From: Suren Baghdasaryan <surenb@google.com>
Date: Thu, 26 Dec 2024 21:16:39 +0000 (-0800)
Subject: alloc_tag: skip pgalloc_tag_swap if profiling is disabled
X-Git-Tag: v6.13~14^2~5
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=05c82ee363f64c64b87a0cfd744298e9333475f5;p=thirdparty%2Fkernel%2Flinux.git

alloc_tag: skip pgalloc_tag_swap if profiling is disabled

When memory allocation profiling is disabled, there is no need to swap
allocation tags during migration.  Skip it to avoid unnecessary overhead.

Once I added these checks, the overhead of the mode when memory profiling
is enabled but turned off went down by about 50%.

Link: https://lkml.kernel.org/r/20241226211639.1357704-2-surenb@google.com
Fixes: e0a955bf7f61 ("mm/codetag: add pgalloc_tag_copy()")
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Cc: David Wang <00107082@163.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zhenhua Huang <quic_zhenhuah@quicinc.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/lib/alloc_tag.c b/lib/alloc_tag.c
index 7dcebf118a3e6..65e706e1bc199 100644
--- a/lib/alloc_tag.c
+++ b/lib/alloc_tag.c
@@ -195,6 +195,9 @@ void pgalloc_tag_swap(struct folio *new, struct folio *old)
 	union codetag_ref ref_old, ref_new;
 	struct alloc_tag *tag_old, *tag_new;
 
+	if (!mem_alloc_profiling_enabled())
+		return;
+
 	tag_old = pgalloc_tag_get(&old->page);
 	if (!tag_old)
 		return;