From: Vlastimil Babka <vbabka@suse.cz>
To: Qian Cai <cai@lca.pw>, Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
kasan-dev@googlegroups.com,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Matthew Wilcox <willy@infradead.org>,
Mel Gorman <mgorman@techsingularity.net>,
Michal Hocko <mhocko@kernel.org>,
Dmitry Vyukov <dvyukov@google.com>,
Walter Wu <walter-zh.wu@mediatek.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>
Subject: Re: [PATCH v2 2/3] mm, page_owner: decouple freeing stack trace from debug_pagealloc
Date: Mon, 30 Sep 2019 23:39:34 +0200 [thread overview]
Message-ID: <eccee04f-a56e-6f6f-01c6-e94d94bba4c5@suse.cz> (raw)
In-Reply-To: <1569847787.5576.244.camel@lca.pw>
On 9/30/19 2:49 PM, Qian Cai wrote:
>> --- a/Documentation/admin-guide/kernel-parameters.txt
>> +++ b/Documentation/admin-guide/kernel-parameters.txt
>> @@ -3237,6 +3237,14 @@
>> we can turn it on.
>> on: enable the feature
>>
>> + page_owner_free=
>> + [KNL] When enabled together with page_owner, store also
>> + the stack of who frees a page, for error page dump
>> + purposes. This is also implicitly enabled by
>> + debug_pagealloc=on or KASAN, so only page_owner=on is
>> + sufficient in those cases.
>> + on: enable the feature
>> +
>
> If users are willing to set page_owner=on, what prevent them from enabling KASAN
> as well? That way, we don't need this additional parameter.
Well, my use case is shipping production kernels with CONFIG_PAGE_OWNER
and CONFIG_DEBUG_PAGEALLOC enabled, and instructing users to boot-time
enable only for troubleshooting a crash or memory leak, without a need
to install a debug kernel. Things like static keys and page_ext
allocations makes this possible without CPU and memory overhead when not
boot-time enabled. I don't know too much about KASAN internals, but I
assume it's not possible to use it that way on production kernels yet?
> I read that KASAN
> supposes to be semi-production use ready, so the overhead is relatively low.
> There is even a choice to have KASAN_SW_TAGS on arm64 to work better with small
> devices.
next prev parent reply other threads:[~2019-09-30 21:43 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-30 12:29 [PATCH v2 0/3] followups to debug_pagealloc improvements through page_owner Vlastimil Babka
2019-09-30 12:29 ` [PATCH v2 1/3] mm, page_owner: fix off-by-one error in __set_page_owner_handle() Vlastimil Babka
2019-09-30 12:29 ` [PATCH v2 2/3] mm, page_owner: decouple freeing stack trace from debug_pagealloc Vlastimil Babka
2019-09-30 12:49 ` Qian Cai
2019-09-30 21:39 ` Vlastimil Babka [this message]
2019-09-30 23:49 ` Qian Cai
2019-10-01 8:07 ` Vlastimil Babka
2019-10-01 11:51 ` Kirill A. Shutemov
2019-10-01 12:26 ` Qian Cai
2019-10-01 12:31 ` Kirill A. Shutemov
2019-10-01 12:32 ` Vlastimil Babka
2019-10-01 12:35 ` Vlastimil Babka
2019-10-01 13:18 ` Qian Cai
2019-10-01 14:15 ` Vlastimil Babka
2019-10-01 11:35 ` Kirill A. Shutemov
2019-09-30 12:29 ` [PATCH v2 3/3] mm, page_owner: rename flag indicating that page is allocated Vlastimil Babka
2019-09-30 12:49 ` Vlastimil Babka
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