kvmppc_do_h_enter: Fixes where local_irq_restore() must be placed (after
the last usage of ptep).
Given that some of these functions can be called in real mode, and others
always are, we use __{begin,end}_lockless_pgtbl_walk so we can decide when
to disable interrupts.
Signed-off-by: Leonardo Bras
,
so there is no need to repeat it here.
Variable that saves the irq mask was renamed from flags to irq_mask so it
doesn't lose meaning now it's not directly passed to local_irq_* functions.
Signed-off-by: Leonardo Bras
---
arch/powerpc/kvm/e500_mmu_host.c | 9 +
1 file changed, 5
,restore} is already inside {begin,end}_lockless_pgtbl_walk,
so there is no need to repeat it here.
Variable that saves the irq mask was renamed from flags to irq_mask so it
doesn't lose meaning now it's not directly passed to local_irq_* functions.
Signed-off-by: Leonardo Bras
---
arch/powerpc/mm
meaning now it's not directly passed to local_irq_* functions.
Signed-off-by: Leonardo Bras
---
arch/powerpc/perf/callchain.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/perf/callchain.c b/arch/powerpc/perf/callchain.c
index cbc251981209..fd9979e69f36
Applies the new functions used for tracking lockless pgtable walks on
addr_to_pfn().
local_irq_{save,restore} is already inside {begin,end}_lockless_pgtbl_walk,
so there is no need to repeat it here.
Signed-off-by: Leonardo Bras
---
arch/powerpc/kernel/mce_power.c | 6 +++---
1 file changed, 3
argument that allows interrupt enable/disable to be skipped:
__begin_lockless_pgtbl_walk() and __end_lockless_pgtbl_walk().
Functions similar to the generic ones are also exported, by calling
the above functions with parameter {en,dis}able_irq = true.
Signed-off-by: Leonardo Bras
---
arch/powerpc
inside
{begin,end}_lockless_pgtbl_walk, there should be no change in the
workings.
Signed-off-by: Leonardo Bras
---
mm/gup.c | 10 +-
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/mm/gup.c b/mm/gup.c
index 1b521e0ac1de..04e6f46993b6 100644
--- a/mm/gup.c
+++ b/mm/gup.c
to make sure there is no speculative
read outside the interrupt disabled area. Other than that, it is not
supposed to have any change of behavior from current code.
It is planned to allow arch-specific versions, so that additional steps can
be added while keeping the code clean.
Signed-off-by: Leonardo
xed behavior of decrementing before last ptep was used
Link: http://patchwork.ozlabs.org/patch/1163093/
Special thanks for:
Aneesh Kumar, Nick Piggin, Paul Mackerras, Michael Ellerman, Fabiano Rosas,
Dipankar Sarma and Oliver O'Halloran.
Leonardo Bras (11):
asm-generic/pgtable: Adds gene
munmap's time
reduction from 275 seconds to 39ms.
Signed-off-by: Leonardo Bras
---
arch/powerpc/include/asm/book3s/64/pgtable.h | 25 +---
arch/powerpc/include/asm/book3s/64/radix.h | 3 ++-
arch/powerpc/mm/book3s64/radix_pgtable.c | 6 +++--
3 files changed, 28 insertions(+), 6
roach to find the related vhost_dev's.
What do you think?
Best regards,
Leonardo Bras
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with this.
In this case, qemu does free the vhost IOTLB entry, which fixes the bug.
