| Message ID | 20220616120033.1976732-1-mpe@ellerman.id.au (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | powerpc/mm: Move CMA reservations after initmem_init() | expand |
Michael Ellerman <mpe@ellerman.id.au> writes: > After commit 11ac3e87ce09 ("mm: cma: use pageblock_order as the single > alignment") there is an error at boot about the KVM CMA reservation > failing, eg: > > kvm_cma_reserve: reserving 6553 MiB for global area > cma: Failed to reserve 6553 MiB > > That makes it impossible to start KVM guests using the hash MMU with > more than 2G of memory, because the VM is unable to allocate a large > enough region for the hash page table, eg: > > $ qemu-system-ppc64 -enable-kvm -M pseries -m 4G ... > qemu-system-ppc64: Failed to allocate KVM HPT of order 25: Cannot allocate memory > > Aneesh pointed out that this happens because when kvm_cma_reserve() is > called, pageblock_order has not been initialised yet, and is still zero, > causing the checks in cma_init_reserved_mem() against > CMA_MIN_ALIGNMENT_PAGES to fail. > > Fix it by moving the call to kvm_cma_reserve() after initmem_init(). The > pageblock_order is initialised in sparse_init() which is called from > initmem_init(). > > Also move the hugetlb CMA reservation. > Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> > Fixes: 11ac3e87ce09 ("mm: cma: use pageblock_order as the single alignment") > Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> > --- > arch/powerpc/kernel/setup-common.c | 13 +++++++------ > 1 file changed, 7 insertions(+), 6 deletions(-) > > diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c > index eb0077b302e2..1a02629ec70b 100644 > --- a/arch/powerpc/kernel/setup-common.c > +++ b/arch/powerpc/kernel/setup-common.c > @@ -935,12 +935,6 @@ void __init setup_arch(char **cmdline_p) > /* Print various info about the machine that has been gathered so far. */ > print_system_info(); > > - /* Reserve large chunks of memory for use by CMA for KVM. */ > - kvm_cma_reserve(); > - > - /* Reserve large chunks of memory for us by CMA for hugetlb */ > - gigantic_hugetlb_cma_reserve(); > - > klp_init_thread_info(&init_task); > > setup_initial_init_mm(_stext, _etext, _edata, _end); > @@ -955,6 +949,13 @@ void __init setup_arch(char **cmdline_p) > > initmem_init(); > > + /* > + * Reserve large chunks of memory for use by CMA for KVM and hugetlb. These must > + * be called after initmem_init(), so that pageblock_order is initialised. > + */ > + kvm_cma_reserve(); > + gigantic_hugetlb_cma_reserve(); > + > early_memtest(min_low_pfn << PAGE_SHIFT, max_low_pfn << PAGE_SHIFT); > > if (ppc_md.setup_arch) > -- > 2.35.3
On 16 Jun 2022, at 8:00, Michael Ellerman wrote: > After commit 11ac3e87ce09 ("mm: cma: use pageblock_order as the single > alignment") there is an error at boot about the KVM CMA reservation > failing, eg: > > kvm_cma_reserve: reserving 6553 MiB for global area > cma: Failed to reserve 6553 MiB > > That makes it impossible to start KVM guests using the hash MMU with > more than 2G of memory, because the VM is unable to allocate a large > enough region for the hash page table, eg: > > $ qemu-system-ppc64 -enable-kvm -M pseries -m 4G ... > qemu-system-ppc64: Failed to allocate KVM HPT of order 25: Cannot allocate memory > > Aneesh pointed out that this happens because when kvm_cma_reserve() is > called, pageblock_order has not been initialised yet, and is still zero, > causing the checks in cma_init_reserved_mem() against > CMA_MIN_ALIGNMENT_PAGES to fail. > > Fix it by moving the call to kvm_cma_reserve() after initmem_init(). The > pageblock_order is initialised in sparse_init() which is called from > initmem_init(). > > Also move the hugetlb CMA reservation. > > Fixes: 11ac3e87ce09 ("mm: cma: use pageblock_order as the single alignment") > Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> > --- > arch/powerpc/kernel/setup-common.c | 13 +++++++------ > 1 file