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Re: [Qemu-devel] [PATCH] Memory: use memory address space for cpu-memory
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH] Memory: use memory address space for cpu-memory |
Date: |
Thu, 18 May 2017 23:38:40 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.1.0 |
On 17/05/2017 19:01, Xu, Anthony wrote:
>>> - AddressSpace *as = address_space_init_shareable(cpu->memory,
>>> - "cpu-memory");
>>> + AddressSpace *as;
>>> + if (cpu->memory == address_space_memory.root) {
>>> + address_space_memory.ref_count++;
>> probably this would cause reference leak when vcpu is destroyed
> I thought address_space_destroy is called when vcpu is unplugged,
> seems that's not the case, then ref_count++ is not needed.
It should be called. Alternatively you could try adding a new function
to mark address_space_memory as a never-destroyed AddressSpace:
diff --git a/include/exec/memory.h b/include/exec/memory.h
index 99e0f54d86..b27b288c8f 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -290,6 +290,7 @@ struct AddressSpace {
MemoryRegion *root;
int ref_count;
bool malloced;
+ bool shared;
/* Accessed via RCU. */
struct FlatView *current_map;
diff --git a/memory.c b/memory.c
index b727f5ec0e..190cd3d5ce 100644
--- a/memory.c
+++ b/memory.c
@@ -2432,6 +2432,7 @@ void address_space_init(AddressSpace *as, MemoryRegion
*root, const char *name)
as->ref_count = 1;
as->root = root;
as->malloced = false;
+ as->shared = false;
as->current_map = g_new(FlatView, 1);
flatview_init(as->current_map);
as->ioeventfd_nb = 0;
@@ -2460,12 +2461,18 @@ static void do_address_space_destroy(AddressSpace *as)
}
}
+void address_space_init_static(AddressSpace *as, MemoryRegion *root, const
char *name)
+{
+ address_space_init(as, root, name);
+ as->shared = true;
+}
+
AddressSpace *address_space_init_shareable(MemoryRegion *root, const char
*name)
{
AddressSpace *as;
QTAILQ_FOREACH(as, &address_spaces, address_spaces_link) {
- if (root == as->root && as->malloced) {
+ if (root == as->root && as->shared) {
as->ref_count++;
return as;
}
@@ -2474,6 +2481,7 @@ AddressSpace *address_space_init_shareable(MemoryRegion
*root, const char *name)
as = g_malloc0(sizeof *as);
address_space_init(as, root, name);
as->malloced = true;
+ as->shared = true;
return as;
}
@@ -2485,6 +2493,8 @@ void address_space_destroy(AddressSpace *as)
if (as->ref_count) {
return;
}
+ assert(!as->shared || as->malloced);
+
/* Flush out anything from MemoryListeners listening in on this */
memory_region_transaction_begin();
as->root = NULL;
then CPUs can keep using address_space_init_shareable.
Paolo
- [Qemu-devel] [PATCH] Memory: use memory address space for cpu-memory, Anthony Xu, 2017/05/16
- Re: [Qemu-devel] [PATCH] Memory: use memory address space for cpu-memory, Igor Mammedov, 2017/05/17
- Re: [Qemu-devel] [PATCH] Memory: use memory address space for cpu-memory, Xu, Anthony, 2017/05/17
- Re: [Qemu-devel] [PATCH] Memory: use memory address space for cpu-memory,
Paolo Bonzini <=
- Re: [Qemu-devel] [PATCH] Memory: use memory address space for cpu-memory, Xu, Anthony, 2017/05/18
- Re: [Qemu-devel] [PATCH] Memory: use memory address space for cpu-memory, Paolo Bonzini, 2017/05/18
- Re: [Qemu-devel] [PATCH] Memory: use memory address space for cpu-memory, Xu, Anthony, 2017/05/18
- Re: [Qemu-devel] [PATCH] Memory: use memory address space for cpu-memory, Paolo Bonzini, 2017/05/19