From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43475) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W8qPI-0004eJ-5n for qemu-devel@nongnu.org; Thu, 30 Jan 2014 07:07:50 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1W8qPB-0007pA-Uh for qemu-devel@nongnu.org; Thu, 30 Jan 2014 07:07:44 -0500 Received: from mail-pd0-f176.google.com ([209.85.192.176]:57972) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W8qPB-0007p4-OL for qemu-devel@nongnu.org; Thu, 30 Jan 2014 07:07:37 -0500 Received: by mail-pd0-f176.google.com with SMTP id w10so2937569pde.7 for ; Thu, 30 Jan 2014 04:07:37 -0800 (PST) Message-ID: <52EA4083.9040309@ozlabs.ru> Date: Thu, 30 Jan 2014 23:07:31 +1100 From: Alexey Kardashevskiy MIME-Version: 1.0 References: <1390974639-24880-1-git-send-email-aik@ozlabs.ru> <52E8AE32.7000200@redhat.com> <52E8B80B.5060904@ozlabs.ru> <52E8D1F8.3020404@redhat.com> In-Reply-To: <52E8D1F8.3020404@redhat.com> Content-Type: text/plain; charset=KOI8-R 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: Paolo Bonzini , qemu-devel@nongnu.org Cc: Orit Wasserman , Juan Quintela On 01/29/2014 09:03 PM, Paolo Bonzini wrote: > 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"? Ok, done. But I still wonder why there are still TARGET_PAGE_SIZE vs. getpagesize() and why bitmap formats are different between KVM and QEMU - is it just an old stuff which has to be fixes some day or something more? >> 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. -- Alexey