From 6ded39998a40e7547625ba66a435029a31637f1c Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Tue, 26 Jul 2011 14:26:13 +0300 Subject: [PATCH] memory: transaction API Allow changes to the memory hierarchy to be accumulated and made visible all at once. This reduces computational effort, especially when an accelerator (e.g. kvm) is involved. Useful when a single register update causes multiple changes to an address space. Signed-off-by: Avi Kivity Signed-off-by: Anthony Liguori --- memory.c | 18 ++++++++++++++++++ memory.h | 8 ++++++++ 2 files changed, 26 insertions(+) diff --git a/memory.c b/memory.c index 7a5670e2a9..5c6e63df3f 100644 --- a/memory.c +++ b/memory.c @@ -18,6 +18,8 @@ #include "kvm.h" #include +unsigned memory_region_transaction_depth = 0; + typedef struct AddrRange AddrRange; struct AddrRange { @@ -626,6 +628,10 @@ static void address_space_update_topology(AddressSpace *as) static void memory_region_update_topology(void) { + if (memory_region_transaction_depth) { + return; + } + if (address_space_memory.root) { address_space_update_topology(&address_space_memory); } @@ -634,6 +640,18 @@ static void memory_region_update_topology(void) } } +void memory_region_transaction_begin(void) +{ + ++memory_region_transaction_depth; +} + +void memory_region_transaction_commit(void) +{ + assert(memory_region_transaction_depth); + --memory_region_transaction_depth; + memory_region_update_topology(); +} + void memory_region_init(MemoryRegion *mr, const char *name, uint64_t size) diff --git a/memory.h b/memory.h index c280a39d2c..4e518b2a1b 100644 --- a/memory.h +++ b/memory.h @@ -456,6 +456,14 @@ void memory_region_add_subregion_overlap(MemoryRegion *mr, void memory_region_del_subregion(MemoryRegion *mr, MemoryRegion *subregion); +/* Start a transaction; changes will be accumulated and made visible only + * when the transaction ends. + */ +void memory_region_transaction_begin(void); +/* Commit a transaction and make changes visible to the guest. + */ +void memory_region_transaction_commit(void); + #endif #endif -- 2.34.1