All of lore.kernel.org
 help / color / mirror / Atom feed
From: Jakub Kicinski <jakub.kicinski@netronome.com>
To: alexei.starovoitov@gmail.com, daniel@iogearbox.net, yhs@fb.com
Cc: netdev@vger.kernel.org, oss-drivers@netronome.com,
	Jakub Kicinski <jakub.kicinski@netronome.com>
Subject: [RFC bpf-next v4 07/12] bpf: notify offload JITs about optimizations
Date: Mon, 31 Dec 2018 17:37:38 -0800	[thread overview]
Message-ID: <20190101013743.23935-8-jakub.kicinski@netronome.com> (raw)
In-Reply-To: <20190101013743.23935-1-jakub.kicinski@netronome.com>

Let offload JITs know when instructions are replaced and optimized
out, so they can update their state appropriately.  The optimizations
are best effort, if JIT returns an error from any callback verifier
will stop notifying it as state may now be out of sync, but the
verifier continues making progress.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
---
 include/linux/bpf.h          |  7 +++++++
 include/linux/bpf_verifier.h |  5 +++++
 kernel/bpf/offload.c         | 35 +++++++++++++++++++++++++++++++++++
 kernel/bpf/verifier.c        |  6 ++++++
 4 files changed, 53 insertions(+)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index e734f163bd0b..3851529062ec 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -268,9 +268,15 @@ struct bpf_verifier_ops {
 };
 
 struct bpf_prog_offload_ops {
+	/* verifier basic callbacks */
 	int (*insn_hook)(struct bpf_verifier_env *env,
 			 int insn_idx, int prev_insn_idx);
 	int (*finalize)(struct bpf_verifier_env *env);
+	/* verifier optimization callbacks (called after .finalize) */
+	int (*replace_insn)(struct bpf_verifier_env *env, u32 off,
+			    struct bpf_insn *insn);
+	int (*remove_insns)(struct bpf_verifier_env *env, u32 off, u32 cnt);
+	/* program management callbacks */
 	int (*prepare)(struct bpf_prog *prog);
 	int (*translate)(struct bpf_prog *prog);
 	void (*destroy)(struct bpf_prog *prog);
@@ -283,6 +289,7 @@ struct bpf_prog_offload {
 	void			*dev_priv;
 	struct list_head	offloads;
 	bool			dev_state;
+	bool			opt_failed;
 	void			*jited_image;
 	u32			jited_len;
 };
diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
index 414d1aeba897..ff6653fc8c45 100644
--- a/include/linux/bpf_verifier.h
+++ b/include/linux/bpf_verifier.h
@@ -253,5 +253,10 @@ int bpf_prog_offload_verifier_prep(struct bpf_prog *prog);
 int bpf_prog_offload_verify_insn(struct bpf_verifier_env *env,
 				 int insn_idx, int prev_insn_idx);
 int bpf_prog_offload_finalize(struct bpf_verifier_env *env);
+void
+bpf_prog_offload_replace_insn(struct bpf_verifier_env *env, u32 off,
+			      struct bpf_insn *insn);
+void
+bpf_prog_offload_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt);
 
 #endif /* _LINUX_BPF_VERIFIER_H */
diff --git a/kernel/bpf/offload.c b/kernel/bpf/offload.c
index 54cf2b9c44a4..39dba8c90331 100644
--- a/kernel/bpf/offload.c
+++ b/kernel/bpf/offload.c
@@ -173,6 +173,41 @@ int bpf_prog_offload_finalize(struct bpf_verifier_env *env)
 	return ret;
 }
 
