[PATCH v4 bpf-next 8/8] bpf: simplify select_bpf_prog_pack_size

From: Song Liu <song@kernel.org>
To: <linux-kernel@vger.kernel.org>, <bpf@vger.kernel.org>,
	<linux-mm@kvack.org>
Cc: <ast@kernel.org>, <daniel@iogearbox.net>, <peterz@infradead.org>,
	<mcgrof@kernel.org>, <torvalds@linux-foundation.org>,
	<rick.p.edgecombe@intel.com>, <kernel-team@fb.com>,
	Song Liu <song@kernel.org>
Subject: [PATCH v4 bpf-next 8/8] bpf: simplify select_bpf_prog_pack_size
Date: Fri, 20 May 2022 16:57:58 -0700	[thread overview]
Message-ID: <20220520235758.1858153-9-song@kernel.org> (raw)
In-Reply-To: <20220520235758.1858153-1-song@kernel.org>

Use huge_vmalloc_supported to simplify select_bpf_prog_pack_size, so that
we don't allocate some huge pages and free them immediately.

Suggested-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Song Liu <song@kernel.org>
---
 kernel/bpf/core.c | 15 ++++-----------
 1 file changed, 4 insertions(+), 11 deletions(-)

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index b64d91fcb0ba..b5dcc8f182b3 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -854,22 +854,15 @@ static LIST_HEAD(pack_list);
 static size_t select_bpf_prog_pack_size(void)
 {
 	size_t size;
-	void *ptr;
-
-	size = BPF_HPAGE_SIZE * num_online_nodes();
-	ptr = module_alloc_huge(size);
 
-	/* Test whether we can get huge pages. If not just use PAGE_SIZE
-	 * packs.
-	 */
-	if (!ptr || !is_vm_area_hugepages(ptr)) {
+	if (huge_vmalloc_supported()) {
+		size = BPF_HPAGE_SIZE * num_online_nodes();
+		bpf_prog_pack_mask = BPF_HPAGE_MASK;
+	} else {
 		size = PAGE_SIZE;
 		bpf_prog_pack_mask = PAGE_MASK;
-	} else {
-		bpf_prog_pack_mask = BPF_HPAGE_MASK;
 	}
 
-	vfree(ptr);
 	return size;
 }
 
-- 
2.30.2

