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From: Michael Ellerman <mpe@ellerman.id.au>
To: Christoph Lameter <cl@linux.com>, Hugh Dickins <hughd@google.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
	linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org
Subject: Re: 4.12-rc ppc64 4k-page needs costly allocations
Date: Thu, 08 Jun 2017 15:52:35 +1000	[thread overview]
Message-ID: <87a85jdo0s.fsf@concordia.ellerman.id.au> (raw)
In-Reply-To: <alpine.DEB.2.20.1706020931080.28919@east.gentwo.org>

Christoph Lameter <cl@linux.com> writes:

> On Thu, 1 Jun 2017, Hugh Dickins wrote:
>
>> Thanks a lot for working that out.  Makes sense, fully understood now,
>> nothing to worry about (though makes one wonder whether it's efficient
>> to use ctors on high-alignment caches; or whether an internal "zero-me"
>> ctor would be useful).
>
> Use kzalloc to zero it.

But that's changing a per slab creation memset into a per object
allocation memset, isn't it?

> And here is another example of using slab allocations for page frames.
> Use the page allocator for this? The page allocator is there for
> allocating page frames. The slab allocator main purpose is to allocate
> small objects....

Well usually they are small (< PAGE_SIZE), because we have 64K pages.

But we could rework the code to use the page allocator on 4K configs.

cheers

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  reply	other threads:[~2017-06-08  5:52 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-30 19:43 Hugh Dickins
2017-05-31  6:46 ` Michael Ellerman
2017-05-31 14:09   ` Christoph Lameter
2017-05-31 18:44     ` Hugh Dickins
2017-05-31 19:02       ` Mathieu Malaterre
2017-06-01 15:31       ` Christoph Lameter
2017-06-01 17:22         ` Hugh Dickins
2017-06-01 18:16           ` Christoph Lameter
2017-06-01 18:37             ` Hugh Dickins
2017-06-02  3:09               ` Michael Ellerman
2017-06-02  4:00                 ` Hugh Dickins
2017-06-02 14:33                   ` Christoph Lameter
2017-06-08  5:44                   ` Michael Ellerman
2017-06-02 14:32               ` Christoph Lameter
2017-06-08  5:52                 ` Michael Ellerman [this message]
2017-05-31 14:06 ` Christoph Lameter
2017-06-01  4:19 ` Aneesh Kumar K.V
2017-06-01 16:57   ` Hugh Dickins

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