Messages in this thread | | | Date | Mon, 28 Dec 2015 12:05:51 +0200 | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCH 1/8] mm: Add optional support for PUD-sized transparent hugepages |
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On Thu, Dec 24, 2015 at 11:20:30AM -0500, Matthew Wilcox wrote: > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 4bf3811..e14634f 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -1958,6 +1977,17 @@ static inline spinlock_t *pmd_lock(struct mm_struct *mm, pmd_t *pmd) > return ptl; > } > > +/* > + * No scalability reason to split PUD locks yet, but follow the same pattern > + * as the PMD locks to make it easier if we have to. > + */
I don't think it makes any good unless you convert all other places where we use page_table_lock to protect pud table (like __pud_alloc()) to the same API. I think this would deserve separate patch.
> +static inline spinlock_t *pud_lock(struct mm_struct *mm, pud_t *pud) > +{ > + spinlock_t *ptl = &mm->page_table_lock; > + spin_lock(ptl); > + return ptl; > +} > + > extern void free_area_init(unsigned long * zones_size); > extern void free_area_init_node(int nid, unsigned long * zones_size, > unsigned long zone_start_pfn, unsigned long *zholes_size);
...
> diff --git a/mm/memory.c b/mm/memory.c > index 416b129..7328df0 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -1220,9 +1220,27 @@ static inline unsigned long zap_pud_range(struct mmu_gather *tlb, > pud = pud_offset(pgd, addr); > do { > next = pud_addr_end(addr, end); > + if (pud_trans_huge(*pud) || pud_devmap(*pud)) { > + if (next - addr != HPAGE_PUD_SIZE) { > +#ifdef CONFIG_DEBUG_VM
IS_ENABLED(CONFIG_DEBUG_VM) ?
> + if (!rwsem_is_locked(&tlb->mm->mmap_sem)) { > + pr_err("%s: mmap_sem is unlocked! addr=0x%lx end=0x%lx vma->vm_start=0x%lx vma->vm_end=0x%lx\n", > + __func__, addr, end, > + vma->vm_start, > + vma->vm_end);
dump_vma(), I guess.
> + BUG(); > + } > +#endif > + split_huge_pud(vma, pud, addr); > + } else if (zap_huge_pud(tlb, vma, pud, addr)) > + goto next; > + /* fall through */ > + } > if (pud_none_or_clear_bad(pud)) > continue; > next = zap_pmd_range(tlb, vma, pud, addr, next, details); > +next: > + cond_resched(); > } while (pud++, addr = next, addr != end); > > return addr; -- Kirill A. Shutemov
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