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From: Con Kolivas <kernel@kolivas.org>
To: Andrew Morton <akpm@osdl.org>
Cc: ck@vds.kolivas.org, linux-kernel@vger.kernel.org, wli@holomorphy.com
Subject: Re: Preempt Threshold Measurements
Date: Wed, 14 Jul 2004 07:52:47 +1000	[thread overview]
Message-ID: <40F459AF.1040501@kolivas.org> (raw)
In-Reply-To: <20040712231406.427caa2a.akpm@osdl.org>

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Andrew Morton wrote:
> This can run under one of two depths of lock_kernel.  filemap_fdatawrite()
> and filemap_fdatawait() both do cond_resched(), so this is odd.
> 
> Try this:
> 
> --- 25/mm/truncate.c~truncate_inode_pages-latency-fix	2004-07-12 23:12:53.871816320 -0700
> +++ 25-akpm/mm/truncate.c	2004-07-12 23:13:00.993733624 -0700
> @@ -155,6 +155,7 @@ void truncate_inode_pages(struct address
>  
>  	next = start;
>  	for ( ; ; ) {
> +		cond_resched();
>  		if (!pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
>  			if (next == start)
>  				break;
> _

I had a few of these with this patch. Is it cond_resched'ing twice?

Con

2ms non-preemptible critical section violated 1 ms preempt threshold 
starting at flush_commit_list+0x11d/0x3ee and ending at schedule+0x216/0x841
  [<c011d769>] dec_preempt_count+0x14f/0x151
  [<c031d716>] schedule+0x216/0x841
  [<c031d716>] schedule+0x216/0x841
  [<c01085c7>] do_IRQ+0x176/0x1eb
  [<c01040b3>] cpu_idle+0x3a/0x3c
  [<c040094c>] start_kernel+0x19c/0x1e8
  [<c0400402>] unknown_bootoption+0x0/0x15e

2ms non-preemptible critical section violated 1 ms preempt threshold 
starting at do_journal_end+0x539/0xae8 and ending at schedule+0x216/0x841
  [<c011d769>] dec_preempt_count+0x14f/0x151
  [<c031d716>] schedule+0x216/0x841
  [<c031d716>] schedule+0x216/0x841
  [<c0116284>] smp_apic_timer_interrupt+0x97/0x166
  [<c01040b3>] cpu_idle+0x3a/0x3c
  [<c0120659>] call_console_drivers+0xcd/0xea
  [<c01209da>] release_console_sem+0xa3/0x101
  [<c012088a>] printk+0x13d/0x19c

2ms non-preemptible critical section violated 1 ms preempt threshold 
starting at flush_async_commits+0x1b/0xf7 and ending at schedule+0x216/0x841
  [<c011d769>] dec_preempt_count+0x14f/0x151
  [<c031d716>] schedule+0x216/0x841
  [<c031d716>] schedule+0x216/0x841
  [<c011b88c>] load_balance+0x147/0x1ff
  [<c0116284>] smp_apic_timer_interrupt+0x97/0x166
  [<c010604e>] work_resched+0x5/0x16

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  parent reply	other threads:[~2004-07-13 21:54 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-07-12 23:43 Preempt Threshold Measurements Gabriel Devenyi
2004-07-12 23:59 ` Con Kolivas
2004-07-13  0:15   ` Gabriel Devenyi
2004-07-13  2:40 ` William Lee Irwin III
2004-07-13  2:48   ` [ck] " Gabriel Devenyi
2004-07-13  2:54     ` Con Kolivas
2004-07-13  4:01       ` Andrew Morton
2004-07-13  5:51         ` Con Kolivas
2004-07-13  6:14           ` Andrew Morton
2004-07-13  8:03             ` Lee Revell
2004-07-13 10:26             ` Con Kolivas
2004-07-13 21:52             ` Con Kolivas [this message]
2004-07-13 10:08         ` William Lee Irwin III
2004-07-13 10:40           ` William Lee Irwin III
2004-07-13 11:07             ` Lenar Lõhmus
2004-07-13 11:13               ` William Lee Irwin III
2004-07-13  2:55     ` [ck] " William Lee Irwin III
2004-07-13  3:09       ` Gabriel Devenyi
2004-07-13  4:07       ` Andrew Morton
2004-07-13  5:34         ` Con Kolivas
2004-07-13  5:48           ` Nick Piggin
2004-07-13 10:14             ` William Lee Irwin III
2004-07-14 10:15 ` [ck] " Jens Bergmann

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