From: Zachary Amsden <zach@vmware.com>
To: Andi Kleen <ak@novell.com>
Cc: Jan Beulich <jbeulich@novell.com>,
linux-kernel@vger.kernel.org, patches@x86-64.org
Subject: Re: [patches] [PATCH] [28/34] i386: pte xchg optimization
Date: Wed, 02 May 2007 12:19:27 -0700 [thread overview]
Message-ID: <4638E43F.6000806@vmware.com> (raw)
In-Reply-To: <200705021305.40525.ak@novell.com>
Andi Kleen wrote:
>> I always wondered why the xchg is necessary here at all. If the process of
>> tearing down a page table entry has started, other users of the mapped
>> linear address are broken anyway - why is it necessary to still monitor the
>> effect they may have on the A/D bits, unless this is a transient tear down?
>>
>> Checking for the uses of ptep_get_and_clear, I would judge that the use in
>> change_pte_range() may in fact need the xchg, but the uses in
>> vunmap_pte_range() and zap_pte_range() shouldn't.
>>
>
> Yes I agree. Might be a nice speed up for exit to distingush the cases.
>
That is what I did in this patch - but with care zap_pte_range can also
be called in non-teardown cases when unmapping (when !fullmm) and user
mappings could still be in effect on remote processors.
Zach
next prev parent reply other threads:[~2007-05-02 19:21 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-30 15:49 [PATCH] [0/34] x86 candidate patches for review VI: MTRR, APIC, more paravirt, misc Andi Kleen
2007-04-30 15:49 ` [PATCH] [1/34] x86_64: Move mtrr prototypes from proto.h to mtrr.h Andi Kleen
2007-04-30 15:49 ` [PATCH] [2/34] x86: Adds mtrr_save_fixed_ranges() for use in two later patches Andi Kleen
2007-04-30 15:49 ` [PATCH] [3/34] x86: Save the MTRRs of the BSP before booting an AP Andi Kleen
2007-04-30 15:49 ` [PATCH] [4/34] x86: Save and restore the fixed-range MTRRs of the BSP when suspending Andi Kleen
2007-04-30 15:49 ` [PATCH] [5/34] i386: Enable support for fixed-range IORRs to keep RdMem & WrMem in sync Andi Kleen
2007-04-30 15:49 ` [PATCH] [6/34] i386: safe_apic_wait_icr_idle - i386 Andi Kleen
2007-04-30 15:49 ` [PATCH] [7/34] x86_64: safe_apic_wait_icr_idle - x86_64 Andi Kleen
2007-04-30 15:49 ` [PATCH] [8/34] i386: use safe_apic_wait_icr_idle - i386 Andi Kleen
2007-04-30 15:49 ` [PATCH] [9/34] x86_64: use safe_apic_wait_icr_idle in smpboot.c - x86_64 Andi Kleen
2007-04-30 15:49 ` [PATCH] [10/34] i386: use safe_apic_wait_icr_idle in smpboot.c Andi Kleen
2007-04-30 15:49 ` [PATCH] [11/34] x86_64: use safe_apic_wait_icr_idle in smpboot.c - x86_64 Andi Kleen
2007-04-30 15:49 ` [PATCH] [12/34] i386: __send_IPI_dest_field - i386 Andi Kleen
2007-04-30 15:49 ` [PATCH] [13/34] x86_64: __send_IPI_dest_field - x86_64 Andi Kleen
2007-04-30 15:49 ` [PATCH] [14/34] i386: Use safe_apic_wait_icr_idle in safe_apic_wait_icr_idle - i386 Andi Kleen
2007-04-30 15:49 ` [PATCH] [15/34] x86_64: Use safe_apic_wait_icr_idle in __send_IPI_dest_field - x86_64 Andi Kleen
2007-04-30 15:49 ` [PATCH] [16/34] i386: fix mtrr sections Andi Kleen
2007-05-02 17:08 ` Bernhard Kaindl
2007-05-03 11:16 ` Bernhard Kaindl
2007-05-03 11:19 ` Andi Kleen
2007-05-03 15:12 ` Randy Dunlap
2007-04-30 15:49 ` [PATCH] [17/34] x86: PARAVIRT: Add a sched_clock paravirt_op Andi Kleen
2007-04-30 15:49 ` [PATCH] [18/34] i386: PARAVIRT: fix startup_ipi_hook config dependency Andi Kleen
2007-04-30 15:49 ` [PATCH] [19/34] x86_64: move __vgetcpu_mode & __jiffies to the vsyscall_2 zone Andi Kleen
2007-04-30 15:49 ` [PATCH] [20/34] i386: avoid checking for cpu gone when CONFIG_HOTPLUG_CPU not defined Andi Kleen
2007-04-30 15:49 ` [PATCH] [21/34] i386: replace spin_lock_irqsave with spin_lock Andi Kleen
2007-04-30 15:49 ` [PATCH] [22/34] i386: clean up flush_tlb_others fn Andi Kleen
2007-04-30 15:49 ` [PATCH] [23/34] i386: check capability Andi Kleen
2007-04-30 15:49 ` [PATCH] [24/34] x86_64: Auto compute __NR_syscall_max at compile time Andi Kleen
2007-04-30 15:49 ` [PATCH] [25/34] x86_64: skip cache_free_alien() on non NUMA Andi Kleen
2007-04-30 15:49 ` [PATCH] [26/34] i386: remove xtime_lock'ing around cpufreq notifier Andi Kleen
2007-04-30 15:50 ` [PATCH] [27/34] i386: pte clear optimization Andi Kleen
2007-04-30 15:50 ` [PATCH] [28/34] i386: pte xchg optimization Andi Kleen
2007-05-02 10:52 ` [patches] " Jan Beulich
2007-05-02 11:05 ` Andi Kleen
2007-05-02 19:19 ` Zachary Amsden [this message]
2007-04-30 15:50 ` [PATCH] [29/34] i386: pte simplify ops Andi Kleen
2007-04-30 15:50 ` [PATCH] [30/34] i386: convert the monitor thread to use the kthread API Andi Kleen
2007-04-30 16:55 ` James Bottomley
2007-04-30 17:56 ` Andi Kleen
2007-04-30 15:50 ` [PATCH] [31/34] i386: convert to " Andi Kleen
2007-04-30 15:50 ` [PATCH] [32/34] x86_64: unexport cpu_llc_id Andi Kleen
2007-04-30 15:50 ` [PATCH] [34/34] x86_64: ignore vgacon if hardware not present Andi Kleen
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