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Perf updates:

Browse source 
Core:
 
    - Better handling of page table leaves on archictectures which have
      architectures have non-pagetable aligned huge/large pages.  For such
      architectures a leaf can actually be part of a larger entry.
 
    - Prevent a deadlock vs. exec_update_mutex
 
  Architectures:
 
    - The related updates for page size calculation of leaf entries
 
    - The usual churn to support new CPUs
 
    - Small fixes and improvements all over the place
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Merge tag 'perf-core-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf updates from Thomas Gleixner:
 "Core:

   - Better handling of page table leaves on archictectures which have
     architectures have non-pagetable aligned huge/large pages. For such
     architectures a leaf can actually be part of a larger entry.

   - Prevent a deadlock vs exec_update_mutex

  Architectures:

   - The related updates for page size calculation of leaf entries

   - The usual churn to support new CPUs

   - Small fixes and improvements all over the place"

* tag 'perf-core-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
  perf/x86/intel: Add Tremont Topdown support
  uprobes/x86: Fix fall-through warnings for Clang
  perf/x86: Fix fall-through warnings for Clang
  kprobes/x86: Fix fall-through warnings for Clang
  perf/x86/intel/lbr: Fix the return type of get_lbr_cycles()
  perf/x86/intel: Fix rtm_abort_event encoding on Ice Lake
  x86/kprobes: Restore BTF if the single-stepping is cancelled
  perf: Break deadlock involving exec_update_mutex
  sparc64/mm: Implement pXX_leaf_size() support
  powerpc/8xx: Implement pXX_leaf_size() support
  arm64/mm: Implement pXX_leaf_size() support
  perf/core: Fix arch_perf_get_page_size()
  mm: Introduce pXX_leaf_size()
  mm/gup: Provide gup_get_pte() more generic
  perf/x86/intel: Add event constraint for CYCLE_ACTIVITY.STALLS_MEM_ANY
  perf/x86/intel/uncore: Add Rocket Lake support
  perf/x86/msr: Add Rocket Lake CPU support
  perf/x86/cstate: Add Rocket Lake CPU support
  perf/x86/intel: Add Rocket Lake CPU support
  perf,mm: Handle non-page-table-aligned hugetlbfs
  ...
This commit is contained in:
Linus Torvalds 2020-12-14 17:34:12 -08:00
commit 8a8ca83ec3
21 changed files with 349 additions and 108 deletions
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71
include/linux/pgtable.h
View file

@ -258,6 +258,61 @@ static inline pte_t ptep_get(pte_t *ptep)
}
#endif
#ifdef CONFIG_GUP_GET_PTE_LOW_HIGH
/*
* WARNING: only to be used in the get_user_pages_fast() implementation.
*
* With get_user_pages_fast(), we walk down the pagetables without taking any
* locks. For this we would like to load the pointers atomically, but sometimes
* that is not possible (e.g. without expensive cmpxchg8b on x86_32 PAE). What
* we do have is the guarantee that a PTE will only either go from not present
* to present, or present to not present or both -- it will not switch to a
* completely different present page without a TLB flush in between; something
* that we are blocking by holding interrupts off.
*
* Setting ptes from not present to present goes:
*
* ptep->pte_high = h;
* smp_wmb();
* ptep->pte_low = l;
*
* And present to not present goes:
*
* ptep->pte_low = 0;
* smp_wmb();
* ptep->pte_high = 0;
*
* We must ensure here that the load of pte_low sees 'l' IFF pte_high sees 'h'.
* We load pte_high *after* loading pte_low, which ensures we don't see an older
* value of pte_high. *Then* we recheck pte_low, which ensures that we haven't
* picked up a changed pte high. We might have gotten rubbish values from
* pte_low and pte_high, but we are guaranteed that pte_low will not have the
* present bit set *unless* it is 'l'. Because get_user_pages_fast() only
* operates on present ptes we're safe.
*/
static inline pte_t ptep_get_lockless(pte_t *ptep)
{
pte_t pte;
do {
pte.pte_low = ptep->pte_low;
smp_rmb();
pte.pte_high = ptep->pte_high;
smp_rmb();
} while (unlikely(pte.pte_low != ptep->pte_low));
return pte;
}
#else /* CONFIG_GUP_GET_PTE_LOW_HIGH */
/*
* We require that the PTE can be read atomically.
*/
static inline pte_t ptep_get_lockless(pte_t *ptep)
{
return ptep_get(ptep);
}
#endif /* CONFIG_GUP_GET_PTE_LOW_HIGH */
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
#ifndef __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR
static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm,
@ -1494,4 +1549,20 @@ typedef unsigned int pgtbl_mod_mask;
#define pmd_leaf(x) 0
#endif
#ifndef pgd_leaf_size
#define pgd_leaf_size(x) (1ULL << PGDIR_SHIFT)
#endif
#ifndef p4d_leaf_size
#define p4d_leaf_size(x) P4D_SIZE
#endif
#ifndef pud_leaf_size
#define pud_leaf_size(x) PUD_SIZE
#endif
#ifndef pmd_leaf_size
#define pmd_leaf_size(x) PMD_SIZE
#endif
#ifndef pte_leaf_size
#define pte_leaf_size(x) PAGE_SIZE
#endif
#endif /* _LINUX_PGTABLE_H */