From: David Miller <davem@davemloft.net>
To: hannes@cmpxchg.org
Cc: x86@kernel.org, akpm@linux-foundation.org, ben@decadent.org.uk,
linux-mm@kvack.org, linux-arch@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [patch 2/5] sparse-vmemmap: specify vmemmap population range in bytes
Date: Wed, 20 Mar 2013 14:43:41 -0400 (EDT) [thread overview]
Message-ID: <20130320.144341.680730923044605208.davem@davemloft.net> (raw)
In-Reply-To: <1363802612-32127-3-git-send-email-hannes@cmpxchg.org>
From: Johannes Weiner <hannes@cmpxchg.org>
Date: Wed, 20 Mar 2013 14:03:29 -0400
> The sparse code, when asking the architecture to populate the vmemmap,
> specifies the section range as a starting page and a number of pages.
>
> This is an awkward interface, because none of the arch-specific code
> actually thinks of the range in terms of 'struct page' units and
> always translates it to bytes first.
>
> In addition, later patches mix huge page and regular page backing for
> the vmemmap. For this, they need to call vmemmap_populate_basepages()
> on sub-section ranges with PAGE_SIZE and PMD_SIZE in mind. But these
> are not necessarily multiples of the 'struct page' size and so this
> unit is too coarse.
>
> Just translate the section range into bytes once in the generic sparse
> code, then pass byte ranges down the stack.
>
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Boot tested on sparc64:
Acked-by: David S. Miller <davem@davemloft.net>
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next prev parent reply other threads:[~2013-03-20 18:43 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-20 18:03 [patch 0/5] sparse-vmemmap: hotplug fixes & cleanups Johannes Weiner
2013-03-20 18:03 ` [patch 1/5] mm: Try harder to allocate vmemmap blocks Johannes Weiner
2013-03-20 18:03 ` [patch 2/5] sparse-vmemmap: specify vmemmap population range in bytes Johannes Weiner
2013-03-20 18:43 ` David Miller [this message]
2013-03-20 18:03 ` [patch 3/5] x86-64: remove dead debugging code for !pse setups Johannes Weiner
2013-03-20 18:03 ` [patch 4/5] x86-64: use vmemmap_populate_basepages() " Johannes Weiner
2013-03-20 18:03 ` [patch 5/5] x86-64: fall back to regular page vmemmap on allocation failure Johannes Weiner
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