| Message ID | 20180914153056.3644-6-npiggin@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 5141c182d75b4004c41ac2dc5af081b457b3e8cb |
| Headers | show |
| Series | SLB miss conversion to C, and SLB optimisations | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | next/apply_patch Successfully applied |
| snowpatch_ozlabs/checkpatch | success | Test checkpatch on branch next |
Nicholas Piggin <npiggin@gmail.com> writes: > The SLBIA IH=1 hint will remove all non-zero SLBEs, but only > invalidate ERAT entries associated with a class value of 1, for > processors that support the hint (e.g., POWER6 and newer), which > Linux assigns to user addresses. > > This prevents kernel ERAT entries from being invalidated when > context switchig (if the thread faulted in more than 8 user SLBEs). how about renaming stuff to indicate kernel ERAT entries are kept? something like slb_flush_and_rebolt_user()? > > Signed-off-by: Nicholas Piggin <npiggin@gmail.com> > --- > arch/powerpc/mm/slb.c | 38 +++++++++++++++++++++++--------------- > 1 file changed, 23 insertions(+), 15 deletions(-) > > diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c > index a5e58f11d676..03fa1c663ccf 100644 > --- a/arch/powerpc/mm/slb.c > +++ b/arch/powerpc/mm/slb.c > @@ -128,13 +128,21 @@ void slb_flush_all_realmode(void) > asm volatile("slbmte %0,%0; slbia" : : "r" (0)); > } > > -static void __slb_flush_and_rebolt(void) > +void slb_flush_and_rebolt(void) > { > /* If you change this make sure you change SLB_NUM_BOLTED > * and PR KVM appropriately too. */ > unsigned long linear_llp, lflags; > unsigned long ksp_esid_data, ksp_vsid_data; > > + WARN_ON(!irqs_disabled()); > + > + /* > + * We can't take a PMU exception in the following code, so hard > + * disable interrupts. > + */ > + hard_irq_disable(); > + > linear_llp = mmu_psize_defs[mmu_linear_psize].sllp; > lflags = SLB_VSID_KERNEL | linear_llp; > > @@ -160,20 +168,7 @@ static void __slb_flush_and_rebolt(void) > :: "r"(ksp_vsid_data), > "r"(ksp_esid_data) > : "memory"); > -} > > -void slb_flush_and_rebolt(void) > -{ > - > - WARN_ON(!irqs_disabled()); > - > - /* > - * We can't take a PMU exception in the following code, so hard > - * disable interrupts. > - */ > - hard_irq_disable(); > - > - __slb_flush_and_rebolt(); > get_paca()->slb_cache_ptr = 0; > } > > @@ -248,7 +243,20 @@ void switch_slb(struct task_struct *tsk, struct mm_struct *mm) > > asm volatile("isync" : : : "memory"); > } else { > - __slb_flush_and_rebolt(); > + struct slb_shadow *p = get_slb_shadow(); > + unsigned long ksp_esid_data = > + be64_to_cpu(p->save_area[KSTACK_INDEX].esid); > + unsigned long ksp_vsid_data = > + be64_to_cpu(p->save_area[KSTACK_INDEX].vsid); > + > + asm volatile("isync\n" > + PPC_SLBIA(1) "\n" > + "slbmte %0,%1\n" > + "isync" > + :: "r"(ksp_vsid_data), > + "r"(ksp_esid_data)); > + > + asm volatile("isync" : : : "memory"); > } > > get_paca()->slb_cache_ptr = 0; > -- > 2.18.0
On Mon, 17 Sep 2018 11:38:35 +0530 "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> wrote: > Nicholas Piggin <npiggin@gmail.com> writes: > > > The SLBIA IH=1 hint will remove all non-zero SLBEs, but only > > invalidate ERAT entries associated with a class value of 1, for > > processors that support the hint (e.g., POWER6 and newer), which > > Linux assigns to user addresses. > > > > This prevents kernel ERAT entries from being invalidated when > > context switchig (if the thread faulted in more than 8 user SLBEs). > > > how about renaming stuff to indicate kernel ERAT entries are kept? > something like slb_flush_and_rebolt_user()? User mappings aren't bolted though. I consider rebolt to mean update the bolted kernel mappings when something has changed (like vmalloc segment update). That doesn't need to be done here, so I think this is okay. I can add a comment though. Thanks, Nick > > > > > Signed-off-by: Nicholas Piggin <npiggin@gmail.com> > > --- > > arch/powerpc/mm/slb.c | 38 +++++++++++++++++++++++--------------- > > 1 file changed, 23 insertions(+), 15 deletions(-) > > > > diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c > > index