Messages in this thread | | | Date | Wed, 22 Jul 2015 08:59:30 +0800 | From | Baoquan He <> | Subject | Re: [PATCH v2] Do not reserve crashkernel high memory if crashkernel low memory reserving failed |
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On 07/21/15 at 12:22pm, Yinghai Lu wrote: > On Tue, Jul 21, 2015 at 1:58 AM, Baoquan He <bhe@redhat.com> wrote: > > > Maybe system which don't need low memory is rare, only for testing? > > No, it is not rare. > > All recent intel based systems with iommu support does not need low.
Yeah, you are right.
> > And those systems get punished by following patch: > > | commit 94fb9334182284e8e7e4bcb9125c25dc33af19d4 > | Author: Joerg Roedel <jroedel@suse.de> > | Date: Wed Jun 10 17:49:42 2015 +0200 > | > | x86/crash: Allocate enough low memory when crashkernel=high > > that reserve 256M low always. and those 256M get wasted. > > That commit should only be used to workaround some systems that > have partial iommu support.
Those big servers mostly has hardware iommu. But they still can enable swiotlb suport. Then low memory is needed.
> > Yinghai
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