Date: Thu, 19 Nov 2009 08:26:27 +0000 (GMT) From: Robert Watson <rwatson@FreeBSD.org> To: Jung-uk Kim <jkim@FreeBSD.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r199498 - in head/sys: amd64/amd64 i386/i386 net Message-ID: <alpine.BSF.2.00.0911190819550.12162@fledge.watson.org> In-Reply-To: <200911182340.nAINeJ3W087652@svn.freebsd.org> References: <200911182340.nAINeJ3W087652@svn.freebsd.org>
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On Wed, 18 Nov 2009, Jung-uk Kim wrote:
> - Change internal function bpf_jit_compile() to return allocated size of
> the generated binary and remove page size limitation for userland.
> - Use contigmalloc(9)/contigfree(9) instead of malloc(9)/free(9) to make
> sure the generated binary aligns properly and make it physically contiguous.
Is physical contiguity actually required here -- I would have thought virtual
contiguity and alignment would be sufficient, in which case the normal trick
is to allocate using malloc the size + min-align + 1 and then fudge the
pointer forward until it's properly aligned.
Also, in 9.x I'm going to be looking at parallel execution within BPF
descriptors, and I notice that the JIT compiles the register array pointer
into the generated code, rather than allowing a pointer to be passed in to
each instance. I guess it's non-trivial to change that, suggesting that we
have a pool of compiled instances, but it would be preferable to be able to do
what the normal BPF code does: allocate a per-thread register block when
needed.
Robert N M Watson
Computer Laboratory
University of Cambridge
> Modified:
> head/sys/amd64/amd64/bpf_jit_machdep.c
> head/sys/i386/i386/bpf_jit_machdep.c
> head/sys/net/bpf_jitter.c
> head/sys/net/bpf_jitter.h
>
> Modified: head/sys/amd64/amd64/bpf_jit_machdep.c
> ==============================================================================
> --- head/sys/amd64/amd64/bpf_jit_machdep.c Wed Nov 18 22:53:05 2009 (r199497)
> +++ head/sys/amd64/amd64/bpf_jit_machdep.c Wed Nov 18 23:40:19 2009 (r199498)
> @@ -53,7 +53,7 @@ __FBSDID("$FreeBSD$");
>
> #include <amd64/amd64/bpf_jit_machdep.h>
>
> -bpf_filter_func bpf_jit_compile(struct bpf_insn *, u_int, int *);
> +bpf_filter_func bpf_jit_compile(struct bpf_insn *, u_int, size_t *, int *);
>
> /*
> * emit routine to update the jump table
> @@ -97,7 +97,7 @@ emit_code(bpf_bin_stream *stream, u_int
> * Function that does the real stuff
> */
> bpf_filter_func
> -bpf_jit_compile(struct bpf_insn *prog, u_int nins, int *mem)
> +bpf_jit_compile(struct bpf_insn *prog, u_int nins, size_t *size, int *mem)
> {
> bpf_bin_stream stream;
> struct bpf_insn *ins;
> @@ -481,23 +481,21 @@ bpf_jit_compile(struct bpf_insn *prog, u
> #ifndef _KERNEL
> if (mprotect(stream.ibuf, stream.cur_ip,
> PROT_READ | PROT_EXEC) != 0) {
> - munmap(stream.ibuf, BPF_JIT_MAXSIZE);
> + munmap(stream.ibuf, stream.cur_ip);
> stream.ibuf = NULL;
> }
> #endif
> + *size = stream.cur_ip;
> break;
> }
>
> #ifdef _KERNEL
> - stream.ibuf = (char *)malloc(stream.cur_ip, M_BPFJIT, M_NOWAIT);
> + stream.ibuf = (char *)contigmalloc(stream.cur_ip, M_BPFJIT,
> + M_NOWAIT, 0, ~0ULL, 16, 0);
> if (stream.ibuf == NULL)
> break;
> #else
> - if (stream.cur_ip > BPF_JIT_MAXSIZE) {
> - stream.ibuf = NULL;
> - break;
> - }
> - stream.ibuf = (char *)mmap(NULL, BPF_JIT_MAXSIZE,
> + stream.ibuf = (char *)mmap(NULL, stream.cur_ip,
> PROT_READ | PROT_WRITE, MAP_ANON, -1, 0);
> if (stream.ibuf == MAP_FAILED) {
> stream.ibuf = NULL;
>
> Modified: head/sys/i386/i386/bpf_jit_machdep.c
> ==============================================================================
> --- head/sys/i386/i386/bpf_jit_machdep.c Wed Nov 18 22:53:05 2009 (r199497)
> +++ head/sys/i386/i386/bpf_jit_machdep.c Wed Nov 18 23:40:19 2009 (r199498)
> @@ -53,7 +53,7 @@ __FBSDID("$FreeBSD$");
