Messages in this thread | | | Date | Sat, 14 Jan 2012 11:24:06 +0800 | Subject | Re: [PATCH 2/6] thp: optimize away unnecessary page table locking | From | Hillf Danton <> |
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On Fri, Jan 13, 2012 at 11:14 PM, Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> wrote: > Hi Hillf, > > (1/13/2012 7:04), Hillf Danton wrote: > [...] >>> +/* >>> + * Returns 1 if a given pmd is mapping a thp and stable (not under splitting.) >>> + * Returns 0 otherwise. Note that if it returns 1, this routine returns without >>> + * unlocking page table locks. So callers must unlock them. >>> + */ >>> +int pmd_trans_huge_stable(pmd_t *pmd, struct vm_area_struct *vma) >>> +{ >>> + VM_BUG_ON(!rwsem_is_locked(&vma->vm_mm->mmap_sem)); >>> + >>> + if (!pmd_trans_huge(*pmd)) >>> + return 0; >>> + >>> + spin_lock(&vma->vm_mm->page_table_lock); >>> + if (likely(pmd_trans_huge(*pmd))) { >>> + if (pmd_trans_splitting(*pmd)) { >>> + spin_unlock(&vma->vm_mm->page_table_lock); >>> + wait_split_huge_page(vma->anon_vma, pmd); >>> + return 0; >>> + } else { >> >> spin_unlock(&vma->vm_mm->page_table_lock); yes? > > No. Unlocking is supposed to be done by the caller as commented. > Thanks for correcting /Hillf -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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