netdev - [PATCH 12/14] bpf: Allow no charge for bpf prog

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Date:   Sat, 19 Mar 2022 17:30:34 +0000
From:   Yafang Shao <laoar.shao@...il.com>
To:     roman.gushchin@...ux.dev, ast@...nel.org, daniel@...earbox.net,
        andrii@...nel.org, kafai@...com, songliubraving@...com, yhs@...com,
        john.fastabend@...il.com, kpsingh@...nel.org, shuah@...nel.org
Cc:     netdev@...r.kernel.org, bpf@...r.kernel.org,
        linux-kselftest@...r.kernel.org, Yafang Shao <laoar.shao@...il.com>
Subject: [PATCH 12/14] bpf: Allow no charge for bpf prog

Allow not to charge memory used by bpf progs. This includes the memory
used by bpf progs itself, auxxiliary data, statistics and bpf line info.

Signed-off-by: Yafang Shao <laoar.shao@...il.com>
---
 kernel/bpf/core.c    | 12 ++++++++++--
 kernel/bpf/syscall.c |  6 ++++--
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 0f68b8203c18..7aa750e8bd7d 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -144,12 +144,17 @@ EXPORT_SYMBOL_GPL(bpf_prog_alloc);
 
 int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog)
 {
+	gfp_t gfp_flags = GFP_KERNEL | __GFP_NOWARN;
+
 	if (!prog->aux->nr_linfo || !prog->jit_requested)
 		return 0;
 
+	if (!prog->aux->no_charge)
+		gfp_flags |= __GFP_ACCOUNT;
+
 	prog->aux->jited_linfo = kvcalloc(prog->aux->nr_linfo,
 					  sizeof(*prog->aux->jited_linfo),
-					  GFP_KERNEL_ACCOUNT | __GFP_NOWARN);
+					  gfp_flags);
 	if (!prog->aux->jited_linfo)
 		return -ENOMEM;
 
@@ -224,7 +229,7 @@ void bpf_prog_fill_jited_linfo(struct bpf_prog *prog,
 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
 				  gfp_t gfp_extra_flags)
 {
-	gfp_t gfp_flags = GFP_KERNEL_ACCOUNT | __GFP_ZERO | gfp_extra_flags;
+	gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
 	struct bpf_prog *fp;
 	u32 pages;
 
@@ -233,6 +238,9 @@ struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
 	if (pages <= fp_old->pages)
 		return fp_old;
 
+	if (!fp_old->aux->no_charge)
+		gfp_flags |= __GFP_ACCOUNT;
+
 	fp = __vmalloc(size, gfp_flags);
 	if (fp) {
 		memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE);
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index fdfbb4d0d5e0..e386b549fafc 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -2218,9 +2218,10 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr)
 	enum bpf_prog_type type = attr->prog_type;
 	struct bpf_prog *prog, *dst_prog = NULL;
 	struct btf *attach_btf = NULL;
-	int err;
+	gfp_t gfp_flags = GFP_USER;
 	char license[128];
 	bool is_gpl;
+	int err;
 
 	if (CHECK_ATTR(BPF_PROG_LOAD))
 		return -EINVAL;
@@ -2305,7 +2306,8 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr)
 	}
 
 	/* plain bpf_prog allocation */
-	prog = bpf_prog_alloc(bpf_prog_size(attr->insn_cnt), GFP_USER | __GFP_ACCOUNT);
+	prog = bpf_prog_alloc(bpf_prog_size(attr->insn_cnt),
+				prog_flags_no_charge(gfp_flags, attr));
 	if (!prog) {
 		if (dst_prog)
 			bpf_prog_put(dst_prog);
-- 
2.17.1