From: Peter Zijlstra <peterz@infradead.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: David Howells <dhowells@redhat.com>, Ingo Molnar <mingo@elte.hu>,
Yong Zhang <yong.zhang0@gmail.com>,
linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: schedule() && prev/current (Was: [PATCH 3/3] Make get_current() __attribute__((const)))
Date: Wed, 19 May 2010 08:21:19 +0200 [thread overview]
Message-ID: <1274250079.5605.9967.camel@twins> (raw)
In-Reply-To: <20100518212220.GA5092@redhat.com>
On Tue, 2010-05-18 at 23:22 +0200, Oleg Nesterov wrote:
> And, looking at this patch I think that schedule() can be simplified
> a little bit.
>
> "sched: Reassign prev and switch_count when reacquire_kernel_lock() fail"
> commit 6d558c3ac9b6508d26fd5cadccce51fc9d726b1c says:
>
> Assume A->B schedule is processing,
> ...
> Then on B's context,
> ...
> prev and switch_count are related to A
>
> How so? switch_count - yes, we should change it. But prev must be
> equal to B, and it must be equal to current. When we return from
> switch_to() registers/stack should be restored correctly, so we
> can do
What if schedule() got called at a different stack depth than we are
now?
I don't think we can assume anything about the stack context we just
switched to.
next prev parent reply other threads:[~2010-05-19 6:21 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-18 16:45 [PATCH 1/3] Reduce get_current() to the asm-generic implementation where possible David Howells
2010-05-18 16:45 ` [PATCH 2/3] Mark the 'current' pointer register read-only when such a thing exists David Howells
2010-05-18 21:05 ` David Miller
2010-05-18 16:45 ` [PATCH 3/3] Make get_current() __attribute__((const)) David Howells
2010-05-18 21:22 ` schedule() && prev/current (Was: [PATCH 3/3] Make get_current() __attribute__((const))) Oleg Nesterov
2010-05-19 6:21 ` Peter Zijlstra [this message]
2010-05-19 10:27 ` Oleg Nesterov
2010-05-19 10:37 ` Peter Zijlstra
2010-05-19 12:57 ` [PATCH] schedule: simplify the reacquire_kernel_lock() logic Oleg Nesterov
2010-05-19 12:57 ` Oleg Nesterov
2010-05-19 13:11 ` Yong Zhang
2010-05-19 13:07 ` schedule() && prev/current (Was: [PATCH 3/3] Make get_current() __attribute__((const))) Yong Zhang
2010-05-19 13:07 ` Yong Zhang
2010-05-18 17:39 ` [PATCH 1/3] Reduce get_current() to the asm-generic implementation where possible Kyle McMartin
2010-05-18 19:47 ` Jamie Lokier
2010-05-19 6:21 ` Nick Piggin
2010-05-19 11:02 ` Oleg Nesterov
2010-05-21 10:13 ` David Howells
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