Signed-off-by: Leonardo Bras
---
arch/powerpc/kvm/book3s_64_vio.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c
index 883a66e76638..841eff3f6392
On Sun, 2019-12-01 at 22:45 -0800, Ram Pai wrote:
> @@ -206,8 +224,7 @@ static int tce_buildmulti_pSeriesLP(struct iommu_table
> *tbl, long tcenum,
> * from iommu_alloc{,_sg}()
> */
> if (!tcep) {
> - tcep = (__be64 *)__get_free_page(GFP_ATOMIC);
> -
On Wed, 2019-11-27 at 17:40 +0100, Paolo Bonzini wrote:
> > diff --git a/arch/powerpc/kvm/book3s_64_vio.c
> > b/arch/powerpc/kvm/book3s_64_vio.c
> > index 5834db0a54c6..a402ead833b6 100644
> > --- a/arch/powerpc/kvm/book3s_64_vio.c
> > +++ b/arch/powerpc/kvm/book3s_64_vio.c
> > @@ -316,14 +316,13
On Thu, 2019-11-28 at 09:57 +1100, Paul Mackerras wrote:
> There isn't a potential use-after-free here. We are relying on the
> property that the release function (kvm_vm_release) cannot be called
> in parallel with this function. The reason is that this function
>
On Wed, 2019-11-27 at 17:40 +0100, Paolo Bonzini wrote:
> >
> >if (ret >= 0)
> >list_add_rcu(>list, >arch.spapr_tce_tables);
> > - else
> > - kvm_put_kvm(kvm);
> >
> >mutex_unlock(>lock);
> >
> >if (ret >= 0)
> >
Result of Travis-CI testing the change:
https://travis-ci.org/LeoBras/linux-ppc/builds/617712012
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code, relying
more in the contents of kvm struct.
Signed-off-by: Leonardo Bras
---
arch/powerpc/kvm/booke.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index be9a45874194..fd7bdb4f8f87 100644
--- a/arch/powerpc/kvm/booke.c
code, relying
more in the contents of kvm struct.
Signed-off-by: Leonardo Bras
---
arch/powerpc/kvm/book3s_64_mmu_hv.c | 4 ++--
arch/powerpc/kvm/book3s_64_vio.c| 10 ++
arch/powerpc/kvm/book3s_hv.c| 10 +-
3 files changed, 13 insertions(+), 11 deletions(-)
diff --git
le 'use after free' on kvm_vm_ioctl_create_spapr_tce
- Fixes undeclared variable error
Leonardo Bras (2):
powerpc/kvm/book3s: Replace current->mm by kvm->mm
powerpc/kvm/book3e: Replace current->mm by kvm->mm
arch/powerpc/kvm/book3s_64_mmu_hv.c | 4 ++--
arch/powerpc/kvm/book3s_64_vio.c| 1
Fixes a possible 'use after free' of kvm variable.
It does use mutex_unlock(>lock) after possible freeing a variable
with kvm_put_kvm(kvm).
Signed-off-by: Leonardo Bras
---
arch/powerpc/kvm/book3s_64_vio.c | 3 +--
virt/kvm/kvm_main.c | 8
2 files changed, 5 inserti
On Thu, 2019-11-14 at 15:43 -0300, Leonardo Bras wrote:
> > If the kvm_put_kvm() you've moved actually caused the last
> > reference
> > to
> > be dropped that would mean that our caller had passed us a kvm
> > struct
> > without holding a reference to it, and t
On Tue, 2019-11-12 at 15:57 +1100, Michael Ellerman wrote:
> Hi Leonardo,
Hello Micheal, thanks for the feedback!
>
> Leonardo Bras writes:
> > Fixes a possible 'use after free' of kvm variable in
> > kvm_vm_ioctl_create_spapr_tce, where it does a mutex_unlock(
On Thu, 2019-11-14 at 20:07 +1100, Michael Ellerman wrote:
> On Fri, 2019-08-02 at 13:39:15 UTC, Leonardo Bras wrote:
> > Changes the return variable to bool (as the return value) and
> > avoids doing a ternary operation before returning.
> >
> > Signed-off-by: Leonard
code, relying
more in the contents of kvm struct.
Signed-off-by: Leonardo Bras
---
arch/powerpc/kvm/booke.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index be9a45874194..fd7bdb4f8f87 100644
--- a/arch/powerpc/kvm/booke.c
code, relying
more in the contents of kvm struct.
