From: Tejun Heo <tj@kernel.org>
To: David Howells <dhowells@redhat.com>
Cc: torvalds@osdl.org, akpm@linux-foundation.org,
linux-am33-list@redhat.com, linux-kernel@vger.kernel.org,
Akira Takeuchi <takeuchi.akr@jp.panasonic.com>,
Mark Salter <msalter@redhat.com>
Subject: Re: [PATCH] MN10300: Fix the PERCPU() alignment to allow for workqueues
Date: Tue, 26 Oct 2010 11:10:58 +0200 [thread overview]
Message-ID: <4CC69B22.2050708@kernel.org> (raw)
In-Reply-To: <20101025224111.7798.38960.stgit@warthog.procyon.org.uk>
Hello,
On 10/26/2010 12:41 AM, David Howells wrote:
> PERCPU() alignment on MN13000, however, is only 32 bytes as set in
> vmlinux.lds.S. So we set this to PAGE_SIZE (4096) to match most other arches
> and stick a comment in alloc_cwqs() for anyone else who triggers the assertion.
Ah, okay, but I'm not quite sure how that would affect the alignment
of dynamically allocated percpu memory. Is this SMP or UP build? Can
you please double check the bug doesn't trigger with the section
alignment updated?
> - PERCPU(32)
> + PERCPU(PAGE_SIZE)
Hmmm... during initialization, the initial percpu memory is
re-allocated using bootmem allocator with proper alignment and the
output section is just used as data source and discarded once init is
complete. So, unless I'm mistaken, I don't think this would affect
anything. That said, I think it might be better to just remove the
alignment parameter from the macro and force align to PAGE_SIZE. It
doesn't really help anything.
Thanks.
--
tejun
next prev parent reply other threads:[~2010-10-26 9:11 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-25 22:41 [PATCH] MN10300: Fix the PERCPU() alignment to allow for workqueues David Howells
2010-10-26 9:10 ` Tejun Heo [this message]
2010-10-26 10:22 ` David Howells
2010-10-26 12:14 ` Tejun Heo
2010-10-26 12:27 ` Tejun Heo
2010-10-26 12:45 ` [PATCH] x86, percpu: revert commit fe8e0c25 Tejun Heo
2010-10-26 13:25 ` Ingo Molnar
2010-10-26 13:34 ` Tejun Heo
2010-10-26 13:49 ` Brian Gerst
2010-10-26 15:08 ` Linus Torvalds
2010-10-27 5:43 ` [PATCH] x86-32: Allocate irq stacks seperate from percpu area Brian Gerst
2010-10-27 6:07 ` Eric Dumazet
2010-10-27 9:57 ` Peter Zijlstra
2010-10-27 13:33 ` Eric Dumazet
2010-10-27 13:42 ` Tejun Heo
2010-10-27 13:57 ` Eric Dumazet
2010-10-27 14:00 ` Tejun Heo
2010-10-27 14:24 ` Eric Dumazet
2010-10-27 14:39 ` Tejun Heo
2010-10-27 14:39 ` Eric Dumazet
2010-10-27 14:43 ` Tejun Heo
2010-10-27 15:21 ` Eric Dumazet
2010-10-27 15:35 ` Tejun Heo
2010-10-27 16:07 ` Eric Dumazet
2010-10-27 17:33 ` [PATCH] numa: fix slab_node(MPOL_BIND) Eric Dumazet
2010-10-28 15:59 ` Linus Torvalds
2010-10-28 16:27 ` Eric Dumazet
2010-10-28 16:45 ` Mel Gorman
2010-10-28 16:55 ` Christoph Lameter
2010-10-28 21:07 ` Andrew Morton
2010-10-29 14:55 ` Christoph Lameter
2010-10-27 20:55 ` [PATCH] x86-32: Allocate irq stacks seperate from percpu area Eric Dumazet
2010-10-28 12:01 ` Tejun Heo
2010-10-28 12:30 ` Eric Dumazet
2010-10-28 14:40 ` [PATCH] x86-32: NUMA irq stacks allocations Eric Dumazet
2010-10-29 6:43 ` [tip:x86/urgent] x86-32: Restore irq stacks NUMA-aware allocations tip-bot for Eric Dumazet
2010-10-29 18:32 ` Peter Zijlstra
2010-10-29 20:09 ` Cyrill Gorcunov
2010-10-29 20:28 ` Cyrill Gorcunov
2010-10-29 20:53 ` Eric Dumazet
2010-10-29 20:59 ` Cyrill Gorcunov
2010-10-29 20:58 ` Eric Dumazet
2010-10-29 21:21 ` Cyrill Gorcunov
2010-10-27 15:19 ` [PATCH] x86-32: Allocate irq stacks seperate from percpu area Linus Torvalds
2010-10-27 15:30 ` Ingo Molnar
2010-10-27 15:33 ` Ingo Molnar
2010-10-27 15:40 ` Tejun Heo
2010-10-27 15:43 ` Ingo Molnar
2010-10-27 16:03 ` [tip:x86/urgent] " tip-bot for Brian Gerst
2010-10-27 16:04 ` [tip:x86/urgent] percpu: Remove the multi-page alignment facility tip-bot for Ingo Molnar
2010-10-26 14:06 ` [RFC PATCH] percpu: always align percpu output section to PAGE_SIZE Tejun Heo
2011-03-24 6:46 ` [Uclinux-dist-devel] " Mike Frysinger
2011-03-24 8:25 ` Tejun Heo
2011-03-24 8:51 ` Tejun Heo
2011-03-24 13:46 ` Mike Frysinger
2011-03-24 17:51 ` Tejun Heo
2011-03-24 8:54 ` [PATCH UPDATED] " Tejun Heo
2010-10-26 14:50 ` [PATCH] MN10300: Fix the PERCPU() alignment to allow for workqueues David Howells
2010-10-26 14:56 ` Tejun Heo
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