From: Kui-Feng Lee <sinquersw@gmail.com>
To: Martin KaFai Lau <martin.lau@linux.dev>,
Kui-Feng Lee <thinker.li@gmail.com>
Cc: kuifeng@meta.com, bpf@vger.kernel.org, ast@kernel.org,
song@kernel.org, kernel-team@meta.com, andrii@kernel.org
Subject: Re: [PATCH bpf-next v3 2/3] bpf: struct_ops supports more than one page for trampolines.
Date: Sat, 24 Feb 2024 07:43:07 -0800 [thread overview]
Message-ID: <c3080ecb-abb0-4d47-a8f5-607e7082b1ef@gmail.com> (raw)
In-Reply-To: <9d2dbd18-0d64-458a-8c95-9d549eabd3cf@linux.dev>
On 2/23/24 22:19, Martin KaFai Lau wrote:
> On 2/23/24 7:03 PM, Kui-Feng Lee wrote:
>> +static void bpf_struct_ops_map_free_image(struct bpf_struct_ops_map
>> *st_map)
>> +{
>> + int i;
>> + void *image;
>> +
>> + bpf_jit_uncharge_modmem(PAGE_SIZE * st_map->image_pages_cnt);
>> + for (i = 0; i < st_map->image_pages_cnt; i++) {
>> + image = st_map->image_pages[i];
>> + arch_free_bpf_trampoline(image, PAGE_SIZE);
>> + }
>> + st_map->image_pages_cnt = 0;
>> +}
>> +
>
> [ ... ]
>
>> @@ -133,7 +128,8 @@ int bpf_struct_ops_test_run(struct bpf_prog *prog,
>> const union bpf_attr *kattr,
>> err = bpf_struct_ops_prepare_trampoline(tlinks, link,
>> &st_ops->func_models[op_idx],
>> &dummy_ops_test_ret_function,
>> - image, image + PAGE_SIZE);
>> + &image, &image_off,
>> + true);
>> if (err < 0)
>> goto out;
>> @@ -147,6 +143,8 @@ int bpf_struct_ops_test_run(struct bpf_prog *prog,
>> const union bpf_attr *kattr,
>> err = -EFAULT;
>> out:
>> kfree(args);
>> + if (image)
>> + bpf_jit_uncharge_modmem(PAGE_SIZE);
>> arch_free_bpf_trampoline(image, PAGE_SIZE);
>
> It seems my last reply on v2 has crossed over with v3.
>
> The bpf_struct_ops_free_trampoline() highlighted in my last reply should
> address your concern in v2 that the caller needs to remember
> the bpf_jit_uncharge_modmem here.
>
> I think the trampoline alloc(aka prepare here)/free pair that you also
> suggested in v2 discussion is a nice match here and work as a
> charge+alloc and uncharge+free pair.
sure
>
>> if (link)
>> bpf_link_put(&link->link);
>
next prev parent reply other threads:[~2024-02-24 15:43 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-24 3:02 [PATCH bpf-next v3 0/3] Allow struct_ops maps with a large number of programs Kui-Feng Lee
2024-02-24 3:03 ` [PATCH bpf-next v3 1/3] bpf, net: validate struct_ops when updating value Kui-Feng Lee
2024-02-24 3:03 ` [PATCH bpf-next v3 2/3] bpf: struct_ops supports more than one page for trampolines Kui-Feng Lee
2024-02-24 6:19 ` Martin KaFai Lau
2024-02-24 15:43 ` Kui-Feng Lee [this message]
2024-02-24 3:03 ` [PATCH bpf-next v3 3/3] selftests/bpf: Test struct_ops maps with a large number of program links Kui-Feng Lee
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