From: Ard Biesheuvel <ardb@kernel.org>
To: akpm@linux-foundation.org
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Ard Biesheuvel <ardb@kernel.org>
Subject: [PATCH] mm: make 'highmem' symbol ro_after_init
Date: Mon, 24 Jan 2022 18:05:55 +0100 [thread overview]
Message-ID: <20220124170555.1054480-1-ardb@kernel.org> (raw)
The 'highmem' variable is only set at boot, so we can make it
ro_after_init and prevent it from being corrupted inadvertently, or from
ending up in a contended cacheline.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
mm/memory.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/memory.c b/mm/memory.c
index c125c4969913..50e82cb94ccc 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -106,7 +106,7 @@ EXPORT_SYMBOL(mem_map);
* highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
* and ZONE_HIGHMEM.
*/
-void *high_memory;
+void *high_memory __ro_after_init;
EXPORT_SYMBOL(high_memory);
/*
--
2.30.2
next reply other threads:[~2022-01-24 17:06 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-24 17:05 Ard Biesheuvel [this message]
2022-01-24 18:17 ` [PATCH] mm: make 'highmem' symbol ro_after_init David Rientjes
2022-01-24 18:31 ` Matthew Wilcox
2022-01-26 21:38 ` Mike Rapoport
2022-01-28 9:07 ` Ard Biesheuvel
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20220124170555.1054480-1-ardb@kernel.org \
--to=ardb@kernel.org \
--cc=akpm@linux-foundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).