changed, 7 insertions(+), 6 deletions(-) > > diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c > index eb0077b302e2..1a02629ec70b 100644 > --- a/arch/powerpc/kernel/setup-common.c > +++ b/arch/powerpc/kernel/setup-common.c > @@ -935,12 +935,6 @@ void __init setup_arch(char **cmdline_p) > /* Print various info about the machine that has been gathered so far. */ > print_system_info(); > > - /* Reserve large chunks of memory for use by CMA for KVM. */ > - kvm_cma_reserve(); > - > - /* Reserve large chunks of memory for us by CMA for hugetlb */ > - gigantic_hugetlb_cma_reserve(); > - > klp_init_thread_info(&init_task); > > setup_initial_init_mm(_stext, _etext, _edata, _end); > @@ -955,6 +949,13 @@ void __init setup_arch(char **cmdline_p) > > initmem_init(); > > + /* > + * Reserve large chunks of memory for use by CMA for KVM and hugetlb. These must > + * be called after initmem_init(), so that pageblock_order is initialised. > + */ > + kvm_cma_reserve(); > + gigantic_hugetlb_cma_reserve(); > + > early_memtest(min_low_pfn << PAGE_SHIFT, max_low_pfn << PAGE_SHIFT); > > if (ppc_md.setup_arch) > -- > 2.35.3 Thank you for the fix. Reviewed-by: Zi Yan <ziy@nvidia.com> -- Best Regards, Yan, Zi
On Thu, 16 Jun 2022 22:00:33 +1000, Michael Ellerman wrote: > After commit 11ac3e87ce09 ("mm: cma: use pageblock_order as the single > alignment") there is an error at boot about the KVM CMA reservation > failing, eg: > > kvm_cma_reserve: reserving 6553 MiB for global area > cma: Failed to reserve 6553 MiB > > [...] Applied to powerpc/fixes. [1/1] powerpc/mm: Move CMA reservations after initmem_init() https://git.kernel.org/powerpc/c/6cf06c17e94f26c290fd3370a5c36514ae15ac43 cheers
diff --git a/arch/powerpc/kernel/setup-common.c b/arch/powerpc/kernel/setup-common.c index eb0077b302e2..1a02629ec70b 100644 --- a/arch/powerpc/kernel/setup-common.c +++ b/arch/powerpc/kernel/setup-common.c @@ -935,12 +935,6 @@ void __init setup_arch(char **cmdline_p) /* Print various info about the machine that has been gathered so far. */ print_system_info(); - /* Reserve large chunks of memory for use by CMA for KVM. */ - kvm_cma_reserve(); - - /* Reserve large chunks of memory for us by CMA for hugetlb */ - gigantic_hugetlb_cma_reserve(); - klp_init_thread_info(&init_task); setup_initial_init_mm(_stext, _etext, _edata, _end); @@ -955,6 +949,13 @@ void __init setup_arch(char **cmdline_p) initmem_init(); + /* + * Reserve large chunks of memory for use by CMA for KVM and hugetlb. These must + * be called after initmem_init(), so that pageblock_order is initialised. + */ + kvm_cma_reserve(); + gigantic_hugetlb_cma_reserve(); + early_memtest(min_low_pfn << PAGE_SHIFT, max_low_pfn << PAGE_SHIFT); if (ppc_md.setup_arch)
After commit 11ac3e87ce09 ("mm: cma: use pageblock_order as the single alignment") there is an error at boot about the KVM CMA reservation failing, eg: kvm_cma_reserve: reserving 6553 MiB for global area cma: Failed to reserve 6553 MiB That makes it impossible to start KVM guests using the hash MMU with more than 2G of memory, because the VM is unable to allocate a large enough region for the hash page table, eg: $ qemu-system-ppc64 -enable-kvm -M pseries -m 4G ... qemu-system-ppc64: Failed to allocate KVM HPT of order 25: Cannot allocate memory Aneesh pointed out that this happens because when kvm_cma_reserve() is called, pageblock_order has not been initialised yet, and is still zero, causing the checks in cma_init_reserved_mem() against CMA_MIN_ALIGNMENT_PAGES to fail. Fix it by moving the call to kvm_cma_reserve() after initmem_init(). The pageblock_order is initialised in sparse_init() which is called from initmem_init(). Also move the hugetlb CMA reservation. Fixes: 11ac3e87ce09 ("mm: cma: use pageblock_order as the single alignment") Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> --- arch/powerpc/kernel/setup-common.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-)