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Message-ID: <20230218002819.1486479-20-jthoughton@google.com>
Date: Sat, 18 Feb 2023 00:27:52 +0000
From: James Houghton <jthoughton@...gle.com>
To: Mike Kravetz <mike.kravetz@...cle.com>,
Muchun Song <songmuchun@...edance.com>,
Peter Xu <peterx@...hat.com>,
Andrew Morton <akpm@...ux-foundation.org>
Cc: David Hildenbrand <david@...hat.com>,
David Rientjes <rientjes@...gle.com>,
Axel Rasmussen <axelrasmussen@...gle.com>,
Mina Almasry <almasrymina@...gle.com>,
"Zach O'Keefe" <zokeefe@...gle.com>,
Manish Mishra <manish.mishra@...anix.com>,
Naoya Horiguchi <naoya.horiguchi@....com>,
"Dr . David Alan Gilbert" <dgilbert@...hat.com>,
"Matthew Wilcox (Oracle)" <willy@...radead.org>,
Vlastimil Babka <vbabka@...e.cz>,
Baolin Wang <baolin.wang@...ux.alibaba.com>,
Miaohe Lin <linmiaohe@...wei.com>,
Yang Shi <shy828301@...il.com>,
Frank van der Linden <fvdl@...gle.com>,
Jiaqi Yan <jiaqiyan@...gle.com>, linux-mm@...ck.org,
linux-kernel@...r.kernel.org,
James Houghton <jthoughton@...gle.com>
Subject: [PATCH v2 19/46] hugetlb: add HGM support to hugetlb_change_protection
The main change here is to do a high-granularity walk and pulling the
shift from the walk (not from the hstate).
Signed-off-by: James Houghton <jthoughton@...gle.com>
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index ecf1a28dbaaa..7321c6602d6f 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -6900,15 +6900,15 @@ long hugetlb_change_protection(struct vm_area_struct *vma,
{
struct mm_struct *mm = vma->vm_mm;
unsigned long start = address;
- pte_t *ptep;
pte_t pte;
struct hstate *h = hstate_vma(vma);
- long pages = 0, psize = huge_page_size(h);
+ long base_pages = 0, psize = huge_page_size(h);
bool shared_pmd = false;
struct mmu_notifier_range range;
unsigned long last_addr_mask;
bool uffd_wp = cp_flags & MM_CP_UFFD_WP;
bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE;
+ struct hugetlb_pte hpte;
/*
* In the case of shared PMDs, the area to flush could be beyond
@@ -6926,39 +6926,43 @@ long hugetlb_change_protection(struct vm_area_struct *vma,
hugetlb_vma_lock_write(vma);
i_mmap_lock_write(vma->vm_file->f_mapping);
last_addr_mask = hugetlb_mask_last_page(h);
- for (; address < end; address += psize) {
+ while (address < end) {
spinlock_t *ptl;
- ptep = hugetlb_walk(vma, address, psize);
- if (!ptep) {
+ if (hugetlb_full_walk(&hpte, vma, address)) {
if (!uffd_wp) {
- address |= last_addr_mask;
+ address = (address | last_addr_mask) + psize;
continue;
}
/*
* Userfaultfd wr-protect requires pgtable
* pre-allocations to install pte markers.
+ *
+ * Use hugetlb_full_walk_alloc to allocate
+ * the hstate-level PTE.
*/
- ptep = huge_pte_alloc(mm, vma, address, psize);
- if (!ptep) {
- pages = -ENOMEM;
+ if (hugetlb_full_walk_alloc(&hpte, vma,
+ address, psize)) {
+ base_pages = -ENOMEM;
break;
}
}
- ptl = huge_pte_lock(h, mm, ptep);
- if (huge_pmd_unshare(mm, vma, address, ptep)) {
+
+ ptl = hugetlb_pte_lock(&hpte);
+ if (hugetlb_pte_size(&hpte) == psize &&
+ huge_pmd_unshare(mm, vma, address, hpte.ptep)) {
/*
* When uffd-wp is enabled on the vma, unshare
* shouldn't happen at all. Warn about it if it
* happened due to some reason.