Signed-off-by: Leonardo Bras
---
arch/powerpc/kvm/book3s_64_mmu_hv.c | 10 +-
arch/powerpc/kvm/book3s_64_vio.c| 10 ++
arch/powerpc/kvm/book3s_hv.c| 10 +-
3 files changed, 16 insertions(+), 14 deletions(-)
'use after free' on kvm_vm_ioctl_create_spapr_tce
- Fixes undeclared variable error
Build test:
- https://travis-ci.org/LeoBras/linux-ppc/builds/608807573
Leonardo Bras (4):
powerpc/kvm/book3s: Fixes possible 'use after release' of kvm
powerpc/kvm/book3s: Replace current->mm by kvm->mm
code, relying
more in the contents of kvm struct.
Signed-off-by: Leonardo Bras
---
arch/powerpc/kvm/e500_mmu_host.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/kvm/e500_mmu_host.c b/arch/powerpc/kvm/e500_mmu_host.c
index 321db0fdb9db..425d13806645 100644
Fixes a possible 'use after free' of kvm variable in
kvm_vm_ioctl_create_spapr_tce, where it does a mutex_unlock(>lock)
after a kvm_put_kvm(kvm).
Signed-off-by: Leonardo Bras
---
arch/powerpc/kvm/book3s_64_vio.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/arch/powe
On Fri, 2019-10-04 at 13:28 +0200, Peter Zijlstra wrote:
> > Could you please explain it?
> > I mean, why this breaks tmpfs-thp?
> > Also, why mm_cpumask() is also broken?
>
> Because shared pages are not bound by a mm; or does it not share the thp
> state between mappings?
By what I could
On Tue, 2019-10-08 at 17:43 +, Christopher Lameter wrote:
> On Tue, 8 Oct 2019, Leonardo Bras wrote:
>
> > > You are creating contention on a single exclusive cacheline. Doesnt this
> > > defeat the whole purpose of the lockless page table walk? Use mmap_sem or
> &
On Tue, 2019-10-08 at 15:11 +, Christopher Lameter wrote:
>
> On Wed, 2 Oct 2019, Leonardo Bras wrote:
>
> > +
> > +inline unsigned long __begin_lockless_pgtbl_walk(struct mm_struct *mm,
> > +bool disable_irq)
> >
On Thu, 2019-10-03 at 13:49 -0700, John Hubbard wrote:
> Yes. And to clarify, I was assuming that the changes to mm/gup.c were
> required in order to accomplish your goals. Given that assumption, I
> wanted the generic code to be "proper", and that's what that feedback
> is about.
You assumed
Hello Peter, thanks for the feedback!
On Thu, 2019-10-03 at 13:51 +0200, Peter Zijlstra wrote:
> On Thu, Oct 03, 2019 at 09:11:45AM +0200, Peter Zijlstra wrote:
> > On Wed, Oct 02, 2019 at 10:33:15PM -0300, Leonardo Bras wrote:
> > > diff --git a/include/asm-generic/pgtab
On Thu, 2019-10-03 at 09:44 +0200, Peter Zijlstra wrote:
> This shouldn't be a user visible option at all. Either the arch needs
> it and selects it or not.
You are right. I will do that on v6.
Thanks for the feedback!
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Hello Peter, thanks for the feedback!
On Thu, 2019-10-03 at 09:29 +0200, Peter Zijlstra wrote:
> On Wed, Oct 02, 2019 at 10:33:14PM -0300, Leonardo Bras wrote:
> > If a process (qemu) with a lot of CPUs (128) try to munmap() a large
> > chunk of memory (496GB) mapped with THP, it t
On Thu, 2019-10-03 at 16:04 -0300, Leonardo Bras wrote:
> On Wed, 2019-10-02 at 22:08 -0400, Qian Cai wrote:
> > Can’t this name and all those new *lockless* function names be shorter?
