From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34785) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W8Rzp-00057k-Qx for qemu-devel@nongnu.org; Wed, 29 Jan 2014 05:03:54 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1W8Rzk-0003SX-ND for qemu-devel@nongnu.org; Wed, 29 Jan 2014 05:03:49 -0500 Received: from mx1.redhat.com ([209.132.183.28]:27511) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W8Rzk-0003SE-Ef for qemu-devel@nongnu.org; Wed, 29 Jan 2014 05:03:44 -0500 Message-ID: <52E8D1F8.3020404@redhat.com> Date: Wed, 29 Jan 2014 11:03:36 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: <1390974639-24880-1-git-send-email-aik@ozlabs.ru> <52E8AE32.7000200@redhat.com> <52E8B80B.5060904@ozlabs.ru> In-Reply-To: <52E8B80B.5060904@ozlabs.ru> Content-Type: text/plain; charset=KOI8-R; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] Revert "memory: syncronize kvm bitmap using bitmaps operations" List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexey Kardashevskiy , qemu-devel@nongnu.org Cc: Orit Wasserman , Juan Quintela Il 29/01/2014 09:12, Alexey Kardashevskiy ha scritto: > On 01/29/2014 06:30 PM, Paolo Bonzini wrote: >> Il 29/01/2014 06:50, Alexey Kardashevskiy ha scritto: >>> Since 64K system page size is quite popular configuration on PPC64, >>> the original patch breaks migration. >>> >>> Signed-off-by: Alexey Kardashevskiy >>> --- >>> include/exec/ram_addr.h | 54 >>> +++++++++++++++++-------------------------------- >>> 1 file changed, 18 insertions(+), 36 deletions(-) >>> >>> diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h >>> index 33c8acc..c6736ed 100644 >>> --- a/include/exec/ram_addr.h >>> +++ b/include/exec/ram_addr.h >>> @@ -83,47 +83,29 @@ static inline void >>> cpu_physical_memory_set_dirty_lebitmap(unsigned long *bitmap, >>> ram_addr_t start, >>> ram_addr_t pages) >>> { >>> - unsigned long i, j; >>> + unsigned int i, j; >>> unsigned long page_number, c; >>> hwaddr addr; >>> ram_addr_t ram_addr; >>> - unsigned long len = (pages + HOST_LONG_BITS - 1) / HOST_LONG_BITS; >>> + unsigned int len = (pages + HOST_LONG_BITS - 1) / HOST_LONG_BITS; >>> unsigned long hpratio = getpagesize() / TARGET_PAGE_SIZE; >>> - unsigned long page = BIT_WORD(start >> TARGET_PAGE_BITS); >>> >>> - /* start address is aligned at the start of a word? */ >>> - if (((page * BITS_PER_LONG) << TARGET_PAGE_BITS) == start) { >> >> Why not just add " && hpratio == 1" here? > > Or fix dirty map to make it 1 bit per system page size (may be the fix is > coming, who knows, but I am just not ready to do this now). Or do tricks > with bits and support hpratio!=1. I could not choose and decided to revert > it for now :) Can you post the patch that adds " && hpratio == 1"? > Do we really earn a lot here? Yes, because this is the only part of migration that runs with the iothread lock taken. Without Juan's patches you can see large guests hiccups that last a few seconds. Paolo