Messages in this thread | | | Date | Thu, 21 Feb 2008 14:23:03 -0800 | From | "H. Peter Anvin" <> | Subject | Re: 2.6.25-rc1 xen pvops regression |
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Ian Campbell wrote: > On Thu, 2008-02-21 at 13:37 -0800, Jeremy Fitzhardinge wrote: >> H. Peter Anvin wrote: >>>> Still curious about why a pagetable page is ending up in that range >>>> though. Seems like it shouldn't be possible, since we shouldn't be >>>> allowed to allocate from those pages, at least until the DMI probe >>>> has happened... Unless the early allocator is only excluded from >>>> e820 reserved pages, which would cause a problem on systems which >>>> don't reserve the DMI space... HPA? >>>> >>> I thought the problem was a Xen-provided pagetable from before Linux >>> started? >> Hm, I don't think so. The domain-builder pagetable is put after the >> kernel, so it shouldn't be under 1M. > > I can confirm that it is Linux which is allocating it. The call path: > # xm create -c debian-x86_32p-1 > Using config file "/etc/xen/debian-x86_32p-1". > Started domain debian-1 > xen_alloc_pt_init PFN f0 > Pid: 0, comm: swapper Not tainted 2.6.25-rc2 #68 > [<c02ecb6b>] xen_alloc_pt_init+0x4b/0x60 > [<c02f5e2b>] one_page_table_init+0x8b/0xf0 > [<c02f63df>] paging_init+0x3bf/0x520 > [<c02ee444>] setup_arch+0x2a4/0x410 > [<c02e9a64>] start_kernel+0x64/0x380 > [<c02efd7f>] cpu_detect+0x6f/0xf0 > [<c02ed1a1>] xen_start_kernel+0x2f1/0x310 > ======================= > Entering add_active_range(0, 0, 262144) 0 entries of 256 used > Zone PFN ranges: > DMA 0 -> 4096 >
What is the e820 information you feed the kernel? We should only ever allocate page tables out of available RAM, not any other type of memory (reserved or not).
-hpa
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