /* * cBPF reuse of a dirty pack triggers a flush, so prefer a - * clean pack for cBPF. eBPF never flushes, so pick the first - * free pack, dirty or clean. + * clean pack for cBPF. eBPF never flushes, so steer it to a + * dirty pack and keep clean packs free for cBPF. */ - if (!was_classic || !pack->arch_flush_needed) + if (was_classic ^ pack->arch_flush_needed) goto found_free_area; if (!fallback_pack) { fallback_pack = pack; |