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[Qemu-devel] [RFC PATCH 2/2] mem: prepare address_space listener rcu sty
From: |
Liu Ping Fan |
Subject: |
[Qemu-devel] [RFC PATCH 2/2] mem: prepare address_space listener rcu style |
Date: |
Mon, 13 May 2013 11:21:04 +0800 |
From: Liu Ping Fan <address@hidden>
Each address space listener has PhysPageMap *cur_map, *next_map,
the switch from cur_map to next_map complete the RCU style. The
mem_commit() do the switch, and it is against reader but AddressSpace's
lock or later RCU mechanism (around address_space_translate() ).
Signed-off-by: Liu Ping Fan <address@hidden>
---
exec.c | 36 +++++++++++++++++++++++++++---------
include/exec/memory-internal.h | 11 ++++++++++-
2 files changed, 37 insertions(+), 10 deletions(-)
diff --git a/exec.c b/exec.c
index bb4e540..e5871d6 100644
--- a/exec.c
+++ b/exec.c
@@ -186,24 +186,26 @@ static void phys_page_set(AddressSpaceDispatch *d,
hwaddr index, hwaddr nb,
uint16_t leaf)
{
+ PhysPageMap *map = d->next_map;
/* Wildly overreserve - it doesn't matter much. */
phys_map_node_reserve(3 * P_L2_LEVELS);
- phys_page_set_level(&d->phys_map, &index, &nb, leaf, P_L2_LEVELS - 1);
+ phys_page_set_level(&map->root, &index, &nb, leaf, P_L2_LEVELS - 1);
}
static PhysSection *phys_section_find(AddressSpaceDispatch *d,
hwaddr index)
{
- PhysPageEntry lp = d->phys_map;
PhysPageEntry *p;
- PhysSection *phys_sections = cur_pgtbl->phys_sections;
- Node *phys_map_nodes = cur_pgtbl->phys_map_nodes;
+ PhysPageEntry lp = d->cur_map->root;
+ PhysPageTable *pgtbl = d->cur_map->pgtbl;
+ PhysSection *phys_sections = pgtbl->phys_sections;
+ Node *phys_map_nodes = pgtbl->phys_map_nodes;
int i;
for (i = P_L2_LEVELS - 1; i >= 0 && !lp.is_leaf; i--) {
if (lp.ptr == PHYS_MAP_NODE_NIL) {
- return &phys_sections[cur_pgtbl->phys_section_unassigned];
+ return &phys_sections[pgtbl->phys_section_unassigned];
}
p = phys_map_nodes[lp.ptr];
lp = p[(index >> (i * L2_BITS)) & (L2_SIZE - 1)];
@@ -234,7 +236,7 @@ MemoryRegionSection *address_space_translate(AddressSpace
*as, hwaddr addr,
IOMMUTLBEntry iotlb;
MemoryRegionSection *section;
hwaddr len = *plen;
-
+ PhysPageTable *pgtbl = cur_pgtbl;
for (;;) {
section = address_space_lookup_region(as, addr);
@@ -254,7 +256,7 @@ MemoryRegionSection *address_space_translate(AddressSpace
*as, hwaddr addr,
| (addr & iotlb.addr_mask));
len = MIN(len, (addr | iotlb.addr_mask) - addr + 1);
if (!iotlb.perm[is_write]) {
- section =
&cur_pgtbl->phys_sections[cur_pgtbl->phys_section_unassigned].section;
+ section =
&pgtbl->phys_sections[pgtbl->phys_section_unassigned].section;
break;
}
@@ -1703,7 +1705,21 @@ static void mem_begin(MemoryListener *listener)
{
AddressSpaceDispatch *d = container_of(listener, AddressSpaceDispatch,
listener);
- d->phys_map.ptr = PHYS_MAP_NODE_NIL;
+ d->next_map = g_new0(PhysPageMap, 1);
+ d->next_map->pgtbl = next_pgtbl;
+}
+
+static void mem_commit(MemoryListener *listener)
+{
+ AddressSpaceDispatch *d = container_of(listener, AddressSpaceDispatch,
listener);
+ PhysPageMap *m = d->cur_map;
+
+ d->cur_map = d->next_map;
+ /* Fixme, Currently, we rely on biglock or address-space lock against
+ * reader. So here, we can safely drop it.
