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From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Qian Cai <cai@lca.pw>, Andrew Morton <akpm@linux-foundation.org>,
	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: Tue, 1 Oct 2019 14:51:14 +0300	[thread overview]
Message-ID: <20191001115114.gnala74q3ydreuii@box> (raw)
In-Reply-To: <218f6fa7-a91e-4630-12ea-52abb6762d55@suse.cz>

On Tue, Oct 01, 2019 at 10:07:44AM +0200, Vlastimil Babka wrote:
> On 10/1/19 1:49 AM, Qian Cai wrote:
> > 
> > 
> >> On Sep 30, 2019, at 5:43 PM, Vlastimil Babka <vbabka@suse.cz> wrote:
> >>
> >> 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?
> > 
> > In that case, why can’t users just simply enable page_owner=on and
> > debug_pagealloc=on for troubleshooting? The later makes the kernel
> > slower, but I am not sure if it is worth optimization by adding a new
> > parameter. There have already been quite a few MM-related kernel
> > parameters that could tidy up a bit in the future.
> 
> They can do that and it was intention, yes. The extra parameter was
> requested by Kirill, so I'll defer the answer to him :)

DEBUG_PAGEALLOC is much more intrusive debug option. Not all architectures
support it in an efficient way. Some require hibernation.

I don't see a reason to tie these two option together.

-- 
 Kirill A. Shutemov


  reply	other threads:[~2019-10-01 11:51 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
2019-09-30 23:49       ` Qian Cai
2019-10-01  8:07         ` Vlastimil Babka
2019-10-01 11:51           ` Kirill A. Shutemov [this message]
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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