From: Vlastimil Babka <vbabka@suse.cz>
To: Marco Elver <elver@google.com>, Dave Hansen <dave.hansen@intel.com>
Cc: glider@google.com, akpm@linux-foundation.org,
catalin.marinas@arm.com, cl@linux.com, rientjes@google.com,
iamjoonsoo.kim@lge.com, mark.rutland@arm.com, penberg@kernel.org,
hpa@zytor.com, paulmck@kernel.org, andreyknvl@google.com,
aryabinin@virtuozzo.com, luto@kernel.org, bp@alien8.de,
dave.hansen@linux.intel.com, dvyukov@google.com,
edumazet@google.com, gregkh@linuxfoundation.org,
mingo@redhat.com, jannh@google.com, corbet@lwn.net,
keescook@chromium.org, peterz@infradead.org, cai@lca.pw,
tglx@linutronix.de, will@kernel.org, x86@kernel.org,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
kasan-dev@googlegroups.com, linux-arm-kernel@lists.infradead.org,
linux-mm@kvack.org
Subject: Re: [PATCH RFC 00/10] KFENCE: A low-overhead sampling-based memory safety error detector
Date: Tue, 8 Sep 2020 17:36:44 +0200 [thread overview]
Message-ID: <feb73053-17a6-8b43-5b2b-51a813e81622@suse.cz> (raw)
In-Reply-To: <20200908153102.GB61807@elver.google.com>
On 9/8/20 5:31 PM, Marco Elver wrote:
>>
>> How much memory overhead does this end up having? I know it depends on
>> the object size and so forth. But, could you give some real-world
>> examples of memory consumption? Also, what's the worst case? Say I
>> have a ton of worst-case-sized (32b) slab objects. Will I notice?
>
> KFENCE objects are limited (default 255). If we exhaust KFENCE's memory
> pool, no more KFENCE allocations will occur.
> Documentation/dev-tools/kfence.rst gives a formula to calculate the
> KFENCE pool size:
>
> The total memory dedicated to the KFENCE memory pool can be computed as::
>
> ( #objects + 1 ) * 2 * PAGE_SIZE
>
> Using the default config, and assuming a page size of 4 KiB, results in
> dedicating 2 MiB to the KFENCE memory pool.
>
> Does that clarify this point? Or anything else that could help clarify
> this?
Hmm did you observe that with this limit, a long-running system would eventually
converge to KFENCE memory pool being filled with long-aged objects, so there
would be no space to sample new ones?
> Thanks,
> -- Marco
>
next prev parent reply other threads:[~2020-09-08 15:36 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-07 13:40 Marco Elver
2020-09-07 13:40 ` [PATCH RFC 01/10] mm: add Kernel Electric-Fence infrastructure Marco Elver
2020-09-07 15:41 ` Jonathan Cameron
2020-09-07 16:38 ` Marco Elver
2020-09-10 14:57 ` Dmitry Vyukov
2020-09-10 15:06 ` Marco Elver
2020-09-10 15:48 ` Dmitry Vyukov
2020-09-10 16:22 ` Marco Elver
2020-09-10 15:42 ` Dmitry Vyukov
2020-09-10 16:19 ` Alexander Potapenko
2020-09-10 17:11 ` Dmitry Vyukov
2020-09-10 17:41 ` Marco Elver
2020-09-10 20:25 ` Paul E. McKenney
2020-09-15 13:57 ` SeongJae Park
2020-09-15 14:14 ` Marco Elver
2020-09-15 14:26 ` SeongJae Park
