From: Igor Stoppa <igor.stoppa@huawei.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: <keescook@chromium.org>, <david@fromorbit.com>,
<rppt@linux.vnet.ibm.com>, <mhocko@kernel.org>,
<labbott@redhat.com>, <linux-security-module@vger.kernel.org>,
<linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>,
<kernel-hardening@lists.openwall.com>
Subject: Re: [RFC PATCH v19 0/8] mm: security: ro protection for dynamic data
Date: Thu, 15 Mar 2018 15:43:49 +0200 [thread overview]
Message-ID: <fc984bf4-c46a-976c-ec74-ad89dc3d150e@huawei.com> (raw)
In-Reply-To: <20180314173343.GJ29631@bombadil.infradead.org>
On 14/03/2018 19:33, Matthew Wilcox wrote:
> On Wed, Mar 14, 2018 at 06:11:22PM +0200, Igor Stoppa wrote:
[...]
>> Probably page_frag does well with relatively large allocations, while
>> genalloc seems to be better for small (few allocation units) allocations.
>
> I don't understand why you would think that. If you allocate 4096 1-byte
> elements, page_frag will just use up a page. Doing the same thing with
> genalloc requires allocating two bits per byte (1kB of bitmap), plus
> other overheads.
I had misunderstood the amount of page_frag structures needed.
--
igor
WARNING: multiple messages have this Message-ID (diff)
From: igor.stoppa@huawei.com (Igor Stoppa)
To: linux-security-module@vger.kernel.org
Subject: [RFC PATCH v19 0/8] mm: security: ro protection for dynamic data
Date: Thu, 15 Mar 2018 15:43:49 +0200 [thread overview]
Message-ID: <fc984bf4-c46a-976c-ec74-ad89dc3d150e@huawei.com> (raw)
In-Reply-To: <20180314173343.GJ29631@bombadil.infradead.org>
On 14/03/2018 19:33, Matthew Wilcox wrote:
> On Wed, Mar 14, 2018 at 06:11:22PM +0200, Igor Stoppa wrote:
[...]
>> Probably page_frag does well with relatively large allocations, while
>> genalloc seems to be better for small (few allocation units) allocations.
>
> I don't understand why you would think that. If you allocate 4096 1-byte
> elements, page_frag will just use up a page. Doing the same thing with
> genalloc requires allocating two bits per byte (1kB of bitmap), plus
> other overheads.
I had misunderstood the amount of page_frag structures needed.
--
igor
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WARNING: multiple messages have this Message-ID (diff)
From: Igor Stoppa <igor.stoppa@huawei.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: keescook@chromium.org, david@fromorbit.com,
rppt@linux.vnet.ibm.com, mhocko@kernel.org, labbott@redhat.com,
linux-security-module@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org,
kernel-hardening@lists.openwall.com
Subject: Re: [RFC PATCH v19 0/8] mm: security: ro protection for dynamic data
Date: Thu, 15 Mar 2018 15:43:49 +0200 [thread overview]
Message-ID: <fc984bf4-c46a-976c-ec74-ad89dc3d150e@huawei.com> (raw)
In-Reply-To: <20180314173343.GJ29631@bombadil.infradead.org>
On 14/03/2018 19:33, Matthew Wilcox wrote:
> On Wed, Mar 14, 2018 at 06:11:22PM +0200, Igor Stoppa wrote:
[...]
>> Probably page_frag does well with relatively large allocations, while
>> genalloc seems to be better for small (few allocation units) allocations.
>
> I don't understand why you would think that. If you allocate 4096 1-byte
> elements, page_frag will just use up a page. Doing the same thing with
> genalloc requires allocating two bits per byte (1kB of bitmap), plus
> other overheads.
I had misunderstood the amount of page_frag structures needed.
