From: Kees Cook <keescook@chromium.org>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: 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>, Jann Horn <jannh@google.com>,
Vijayanand Jitta <vjitta@codeaurora.org>
Subject: Re: [RFC PATCH 5/5] mm, slub: make reclaim_account attribute read-only
Date: Fri, 5 Jun 2020 14:07:26 -0700 [thread overview]
Message-ID: <202006051407.2B00B067@keescook> (raw)
In-Reply-To: <20200602141519.7099-6-vbabka@suse.cz>
On Tue, Jun 02, 2020 at 04:15:19PM +0200, Vlastimil Babka wrote:
> The attribute reflects the SLAB_RECLAIM_ACCOUNT cache flag. It's not clear why
> this attribute was writable in the first place, as it's tied to how the cache
> is used by its creator, it's not a user tunable. Furthermore:
>
> - it affects slab merging, but that's not being checked while toggled
> - if affects whether __GFP_RECLAIMABLE flag is used to allocate page, but
> the runtime toggle doesn't update allocflags
> - it affects cache_vmstat_idx() so runtime toggle might lead to incosistency
> of NR_SLAB_RECLAIMABLE and NR_SLAB_UNRECLAIMABLE
>
> Thus make it read-only.
>
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Kees Cook <keescook@chromium.org>
--
Kees Cook
next prev parent reply other threads:[~2020-06-05 21:07 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-02 14:15 [RFC PATCH 0/5] replace runtime slub_debug toggling with more capable boot parameter Vlastimil Babka
2020-06-02 14:15 ` [RFC PATCH 1/5] mm, slub: extend slub_debug syntax for multiple blocks Vlastimil Babka
2020-06-05 21:06 ` Kees Cook
2020-06-08 16:58 ` Vlastimil Babka
2020-06-02 14:15 ` [RFC PATCH 2/5] mm, slub: make some slub_debug related attributes read-only Vlastimil Babka
2020-06-05 21:06 ` Kees Cook
2020-06-06 0:32 ` Roman Gushchin
2020-06-02 14:15 ` [RFC PATCH 3/5] mm, slub: remove runtime allocation order changes Vlastimil Babka
2020-06-05 21:06 ` Kees Cook
2020-06-06 0:32 ` Roman Gushchin
2020-06-02 14:15 ` [RFC PATCH 4/5] mm, slub: make remaining slub_debug related attributes read-only Vlastimil Babka
2020-06-05 21:07 ` Kees Cook
2020-06-06 0:33 ` Roman Gushchin
2020-06-02 14:15 ` [RFC PATCH 5/5] mm, slub: make reclaim_account attribute read-only Vlastimil Babka
2020-06-05 21:07 ` Kees Cook [this message]
2020-06-06 0:34 ` Roman Gushchin
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