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Date: Thu, 27 May 2021 16:21:39 -0400
From: Peter Xu <peterx@...hat.com>
To: linux-mm@...ck.org, linux-kernel@...r.kernel.org
Cc: Andrea Arcangeli <aarcange@...hat.com>,
"Kirill A . Shutemov" <kirill@...temov.name>,
Axel Rasmussen <axelrasmussen@...gle.com>,
Nadav Amit <nadav.amit@...il.com>,
Hugh Dickins <hughd@...gle.com>,
Jerome Glisse <jglisse@...hat.com>,
Jason Gunthorpe <jgg@...pe.ca>, peterx@...hat.com,
Andrew Morton <akpm@...ux-foundation.org>,
Miaohe Lin <linmiaohe@...wei.com>,
Mike Rapoport <rppt@...ux.vnet.ibm.com>,
Matthew Wilcox <willy@...radead.org>,
Mike Kravetz <mike.kravetz@...cle.com>
Subject: [PATCH v3 10/27] mm: Pass zap_flags into unmap_mapping_pages()
Give unmap_mapping_pages() more power by allowing to specify a zap flag so that
it can pass in more information than "whether we'd also like to zap cow pages".
With the new flag, we can remove the even_cow parameter because even_cow==false
equals to zap_flags==ZAP_FLAG_CHECK_MAPPING, while even_cow==true means a none
zap flag to pass in (though in most cases we have had even_cow==false).
No functional change intended.
Signed-off-by: Peter Xu <peterx@...hat.com>
---
fs/dax.c | 10 ++++++----
include/linux/mm.h | 4 ++--
mm/khugepaged.c | 3 ++-
mm/memory.c | 15 ++++++++-------
mm/truncate.c | 11 +++++++----
5 files changed, 25 insertions(+), 18 deletions(-)
diff --git a/fs/dax.c b/fs/dax.c
index 62352cbcf0f4..09d482c1595b 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -528,7 +528,7 @@ static void *grab_mapping_entry(struct xa_state *xas,
xas_unlock_irq(xas);
unmap_mapping_pages(mapping,
xas->xa_index & ~PG_PMD_COLOUR,
- PG_PMD_NR, false);
+ PG_PMD_NR, ZAP_FLAG_CHECK_MAPPING);
xas_reset(xas);
xas_lock_irq(xas);
}
@@ -623,7 +623,8 @@ struct page *dax_layout_busy_page_range(struct address_space *mapping,
* guaranteed to either see new references or prevent new
* references from being established.
*/
- unmap_mapping_pages(mapping, start_idx, end_idx - start_idx + 1, 0);
+ unmap_mapping_pages(mapping, start_idx, end_idx - start_idx + 1,
+ ZAP_FLAG_CHECK_MAPPING);
xas_lock_irq(&xas);
xas_for_each(&xas, entry, end_idx) {
@@ -754,9 +755,10 @@ static void *dax_insert_entry(struct xa_state *xas,
/* we are replacing a zero page with block mapping */
if (dax_is_pmd_entry(entry))
unmap_mapping_pages(mapping, index & ~PG_PMD_COLOUR,
- PG_PMD_NR, false);
+ PG_PMD_NR, ZAP_FLAG_CHECK_MAPPING);
else /* pte entry */
- unmap_mapping_pages(mapping, index, 1, false);
+ unmap_mapping_pages(mapping, index, 1,
+ ZAP_FLAG_CHECK_MAPPING);
}
xas_reset(xas);
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 1adf313a01fe..b1fb2826e29c 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1803,7 +1803,7 @@ extern int fixup_user_fault(struct mm_struct *mm,
unsigned long address, unsigned int fault_flags,
bool *unlocked);
void unmap_mapping_pages(struct address_space *mapping,
- pgoff_t start, pgoff_t nr, bool even_cows);
+ pgoff_t start, pgoff_t nr, unsigned long zap_flags);
void unmap_mapping_range(struct address_space *mapping,
loff_t const holebegin, loff_t const holelen, int even_cows);
#else
@@ -1823,7 +1823,7 @@ static inline int fixup_user_fault(struct mm_struct *mm, unsigned long address,
return -EFAULT;
}
static inline void unmap_mapping_pages(struct address_space *mapping,
- pgoff_t start, pgoff_t nr, bool even_cows) { }
+ pgoff_t start, pgoff_t nr, unsigned long zap_flags) { }
static inline void unmap_mapping_range(struct address_space *mapping,
loff_t const holebegin, loff_t const holelen, int even_cows) { }
#endif
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 7376a9b5bfc9..9e89a032e2fd 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1830,7 +1830,8 @@ static void collapse_file(struct mm_struct *mm,
}
if (page_mapped(page))
- unmap_mapping_pages(mapping, index, 1, false);
+ unmap_mapping_pages(mapping, index, 1,
+ ZAP_FLAG_CHECK_MAPPING);
xas_lock_irq(&xas);
xas_set(&xas, index);
diff --git a/mm/memory.c b/mm/memory.c
index 8a3751be87ba..319552efc782 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3316,7 +3316,10 @@ static inline void unmap_mapping_range_tree(struct rb_root_cached *root,
* @mapping: The address space containing pages to be unmapped.