--
igor
next prev parent reply other threads:[~2018-03-15 13:43 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-13 21:45 [RFC PATCH v19 0/8] mm: security: ro protection for dynamic data Igor Stoppa
2018-03-13 21:45 ` Igor Stoppa
2018-03-13 21:45 ` Igor Stoppa
2018-03-13 21:45 ` [PATCH 1/8] genalloc: track beginning of allocations Igor Stoppa
2018-03-13 21:45 ` Igor Stoppa
2018-03-13 21:45 ` Igor Stoppa
2018-03-13 21:45 ` [PATCH 2/8] Add label to genalloc.rst for cross reference Igor Stoppa
2018-03-13 21:45 ` Igor Stoppa
2018-03-13 21:45 ` Igor Stoppa
2018-03-13 21:45 ` [PATCH 3/8] genalloc: selftest Igor Stoppa
2018-03-13 21:45 ` Igor Stoppa
2018-03-13 21:45 ` Igor Stoppa
2018-03-13 21:45 ` [PATCH 4/8] struct page: add field for vm_struct Igor Stoppa
2018-03-13 21:45 ` Igor Stoppa
2018-03-13 21:45 ` Igor Stoppa
2018-03-13 22:00 ` Matthew Wilcox
2018-03-13 22:00 ` Matthew Wilcox
2018-03-14 17:43 ` J Freyensee
2018-03-14 17:43 ` J Freyensee
2018-03-15 9:38 ` Igor Stoppa
2018-03-15 9:38 ` Igor Stoppa
2018-03-15 9:38 ` Igor Stoppa
2018-03-15 18:51 ` J Freyensee
2018-03-15 18:51 ` J Freyensee
2018-03-13 21:45 ` [PATCH 5/8] Protectable Memory Igor Stoppa
2018-03-13 21:45 ` Igor Stoppa
2018-03-13 21:45 ` Igor Stoppa
2018-03-14 12:15 ` Matthew Wilcox
2018-03-14 12:15 ` Matthew Wilcox
2018-03-14 13:02 ` Igor Stoppa
2018-03-14 13:02 ` Igor Stoppa
2018-03-14 13:02 ` Igor Stoppa
2018-03-14 17:40 ` J Freyensee
2018-03-14 17:40 ` J Freyensee
2018-03-14 17:40 ` J Freyensee
2018-03-13 21:45 ` [PATCH 6/8] Pmalloc selftest Igor Stoppa
2018-03-13 21:45 ` Igor Stoppa
2018-03-13 21:45 ` Igor Stoppa
2018-03-14 12:25 ` Matthew Wilcox
2018-03-14 12:25 ` Matthew Wilcox
2018-03-25 1:32 ` Igor Stoppa
2018-03-25 1:32 ` Igor Stoppa
2018-03-25 1:32 ` Igor Stoppa
2018-03-13 21:45 ` [PATCH 7/8] lkdtm: crash on overwriting protected pmalloc var Igor Stoppa
2018-03-13 21:45 ` Igor Stoppa
2018-03-13 21:45 ` Igor Stoppa
2018-03-13 21:45 ` [PATCH 8/8] Documentation for Pmalloc Igor Stoppa
2018-03-13 21:45 ` Igor Stoppa
2018-03-13 21:45 ` Igor Stoppa
2018-03-14 11:21 ` [RFC PATCH v19 0/8] mm: security: ro protection for dynamic data Igor Stoppa
2018-03-14 11:21 ` Igor Stoppa
2018-03-14 11:21 ` Igor Stoppa
2018-03-14 11:56 ` Matthew Wilcox
2018-03-14 11:56 ` Matthew Wilcox
2018-03-14 12:55 ` Igor Stoppa
2018-03-14 12:55 ` Igor Stoppa
2018-03-14 12:55 ` Igor Stoppa
2018-03-14 13:04 ` Matthew Wilcox
2018-03-14 13:04 ` Matthew Wilcox
2018-03-14 16:11 ` Igor Stoppa
2018-03-14 16:11 ` Igor Stoppa
2018-03-14 16:11 ` Igor Stoppa
2018-03-14 17:33 ` Matthew Wilcox
2018-03-14 17:33 ` Matthew Wilcox
2018-03-15 13:43 ` Igor Stoppa [this message]
2018-03-15 13:43 ` Igor Stoppa
2018-03-15 13:43 ` Igor Stoppa
2018-03-19 18:04 ` Igor Stoppa
2018-03-19 18:04 ` Igor Stoppa
2018-03-19 18:04 ` Igor Stoppa
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