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From: Manfred Spraul <manfreds@colorfullife.com>
To: linux-mm@kvack.org
Subject: active_mm & SMP & TLB flush: possible bug
Date: Wed, 28 Jul 1999 14:30:08 +0200	[thread overview]
Message-ID: <379EF7D0.375C78A4@colorfullife.com> (raw)

I think that active_mm breaks CLEVER_SMP_INVALIDATE
(linux/asm-i386/pgtable.h)
(version 2.3.11)

e.g. flush_tlb():
CPU 1 executes thread A, CPU2 waits in
the idle thread with a lazy TLB context of thread A.

CPU1: flush_tlb() causes no IPI because
current->mm->mm_users is still 1.

if these 2 CPU switch their roles, then we use an outdates
TLB cache.

-------------
BTW, where can I find more details about the active_mm implementation?
specifically, I'd like to know why active_mm was added to
"struct task_struct".
>From my first impression, it's a CPU specific information
(every CPU has exactly one active_mm, threads which are not running have
no
active_mm), so I'd have used a global array[NR_CPUS].


	Manfred
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             reply	other threads:[~1999-07-28 12:28 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
1999-07-28 12:30 Manfred Spraul [this message]
1999-07-28 15:46 ` active_mm & SMP & TLB flush: possible bug Benjamin C.R. LaHaise
1999-07-28 18:07 ` Kanoj Sarcar
  -- strict thread matches above, loose matches on Subject: below --
1999-07-28 16:58 Manfred Spraul
1999-07-28 18:35 Manfred Spraul, Benjamin C.R. LaHaise

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