From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <3E5A6D3F.9030101@mvista.com> Date: Mon, 24 Feb 2003 11:06:39 -0800 From: Todd Poynor MIME-Version: 1.0 To: brian.auld@adic.com Cc: linuxppc-embedded@lists.linuxppc.org Subject: Re: Kernel Preemption patch References: <5.1.0.14.2.20030224095828.03022e38@mail.ebshome.net> In-Reply-To: <5.1.0.14.2.20030224095828.03022e38@mail.ebshome.net> Content-Type: text/plain; charset=us-ascii; format=flowed Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: At 07:56 AM 2/24/2003, brian.auld@adic.com wrote: > However, I noticed that your 'preempt_enable' at the bottom of the > exerp has > been changed from 'preempt_enable' as in the RML patch, to > 'preempt_enable_no_reshed'. What's the reason for this inconsistency? The preempt_enable_no_reshed avoids a kernel stack overflow seen in certain cases of heavy preemption, where each nested call to reschedule on preemption is interrupted and again requests a preemption. The proper place to check for another preemption is at the top-level interrupt/exception handler, so that we iterate and not recurse. Oops, MontaVista needs to contribute this bug fix back to RML's public patch, I'll put it on my list. -- Todd ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/