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Commit ed515b68 authored by Aneesh Kumar K.V's avatar Aneesh Kumar K.V Committed by Michael Ellerman
Browse files

powerpc/mm/hugetlb: Update hugetlb related locks 



With split pmd page table lock enabled, we don't use mm->page_table_lock when
updating pmd entries. This patch update hugetlb path to use the right lock
when inserting huge page directory entries into page table.

ex: if we are using hugepd and inserting hugepd entry at the pmd level, we
use pmd_lockptr, which based on config can be split pmd lock.

For update huge page directory entries itself we use mm->page_table_lock. We
do have a helper huge_pte_lockptr() for that.

Fixes: 675d9952 ("powerpc/book3s64: Enable split pmd ptlock")
Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 91d06971

arch/powerpc/mm/hugetlbpage.c

+23 −10
Original line number Diff line number Diff line
@@ -52,7 +52,8 @@ pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr, unsigned long s 
}



static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,

			   unsigned long address, unsigned pdshift, unsigned pshift)

			   unsigned long address, unsigned int pdshift,

			   unsigned int pshift, spinlock_t *ptl)

{

	struct kmem_cache *cachep;

	pte_t *new;
@@ -82,8 +83,7 @@ static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp, 
	 */

	smp_wmb();



	spin_lock(&mm->page_table_lock);



	spin_lock(ptl);

	/*

	 * We have multiple higher-level entries that point to the same

	 * actual pte location.  Fill in each as we go and backtrack on error.
@@ -113,7 +113,7 @@ static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp, 
			*hpdp = __hugepd(0);

		kmem_cache_free(cachep, new);

	}

	spin_unlock(&mm->page_table_lock);

	spin_unlock(ptl);

	return 0;

}
@@ -138,6 +138,7 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz 
	hugepd_t *hpdp = NULL;

	unsigned pshift = __ffs(sz);

	unsigned pdshift = PGDIR_SHIFT;

	spinlock_t *ptl;



	addr &= ~(sz-1);

	pg = pgd_offset(mm, addr);
@@ -146,39 +147,46 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz 
	if (pshift == PGDIR_SHIFT)

		/* 16GB huge page */

		return (pte_t *) pg;

	else if (pshift > PUD_SHIFT)

	else if (pshift > PUD_SHIFT) {

		/*

		 * We need to use hugepd table

		 */

		ptl = &mm->page_table_lock;

		hpdp = (hugepd_t *)pg;

	else {

	} else {

		pdshift = PUD_SHIFT;

		pu = pud_alloc(mm, pg, addr);

		if (pshift == PUD_SHIFT)

			return (pte_t *)pu;

		else if (pshift > PMD_SHIFT)

		else if (pshift > PMD_SHIFT) {

			ptl = pud_lockptr(mm, pu);

			hpdp = (hugepd_t *)pu;

		else {

		} else {

			pdshift = PMD_SHIFT;

			pm = pmd_alloc(mm, pu, addr);

			if (pshift == PMD_SHIFT)

				/* 16MB hugepage */

				return (pte_t *)pm;

			else

			else {

				ptl = pmd_lockptr(mm, pm);

				hpdp = (hugepd_t *)pm;

			}

		}

	}

#else

	if (pshift >= HUGEPD_PGD_SHIFT) {

		ptl = &mm->page_table_lock;

		hpdp = (hugepd_t *)pg;

	} else {

		pdshift = PUD_SHIFT;

		pu = pud_alloc(mm, pg, addr);

		if (pshift >= HUGEPD_PUD_SHIFT) {

			ptl = pud_lockptr(mm, pu);

			hpdp = (hugepd_t *)pu;

		} else {

			pdshift = PMD_SHIFT;

			pm = pmd_alloc(mm, pu, addr);

			ptl = pmd_lockptr(mm, pm);

			hpdp = (hugepd_t *)pm;

		}

	}
@@ -188,7 +196,8 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz 


	BUG_ON(!hugepd_none(*hpdp) && !hugepd_ok(*hpdp));



	if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr, pdshift, pshift))

	if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr,

						  pdshift, pshift, ptl))

		return NULL;



	return hugepte_offset(*hpdp, addr, pdshift);
@@ -499,6 +508,10 @@ struct page *follow_huge_pd(struct vm_area_struct *vma, 
	struct mm_struct *mm = vma->vm_mm;



retry:

	/*

	 * hugepage directory entries are protected by mm->page_table_lock

	 * Use this instead of huge_pte_lockptr

	 */

	ptl = &mm->page_table_lock;

	spin_lock(ptl);

arch/powerpc/mm/pgtable.c

+7 −5
Original line number Diff line number Diff line
@@ -249,17 +249,19 @@ extern int huge_ptep_set_access_flags(struct vm_area_struct *vma, 
	if (changed) {



#ifdef CONFIG_PPC_BOOK3S_64

		struct hstate *hstate = hstate_file(vma->vm_file);

		psize = hstate_get_psize(hstate);

		struct hstate *h = hstate_vma(vma);



		psize = hstate_get_psize(h);

#ifdef CONFIG_DEBUG_VM

		assert_spin_locked(huge_pte_lockptr(h, vma->vm_mm, ptep));

#endif



#else

		/*

		 * Not used on non book3s64 platforms. But 8xx

		 * can possibly use tsize derived from hstate.

		 */

		psize = 0;

#endif

#ifdef CONFIG_DEBUG_VM

		assert_spin_locked(&vma->vm_mm->page_table_lock);

#endif

		__ptep_set_access_flags(vma, ptep, pte, addr, psize);

	}