*/
WARN_ON_ONCE(uffd_wp || uffd_wp_resolve);
- pages++;
+ base_pages += psize / PAGE_SIZE;
spin_unlock(ptl);
shared_pmd = true;
- address |= last_addr_mask;
+ address = (address | last_addr_mask) + psize;
continue;
}
- pte = huge_ptep_get(ptep);
+ pte = huge_ptep_get(hpte.ptep);
if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
/* Nothing to do. */
} else if (unlikely(is_hugetlb_entry_migration(pte))) {
@@ -6974,7 +6978,7 @@ long hugetlb_change_protection(struct vm_area_struct *vma,
entry = make_readable_migration_entry(
swp_offset(entry));
newpte = swp_entry_to_pte(entry);
- pages++;
+ base_pages += hugetlb_pte_size(&hpte) / PAGE_SIZE;
}
if (uffd_wp)
@@ -6982,34 +6986,49 @@ long hugetlb_change_protection(struct vm_area_struct *vma,
else if (uffd_wp_resolve)
newpte = pte_swp_clear_uffd_wp(newpte);
if (!pte_same(pte, newpte))
- set_huge_pte_at(mm, address, ptep, newpte);
+ set_huge_pte_at(mm, address, hpte.ptep, newpte);
} else if (unlikely(is_pte_marker(pte))) {
/* No other markers apply for now. */
WARN_ON_ONCE(!pte_marker_uffd_wp(pte));
if (uffd_wp_resolve)
/* Safe to modify directly (non-present->none). */
- huge_pte_clear(mm, address, ptep, psize);
+ huge_pte_clear(mm, address, hpte.ptep,
+ hugetlb_pte_size(&hpte));
} else if (!huge_pte_none(pte)) {
pte_t old_pte;
- unsigned int shift = huge_page_shift(hstate_vma(vma));
+ unsigned int shift = hpte.shift;
+
+ if (unlikely(!hugetlb_pte_present_leaf(&hpte, pte))) {
+ /*
+ * Someone split the PTE from under us, so retry
+ * the walk,
+ */
+ spin_unlock(ptl);
+ continue;
+ }
- old_pte = huge_ptep_modify_prot_start(vma, address, ptep);
+ old_pte = huge_ptep_modify_prot_start(
+ vma, address, hpte.ptep);
pte = huge_pte_modify(old_pte, newprot);
- pte = arch_make_huge_pte(pte, shift, vma->vm_flags);
+ pte = arch_make_huge_pte(
+ pte, shift, vma->vm_flags);
if (uffd_wp)
pte = huge_pte_mkuffd_wp(pte);
else if (uffd_wp_resolve)
pte = huge_pte_clear_uffd_wp(pte);
- huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, pte);
- pages++;
+ huge_ptep_modify_prot_commit(
+ vma, address, hpte.ptep,
+ old_pte, pte);
+ base_pages += hugetlb_pte_size(&hpte) / PAGE_SIZE;
} else {
/* None pte */
if (unlikely(uffd_wp))
/* Safe to modify directly (none->non-present). */
- set_huge_pte_at(mm, address, ptep,
+ set_huge_pte_at(mm, address, hpte.ptep,
make_pte_marker(PTE_MARKER_UFFD_WP));
}
spin_unlock(ptl);
+ address += hugetlb_pte_size(&hpte);
}
/*
* Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
@@ -7032,7 +7051,7 @@ long hugetlb_change_protection(struct vm_area_struct *vma,
hugetlb_vma_unlock_write(vma);
mmu_notifier_invalidate_range_end(&range);
- return pages > 0 ? (pages << h->order) : pages;
+ return base_pages;
}
/* Return true if reservation was successful, false otherwise. */
--
2.39.2.637.g21b0678d19-goog
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