| Message ID | 1389593064-32664-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Benjamin Herrenschmidt |
| Headers | show |
On Mon, 2014-01-13 at 11:34 +0530, Aneesh Kumar K.V wrote: > From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> > > This patch fix the below crash Andrea, can you ack the generic bit please ? Thanks ! Cheers, Ben. > NIP [c00000000004cee4] .__hash_page_thp+0x2a4/0x440 > LR [c0000000000439ac] .hash_page+0x18c/0x5e0 > ... > Call Trace: > [c000000736103c40] [00001ffffb000000] 0x1ffffb000000(unreliable) > [437908.479693] [c000000736103d50] [c0000000000439ac] .hash_page+0x18c/0x5e0 > [437908.479699] [c000000736103e30] [c00000000000924c] .do_hash_page+0x4c/0x58 > > On ppc64 we use the pgtable for storing the hpte slot information and > store address to the pgtable at a constant offset (PTRS_PER_PMD) from > pmd. On mremap, when we switch the pmd, we need to withdraw and deposit > the pgtable again, so that we find the pgtable at PTRS_PER_PMD offset > from new pmd. > > We also want to move the withdraw and deposit before the set_pmd so > that, when page fault find the pmd as trans huge we can be sure that > pgtable can be located at the offset. > > Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> > --- > Changes from V3: > * Drop "powerpc: mm: Move ppc64 page table range definitions to separate header"" patch > > arch/powerpc/include/asm/pgtable-ppc64.h | 14 ++++++++++++++ > include/asm-generic/pgtable.h | 12 ++++++++++++ > mm/huge_memory.c | 14 +++++--------- > 3 files changed, 31 insertions(+), 9 deletions(-) > > diff --git a/arch/powerpc/include/asm/pgtable-ppc64.h b/arch/powerpc/include/asm/pgtable-ppc64.h > index 4a191c472867..d27960c89a71 100644 > --- a/arch/powerpc/include/asm/pgtable-ppc64.h > +++ b/arch/powerpc/include/asm/pgtable-ppc64.h > @@ -558,5 +558,19 @@ extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp); > #define __HAVE_ARCH_PMDP_INVALIDATE > extern void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address, > pmd_t *pmdp); > + > +#define pmd_move_must_withdraw pmd_move_must_withdraw > +typedef struct spinlock spinlock_t; > +static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, > + spinlock_t *old_pmd_ptl) > +{ > + /* > + * Archs like ppc64 use pgtable to store per pmd > + * specific information. So when we switch the pmd, > + * we should also withdraw and deposit the pgtable > + */ > + return true; > +} > + > #endif /* __ASSEMBLY__ */ > #endif /* _ASM_POWERPC_PGTABLE_PPC64_H_ */ > diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h > index db0923458940..8e4f41d9af4d 100644 > --- a/include/asm-generic/pgtable.h > +++ b/include/asm-generic/pgtable.h > @@ -558,6 +558,18 @@ static inline pmd_t pmd_read_atomic(pmd_t *pmdp) > } > #endif > > +#ifndef pmd_move_must_withdraw > +static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, > + spinlock_t *old_pmd_ptl) > +{ > + /* > + * With split pmd lock we also need to move preallocated > + * PTE page table if new_pmd is on different PMD page table. > + */ > + return new_pmd_ptl != old_pmd_ptl; > +} > +#endif > + > /* > * This function is meant to be used by sites walking pagetables with > * the mmap_sem hold in read mode to protect against MADV_DONTNEED and > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 95d1acb0f3d2..5d80c53b87cb 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -1502,19 +1502,15 @@ int move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma, > spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); > pmd = pmdp_get_and_clear(mm, old_addr, old_pmd); > VM_BUG_ON(!pmd_none(*new_pmd)); > - set_pmd_at(mm, new_addr, new_pmd, pmd_mksoft_dirty(pmd)); > - if (new_ptl != old_ptl) { > - pgtable_t pgtable; > > - /* > - * Move preallocated PTE page table if new_pmd is on > - * different PMD page table. > - */ > + if (pmd_move_must_withdraw(new_ptl, old_ptl)) { > + pgtable_t pgtable; > pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); > pgtable_trans_huge_deposit(mm, new_pmd, pgtable); > - > - spin_unlock(new_ptl); > } > + set_pmd_at(mm, new_addr, new_pmd, pmd_mksoft_dirty(pmd)); > + if (new_ptl != old_ptl) > + spin_unlock(new_ptl); > spin_unlock(old_ptl); > } > out:
Benjamin Herrenschmidt <benh@kernel.crashing.org> writes: > On Mon, 2014-01-13 at 11:34 +0530, Aneesh Kumar K.V wrote: >> From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> >> >> This patch fix the below crash > > Andrea, can you ack the generic bit please ? > > Thanks ! Kirill A. Shutemov did ack an earlier version http://article.gmane.org/gmane.linux.kernel.mm/111368 -aneesh
On Mon, 2014-01-13 at 15:16 +0530, Aneesh Kumar K.V wrote: > Benjamin Herrenschmidt <benh@kernel.crashing.org> writes: > > > On Mon, 2014-01-13 at 11:34 +0530, Aneesh Kumar K.V wrote: > >> From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> > >> > >> This patch fix the below crash > > > > Andrea, can you ack the generic bit please ? > > > > Thanks ! > > Kirill A. Shutemov did ack an earlier version > > http://article.gmane.org/gmane.linux.kernel.mm/111368 Doesn't help. If I'm going to send Linus a patch with a generic change like that, I need an ack of that exact version of the change by a senior mm person such as Andrea. Cheers, Ben.
