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From: Paolo Bonzini <pbonzini@redhat.com>
To: Alexey Kardashevskiy <aik@ozlabs.ru>, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH qemu v5 04/18] memory: Move AddressSpaceDispatch from AddressSpace to FlatView
Date: Thu, 21 Sep 2017 13:51:40 +0200	[thread overview]
Message-ID: <a5b9c3ac-56fe-c29c-ed19-3eb5a5f159c2@redhat.com> (raw)
In-Reply-To: <20170921085110.25598-5-aik@ozlabs.ru>

On 21/09/2017 10:50, Alexey Kardashevskiy wrote:
> * since FlatView::rcu is used now to dispose FV, call_rcu() in
> address_space_update_topology() is replaced with direct call to
> flatview_unref()

Hmm, this is not correct, as you could have


   thread 1             thread 2             RCU thread
  -------------------------------------------------------------
   rcu_read_lock
   read as->current_map
                        set as->current_map
                        flatview_unref
                           '--> call_rcu
   flatview_ref
   rcu_read_unlock
                                             flatview_destroy

I need to think a bit more about this (and possibly ask Paul...).

Paolo

  reply	other threads:[~2017-09-21 11:51 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-21  8:50 [Qemu-devel] [PATCH qemu v5 00/18] memory: Store physical root MR in FlatView Alexey Kardashevskiy
2017-09-21  8:50 ` [Qemu-devel] [PATCH qemu v5 01/18] exec: Explicitly export target AS from address_space_translate_internal Alexey Kardashevskiy
2017-09-21  8:50 ` [Qemu-devel] [PATCH qemu v5 02/18] memory: Open code FlatView rendering Alexey Kardashevskiy
2017-09-21  8:50 ` [Qemu-devel] [PATCH qemu v5 03/18] memory: Move FlatView allocation to a helper Alexey Kardashevskiy
2017-09-21  8:50 ` [Qemu-devel] [PATCH qemu v5 04/18] memory: Move AddressSpaceDispatch from AddressSpace to FlatView Alexey Kardashevskiy
2017-09-21 11:51   ` Paolo Bonzini [this message]
2017-09-21 13:44     ` Alexey Kardashevskiy
2017-09-21 13:54       ` Paolo Bonzini
2017-09-21  8:50 ` [Qemu-devel] [PATCH qemu v5 05/18] memory: Remove AddressSpace pointer from AddressSpaceDispatch Alexey Kardashevskiy
2017-09-21  8:50 ` [Qemu-devel] [PATCH qemu v5 06/18] memory: Switch memory from using AddressSpace to FlatView Alexey Kardashevskiy
2017-09-21  8:50 ` [Qemu-devel] [PATCH qemu v5 07/18] memory: Cleanup after switching " Alexey Kardashevskiy
2017-09-21  8:51 ` [Qemu-devel] [PATCH qemu v5 08/18] memory: Rename mem_begin/mem_commit/mem_add helpers Alexey Kardashevskiy
2017-09-21  8:51 ` [Qemu-devel] [PATCH qemu v5 09/18] memory: Store physical root MR in FlatView Alexey Kardashevskiy
2017-09-21  8:51 ` [Qemu-devel] [PATCH qemu v5 10/18] memory: Alloc dispatch tree where topology is generared Alexey Kardashevskiy
2017-09-21  8:51 ` [Qemu-devel] [PATCH qemu v5 11/18] memory: Move address_space_update_ioeventfds Alexey Kardashevskiy
2017-09-21  8:51 ` [Qemu-devel] [PATCH qemu v5 12/18] memory: Share FlatView's and dispatch trees between address spaces Alexey Kardashevskiy
2017-09-21  8:51 ` [Qemu-devel] [PATCH qemu v5 13/18] memory: Do not allocate FlatView in address_space_init Alexey Kardashevskiy
2017-09-21  8:51 ` [Qemu-devel] [PATCH qemu v5 14/18] memory: Rework "info mtree" to print flat views and dispatch trees Alexey Kardashevskiy
2017-09-21  8:51 ` [Qemu-devel] [PATCH qemu v5 15/18] memory: Share special empty FlatView Alexey Kardashevskiy
2017-09-21  8:51 ` [Qemu-devel] [PATCH qemu v5 16/18] memory: Get rid of address_space_init_shareable Alexey Kardashevskiy
2017-09-21 23:06   ` Paolo Bonzini
2017-09-21  8:51 ` [Qemu-devel] [PATCH qemu v5 17/18] memory: Create FlatView directly Alexey Kardashevskiy
2017-09-21  8:51 ` [Qemu-devel] [PATCH qemu v5 18/18] memory: Avoid temporary FlatView allocation in a single child case Alexey Kardashevskiy
2017-09-21 10:03 ` [Qemu-devel] [PATCH qemu v5 00/18] memory: Store physical root MR in FlatView Paolo Bonzini
2017-09-21 10:11   ` Alexey Kardashevskiy
2017-09-21 11:38     ` Paolo Bonzini

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