From: Andrzej Hajda <a.hajda@samsung.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: linux-mm@kvack.org, Marek Szyprowski <m.szyprowski@samsung.com>,
linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 0/4] kstrdup optimization
Date: Tue, 30 Dec 2014 08:16:05 +0100 [thread overview]
Message-ID: <54A25135.5030103@samsung.com> (raw)
In-Reply-To: <87egrhws89.fsf@tassilo.jf.intel.com>
On 12/30/2014 07:45 AM, Andi Kleen wrote:
> Andrzej Hajda <a.hajda@samsung.com> writes:
>
>> kstrdup if often used to duplicate strings where neither source neither
>> destination will be ever modified. In such case we can just reuse the source
>> instead of duplicating it. The problem is that we must be sure that
>> the source is non-modifiable and its life-time is long enough.
> What happens if someone is to kfree() these strings?
>
> -Andi
>
kstrdup_const must be accompanied by kfree_const, I did not mention it
in cover letter
but it is described in the 1st patch commit message.
Simpler alternative (but I am not sure if better) would be to add
similar check
(ie. if pointer is in .rodata) to kfree itself.
Regards
Andrzej
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WARNING: multiple messages have this Message-ID (diff)
From: Andrzej Hajda <a.hajda@samsung.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: linux-mm@kvack.org, Marek Szyprowski <m.szyprowski@samsung.com>,
linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 0/4] kstrdup optimization
Date: Tue, 30 Dec 2014 08:16:05 +0100 [thread overview]
Message-ID: <54A25135.5030103@samsung.com> (raw)
In-Reply-To: <87egrhws89.fsf@tassilo.jf.intel.com>
On 12/30/2014 07:45 AM, Andi Kleen wrote:
> Andrzej Hajda <a.hajda@samsung.com> writes:
>
>> kstrdup if often used to duplicate strings where neither source neither
>> destination will be ever modified. In such case we can just reuse the source
>> instead of duplicating it. The problem is that we must be sure that
>> the source is non-modifiable and its life-time is long enough.
> What happens if someone is to kfree() these strings?
>
> -Andi
>
kstrdup_const must be accompanied by kfree_const, I did not mention it
in cover letter
but it is described in the 1st patch commit message.
Simpler alternative (but I am not sure if better) would be to add
similar check
(ie. if pointer is in .rodata) to kfree itself.
Regards
Andrzej
next prev parent reply other threads:[~2014-12-30 7:16 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-29 14:48 [RFC PATCH 0/4] kstrdup optimization Andrzej Hajda
2014-12-29 14:48 ` Andrzej Hajda
2014-12-29 14:48 ` [RFC PATCH 1/4] mm/util: add kstrdup_const Andrzej Hajda
2014-12-29 14:48 ` Andrzej Hajda
2014-12-29 14:48 ` [RFC PATCH 2/4] kernfs: use kstrdup_const for node name allocation Andrzej Hajda
2014-12-29 14:48 ` Andrzej Hajda
2014-12-29 14:48 ` [RFC PATCH 3/4] clk: use kstrdup_const for clock name allocations Andrzej Hajda
2014-12-29 14:48 ` Andrzej Hajda
2014-12-29 14:48 ` [RFC PATCH 4/4] mm/slab: use kstrdup_const for allocating cache names Andrzej Hajda
2014-12-29 14:48 ` Andrzej Hajda
2014-12-30 6:45 ` [RFC PATCH 0/4] kstrdup optimization Andi Kleen
2014-12-30 6:45 ` Andi Kleen
2014-12-30 7:16 ` Andrzej Hajda [this message]
2014-12-30 7:16 ` Andrzej Hajda
2014-12-30 8:32 ` Andreas Mohr
2014-12-30 8:32 ` Andreas Mohr
2014-12-30 21:29 ` Andi Kleen
2014-12-30 21:29 ` Andi Kleen
2015-01-08 10:54 ` Andrzej Hajda
2015-01-08 10:54 ` Andrzej Hajda
2014-12-31 13:05 ` Andrzej Hajda
2014-12-31 13:05 ` Andrzej Hajda
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