Am 10.05.2014 17:33, schrieb Paolo Bonzini:
> Il 10/05/2014 12:51, Peter Lieven ha scritto:
>> we currently look up the ram ptr for each single page. Cache
>> the pointer while we operate on the same block.
>
> Why don't you instead cache the result in the MemoryRegion, so that
> memory_region_get_ram_ptr becomes a simple, inline field access?
This seems to work. Wondering if it has other side implications. Basic tests
like booting vServers and migration work. What about XEN?
diff --git a/include/exec/memory.h b/include/exec/memory.h
index 1d55ad9..3003875 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -161,6 +161,7 @@ struct MemoryRegion {
unsigned ioeventfd_nb;
MemoryRegionIoeventfd *ioeventfds;
NotifierList iommu_notify;
+ void *ram_ptr;
};
/**
diff --git a/memory.c b/memory.c
index 3f1df23..78d4032 100644
--- a/memory.c
+++ b/memory.c
@@ -862,6 +862,7 @@ void memory_region_init(MemoryRegion *mr,
mr->ioeventfd_nb = 0;
mr->ioeventfds = NULL;
mr->flush_coalesced_mmio = false;
+ mr->ram_ptr = NULL;
}
static uint64_t unassigned_mem_read(void *opaque, hwaddr addr,
@@ -1249,7 +1250,12 @@ void *memory_region_get_ram_ptr(MemoryRegion *mr)
assert(mr->terminates);
- return qemu_get_ram_ptr(mr->ram_addr & TARGET_PAGE_MASK);
+ if (mr->ram_ptr) {
+ return mr->ram_ptr;
+ }
+
+ mr->ram_ptr = qemu_get_ram_ptr(mr->ram_addr & TARGET_PAGE_MASK);
+ return mr->ram_ptr;
}
static void memory_region_update_coalesced_range_as(MemoryRegion *mr,
AddressSpace *as)
Peter
>
> Paolo
>
>> Signed-off-by: Peter Lieven <p...@kamp.de>
>> ---
>> arch_init.c | 23 ++++++++++++++++-------
>> 1 file changed, 16 insertions(+), 7 deletions(-)
>>
>> diff --git a/arch_init.c b/arch_init.c
>> index 582b716..ce338aa 100644
>> --- a/arch_init.c
>> +++ b/arch_init.c
>> @@ -594,13 +594,19 @@ static int ram_save_block(QEMUFile *f, bool last_stage)
>> ram_bulk_stage = false;
>> }
>> } else {
>> + static uint8_t *ram_ptr;
>> int ret;
>> uint8_t *p;
>> bool send_async = true;
>> - int cont = (block == last_sent_block) ?
>> - RAM_SAVE_FLAG_CONTINUE : 0;
>> + int cont = 0;
>>
>> - p = memory_region_get_ram_ptr(mr) + offset;
>> + if (block != last_sent_block) {
>> + ram_ptr = memory_region_get_ram_ptr(mr);
>> + } else {
>> + cont = RAM_SAVE_FLAG_CONTINUE;
>> + }
>> +
>> + p = ram_ptr + offset;
>>
>> /* In doubt sent page as normal */
>> bytes_sent = -1;
>> @@ -990,16 +996,17 @@ static inline void *host_from_stream_offset(QEMUFile
>> *f,
>> int flags)
>> {
>> static RAMBlock *block = NULL;
>> + static uint8_t *ram_ptr;
>> char id[256];
>> uint8_t len;
>>
>> if (flags & RAM_SAVE_FLAG_CONTINUE) {
>> - if (!block) {
>> + if (!block || !ram_ptr) {
>> fprintf(stderr, "Ack, bad migration stream!\n");
>> return NULL;
>> }
>>
>> - return memory_region_get_ram_ptr(block->mr) + offset;
>> + return ram_ptr + offset;
>> }
>>
>> len = qemu_get_byte(f);
>> @@ -1007,8 +1014,10 @@ static inline void *host_from_stream_offset(QEMUFile
>> *f,
>> id[len] = 0;
>>
>> QTAILQ_FOREACH(block, &ram_list.blocks, next) {
>> - if (!strncmp(id, block->idstr, sizeof(id)))
>> - return memory_region_get_ram_ptr(block->mr) + offset;
>> + if (!strncmp(id, block->idstr, sizeof(id))) {
>> + ram_ptr = memory_region_get_ram_ptr(block->mr);
>> + return ram_ptr + offset;
>> + }
>> }
>>
>> fprintf(stderr, "Can't find block %s!\n", id);
>>
>