> > There are many functions name with *_locked, so how about dropping
> >
On Wed, 2019-10-02 at 22:08 -0400, Qian Cai wrote:
> Can’t this name and all those new *lockless* function names be shorter?
> There are many functions name with *_locked, so how about dropping
> lockless at all, i.e., PAGE_TABLE_WALK_TRACKING blah blah?
Thanks for the feedback!
Well, in this
Adds config option LOCKLESS_PAGE_TABLE_WALK_TRACKING to make possible
enabling tracking lockless pagetable walks directly from kernel config.
Signed-off-by: Leonardo Bras
---
mm/Kconfig | 11 +++
1 file changed, 11 insertions(+)
diff --git a/mm/Kconfig b/mm/Kconfig
index a5dae9a7eb51
lose meaning now it's not directly passed to local_irq_* functions.
Signed-off-by: Leonardo Bras
---
arch/powerpc/perf/callchain.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/perf/callchain.c b/arch/powerpc/perf/callchain.c
index c84bbd4298a0..43e49d8be344
Skips slow part of serialize_against_pte_lookup if there is no running
lockless pagetable walk.
Signed-off-by: Leonardo Bras
---
arch/powerpc/mm/book3s64/pgtable.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/mm/book3s64/pgtable.c
b/arch/powerpc/mm
to
end_lockless_pgtbl_walk() to mimic the effect of local_irq_enable().
Signed-off-by: Leonardo Bras
---
arch/powerpc/kvm/book3s_64_mmu_hv.c| 6 ++---
arch/powerpc/kvm/book3s_64_mmu_radix.c | 34 +++---
arch/powerpc/kvm/book3s_64_vio_hv.c| 7 +-
3 files changed, 40 insertions(+), 7
-by: Leonardo Bras
---
arch/powerpc/kvm/book3s_hv_nested.c | 22 ++--
arch/powerpc/kvm/book3s_hv_rm_mmu.c | 32 -
2 files changed, 38 insertions(+), 16 deletions(-)
diff --git a/arch/powerpc/kvm/book3s_hv_nested.c
b/arch/powerpc/kvm/book3s_hv_nested.c
index
}_lockless_pgtbl_walk,
so there is no need to repeat it here.
Variable that saves the irq mask was renamed from flags to irq_mask so it
doesn't lose meaning now it's not directly passed to local_irq_* functions.
Signed-off-by: Leonardo Bras
---
arch/powerpc/kvm/e500_mmu_host.c | 9 +
1 file changed, 5
.
local_irq_{save,restore} is already inside {begin,end}_lockless_pgtbl_walk,
so there is no need to repeat it here.
Variable that saves the irq mask was renamed from flags to irq_mask so it
doesn't lose meaning now it's not directly passed to local_irq_* functions.
Signed-off-by: Leonardo Bras
---
arch
Applies the counting-based method for monitoring lockless pgtable walks on
addr_to_pfn().
local_irq_{save,restore} is already inside {begin,end}_lockless_pgtbl_walk,
so there is no need to repeat it here.
Signed-off-by: Leonardo Bras
---
arch/powerpc/kernel/mce_power.c | 6 +++---
1 file
what was already needed to lockless pagetable walks
(disabling interrupt). A memory barrier was also added just to make sure
there is no speculative read outside the interrupt disabled area.
Signed-off-by: Leonardo Bras
---
include/asm-generic/pgtable.h | 58
alk()
Fixed behavior of decrementing before last ptep was used
Link: http://patchwork.ozlabs.org/patch/1163093/
Leonardo Bras (11):
asm-generic/pgtable: Adds generic functions to monitor lockless
pgtable walks
powerpc/mm: Adds counting method to monitor lockless pgtable walks
mm/gup: Appl
to repeat it here.
Signed-off-by: Leonardo Bras
---
mm/gup.c | 10 +-
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/mm/gup.c b/mm/gup.c
index 23a9f9c9d377..52e53b4f39d8 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2319,7 +2319,7 @@ int __get_user_pages_fast(unsigned long start
read outside the interrupt disabled area.
