linux-kernel - [patch V2 m@/6] perf/core: Split out VM accounting

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Message-ID: <20250811070620.527392167@linutronix.de>
Date: Mon, 11 Aug 2025 09:06:39 +0200 (CEST)
From: Thomas Gleixner <tglx@...utronix.de>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Linus Torvalds <torvalds@...uxfoundation.org>,
 Peter Zijlstra <peterz@...radead.org>,
 Ingo Molnar <mingo@...nel.org>,
 Namhyung Kim <namhyung@...nel.org>,
 Arnaldo Carvalho de Melo <acme@...hat.com>,
 Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
 Kees Cook <kees@...nel.org>
Subject: [patch V2 m@/6] perf/core: Split out VM accounting

Similary to the mlock limit calculation the VM accounting is required for
both the ringbuffer and the AUX buffer allocations.

To prepare for splitting them out into seperate functions, move the
accounting into a helper function.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>

---
 kernel/events/core.c |   13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6962,10 +6962,17 @@ static bool perf_mmap_calc_limits(struct
 	return locked <= lock_limit || !perf_is_paranoid() || capable(CAP_IPC_LOCK);
 }
 
+static void perf_mmap_account(struct vm_area_struct *vma, long user_extra, long extra)
+{
+	struct user_struct *user = current_user();
+
+	atomic_long_add(user_extra, &user->locked_vm);
+	atomic64_add(extra, &vma->vm_mm->pinned_vm);
+}
+
 static int perf_mmap(struct file *file, struct vm_area_struct *vma)
 {
 	struct perf_event *event = file->private_data;
-	struct user_struct *user = current_user();
 	unsigned long vma_size, nr_pages;
 	long user_extra = 0, extra = 0;
 	struct mutex *aux_mutex = NULL;
@@ -7136,9 +7143,7 @@ static int perf_mmap(struct file *file,
 
 unlock:
 	if (!ret) {
-		atomic_long_add(user_extra, &user->locked_vm);
-		atomic64_add(extra, &vma->vm_mm->pinned_vm);
-
+		perf_mmap_account(vma, user_extra, extra);
 		atomic_inc(&event->mmap_count);
 	} else if (rb) {
 		/* AUX allocation failed */