From be25d1d4e822a703b19043baff916aec6ac4362d Mon Sep 17 00:00:00 2001
From: Suren Baghdasaryan <surenb@google.com>
Date: Thu, 21 Mar 2024 09:36:41 -0700
Subject: mm: create new codetag references during page splitting
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When a high-order page is split into smaller ones, each newly split page
should get its codetag.  After the split each split page will be
referencing the original codetag.  The codetag's "bytes" counter remains
the same because the amount of allocated memory has not changed, however
the "calls" counter gets increased to keep the counter correct when these
individual pages get freed.

Link: https://lkml.kernel.org/r/20240321163705.3067592-20-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Kees Cook <keescook@chromium.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alex Gaynor <alex.gaynor@gmail.com>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Andreas Hindborg <a.hindborg@samsung.com>
Cc: Benno Lossin <benno.lossin@proton.me>
Cc: "Björn Roy Baron" <bjorn3_gh@protonmail.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Gary Guo <gary@garyguo.net>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Wedson Almeida Filho <wedsonaf@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 mm/huge_memory.c | 2 ++
 mm/page_alloc.c  | 2 ++
 2 files changed, 4 insertions(+)

(limited to 'mm')

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index dd88bb3ea196..25191ab70631 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -38,6 +38,7 @@
 #include <linux/sched/sysctl.h>
 #include <linux/memory-tiers.h>
 #include <linux/compat.h>
+#include <linux/pgalloc_tag.h>
 
 #include <asm/tlb.h>
 #include <asm/pgalloc.h>
@@ -2946,6 +2947,7 @@ static void __split_huge_page(struct page *page, struct list_head *list,
 	/* Caller disabled irqs, so they are still disabled here */
 
 	split_page_owner(head, order, new_order);
+	pgalloc_tag_split(head, 1 << order);
 
 	/* See comment in __split_huge_page_tail() */
 	if (folio_test_anon(folio)) {
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index d3afaf8f983a..e453ee22d489 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2630,6 +2630,7 @@ void split_page(struct page *page, unsigned int order)
 	for (i = 1; i < (1 << order); i++)
 		set_page_refcounted(page + i);
 	split_page_owner(page, order, 0);
+	pgalloc_tag_split(page, 1 << order);
 	split_page_memcg(page, order, 0);
 }
 EXPORT_SYMBOL_GPL(split_page);
@@ -4827,6 +4828,7 @@ static void *make_alloc_exact(unsigned long addr, unsigned int order,
 		struct page *last = page + nr;
 
 		split_page_owner(page, order, 0);
+		pgalloc_tag_split(page, 1 << order);
 		split_page_memcg(page, order, 0);
 		while (page < --last)
 			set_page_refcounted(last);
-- 
cgit