Signed-off-by: Leonardo Bras
---
arch/powerpc/include/asm/book3s/64/pgtable.h | 9 ++
arch/powerpc/mm/book3s64/pgtable.c | 117 +++
2 files changed, 126 insertions(+)
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h
On Tue, 2019-10-01 at 12:04 -0700, John Hubbard wrote:
> On 10/1/19 10:56 AM, Leonardo Bras wrote:
> > On Mon, 2019-09-30 at 14:51 -0700, John Hubbard wrote:
> > > On 9/27/19 4:40 PM, Leonardo Bras wrote:
> ...
> > > > diff --git a/mm/gup.c b/mm/gup.c
> &g
On Mon, 2019-09-30 at 14:47 -0700, John Hubbard wrote:
> On 9/30/19 11:42 AM, Leonardo Bras wrote:
> > On Mon, 2019-09-30 at 10:57 -0700, John Hubbard wrote:
> > > > As I told before, there are cases where this function is called from
> > > > 'real mode' in po
On Mon, 2019-09-30 at 14:51 -0700, John Hubbard wrote:
> On 9/27/19 4:40 PM, Leonardo Bras wrote:
> > As decribed, gup_pgd_range is a lockless pagetable walk. So, in order to
> > monitor against THP split/collapse with the couting method, it's necessary
>
> s/couting/counti
On Mon, 2019-09-30 at 10:57 -0700, John Hubbard wrote:
> > As I told before, there are cases where this function is called from
> > 'real mode' in powerpc, which doesn't disable irqs and may have a
> > tricky behavior if we do. So, encapsulate the irq disable in this
> > function can be a bad
one or more of the PPC Kconfig files should select
> LOCKLESS_PAGE_TABLE_WALK_TRACKING.)
The way it works today is defining it on platform pgtable.h. I agree
that using Kconfig may be a better solution that can make this config
more visible to disable/enable.
Thanks for the feedback,
Leonardo Bras
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On Mon, 2019-09-30 at 14:09 +0300, Kirill A. Shutemov wrote:
> On Fri, Sep 27, 2019 at 08:40:00PM -0300, Leonardo Bras wrote:
> > As decribed, gup_pgd_range is a lockless pagetable walk. So, in order to
> ^ typo
>
Fixed, thanks!
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Skips slow part of serialize_against_pte_lookup if there is no running
lockless pagetable walk.
Signed-off-by: Leonardo Bras
---
arch/powerpc/mm/book3s64/pgtable.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/mm/book3s64/pgtable.c
b/arch/powerpc/mm
Enables count-based monitoring method for lockless pagetable walks on
PowerPC book3s_64.
Other architectures/platforms fallback to using generic dummy functions.
Signed-off-by: Leonardo Bras
---
arch/powerpc/include/asm/book3s/64/pgtable.h | 5 +
1 file changed, 5 insertions(+)
diff --git
+ MSR_EE = 0.
Signed-off-by: Leonardo Bras
---
arch/powerpc/kvm/book3s_64_mmu_hv.c| 2 ++
arch/powerpc/kvm/book3s_64_mmu_radix.c | 30 ++
arch/powerpc/kvm/book3s_64_vio_hv.c| 3 +++
3 files changed, 35 insertions(+)
diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c
+ MSR_EE = 0
kvmppc_do_h_enter: Fixes where local_irq_restore() must be placed (after
the last usage of ptep).
Signed-off-by: Leonardo Bras
---
arch/powerpc/kvm/book3s_hv_nested.c | 22 --
arch/powerpc/kvm/book3s_hv_rm_mmu.c | 18 ++
2 files changed, 34 insertions
Applies the counting-based method for monitoring lockless pgtable walks on
kvmppc_e500_shadow_map().
