From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:52504) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QlfmV-0000il-Qi for qemu-devel@nongnu.org; Tue, 26 Jul 2011 07:26:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QlfmP-0008Gx-CW for qemu-devel@nongnu.org; Tue, 26 Jul 2011 07:26:35 -0400 Received: from mx1.redhat.com ([209.132.183.28]:9090) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QlfmP-0008Fs-1F for qemu-devel@nongnu.org; Tue, 26 Jul 2011 07:26:29 -0400 From: Avi Kivity Date: Tue, 26 Jul 2011 14:26:13 +0300 Message-Id: <1311679582-11211-15-git-send-email-avi@redhat.com> In-Reply-To: <1311679582-11211-1-git-send-email-avi@redhat.com> References: <1311679582-11211-1-git-send-email-avi@redhat.com> Subject: [Qemu-devel] [PATCH v2 14/23] memory: transaction API List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori , 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 | 18 ++++++++++++++++++ memory.h | 8 ++++++++ 2 files changed, 26 insertions(+), 0 deletions(-) diff --git a/memory.c b/memory.c index 7a5670e..5c6e63d 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 c280a39..4e518b2 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 -- 1.7.5.3