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Re: [Qemu-devel] [PATCH v2 03/11] exec: simplify destruction of the phys
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH v2 03/11] exec: simplify destruction of the phys map |
Date: |
Mon, 01 Jul 2013 16:33:41 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130514 Thunderbird/17.0.6 |
Il 01/07/2013 16:23, Jan Kiszka ha scritto:
> On 2013-06-28 18:58, Paolo Bonzini wrote:
>> Do not bother visiting the radix tree when an address space is destroyed.
>
> The "because" is missing, see my comment on the previous patch. If you
> can clarify this, the rest is fine.
After the previous patch, the "because" is that this is has become a
pointless exercise: all you're doing is zeroing out a structure that
will be freed as soon as you come back.
I'll add the justification to both patches.
Paolo
> Jan
>
>>
>> Signed-off-by: Paolo Bonzini <address@hidden>
>> ---
>> exec.c | 34 +---------------------------------
>> 1 file changed, 1 insertion(+), 33 deletions(-)
>>
>> diff --git a/exec.c b/exec.c
>> index e7eadf5..9c77285 100644
>> --- a/exec.c
>> +++ b/exec.c
>> @@ -154,12 +154,6 @@ static uint16_t phys_map_node_alloc(void)
>> return ret;
>> }
>>
>> -static void phys_map_nodes_reset(void)
>> -{
>> - phys_map_nodes_nb = 0;
>> -}
>> -
>> -
>> static void phys_page_set_level(PhysPageEntry *lp, hwaddr *index,
>> hwaddr *nb, uint16_t leaf,
>> int level)
>> @@ -763,31 +757,6 @@ static int subpage_register (subpage_t *mmio, uint32_t
>> start, uint32_t end,
>> uint16_t section);
>> static subpage_t *subpage_init(AddressSpace *as, hwaddr base);
>>
>> -static void destroy_l2_mapping(PhysPageEntry *lp, unsigned level)
>> -{
>> - unsigned i;
>> - PhysPageEntry *p;
>> -
>> - if (lp->ptr == PHYS_MAP_NODE_NIL) {
>> - return;
>> - }
>> -
>> - p = phys_map_nodes[lp->ptr];
>> - for (i = 0; i < L2_SIZE; ++i) {
>> - if (!p[i].is_leaf) {
>> - destroy_l2_mapping(&p[i], level - 1);
>> - }
>> - }
>> - lp->is_leaf = 0;
>> - lp->ptr = PHYS_MAP_NODE_NIL;
>> -}
>> -
>> -static void destroy_all_mappings(AddressSpaceDispatch *d)
>> -{
>> - destroy_l2_mapping(&d->phys_map, P_L2_LEVELS - 1);
>> - phys_map_nodes_reset();
>> -}
>> -
>> static uint16_t phys_section_add(MemoryRegionSection *section)
>> {
>> /* The physical section number is ORed with a page-aligned
>> @@ -820,6 +789,7 @@ static void phys_sections_clear(void)
>> MemoryRegionSection *section = &phys_sections[--phys_sections_nb];
>> phys_section_destroy(section->mr);
>> }
>> + phys_map_nodes_nb = 0;
>> }
>>
>> static void register_subpage(AddressSpaceDispatch *d, MemoryRegionSection
>> *section)
>> @@ -1724,7 +1694,6 @@ static void mem_begin(MemoryListener *listener)
>> {
>> AddressSpaceDispatch *d = container_of(listener, AddressSpaceDispatch,
>> listener);
>>
>> - destroy_all_mappings(d);
>> d->phys_map.ptr = PHYS_MAP_NODE_NIL;
>> }
>>
>> @@ -1791,7 +1760,6 @@ void address_space_destroy_dispatch(AddressSpace *as)
>> AddressSpaceDispatch *d = as->dispatch;
>>
>> memory_listener_unregister(&d->listener);
>> - destroy_l2_mapping(&d->phys_map, P_L2_LEVELS - 1);
>> g_free(d);
>> as->dispatch = NULL;
>> }
>>
>