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Date: Sat, 16 Jun 2018 19:00:45 -0700
From: Matthew Wilcox <willy@...radead.org>
To: linux-mm@...ck.org, linux-fsdevel@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: Matthew Wilcox <willy@...radead.org>, Jan Kara <jack@...e.cz>,
Jeff Layton <jlayton@...hat.com>,
Lukas Czerner <lczerner@...hat.com>,
Ross Zwisler <ross.zwisler@...ux.intel.com>,
Christoph Hellwig <hch@....de>,
Goldwyn Rodrigues <rgoldwyn@...e.com>,
Nicholas Piggin <npiggin@...il.com>,
Ryusuke Konishi <konishi.ryusuke@....ntt.co.jp>,
linux-nilfs@...r.kernel.org, Jaegeuk Kim <jaegeuk@...nel.org>,
Chao Yu <yuchao0@...wei.com>,
linux-f2fs-devel@...ts.sourceforge.net
Subject: [PATCH v14 67/74] dax: Convert dax writeback to XArray
Use XArray iteration instead of a pagevec.
Signed-off-by: Matthew Wilcox <willy@...radead.org>
---
fs/dax.c | 130 ++++++++++++++++++++++++++-----------------------------
1 file changed, 62 insertions(+), 68 deletions(-)
diff --git a/fs/dax.c b/fs/dax.c
index fe5cc4470d99..08595ffde566 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -973,11 +973,9 @@ static void dax_entry_mkclean(struct address_space *mapping, pgoff_t index,
i_mmap_unlock_read(mapping);
}
-static int dax_writeback_one(struct dax_device *dax_dev,
- struct address_space *mapping, pgoff_t index, void *entry)
+static int dax_writeback_one(struct xa_state *xas, struct dax_device *dax_dev,
+ struct address_space *mapping, void *entry)
{
- struct radix_tree_root *pages = &mapping->i_pages;
- void *entry2, **slot;
unsigned long pfn;
long ret = 0;
size_t size;
@@ -989,29 +987,35 @@ static int dax_writeback_one(struct dax_device *dax_dev,
if (WARN_ON(!xa_is_value(entry)))
return -EIO;
- xa_lock_irq(pages);
- entry2 = get_unlocked_mapping_entry(mapping, index, &slot);
- /* Entry got punched out / reallocated? */
- if (!entry2 || WARN_ON_ONCE(!xa_is_value(entry2)))
- goto put_unlocked;
- /*
- * Entry got reallocated elsewhere? No need to writeback. We have to
- * compare pfns as we must not bail out due to difference in lockbit
- * or entry type.
- */
- if (dax_to_pfn(entry2) != dax_to_pfn(entry))
- goto put_unlocked;
- if (WARN_ON_ONCE(dax_is_empty_entry(entry) ||
- dax_is_zero_entry(entry))) {
- ret = -EIO;
- goto put_unlocked;
+ if (unlikely(dax_is_locked(entry))) {
+ void *old_entry = entry;
+
+ entry = get_unlocked_entry(xas);
+
+ /* Entry got punched out / reallocated? */
+ if (!entry || WARN_ON_ONCE(!xa_is_value(entry)))
+ goto put_unlocked;
+ /*
+ * Entry got reallocated elsewhere? No need to writeback.
+ * We have to compare pfns as we must not bail out due to
+ * difference in lockbit or entry type.
+ */
+ if (dax_to_pfn(old_entry) != dax_to_pfn(entry))
+ goto put_unlocked;
+ if (WARN_ON_ONCE(dax_is_empty_entry(entry) ||
+ dax_is_zero_entry(entry))) {
+ ret = -EIO;
+ goto put_unlocked;
+ }
+
+ /* Another fsync thread may have already done this entry */
+ if (!xas_get_tag(xas, PAGECACHE_TAG_TOWRITE))
+ goto put_unlocked;
}
- /* Another fsync thread may have already written back this entry */
- if (!radix_tree_tag_get(pages, index, PAGECACHE_TAG_TOWRITE))
- goto put_unlocked;
/* Lock the entry to serialize with page faults */
- entry = lock_slot(mapping, slot);
+ dax_lock_entry(xas, entry);
+
/*
* We can clear the tag now but we have to be careful so that concurrent
* dax_writeback_one() calls for the same index cannot finish before we
@@ -1019,8 +1023,8 @@ static int dax_writeback_one(struct dax_device *dax_dev,
* at the entry only under the i_pages lock and once they do that
* they will see the entry locked and wait for it to unlock.