>
> #include <i386/i386/bpf_jit_machdep.h>
>
> -bpf_filter_func bpf_jit_compile(struct bpf_insn *, u_int, int *);
> +bpf_filter_func bpf_jit_compile(struct bpf_insn *, u_int, size_t *, int *);
>
> /*
> * emit routine to update the jump table
> @@ -97,7 +97,7 @@ emit_code(bpf_bin_stream *stream, u_int
> * Function that does the real stuff
> */
> bpf_filter_func
> -bpf_jit_compile(struct bpf_insn *prog, u_int nins, int *mem)
> +bpf_jit_compile(struct bpf_insn *prog, u_int nins, size_t *size, int *mem)
> {
> bpf_bin_stream stream;
> struct bpf_insn *ins;
> @@ -504,23 +504,21 @@ bpf_jit_compile(struct bpf_insn *prog, u
> #ifndef _KERNEL
> if (mprotect(stream.ibuf, stream.cur_ip,
> PROT_READ | PROT_EXEC) != 0) {
> - munmap(stream.ibuf, BPF_JIT_MAXSIZE);
> + munmap(stream.ibuf, stream.cur_ip);
> stream.ibuf = NULL;
> }
> #endif
> + *size = stream.cur_ip;
> break;
> }
>
> #ifdef _KERNEL
> - stream.ibuf = (char *)malloc(stream.cur_ip, M_BPFJIT, M_NOWAIT);
> + stream.ibuf = (char *)contigmalloc(stream.cur_ip, M_BPFJIT,
> + M_NOWAIT, 0, ~0ULL, 16, 0);
> if (stream.ibuf == NULL)
> break;
> #else
> - if (stream.cur_ip > BPF_JIT_MAXSIZE) {
> - stream.ibuf = NULL;
> - break;
> - }
> - stream.ibuf = (char *)mmap(NULL, BPF_JIT_MAXSIZE,
> + stream.ibuf = (char *)mmap(NULL, stream.cur_ip,
> PROT_READ | PROT_WRITE, MAP_ANON, -1, 0);
> if (stream.ibuf == MAP_FAILED) {
> stream.ibuf = NULL;
>
> Modified: head/sys/net/bpf_jitter.c
> ==============================================================================
> --- head/sys/net/bpf_jitter.c Wed Nov 18 22:53:05 2009 (r199497)
> +++ head/sys/net/bpf_jitter.c Wed Nov 18 23:40:19 2009 (r199498)
> @@ -51,7 +51,7 @@ __FBSDID("$FreeBSD$");
> #include <net/bpf.h>
> #include <net/bpf_jitter.h>
>
> -bpf_filter_func bpf_jit_compile(struct bpf_insn *, u_int, int *);
> +bpf_filter_func bpf_jit_compile(struct bpf_insn *, u_int, size_t *, int *);
>
> static u_int bpf_jit_accept_all(u_char *, u_int, u_int);
>
> @@ -81,7 +81,8 @@ bpf_jitter(struct bpf_insn *fp, int nins
> }
>
> /* Create the binary */
> - if ((filter->func = bpf_jit_compile(fp, nins, filter->mem)) == NULL) {
> + if ((filter->func = bpf_jit_compile(fp, nins, &filter->size,
> + filter->mem)) == NULL) {
> free(filter, M_BPFJIT);
> return (NULL);
> }
> @@ -94,7 +95,7 @@ bpf_destroy_jit_filter(bpf_jit_filter *f
> {
>
> if (filter->func != bpf_jit_accept_all)
> - free(filter->func, M_BPFJIT);
> + contigfree(filter->func, filter->size, M_BPFJIT);
> free(filter, M_BPFJIT);
> }
> #else
> @@ -116,7 +117,8 @@ bpf_jitter(struct bpf_insn *fp, int nins
> }
>
> /* Create the binary */
> - if ((filter->func = bpf_jit_compile(fp, nins, filter->mem)) == NULL) {
> + if ((filter->func = bpf_jit_compile(fp, nins, &filter->size,
> + filter->mem)) == NULL) {
> free(filter);
> return (NULL);
> }
> @@ -129,7 +131,7 @@ bpf_destroy_jit_filter(bpf_jit_filter *f
> {
>
> if (filter->func != bpf_jit_accept_all)
> - munmap(filter->func, BPF_JIT_MAXSIZE);
> + munmap(filter->func, filter->size);
> free(filter);
> }
> #endif
>
> Modified: head/sys/net/bpf_jitter.h
> ==============================================================================
> --- head/sys/net/bpf_jitter.h Wed Nov 18 22:53:05 2009 (r199497)
> +++ head/sys/net/bpf_jitter.h Wed Nov 18 23:40:19 2009 (r199498)
> @@ -36,8 +36,6 @@
>
> #ifdef _KERNEL
> MALLOC_DECLARE(M_BPFJIT);
> -#else
> -#define BPF_JIT_MAXSIZE PAGE_SIZE
> #endif
>
> extern int bpf_jitter_enable;
> @@ -55,7 +53,7 @@ typedef u_int (*bpf_filter_func)(u_char
> typedef struct bpf_jit_filter {
> /* The native filtering binary, in the form of a bpf_filter_func. */
> bpf_filter_func func;
> -
> + size_t size;
> int mem[BPF_MEMWORDS]; /* Scratch memory */
> } bpf_jit_filter;
>
>
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