On Mon, Jan 13, 2014 at 11:34:24AM +0530, Aneesh Kumar K.V wrote: > From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> > > This patch fix the below crash > > NIP [c00000000004cee4] .__hash_page_thp+0x2a4/0x440 > LR [c0000000000439ac] .hash_page+0x18c/0x5e0 > ... > Call Trace: > [c000000736103c40] [00001ffffb000000] 0x1ffffb000000(unreliable) > [437908.479693] [c000000736103d50] [c0000000000439ac] .hash_page+0x18c/0x5e0 > [437908.479699] [c000000736103e30] [c00000000000924c] .do_hash_page+0x4c/0x58 > > On ppc64 we use the pgtable for storing the hpte slot information and > store address to the pgtable at a constant offset (PTRS_PER_PMD) from > pmd. On mremap, when we switch the pmd, we need to withdraw and deposit > the pgtable again, so that we find the pgtable at PTRS_PER_PMD offset > from new pmd. > > We also want to move the withdraw and deposit before the set_pmd so > that, when page fault find the pmd as trans huge we can be sure that > pgtable can be located at the offset. > > Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
diff --git a/arch/powerpc/include/asm/pgtable-ppc64.h b/arch/powerpc/include/asm/pgtable-ppc64.h index 4a191c472867..d27960c89a71 100644 --- a/arch/powerpc/include/asm/pgtable-ppc64.h +++ b/arch/powerpc/include/asm/pgtable-ppc64.h @@ -558,5 +558,19 @@ extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp); #define __HAVE_ARCH_PMDP_INVALIDATE extern void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address, pmd_t *pmdp); + +#define pmd_move_must_withdraw pmd_move_must_withdraw +typedef struct spinlock spinlock_t; +static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, + spinlock_t *old_pmd_ptl) +{ + /* + * Archs like ppc64 use pgtable to store per pmd + * specific information. So when we switch the pmd, + * we should also withdraw and deposit the pgtable + */ + return true; +} + #endif /* __ASSEMBLY__ */ #endif /* _ASM_POWERPC_PGTABLE_PPC64_H_ */ diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h index db0923458940..8e4f41d9af4d 100644 --- a/include/asm-generic/pgtable.h +++ b/include/asm-generic/pgtable.h @@ -558,6 +558,18 @@ static inline pmd_t pmd_read_atomic(pmd_t *pmdp) } #endif +#ifndef pmd_move_must_withdraw +static inline int pmd_move_must_withdraw(spinlock_t *new_pmd_ptl, + spinlock_t *old_pmd_ptl) +{ + /* + * With split pmd lock we also need to move preallocated + * PTE page table if new_pmd is on different PMD page table. + */ + return new_pmd_ptl != old_pmd_ptl; +} +#endif + /* * This function is meant to be used by sites walking pagetables with * the mmap_sem hold in read mode to protect against MADV_DONTNEED and diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 95d1acb0f3d2..5d80c53b87cb 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1502,19 +1502,15 @@ int move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma, spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); pmd = pmdp_get_and_clear(mm, old_addr, old_pmd); VM_BUG_ON(!pmd_none(*new_pmd)); - set_pmd_at(mm, new_addr, new_pmd, pmd_mksoft_dirty(pmd)); - if (new_ptl != old_ptl) { - pgtable_t pgtable; - /* - * Move preallocated PTE page table if new_pmd is on - * different PMD page table. - */ + if (pmd_move_must_withdraw(new_ptl, old_ptl)) { + pgtable_t pgtable; pgtable = pgtable_trans_huge_withdraw(mm, old_pmd); pgtable_trans_huge_deposit(mm, new_pmd, pgtable); - - spin_unlock(new_ptl); } + set_pmd_at(mm, new_addr, new_pmd, pmd_mksoft_dirty(pmd)); + if (new_ptl != old_ptl) + spin_unlock(new_ptl); spin_unlock(old_ptl); } out: