From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:47233) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QlLkX-0003ed-TD for qemu-devel@nongnu.org; Mon, 25 Jul 2011 10:03:18 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QlLkU-00053M-Gj for qemu-devel@nongnu.org; Mon, 25 Jul 2011 10:03:13 -0400 Received: from mx1.redhat.com ([209.132.183.28]:31034) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QlLkU-00052D-8R for qemu-devel@nongnu.org; Mon, 25 Jul 2011 10:03:10 -0400 From: Avi Kivity Date: Mon, 25 Jul 2011 17:02:55 +0300 Message-Id: <1311602584-23409-15-git-send-email-avi@redhat.com> In-Reply-To: <1311602584-23409-1-git-send-email-avi@redhat.com> References: <1311602584-23409-1-git-send-email-avi@redhat.com> Subject: [Qemu-devel] [PATCH 14/23] memory: transaction API List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kvm@vger.kernel.org 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 --- memory.c | 20 ++++++++++++++++++++ memory.h | 8 ++++++++ 2 files changed, 28 insertions(+), 0 deletions(-) diff --git a/memory.c b/memory.c index 009ad33..370e189 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 { @@ -623,6 +625,10 @@ 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); } @@ -631,6 +637,20 @@ static void memory_region_update_topology(void) } } +void memory_region_transaction_begin(void) +{ + ++memory_region_transaction_depth; +} + +void memory_region_transaction_commit(void) +{ + if (!memory_region_transaction_depth) { + abort(); + } + --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 e4c0ad1..cb3a9b6 100644 --- a/memory.h +++ b/memory.h @@ -246,6 +246,14 @@ 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 -- 1.7.5.3