linux-kernel - [PATCH v4 2/6] alloc_tag: introduce shutdown_mem

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Message-ID: <20241023170759.999909-3-surenb@google.com>
Date: Wed, 23 Oct 2024 10:07:55 -0700
From: Suren Baghdasaryan <surenb@...gle.com>
To: akpm@...ux-foundation.org
Cc: kent.overstreet@...ux.dev, corbet@....net, arnd@...db.de, 
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Subject: [PATCH v4 2/6] alloc_tag: introduce shutdown_mem_profiling helper function

Implement a helper function to disable memory allocation profiling and
use it when creation of /proc/allocinfo fails.
Ensure /proc/allocinfo does not get created when memory allocation
profiling is disabled.

Signed-off-by: Suren Baghdasaryan <surenb@...gle.com>
---
 lib/alloc_tag.c | 33 ++++++++++++++++++++++++++-------
 1 file changed, 26 insertions(+), 7 deletions(-)

diff --git a/lib/alloc_tag.c b/lib/alloc_tag.c
index 81e5f9a70f22..435aa837e550 100644
--- a/lib/alloc_tag.c
+++ b/lib/alloc_tag.c
@@ -8,6 +8,14 @@
 #include <linux/seq_buf.h>
 #include <linux/seq_file.h>
 
+#define ALLOCINFO_FILE_NAME		"allocinfo"
+
+#ifdef CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT
+static bool mem_profiling_support __meminitdata = true;
+#else
+static bool mem_profiling_support __meminitdata;
+#endif
+
 static struct codetag_type *alloc_tag_cttype;
 
 DEFINE_PER_CPU(struct alloc_tag_counters, _shared_alloc_tag);
@@ -144,9 +152,26 @@ size_t alloc_tag_top_users(struct codetag_bytes *tags, size_t count, bool can_sl
 	return nr;
 }
 
+static void __init shutdown_mem_profiling(void)
+{
+	if (mem_alloc_profiling_enabled())
+		static_branch_disable(&mem_alloc_profiling_key);
+
+	if (!mem_profiling_support)
+		return;
+
+	mem_profiling_support = false;
+}
+
 static void __init procfs_init(void)
 {
-	proc_create_seq("allocinfo", 0400, NULL, &allocinfo_seq_op);
+	if (!mem_profiling_support)
+		return;
+
+	if (!proc_create_seq(ALLOCINFO_FILE_NAME, 0400, NULL, &allocinfo_seq_op)) {
+		pr_err("Failed to create %s file\n", ALLOCINFO_FILE_NAME);
+		shutdown_mem_profiling();
+	}
 }
 
 static bool alloc_tag_module_unload(struct codetag_type *cttype,
@@ -174,12 +199,6 @@ static bool alloc_tag_module_unload(struct codetag_type *cttype,
 	return module_unused;
 }
 
-#ifdef CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT
-static bool mem_profiling_support __meminitdata = true;
-#else
-static bool mem_profiling_support __meminitdata;
-#endif
-
 static int __init setup_early_mem_profiling(char *str)
 {
 	bool enable;
-- 
2.47.0.105.g07ac214952-goog