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authorAlexei Starovoitov <ast@fb.com>2017-05-30 13:31:28 -0700
committerDavid S. Miller <davem@davemloft.net>2017-05-31 19:29:47 -0400
commitf696b8f471ec987e987e38206b8eb23c39ee5a86 (patch)
tree9b31d18a68fe91db02039fd999fc1072ab6f76b7 /kernel/bpf
parent71189fa9b092ef125ee741eccb2f5fa916798afd (diff)
downloadlinux-f696b8f471ec987e987e38206b8eb23c39ee5a86.tar.bz2
bpf: split bpf core interpreter
split __bpf_prog_run() interpreter into stack allocation and execution parts. The code section shrinks which helps interpreter performance in some cases. text data bss dec hex filename 26350 10328 624 37302 91b6 kernel/bpf/core.o.before 25777 10328 624 36729 8f79 kernel/bpf/core.o.after Very short programs got slower (due to extra function call): Before: test_bpf: #89 ALU64_ADD_K: 1 + 2 = 3 jited:0 7 PASS test_bpf: #90 ALU64_ADD_K: 3 + 0 = 3 jited:0 8 PASS test_bpf: #91 ALU64_ADD_K: 1 + 2147483646 = 2147483647 jited:0 7 PASS test_bpf: #92 ALU64_ADD_K: 4294967294 + 2 = 4294967296 jited:0 11 PASS test_bpf: #93 ALU64_ADD_K: 2147483646 + -2147483647 = -1 jited:0 7 PASS After: test_bpf: #89 ALU64_ADD_K: 1 + 2 = 3 jited:0 11 PASS test_bpf: #90 ALU64_ADD_K: 3 + 0 = 3 jited:0 11 PASS test_bpf: #91 ALU64_ADD_K: 1 + 2147483646 = 2147483647 jited:0 11 PASS test_bpf: #92 ALU64_ADD_K: 4294967294 + 2 = 4294967296 jited:0 14 PASS test_bpf: #93 ALU64_ADD_K: 2147483646 + -2147483647 = -1 jited:0 10 PASS Longer programs got faster: Before: test_bpf: #266 BPF_MAXINSNS: Ctx heavy transformations jited:0 20286 20513 PASS test_bpf: #267 BPF_MAXINSNS: Call heavy transformations jited:0 31853 31768 PASS test_bpf: #268 BPF_MAXINSNS: Jump heavy test jited:0 9815 PASS test_bpf: #269 BPF_MAXINSNS: Very long jump backwards jited:0 6 PASS test_bpf: #270 BPF_MAXINSNS: Edge hopping nuthouse jited:0 13959 PASS test_bpf: #271 BPF_MAXINSNS: Jump, gap, jump, ... jited:0 210 PASS test_bpf: #272 BPF_MAXINSNS: ld_abs+get_processor_id jited:0 21724 PASS test_bpf: #273 BPF_MAXINSNS: ld_abs+vlan_push/pop jited:0 19118 PASS After: test_bpf: #266 BPF_MAXINSNS: Ctx heavy transformations jited:0 19008 18827 PASS test_bpf: #267 BPF_MAXINSNS: Call heavy transformations jited:0 29238 28450 PASS test_bpf: #268 BPF_MAXINSNS: Jump heavy test jited:0 9485 PASS test_bpf: #269 BPF_MAXINSNS: Very long jump backwards jited:0 12 PASS test_bpf: #270 BPF_MAXINSNS: Edge hopping nuthouse jited:0 13257 PASS test_bpf: #271 BPF_MAXINSNS: Jump, gap, jump, ... jited:0 213 PASS test_bpf: #272 BPF_MAXINSNS: ld_abs+get_processor_id jited:0 19389 PASS test_bpf: #273 BPF_MAXINSNS: ld_abs+vlan_push/pop jited:0 19583 PASS For real world production programs the difference is noise. This patch is first step towards reducing interpreter stack consumption. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel/bpf')
-rw-r--r--kernel/bpf/core.c21
1 files changed, 14 insertions, 7 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 339289402b96..abd410d394bc 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -763,10 +763,10 @@ EXPORT_SYMBOL_GPL(__bpf_call_base);
*
* Decode and execute eBPF instructions.
*/
-static unsigned int __bpf_prog_run(void *ctx, const struct bpf_insn *insn)
+static unsigned int ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn,
+ u64 *stack)
{
- u64 stack[MAX_BPF_STACK / sizeof(u64)];
- u64 regs[MAX_BPF_REG], tmp;
+ u64 tmp;
static const void *jumptable[256] = {
[0 ... 255] = &&default_label,
/* Now overwrite non-defaults ... */
@@ -874,9 +874,6 @@ static unsigned int __bpf_prog_run(void *ctx, const struct bpf_insn *insn)
#define CONT ({ insn++; goto select_insn; })
#define CONT_JMP ({ insn++; goto select_insn; })
- FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)];
- ARG1 = (u64) (unsigned long) ctx;
-
select_insn:
goto *jumptable[insn->code];
@@ -1219,7 +1216,17 @@ load_byte:
WARN_RATELIMIT(1, "unknown opcode %02x\n", insn->code);
return 0;
}
-STACK_FRAME_NON_STANDARD(__bpf_prog_run); /* jump table */
+STACK_FRAME_NON_STANDARD(___bpf_prog_run); /* jump table */
+
+static unsigned int __bpf_prog_run(void *ctx, const struct bpf_insn *insn)
+{
+ u64 stack[MAX_BPF_STACK / sizeof(u64)];
+ u64 regs[MAX_BPF_REG];
+
+ FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)];
+ ARG1 = (u64) (unsigned long) ctx;
+ return ___bpf_prog_run(regs, insn, stack);
+}
bool bpf_prog_array_compatible(struct bpf_array *array,
const struct bpf_prog *fp)