2020-09-07 13:40 ` [PATCH RFC 02/10] x86, kfence: enable KFENCE for x86 Marco Elver
2020-09-07 13:40 ` [PATCH RFC 03/10] arm64, kfence: enable KFENCE for ARM64 Marco Elver
2020-09-09 15:13 ` Marco Elver
2020-09-07 13:40 ` [PATCH RFC 04/10] mm, kfence: insert KFENCE hooks for SLAB Marco Elver
2020-09-11 7:17 ` Dmitry Vyukov
2020-09-11 12:24 ` Marco Elver
2020-09-11 13:03 ` Dmitry Vyukov
2020-09-07 13:40 ` [PATCH RFC 05/10] mm, kfence: insert KFENCE hooks for SLUB Marco Elver
2020-09-07 13:40 ` [PATCH RFC 06/10] kfence, kasan: make KFENCE compatible with KASAN Marco Elver
2020-09-11 7:04 ` Dmitry Vyukov
2020-09-11 13:00 ` Marco Elver
2020-09-07 13:40 ` [PATCH RFC 07/10] kfence, kmemleak: make KFENCE compatible with KMEMLEAK Marco Elver
2020-09-08 11:53 ` Catalin Marinas
2020-09-08 12:29 ` Alexander Potapenko
2020-09-07 13:40 ` [PATCH RFC 08/10] kfence, lockdep: make KFENCE compatible with lockdep Marco Elver
2020-09-07 13:40 ` [PATCH RFC 09/10] kfence, Documentation: add KFENCE documentation Marco Elver
2020-09-07 15:33 ` Andrey Konovalov
2020-09-07 16:33 ` Marco Elver
2020-09-07 17:55 ` Andrey Konovalov
2020-09-07 18:16 ` Marco Elver
2020-09-08 15:54 ` Dave Hansen
2020-09-08 16:14 ` Marco Elver
2020-09-11 7:14 ` Dmitry Vyukov
2020-09-11 7:46 ` Marco Elver
2020-09-07 13:40 ` [PATCH RFC 10/10] kfence: add test suite Marco Elver
2020-09-08 11:48 ` [PATCH RFC 00/10] KFENCE: A low-overhead sampling-based memory safety error detector Vlastimil Babka
2020-09-08 12:16 ` Alexander Potapenko
2020-09-08 14:40 ` Vlastimil Babka
2020-09-08 15:21 ` Marco Elver
2020-09-08 14:52 ` Dave Hansen
2020-09-08 15:31 ` Marco Elver
2020-09-08 15:36 ` Vlastimil Babka [this message]
2020-09-08 15:56 ` Marco Elver
2020-09-11 7:35 ` Dmitry Vyukov
2020-09-11 12:03 ` Marco Elver
2020-09-11 13:09 ` Dmitry Vyukov
2020-09-11 13:33 ` Marco Elver
2020-09-11 16:33 ` Marco Elver
2020-09-08 15:37 ` Dave Hansen
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=feb73053-17a6-8b43-5b2b-51a813e81622@suse.cz \
--to=vbabka@suse.cz \
--cc=akpm@linux-foundation.org \
--cc=andreyknvl@google.com \
--cc=aryabinin@virtuozzo.com \
--cc=bp@alien8.de \
--cc=cai@lca.pw \
--cc=catalin.marinas@arm.com \
--cc=cl@linux.com \
--cc=corbet@lwn.net \
--cc=dave.hansen@intel.com \
--cc=dave.hansen@linux.intel.com \
--cc=dvyukov@google.com \
--cc=edumazet@google.com \
--cc=elver@google.com \
--cc=glider@google.com \
--cc=gregkh@linuxfoundation.org \
--cc=hpa@zytor.com \
--cc=iamjoonsoo.kim@lge.com \
--cc=jannh@google.com \
--cc=kasan-dev@googlegroups.com \
--cc=keescook@chromium.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=luto@kernel.org \
--cc=mark.rutland@arm.com \
--cc=mingo@redhat.com \
--cc=paulmck@kernel.org \
--cc=penberg@kernel.org \
--cc=peterz@infradead.org \
--cc=rientjes@google.com \
--cc=tglx@linutronix.de \
--cc=will@kernel.org \
--cc=x86@kernel.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