Commit Graph

15 Commits

Author SHA1 Message Date
Aneesh Kumar K.V 0f4bc0932e powerpc/mm/cxl: Add the fault handling cpu to mm cpumask
We use mm cpumask for serializing against lockless page table walk.
Anybody who is doing a lockless page table walk is expected to disable
irq and only cpus in mm cpumask is expected do the lockless walk. This
ensure that a THP split can send IPI to only cpus in the mm cpumask,
to make sure there are no parallel lockless page table walk.

Add the CAPI fault handling cpu to the mm cpumask so that we can do
the lockless page table walk while inserting hash page table entries.

Reviewed-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-17 23:31:52 +10:00
Aneesh Kumar K.V fa4531f753 powerpc/mm: Don't send IPI to all cpus on THP updates
Now that we made sure that lockless walk of linux page table is mostly
limitted to current task(current->mm->pgdir) we can update the THP
update sequence to only send IPI to CPUs on which this task has run.
This helps in reducing the IPI overload on systems with large number
of CPUs.

WRT kvm even though kvm is walking page table with vpc->arch.pgdir,
it is done only on secondary CPUs and in that case we have primary CPU
added to task's mm cpumask. Sending an IPI to primary will force the
secondary to do a vm exit and hence this mm cpumask usage is safe
here.

WRT CAPI, we still end up walking linux page table with capi context
MM. For now the pte lookup serialization sends an IPI to all CPUs in
CPI is in use. We can further improve this by adding the CAPI
interrupt handling CPU to task mm cpumask. That will be done in a
later patch.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-08-17 23:31:13 +10:00
Oliver O'Halloran ebd3119793 powerpc/mm: Add devmap support for ppc64
Add support for the devmap bit on PTEs and PMDs for PPC64 Book3S.  This
is used to differentiate device backed memory from transparent huge
pages since they are handled in more or less the same manner by the core
mm code.

Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-07-02 20:40:28 +10:00
Ingo Molnar 589ee62844 sched/headers: Prepare to remove the <linux/mm_types.h> dependency from <linux/sched.h>
Update code that relied on sched.h including various MM types for them.

This will allow us to remove the <linux/mm_types.h> include from <linux/sched.h>.

Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-02 08:42:37 +01:00
Reza Arbab 4b5d62ca17 powerpc/mm: add radix__remove_section_mapping()
Tear down and free the four-level page tables of physical mappings
during memory hotremove.

Borrow the basic structure of remove_pagetable() and friends from the
identically-named x86 functions. Reduce the frequency of tlb flushes and
page_table_lock spinlocks by only doing them in the outermost function.
There was some question as to whether the locking is needed at all.
Leave it for now, but we could consider dropping it.

Memory must be offline to be removed, thus not in use. So there
shouldn't be the sort of concurrent page walking activity here that
might prompt us to use RCU.

Signed-off-by: Reza Arbab <arbab@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-01-31 13:54:19 +11:00
Reza Arbab 6cc27341b2 powerpc/mm: add radix__create_section_mapping()
Wire up memory hotplug page mapping for radix. Share the mapping
function already used by radix_init_pgtable().

Signed-off-by: Reza Arbab <arbab@linux.vnet.ibm.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-01-31 13:54:19 +11:00
Reza Arbab 32b53c012e powerpc/mm: Fix memory hotplug BUG() on radix
Memory hotplug is leading to hash page table calls, even on radix:

  arch_add_memory
    create_section_mapping
      htab_bolt_mapping
        BUG_ON(!ppc_md.hpte_insert);

To fix, refactor {create,remove}_section_mapping() into hash__ and
radix__ variants. Leave the radix versions stubbed for now.

Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Reza Arbab <arbab@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-01-17 10:05:43 +11:00
Aneesh Kumar K.V b3603e174f powerpc/mm: update radix__ptep_set_access_flag to not do full mm tlb flush
When we are updating a pte, we just need to flush the tlb mapping
that pte. Right now we do a full mm flush because we don't track the page
size. Now that we have page size details in pte use that to do the
optimized flush

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-11-28 22:44:33 +11:00
Benjamin Herrenschmidt fe036a0605 powerpc/64/kexec: Fix MMU cleanup on radix
Just using the hash ops won't work anymore since radix will have
NULL in there. Instead create an mmu_cleanup_all() function which
will do the right thing based on the MMU mode.

For Radix, for now I clear UPRT and the PTCR, effectively switching
back to Radix with no partition table setup.

Currently set it to NULL on BookE thought it might be a good idea
to wipe the TLB there (Scott ?)

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-09-23 07:54:17 +10:00
Aneesh Kumar K.V c6d1a767b9 powerpc/mm/radix: Use different pte update sequence for different POWER9 revs
POWER9 DD1 requires pte to be marked invalid (V=0) before updating
it with the new value. This makes this distinction for the different
revisions.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-09-13 17:37:10 +10:00
Michael Ellerman eea8148c69 powerpc/mm: Move register_process_table() out of ppc_md
We want to initialise register_process_table() before ppc_md is setup,
so that it can be called as part of MMU init (at least on Radix ATM).

That no longer works because probe_machine() requires that ppc_md be
empty before it's called, and we now do probe_machine() much later.

So make register_process_table a global for now. It will probably move
into a mmu_radix_ops struct at some point in the future.

This was broken by me when applying commit 7025776ed1 "powerpc/mm:
Move hash table ops to a separate structure" due to conflicts with other
patches.

Fixes: 7025776ed1 ("powerpc/mm: Move hash table ops to a separate structure")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-08-04 20:22:34 +10:00
Aneesh Kumar K.V d8e91e93e9 powerpc/mm/radix: Add tlb flush of THP ptes
Instead of flushing the entire mm, implement a flush_pmd_tlb_range

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-08-01 11:15:10 +10:00
Aneesh Kumar K.V 157d4d0620 powerpc/mm/radix: Add missing tlb flush
This should not have any impact on hash, because hash does tlb
invalidate with every pte update and we don't implement
flush_tlb_* functions for hash. With radix we should make an explicit
call to flush tlb outside pte update.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-06-01 13:47:34 +10:00
Aneesh Kumar K.V bde3eb6222 powerpc/mm/radix: Add radix THP callbacks
The deposited pgtable_t is a pte fragment hence we cannot use page->lru
for linking then together. We use the first two 64 bits for pte fragment
as list_head type to link all deposited fragments together. On withdraw
we properly zero then out.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-05-11 21:53:57 +10:00
Aneesh Kumar K.V 3df33f12be powerpc/mm/thp: Abstraction for THP functions
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2016-05-11 21:53:57 +10:00