The patch below does not apply to the 6.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y git checkout FETCH_HEAD git cherry-pick -x 05c82ee363f64c64b87a0cfd744298e9333475f5 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025012056-marina-lagging-26cc@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 05c82ee363f64c64b87a0cfd744298e9333475f5 Mon Sep 17 00:00:00 2001 From: Suren Baghdasaryan surenb@google.com Date: Thu, 26 Dec 2024 13:16:39 -0800 Subject: [PATCH] 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 7dcebf118a3e..65e706e1bc19 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;