a5e58f11d676..03fa1c663ccf 100644 > > --- a/arch/powerpc/mm/slb.c > > +++ b/arch/powerpc/mm/slb.c > > @@ -128,13 +128,21 @@ void slb_flush_all_realmode(void) > > asm volatile("slbmte %0,%0; slbia" : : "r" (0)); > > } > > > > -static void __slb_flush_and_rebolt(void) > > +void slb_flush_and_rebolt(void) > > { > > /* If you change this make sure you change SLB_NUM_BOLTED > > * and PR KVM appropriately too. */ > > unsigned long linear_llp, lflags; > > unsigned long ksp_esid_data, ksp_vsid_data; > > > > + WARN_ON(!irqs_disabled()); > > + > > + /* > > + * We can't take a PMU exception in the following code, so hard > > + * disable interrupts. > > + */ > > + hard_irq_disable(); > > + > > linear_llp = mmu_psize_defs[mmu_linear_psize].sllp; > > lflags = SLB_VSID_KERNEL | linear_llp; > > > > @@ -160,20 +168,7 @@ static void __slb_flush_and_rebolt(void) > > :: "r"(ksp_vsid_data), > > "r"(ksp_esid_data) > > : "memory"); > > -} > > > > -void slb_flush_and_rebolt(void) > > -{ > > - > > - WARN_ON(!irqs_disabled()); > > - > > - /* > > - * We can't take a PMU exception in the following code, so hard > > - * disable interrupts. > > - */ > > - hard_irq_disable(); > > - > > - __slb_flush_and_rebolt(); > > get_paca()->slb_cache_ptr = 0; > > } > > > > @@ -248,7 +243,20 @@ void switch_slb(struct task_struct *tsk, struct mm_struct *mm) > > > > asm volatile("isync" : : : "memory"); > > } else { > > - __slb_flush_and_rebolt(); > > + struct slb_shadow *p = get_slb_shadow(); > > + unsigned long ksp_esid_data = > > + be64_to_cpu(p->save_area[KSTACK_INDEX].esid); > > + unsigned long ksp_vsid_data = > > + be64_to_cpu(p->save_area[KSTACK_INDEX].vsid); > > + > > + asm volatile("isync\n" > > + PPC_SLBIA(1) "\n" > > + "slbmte %0,%1\n" > > + "isync" > > + :: "r"(ksp_vsid_data), > > + "r"(ksp_esid_data)); > > + > > + asm volatile("isync" : : : "memory"); > > } > > > > get_paca()->slb_cache_ptr = 0; > > -- > > 2.18.0 >
diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c index a5e58f11d676..03fa1c663ccf 100644 --- a/arch/powerpc/mm/slb.c +++ b/arch/powerpc/mm/slb.c @@ -128,13 +128,21 @@ void slb_flush_all_realmode(void) asm volatile("slbmte %0,%0; slbia" : : "r" (0)); } -static void __slb_flush_and_rebolt(void) +void slb_flush_and_rebolt(void) { /* If you change this make sure you change SLB_NUM_BOLTED * and PR KVM appropriately too. */ unsigned long linear_llp, lflags; unsigned long ksp_esid_data, ksp_vsid_data; + WARN_ON(!irqs_disabled()); + + /* + * We can't take a PMU exception in the following code, so hard + * disable interrupts. + */ + hard_irq_disable(); + linear_llp = mmu_psize_defs[mmu_linear_psize].sllp; lflags = SLB_VSID_KERNEL | linear_llp; @@ -160,20 +168,7 @@ static void __slb_flush_and_rebolt(void) :: "r"(ksp_vsid_data), "r"(ksp_esid_data) : "memory"); -} -void slb_flush_and_rebolt(void) -{ - - WARN_ON(!irqs_disabled()); - - /* - * We can't take a PMU exception in the following code, so hard - * disable interrupts. - */ - hard_irq_disable(); - - __slb_flush_and_rebolt(); get_paca()->slb_cache_ptr = 0; } @@ -248,7 +243,20 @@ void switch_slb(struct task_struct *tsk, struct mm_struct *mm) asm volatile("isync" : : : "memory"); } else { - __slb_flush_and_rebolt(); + struct slb_shadow *p = get_slb_shadow(); + unsigned long ksp_esid_data = + be64_to_cpu(p->save_area[KSTACK_INDEX].esid); + unsigned long ksp_vsid_data = + be64_to_cpu(p->save_area[KSTACK_INDEX].vsid); + + asm volatile("isync\n" + PPC_SLBIA(1) "\n" + "slbmte %0,%1\n" + "isync" + :: "r"(ksp_vsid_data), + "r"(ksp_esid_data)); + + asm volatile("isync" : : : "memory"); } get_paca()->slb_cache_ptr = 0;
The SLBIA IH=1 hint will remove all non-zero SLBEs, but only invalidate ERAT entries associated with a class value of 1, for processors that support the hint (e.g., POWER6 and newer), which Linux assigns to user addresses. This prevents kernel ERAT entries from being invalidated when context switchig (if the thread faulted in more than 8 user SLBEs). Signed-off-by: Nicholas Piggin <npiggin@gmail.com> --- arch/powerpc/mm/slb.c | 38 +++++++++++++++++++++++--------------- 1 file changed, 23 insertions(+), 15 deletions(-)