Am 09.06.2013 um 06:12 schrieb liu ping fan <qemul...@gmail.com>: > Hi Peter, > > Is it that sending zero page mostly service the first iteration, ie > bluk-stage? And for the subsequent iteration, dirty pages are normally > not zero. >
Yes most Zero Pages are sent during bulk stage except for busy windows guests or linux with page sanitization. In these cases freed Memory is zeroed. Peter > Thanks > > On Wed, Jun 5, 2013 at 2:09 PM, Peter Lieven <p...@kamp.de> wrote: >> >> Am 05.06.2013 um 05:37 schrieb Alexey Kardashevskiy <a...@ozlabs.ru>: >> >>> On 06/05/2013 05:15 AM, Peter Lieven wrote: >>>> >>>> Am 04.06.2013 um 17:17 schrieb Paolo Bonzini <pbonz...@redhat.com>: >>>> >>>>> Il 04/06/2013 16:48, Peter Lieven ha scritto: >>>>>> Still using 3.2, but strange enough the above example is also not >>>>>> increasing RSS size for me. >>>>>> >>>>>> Can you try the following: >>>>>> qemu git master with 1G of memory (hanging in bios with no boot device) >>>>>> and migrate it. Before migration RSS Size os somewhat >>>>>> around 16MB. After migration its RSS size is in the order of 1G. >>>>> >>>>> That may be a kernel bug. The kernel did not do the copy-on-write trick >>>>> on huge zero pages. It was fixed last year, maybe 3.2 is not enough. >>>>> Try adding a MADV_HUGEPAGE madvise to the testcase and see if it >>>>> reproduces. >>>> >>>> that's it. thanks for the pointer. the huge zero page was introduced in >>>> 3.8. >>>> >>>> paolo, alexey: can you please verify the following works for you: >>>> https://github.com/plieven/qemu/tree/fix-migration >>> >>> These two? >>> 848b796 Tue Jun 4 14:43:04 2013 +0200 Peter Lieven migration: do not >>> overwrite zero pages >>> 2206ac8 Tue Jun 4 14:25:33 2013 +0200 Peter Lieven Revert "migration: do >>> not sent zero pages in bulk stage" >> >> Yes, sorry forgot to mention this. >> >>> >>> That works for me (qemu 1.5, kernel 3.9-rc2). >>> Tested-by: Alexey Kardashevskiy <a...@ozlabs.ru> >> >> Thank you, >> Peter