* @start: Index of first page to be unmapped.
* @nr: Number of pages to be unmapped. 0 to unmap to end of file.
- * @even_cows: Whether to unmap even private COWed pages.
+ * @zap_flags: Zap flags for the process. E.g., when ZAP_FLAG_CHECK_MAPPING is
+ * passed into it, we will only zap the pages that are in the same mapping
+ * specified in the @mapping parameter; otherwise we will not check mapping,
+ * IOW cow pages will be zapped too.
*
* Unmap the pages in this address space from any userspace process which
* has them mmaped. Generally, you want to remove COWed pages as well when
@@ -3324,17 +3327,14 @@ static inline void unmap_mapping_range_tree(struct rb_root_cached *root,
* cache.
*/
void unmap_mapping_pages(struct address_space *mapping, pgoff_t start,
- pgoff_t nr, bool even_cows)
+ pgoff_t nr, unsigned long zap_flags)
{
pgoff_t first_index = start, last_index = start + nr - 1;
struct zap_details details = {
.zap_mapping = mapping,
- .zap_flags = ZAP_FLAG_SKIP_SWAP,
+ .zap_flags = zap_flags | ZAP_FLAG_SKIP_SWAP,
};
- if (!even_cows)
- details.zap_flags |= ZAP_FLAG_CHECK_MAPPING;
-
if (last_index < first_index)
last_index = ULONG_MAX;
@@ -3376,7 +3376,8 @@ void unmap_mapping_range(struct address_space *mapping,
hlen = ULONG_MAX - hba + 1;
}
- unmap_mapping_pages(mapping, hba, hlen, even_cows);
+ unmap_mapping_pages(mapping, hba, hlen, even_cows ?
+ 0 : ZAP_FLAG_CHECK_MAPPING);
}
EXPORT_SYMBOL(unmap_mapping_range);
diff --git a/mm/truncate.c b/mm/truncate.c
index 57a618c4a0d6..85cd84486589 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -172,7 +172,8 @@ truncate_cleanup_page(struct address_space *mapping, struct page *page)
{
if (page_mapped(page)) {
unsigned int nr = thp_nr_pages(page);
- unmap_mapping_pages(mapping, page->index, nr, false);
+ unmap_mapping_pages(mapping, page->index, nr,
+ ZAP_FLAG_CHECK_MAPPING);
}
if (page_has_private(page))
@@ -652,14 +653,15 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
* Zap the rest of the file in one hit.
*/
unmap_mapping_pages(mapping, index,
- (1 + end - index), false);
+ (1 + end - index),
+ ZAP_FLAG_CHECK_MAPPING);
did_range_unmap = 1;
} else {
/*
* Just zap this page
*/
unmap_mapping_pages(mapping, index,
- 1, false);
+ 1, ZAP_FLAG_CHECK_MAPPING);
}
}
BUG_ON(page_mapped(page));
@@ -685,7 +687,8 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
* get remapped later.
*/
if (dax_mapping(mapping)) {
- unmap_mapping_pages(mapping, start, end - start + 1, false);
+ unmap_mapping_pages(mapping, start, end - start + 1,
+ ZAP_FLAG_CHECK_MAPPING);
}
out:
cleancache_invalidate_inode(mapping);
--
2.31.1
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