+void
+bpf_prog_offload_replace_insn(struct bpf_verifier_env *env, u32 off,
+			      struct bpf_insn *insn)
+{
+	const struct bpf_prog_offload_ops *ops;
+	struct bpf_prog_offload *offload;
+	int ret = -EOPNOTSUPP;
+
+	down_read(&bpf_devs_lock);
+	offload = env->prog->aux->offload;
+	if (offload) {
+		ops = offload->offdev->ops;
+		if (!offload->opt_failed && ops->replace_insn)
+			ret = ops->replace_insn(env, off, insn);
+		offload->opt_failed |= ret;
+	}
+	up_read(&bpf_devs_lock);
+}
+
+void
+bpf_prog_offload_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt)
+{
+	struct bpf_prog_offload *offload;
+	int ret = -EOPNOTSUPP;
+
+	down_read(&bpf_devs_lock);
+	offload = env->prog->aux->offload;
+	if (offload) {
+		if (!offload->opt_failed && offload->offdev->ops->remove_insns)
+			ret = offload->offdev->ops->remove_insns(env, off, cnt);
+		offload->opt_failed |= ret;
+	}
+	up_read(&bpf_devs_lock);
+}
+
 static void __bpf_prog_offload_destroy(struct bpf_prog *prog)
 {
 	struct bpf_prog_offload *offload = prog->aux->offload;
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 3efa9f2285fe..bf75c6691be2 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -6350,6 +6350,9 @@ static int verifier_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt)
 	unsigned int orig_prog_len = env->prog->len;
 	int err;
 
+	if (bpf_prog_is_dev_bound(env->prog->aux))
+		bpf_prog_offload_remove_insns(env, off, cnt);
+
 	err = bpf_remove_insns(env->prog, off, cnt);
 	if (err)
 		return err;
@@ -6424,6 +6427,9 @@ static void opt_hard_wire_dead_code_branches(struct bpf_verifier_env *env)
 		else
 			continue;
 
+		if (bpf_prog_is_dev_bound(env->prog->aux))
+			bpf_prog_offload_replace_insn(env, i, &ja);
+
 		memcpy(insn, &ja, sizeof(ja));
 	}
 }
-- 
2.19.2

  parent reply	other threads:[~2019-01-01  1:38 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-01  1:37 [RFC bpf-next v4 00/12] bpf: dead code elimination Jakub Kicinski
2019-01-01  1:37 ` [RFC bpf-next v4 01/12] bpf: change parameters of call/branch offset adjustment Jakub Kicinski
2019-01-01  1:37 ` [RFC bpf-next v4 02/12] bpf: verifier: hard wire branches to dead code Jakub Kicinski
2019-01-01  1:37 ` [RFC bpf-next v4 03/12] bpf: verifier: remove " Jakub Kicinski
2019-01-02  5:25   ` Yonghong Song
2019-01-02 12:23     ` Edward Cree
2019-01-02 18:31     ` Jakub Kicinski
2019-01-02 18:57       ` Yonghong Song
2019-01-02 19:14         ` Jakub Kicinski
2019-01-01  1:37 ` [RFC bpf-next v4 04/12] bpf: verifier: remove unconditional branches by 0 Jakub Kicinski
2019-01-01  1:37 ` [RFC bpf-next v4 05/12] selftests: bpf: add tests for dead code removal Jakub Kicinski
2019-01-01  1:37 ` [RFC bpf-next v4 06/12] bpf: verifier: record original instruction index Jakub Kicinski
2019-01-01  1:37 ` Jakub Kicinski [this message]
2019-01-01  1:37 ` [RFC bpf-next v4 08/12] nfp: bpf: don't use instruction number for jump target Jakub Kicinski
2019-01-01  1:37 ` [RFC bpf-next v4 09/12] nfp: bpf: split up the skip flag Jakub Kicinski
2019-01-01  1:37 ` [RFC bpf-next v4 10/12] nfp: bpf: save original program length Jakub Kicinski
2019-01-01  1:37 ` [RFC bpf-next v4 11/12] nfp: bpf: support optimizing dead branches Jakub Kicinski
2019-01-01  1:37 ` [RFC bpf-next v4 12/12] nfp: bpf: support removing dead code Jakub Kicinski

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190101013743.23935-8-jakub.kicinski@netronome.com \
    --to=jakub.kicinski@netronome.com \
    --cc=alexei.starovoitov@gmail.com \
    --cc=daniel@iogearbox.net \
    --cc=netdev@vger.kernel.org \
    --cc=oss-drivers@netronome.com \
    --cc=yhs@fb.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.