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From: Andrew Morton <akpm@linux-foundation.org>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Michal Hocko <mhocko@kernel.org>,
	Matthew Wilcox <willy@infradead.org>, Qian Cai <cai@lca.pw>
Subject: Re: [PATCH v2] mm: kmemleak: Use mempool allocations for kmemleak objects
Date: Tue, 30 Jul 2019 12:57:43 -0700	[thread overview]
Message-ID: <20190730125743.113e59a9c449847d7f6ae7c3@linux-foundation.org> (raw)
In-Reply-To: <20190727132334.9184-1-catalin.marinas@arm.com>

On Sat, 27 Jul 2019 14:23:33 +0100 Catalin Marinas <catalin.marinas@arm.com> wrote:

> Add mempool allocations for struct kmemleak_object and
> kmemleak_scan_area as slightly more resilient than kmem_cache_alloc()
> under memory pressure. Additionally, mask out all the gfp flags passed
> to kmemleak other than GFP_KERNEL|GFP_ATOMIC.
> 
> A boot-time tuning parameter (kmemleak.mempool) is added to allow a
> different minimum pool size (defaulting to NR_CPUS * 4).

Why would anyone ever want to alter this?  Is there some particular
misbehaviour which this will improve?  If so, what is it?

> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -2011,6 +2011,12 @@
>  			Built with CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF=y,
>  			the default is off.
>  
> +	kmemleak.mempool=
> +			[KNL] Boot-time tuning of the minimum kmemleak
> +			metadata pool size.
> +			Format: <int>
> +			Default: NR_CPUS * 4
> +

This is the only documentation we provide people and it doesn't really
explain anything at all.  IOW, can we do a better job of explaining all this
to the target audience?

Why does the min size need to be tunable anyway?


  reply	other threads:[~2019-07-30 19:57 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-27 13:23 [PATCH v2] mm: kmemleak: Use mempool allocations for kmemleak objects Catalin Marinas
2019-07-30 19:57 ` Andrew Morton [this message]
2019-07-30 20:22   ` Qian Cai
2019-07-30 20:39     ` Andrew Morton
2019-07-31  9:53     ` Catalin Marinas
2019-07-31 12:02       ` Qian Cai
2019-07-31 14:48         ` Catalin Marinas
2019-07-31 14:54           ` Qian Cai
2019-07-31  9:06   ` Michal Hocko
2019-07-31  9:17     ` Catalin Marinas
2019-07-30 20:02 ` Andrew Morton
2019-07-31 15:44   ` Catalin Marinas
2019-08-01  6:41     ` Michal Hocko
2019-08-03 10:48       ` Catalin Marinas
2019-07-31  9:10 ` Michal Hocko

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