Fixes the place where local_irq_restore() is called: previously, if ptep
was NULL, local_irq_restore() would never be called.
Signed-off-by: Leonardo Bras
---
arch/powerpc/kvm/e500_mmu_host.c
-off-by: Leonardo Bras
---
arch/powerpc/mm/book3s64/hash_tlb.c | 2 ++
arch/powerpc/mm/book3s64/hash_utils.c | 12 +++-
2 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/mm/book3s64/hash_tlb.c
b/arch/powerpc/mm/book3s64/hash_tlb.c
index 4a70d8dd39cd
Applies the counting-based method for monitoring lockless pgtable walks on
addr_to_pfn().
Signed-off-by: Leonardo Bras
---
arch/powerpc/kernel/mce_power.c | 13 ++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/kernel/mce_power.c b/arch/powerpc/kernel
Applies the counting-based method for monitoring lockless pgtable walks on
read_user_stack_slow.
Signed-off-by: Leonardo Bras
---
arch/powerpc/perf/callchain.c | 5 -
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/perf/callchain.c b/arch/powerpc/perf/callchain.c
this method.
Signed-off-by: Leonardo Bras
---
mm/gup.c | 8
1 file changed, 8 insertions(+)
diff --git a/mm/gup.c b/mm/gup.c
index 98f13ab37bac..7105c829cf44 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2325,6 +2325,7 @@ static bool gup_fast_permitted(unsigned long start,
unsigned long end)
int
approach, that
counts the number of lockless pagetable walks happening on the process.
Given that there are lockless pagetable walks on generic code, it's
necessary to create dummy functions for archs that won't use the approach.
Signed-off-by: Leonardo Bras
---
include/asm-generic/pgtable.h
ons *_lockless_pgtbl_walk()
Fixed behavior of decrementing before last ptep was used
Link: http://patchwork.ozlabs.org/patch/1163093/
Leonardo Bras (11):
powerpc/mm: Adds counting method to monitor lockless pgtable walks
asm-generic/pgtable: Adds dummy functions to monitor lockless pgta
end_lockless_pgtbl_walk(mm)
Insert after the end of any lockless pgtable walk
(Mostly after the ptep is last used)
running_lockless_pgtbl_walk(mm)
Returns the number of lockless pgtable walks running
Signed-off-by: Leonardo Bras
---
arch/powerpc/include/asm/book3s/64/mmu.h | 3
On Fri, 2019-09-27 at 11:46 -0300, Leonardo Bras wrote:
> I am not sure if it would be ok to use irq_{save,restore} in real mode,
> I will do some more reading of the docs before addressing this.
It looks like it's unsafe to merge irq_{save,restore} in
{start,end}_lockless_pgtbl_walk(
se, that the
> caller can tolerate that.
I am not sure if it would be ok to use irq_{save,restore} in real mode,
I will do some more reading of the docs before addressing this.
>
> 4. Please see the v2 series for any other details I've missed.
>
> thanks,
> --
> John Hub
Skips slow part of serialize_against_pte_lookup if there is no running
lockless pagetable walk.
Signed-off-by: Leonardo Bras
---
arch/powerpc/mm/book3s64/pgtable.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/mm/book3s64/pgtable.c
b/arch/powerpc/mm
Applies the counting-based method for monitoring all book3s_64-related
functions that do lockless pagetable walks.
Signed-off-by: Leonardo Bras
---
arch/powerpc/kvm/book3s_64_mmu_hv.c| 2 ++
arch/powerpc/kvm/book3s_64_mmu_radix.c | 20 ++--
arch/powerpc/kvm
Enables count-based monitoring method for lockless pagetable walks on
PowerPC book3s_64.
Other architectures/platforms fallback to using generic dummy functions.
Signed-off-by: Leonardo Bras
---
arch/powerpc/include/asm/book3s/64/pgtable.h | 5 +
1 file changed, 5 insertions(+)
diff --git
Applies the counting-based method for monitoring lockless pgtable walks on
kvmppc_e500_shadow_map().
