From: Kees Cook <keescook@chromium.org>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
kernel-team@android.com, vinmenon@codeaurora.org,
Matthew Garrett <mjg59@google.com>, Roman Gushchin <guro@fb.com>,
Jann Horn <jannh@google.com>,
Vijayanand Jitta <vjitta@codeaurora.org>
Subject: Re: [PATCH 6/9] mm, slub: introduce static key for slub_debug()
Date: Wed, 17 Jun 2020 10:54:07 -0700 [thread overview]
Message-ID: <202006171050.D48F4B7@keescook> (raw)
In-Reply-To: <20200610163135.17364-7-vbabka@suse.cz>
On Wed, Jun 10, 2020 at 06:31:32PM +0200, Vlastimil Babka wrote:
> One advantage of CONFIG_SLUB_DEBUG is that a generic distro kernel can be built
> with the option enabled, but it's inactive until simply enabled on boot,
> without rebuilding the kernel. With a static key, we can further eliminate the
> overhead of checking whether a cache has a particular debug flag enabled if we
> know that there are no such caches (slub_debug was not enabled during boot). We
> use the same mechanism also for e.g. page_owner, debug_pagealloc or kmemcg
> functionality.
>
> This patch introduces the static key and makes the general check for per-cache
> debug flags kmem_cache_debug() use it. This benefits several call sites,
> including (slow path but still rather frequent) __slab_free(). The next patches
> will add more uses.
>
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> ---
> mm/slub.c | 16 +++++++++++++---
> 1 file changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/mm/slub.c b/mm/slub.c
> index 8dd2925448ae..24d3e5f832aa 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -114,13 +114,21 @@
> * the fast path and disables lockless freelists.
> */
>
> +#ifdef CONFIG_SLUB_DEBUG
> +#ifdef CONFIG_SLUB_DEBUG_ON
> +DEFINE_STATIC_KEY_TRUE(slub_debug_enabled);
> +#else
> +DEFINE_STATIC_KEY_FALSE(slub_debug_enabled);
> +#endif
> +#endif
Yet another potential future user of DEFINE_STATIC_KEY_MAYBE()[1], once
I get it landed. :)
Reviewed-by: Kees Cook <keescook@chromium.org>
[1] https://lore.kernel.org/lkml/20200324203231.64324-2-keescook@chromium.org/
--
Kees Cook
next prev parent reply other threads:[~2020-06-17 17:54 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-10 16:31 [PATCH 0/9] slub_debug fixes and improvements Vlastimil Babka
2020-06-10 16:31 ` [PATCH 1/9] mm, slub: extend slub_debug syntax for multiple blocks Vlastimil Babka
2020-06-10 16:31 ` [PATCH 2/9] mm, slub: make some slub_debug related attributes read-only Vlastimil Babka
2020-06-10 16:31 ` [PATCH 3/9] mm, slub: remove runtime allocation order changes Vlastimil Babka
2020-06-10 16:31 ` [PATCH 4/9] mm, slub: make remaining slub_debug related attributes read-only Vlastimil Babka
2020-06-10 16:31 ` [PATCH 5/9] mm, slub: make reclaim_account attribute read-only Vlastimil Babka
2020-06-10 16:31 ` [PATCH 6/9] mm, slub: introduce static key for slub_debug() Vlastimil Babka
2020-06-10 21:59 ` Roman Gushchin
2020-06-17 17:54 ` Kees Cook [this message]
2020-06-10 16:31 ` [PATCH 7/9] mm, slub: introduce kmem_cache_debug_flags() Vlastimil Babka
2020-06-10 22:06 ` Roman Gushchin
2020-06-17 17:56 ` Kees Cook
2020-06-18 8:32 ` Vlastimil Babka
2020-06-18 8:37 ` Vlastimil Babka
2020-06-18 19:54 ` Roman Gushchin
2020-06-18 19:56 ` Kees Cook
2020-06-10 16:31 ` [PATCH 8/9] mm, slub: extend checks guarded by slub_debug static key Vlastimil Babka
2020-06-10 22:09 ` Roman Gushchin
2020-06-10 16:31 ` [PATCH 9/9] mm, slab/slub: move and improve cache_from_obj() Vlastimil Babka
2020-06-10 22:46 ` Roman Gushchin
2020-06-11 9:56 ` Vlastimil Babka
2020-06-11 20:04 ` Roman Gushchin
2020-06-17 17:49 ` Kees Cook
2020-06-18 10:10 ` Vlastimil Babka
2020-06-18 19:59 ` Kees Cook
2020-06-18 20:05 ` Roman Gushchin
2020-06-19 19:02 ` Kees Cook
2020-06-24 7:57 ` Vlastimil Babka
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=202006171050.D48F4B7@keescook \
--to=keescook@chromium.org \
--cc=akpm@linux-foundation.org \
--cc=cl@linux.com \
--cc=guro@fb.com \
--cc=iamjoonsoo.kim@lge.com \
--cc=jannh@google.com \
--cc=kernel-team@android.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mjg59@google.com \
--cc=penberg@kernel.org \
--cc=rientjes@google.com \
--cc=vbabka@suse.cz \
--cc=vinmenon@codeaurora.org \
--cc=vjitta@codeaurora.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).