*/
- radix_tree_tag_clear(pages, index, PAGECACHE_TAG_TOWRITE);
- xa_unlock_irq(pages);
+ xas_clear_tag(xas, PAGECACHE_TAG_TOWRITE);
+ xas_unlock_irq(xas);
/*
* Even if dax_writeback_mapping_range() was given a wbc->range_start
@@ -1032,7 +1036,7 @@ static int dax_writeback_one(struct dax_device *dax_dev,
pfn = dax_to_pfn(entry);
size = PAGE_SIZE << dax_entry_order(entry);
- dax_entry_mkclean(mapping, index, pfn);
+ dax_entry_mkclean(mapping, xas->xa_index, pfn);
dax_flush(dax_dev, page_address(pfn_to_page(pfn)), size);
/*
* After we have flushed the cache, we can clear the dirty tag. There
@@ -1040,16 +1044,18 @@ static int dax_writeback_one(struct dax_device *dax_dev,
* the pfn mappings are writeprotected and fault waits for mapping
* entry lock.
*/
- xa_lock_irq(pages);
- radix_tree_tag_clear(pages, index, PAGECACHE_TAG_DIRTY);
- xa_unlock_irq(pages);
- trace_dax_writeback_one(mapping->host, index, size >> PAGE_SHIFT);
- put_locked_mapping_entry(mapping, index);
+ xas_reset(xas);
+ xas_lock_irq(xas);
+ xas_store(xas, entry);
+ xas_clear_tag(xas, PAGECACHE_TAG_DIRTY);
+ dax_wake_entry(xas, entry, false);
+
+ trace_dax_writeback_one(mapping->host, xas->xa_index,
+ size >> PAGE_SHIFT);
return ret;
put_unlocked:
- put_unlocked_mapping_entry(mapping, index, entry2);
- xa_unlock_irq(pages);
+ put_unlocked_entry(xas, entry);
return ret;
}
@@ -1061,13 +1067,13 @@ static int dax_writeback_one(struct dax_device *dax_dev,
int dax_writeback_mapping_range(struct address_space *mapping,
struct block_device *bdev, struct writeback_control *wbc)
{
+ XA_STATE(xas, &mapping->i_pages, wbc->range_start >> PAGE_SHIFT);
struct inode *inode = mapping->host;
- pgoff_t start_index, end_index;
- pgoff_t indices[PAGEVEC_SIZE];
+ pgoff_t end_index = wbc->range_end >> PAGE_SHIFT;
struct dax_device *dax_dev;
- struct pagevec pvec;
- bool done = false;
- int i, ret = 0;
+ void *entry;
+ int ret = 0;
+ unsigned int scanned = 0;
if (WARN_ON_ONCE(inode->i_blkbits != PAGE_SHIFT))
return -EIO;
@@ -1079,41 +1085,29 @@ int dax_writeback_mapping_range(struct address_space *mapping,
if (!dax_dev)
return -EIO;
- start_index = wbc->range_start >> PAGE_SHIFT;
- end_index = wbc->range_end >> PAGE_SHIFT;
-
- trace_dax_writeback_range(inode, start_index, end_index);
-
- tag_pages_for_writeback(mapping, start_index, end_index);
+ trace_dax_writeback_range(inode, xas.xa_index, end_index);
- pagevec_init(&pvec);
- while (!done) {
- pvec.nr = find_get_entries_tag(mapping, start_index,
- PAGECACHE_TAG_TOWRITE, PAGEVEC_SIZE,
- pvec.pages, indices);
+ tag_pages_for_writeback(mapping, xas.xa_index, end_index);
- if (pvec.nr == 0)
+ xas_lock_irq(&xas);
+ xas_for_each_tagged(&xas, entry, end_index, PAGECACHE_TAG_TOWRITE) {
+ ret = dax_writeback_one(&xas, dax_dev, mapping, entry);
+ if (ret < 0) {
+ mapping_set_error(mapping, ret);
break;
-
- for (i = 0; i < pvec.nr; i++) {
- if (indices[i] > end_index) {
- done = true;
- break;
- }
-
- ret = dax_writeback_one(dax_dev, mapping, indices[i],
- pvec.pages[i]);
- if (ret < 0) {
- mapping_set_error(mapping, ret);
- goto out;
- }
}
- start_index = indices[pvec.nr - 1] + 1;
+ if (++scanned % XA_CHECK_SCHED)
+ continue;
+
+ xas_pause(&xas);
+ xas_unlock_irq(&xas);
+ cond_resched();
+ xas_lock_irq(&xas);
}
-out:
+ xas_unlock_irq(&xas);
put_dax(dax_dev);
- trace_dax_writeback_range_done(inode, start_index, end_index);
- return (ret < 0 ? ret : 0);
+ trace_dax_writeback_range_done(inode, xas.xa_index, end_index);
+ return ret;
}
EXPORT_SYMBOL_GPL(dax_writeback_mapping_range);
--
2.17.1
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