Signed-off-by: Leonardo Bras
---
arch/powerpc/kvm/e500_mmu_host.c | 4
1 file changed, 4 insertions(+)
diff --git a/arch/powerpc/kvm/e500_mmu_host.c b/arch/powerpc/kvm/e500_mmu_host.c
Applies the counting-based method for monitoring all book3s_hv related
functions that do lockless pagetable walks.
Signed-off-by: Leonardo Bras
---
arch/powerpc/kvm/book3s_hv_nested.c | 8
arch/powerpc/kvm/book3s_hv_rm_mmu.c | 9 -
2 files changed, 16 insertions(+), 1 deletion
Applies the counting-based method for monitoring lockless pgtable walks on
read_user_stack_slow.
Signed-off-by: Leonardo Bras
---
arch/powerpc/perf/callchain.c | 5 -
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/perf/callchain.c b/arch/powerpc/perf/callchain.c
Applies the counting-based method for monitoring all hash-related functions
that do lockless pagetable walks.
Signed-off-by: Leonardo Bras
---
arch/powerpc/mm/book3s64/hash_tlb.c | 2 ++
arch/powerpc/mm/book3s64/hash_utils.c | 7 +++
2 files changed, 9 insertions(+)
diff --git a/arch
this method.
Signed-off-by: Leonardo Bras
---
mm/gup.c | 8
1 file changed, 8 insertions(+)
diff --git a/mm/gup.c b/mm/gup.c
index 98f13ab37bac..eabd6fd15cf8 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2325,6 +2325,7 @@ static bool gup_fast_permitted(unsigned long start,
unsigned long end)
int
approach, that
counts the number of lockless pagetable walks happening on the process.
Given that there are lockless pagetable walks on generic code, it's
necessary to create dummy functions for archs that won't use the approach.
Signed-off-by: Leonardo Bras
---
include/asm-generic/pgtable.h
Applies the counting-based method for monitoring lockless pgtable walks on
addr_to_pfn().
Signed-off-by: Leonardo Bras
---
arch/powerpc/kernel/mce_power.c | 13 ++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/kernel/mce_power.c b/arch/powerpc/kernel
end_lockless_pgtbl_walk(mm)
Insert after the end of any lockless pgtable walk
(Mostly after the ptep is last used)
running_lockless_pgtbl_walk(mm)
Returns the number of lockless pgtable walks running
Signed-off-by: Leonardo Bras
---
arch/powerpc/include/asm/book3s/64/mmu.h | 3
ges since v1:
Isolated atomic operations in functions *_lockless_pgtbl_walk()
Fixed behavior of decrementing before last ptep was used
Link: http://patchwork.ozlabs.org/patch/1163093/
Leonardo Bras (11):
powerpc/mm: Adds counting method to monitor lockless pgtable walks
asm-generic/pgta
before, I think it would
be wiser to send a v3 and gather feedback while I keep trying to
understand how it works, and if it needs additional memory barrier here.
Thanks!
Leonardo Bras
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John Hubbard writes:
> Also, which tree do these patches apply to, please?
I will send a v3 that applies directly over v5.3, and make sure to
include mm mailing list.
Thanks!
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I have done a very simple comparison with gdb disassemble:
By applying this patch, there was a reduction in the function size from
882 to 878 instructions.
(It's a resend, due to not having all the correct lists on my previous
mail)
On Mon, 2019-09-23 at 18:30 -0300, Leonardo Bras wrote
Reduces the number of calls to get_current() in order to get the value of
current->mm by doing it once and storing the value, since it is not
supposed to change inside the same process).