+ * After RCU, should change to call_rcu()
+ */
+ g_free(m);
}
static void core_begin(MemoryListener *listener)
@@ -1771,11 +1787,12 @@ void address_space_init_dispatch(AddressSpace *as)
{
AddressSpaceDispatch *d = g_new(AddressSpaceDispatch, 1);
- d->phys_map = (PhysPageEntry) { .ptr = PHYS_MAP_NODE_NIL, .is_leaf = 0 };
+ d->cur_map = g_new0(PhysPageMap, 1);
d->listener = (MemoryListener) {
.begin = mem_begin,
.region_add = mem_add,
.region_nop = mem_add,
+ .commit = mem_commit,
.priority = 0,
};
as->dispatch = d;
@@ -1787,6 +1804,7 @@ void address_space_destroy_dispatch(AddressSpace *as)
AddressSpaceDispatch *d = as->dispatch;
memory_listener_unregister(&d->listener);
+ g_free(d->cur_map);
g_free(d);
as->dispatch = NULL;
}
diff --git a/include/exec/memory-internal.h b/include/exec/memory-internal.h
index 1b156fd..0dfe260 100644
--- a/include/exec/memory-internal.h
+++ b/include/exec/memory-internal.h
@@ -30,13 +30,22 @@ struct PhysPageEntry {
uint16_t ptr : 15;
};
+struct PhysPageTable;
+typedef struct PhysPageMap PhysPageMap;
+
+struct PhysPageMap {
+ PhysPageEntry root;
+ struct PhysPageTable *pgtbl;
+};
+
typedef struct AddressSpaceDispatch AddressSpaceDispatch;
struct AddressSpaceDispatch {
/* This is a multi-level map on the physical address space.
* The bottom level has pointers to MemoryRegionSections.
*/
- PhysPageEntry phys_map;
+ PhysPageMap *cur_map;
+ PhysPageMap *next_map;
MemoryListener listener;
};
--
1.7.4.4
- [Qemu-devel] [RFC PATCH 0/2] make memory listener prepared for rcu style, Liu Ping Fan, 2013/05/12
- [Qemu-devel] [RFC PATCH 1/2] mem: make phys_section and phys_map_nodes prepared for RCU, Liu Ping Fan, 2013/05/12
- Re: [Qemu-devel] [RFC PATCH 1/2] mem: make phys_section and phys_map_nodes prepared for RCU, Paolo Bonzini, 2013/05/13
- Re: [Qemu-devel] [RFC PATCH 1/2] mem: make phys_section and phys_map_nodes prepared for RCU, liu ping fan, 2013/05/13
- Re: [Qemu-devel] [RFC PATCH 1/2] mem: make phys_section and phys_map_nodes prepared for RCU, Paolo Bonzini, 2013/05/14
- Re: [Qemu-devel] [RFC PATCH 1/2] mem: make phys_section and phys_map_nodes prepared for RCU, liu ping fan, 2013/05/15
- Re: [Qemu-devel] [RFC PATCH 1/2] mem: make phys_section and phys_map_nodes prepared for RCU, liu ping fan, 2013/05/26
- Re: [Qemu-devel] [RFC PATCH 1/2] mem: make phys_section and phys_map_nodes prepared for RCU, Paolo Bonzini, 2013/05/27
- Re: [Qemu-devel] [RFC PATCH 1/2] mem: make phys_section and phys_map_nodes prepared for RCU, liu ping fan, 2013/05/28
[Qemu-devel] [RFC PATCH 2/2] mem: prepare address_space listener rcu style,
Liu Ping Fan <=
- Re: [Qemu-devel] [RFC PATCH 2/2] mem: prepare address_space listener rcu style, Paolo Bonzini, 2013/05/13
- Re: [Qemu-devel] [RFC PATCH 2/2] mem: prepare address_space listener rcu style, liu ping fan, 2013/05/14
- Re: [Qemu-devel] [RFC PATCH 2/2] mem: prepare address_space listener rcu style, Paolo Bonzini, 2013/05/14
- Re: [Qemu-devel] [RFC PATCH 2/2] mem: prepare address_space listener rcu style, liu ping fan, 2013/05/14
- Re: [Qemu-devel] [RFC PATCH 2/2] mem: prepare address_space listener rcu style, Paolo Bonzini, 2013/05/15
- Re: [Qemu-devel] [RFC PATCH 2/2] mem: prepare address_space listener rcu style, liu ping fan, 2013/05/15
- Re: [Qemu-devel] [RFC PATCH 2/2] mem: prepare address_space listener rcu style, Paolo Bonzini, 2013/05/15
Re: [Qemu-devel] [RFC PATCH 2/2] mem: prepare address_space listener rcu style, Paolo Bonzini, 2013/05/16