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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: 675d99529 ("powerpc/book3s64: Enable split pmd ptlock")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Aneesh Kumar K.V 2018-06-01 13:54:24 +05:30 committed by Michael Ellerman
parent 91d0697188
commit ed515b6898
2 changed files with 30 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
arch/powerpc/mm/hugetlbpage.c
View File

@ -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);

12
arch/powerpc/mm/pgtable.c
View File

@ -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);
}