Signed-off-by: Leonardo Bras
---
Re-sending to all lists involved. (I missed kvm ones)
arch/powerpc/
On Mon, 2019-09-23 at 13:27 -0700, John Hubbard wrote:
> I'd also like a second opinion from the "core" -mm maintainers, but it seems
> like
> there is now too much code around the gup_pgd_range() call. Especially since
> there
> are two places where it's called--did you forget the other one in
rged fast. But since I got no feedback, it was not merged and the
present patchset became broken. :(
But I will rebase v3 on top of plain v5.3.
Thanks,
Leonardo Bras
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On Mon, 2019-09-23 at 13:42 -0700, John Hubbard wrote:
> Somewhere, there should be a short comment that explains how the following
> functions
> are meant to be used. And it should include the interaction with irqs, so
> maybe
> if you end up adding that combined wrapper function that does
Thanks for the feedback,
On Mon, 2019-09-23 at 13:39 -0700, John Hubbard wrote:
> Please remember to include linux-mm if there is a v2.
Sure, I will include on v3.
> Nit: seems like it would be nicer to just put it all in one place, and use
> positive logic, and also I think people normally
On Mon, 2019-09-23 at 12:58 -0700, John Hubbard wrote:
>
> CPU 0CPU 1
> -- --
>READ(pte) (re-ordered at run time)
>atomic_inc(val) (no run-time memory barrier!)
>
On Mon, 2019-09-23 at 11:14 -0700, John Hubbard wrote:
> On 9/23/19 10:25 AM, Leonardo Bras wrote:
> [...]
> That part is all fine, but there are no run-time memory barriers in the
> atomic_inc() and atomic_dec() additions, which means that this is not
> safe, because memory oper
On Mon, 2019-09-23 at 15:35 -0300, Leonardo Bras wrote:
> Could you please provide feedback on this patch?
I have done a very simple comparison with gcc disassemble:
By applying this patch, there was a reduction in the function size from
882 to 878 instructions.
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code, relying
more in the contents of kvm struct.
Signed-off-by: Leonardo Bras
---
arch/powerpc/kvm/e500_mmu_host.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/kvm/e500_mmu_host.c b/arch/powerpc/kvm/e500_mmu_host.c
index 321db0fdb9db..425d13806645 100644
code, relying
more in the contents of kvm struct.
Signed-off-by: Leonardo Bras
---
arch/powerpc/kvm/booke.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index be9a45874194..383108263af5 100644
--- a/arch/powerpc/kvm/booke.c
code, relying
more in the contents of kvm struct.
Signed-off-by: Leonardo Bras
---
arch/powerpc/kvm/book3s_64_mmu_hv.c | 4 ++--
arch/powerpc/kvm/book3s_64_vio.c| 6 +++---
arch/powerpc/kvm/book3s_hv.c| 10 +-
3 files changed, 10 insertions(+), 10 deletions(-)
diff --git
rn -EIO;
So this change would be safe.
I split the changes in 3 patches, so it would be easier to read
and reject separated parts. If decided that squashing is better,
I see no problem doing that.
Best regards,
Leonardo Bras (3):
powerpc/kvm/book3s: Replace current->mm by kvm->mm
powerpc/k
On Thu, 2019-09-19 at 23:47 -0300, Leonardo Bras wrote:
> Hello Paul,
> I sent this patch, but I have a question:
>
> > + mm = current->mm;
>
> Here, current->mm is not always the same as kvm->mm?
> Thanks
I have contacted Paul, who said it is eq
ollapse wait for gup_pgd_range() completion in every cpu before
continuing. (here happens the lock)
(As told before, every gup_pgd_range() that occurs after it uses a
updated pmd, so no problem.)
I am sure other archs may have a similar mechanism using
local_irq_{disable,enable}.
Did it answer your quest
On Fri, 2019-09-20 at 13:11 -0700, John Hubbard wrote:
> On 9/20/19 12:50 PM, Leonardo Bras wrote:
> > Skips slow part of serialize_against_pte_lookup if there is no running
> > lockless pagetable walk.
> >
> > Signed-off-by: Leonardo Bras
> > ---
> >
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