From: Matthew Wilcox <willy@infradead.org>
To: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org
Cc: Matthew Wilcox <willy@infradead.org>, Jan Kara <jack@suse.cz>,
Jeff Layton <jlayton@redhat.com>,
Lukas Czerner <lczerner@redhat.com>,
Ross Zwisler <ross.zwisler@linux.intel.com>,
Christoph Hellwig <hch@lst.de>,
Goldwyn Rodrigues <rgoldwyn@suse.com>,
Nicholas Piggin <npiggin@gmail.com>,
Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>,
linux-nilfs@vger.kernel.org, Jaegeuk Kim <jaegeuk@kernel.org>,
Chao Yu <yuchao0@huawei.com>,
linux-f2fs-devel@lists.sourceforge.net
Subject: [PATCH v14 16/74] xarray: Step through an XArray
Date: Sat, 16 Jun 2018 18:59:54 -0700 [thread overview]
Message-ID: <20180617020052.4759-17-willy@infradead.org> (raw)
In-Reply-To: <20180617020052.4759-1-willy@infradead.org>
The xas_next and xas_prev functions move the xas index by one position,
and adjust the rest of the iterator state to match it. This is more
efficient than calling xas_set() as it keeps the iterator at the leaves
of the tree instead of walking the iterator from the root each time.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
---
include/linux/xarray.h | 67 +++++++++++++++++++++++++
lib/test_xarray.c | 109 +++++++++++++++++++++++++++++++++++++++++
lib/xarray.c | 74 ++++++++++++++++++++++++++++
3 files changed, 250 insertions(+)
diff --git a/include/linux/xarray.h b/include/linux/xarray.h
index fa36a0670988..921d41034d7d 100644
--- a/include/linux/xarray.h
+++ b/include/linux/xarray.h
@@ -719,6 +719,12 @@ static inline bool xas_not_node(struct xa_node *node)
return ((unsigned long)node & 3) || !node;
}
+/* True if the node represents RESTART or an error */
+static inline bool xas_frozen(struct xa_node *node)
+{
+ return (unsigned long)node & 2;
+}
+
/* True if the node represents head-of-tree, RESTART or BOUNDS */
static inline bool xas_top(struct xa_node *node)
{
@@ -977,6 +983,67 @@ enum {
for (entry = xas_find_tagged(xas, max, tag); entry; \
entry = xas_next_tagged(xas, max, tag))
+void *__xas_next(struct xa_state *);
+void *__xas_prev(struct xa_state *);
+
+/**
+ * xas_prev() - Move iterator to previous index.
+ * @xas: XArray operation state.
+ *
+ * If the @xas was in an error state, it will remain in an error state
+ * and this function will return %NULL. If the @xas has never been walked,
+ * it will have the effect of calling xas_load(). Otherwise one will be
+ * subtracted from the index and the state will be walked to the correct
+ * location in the array for the next operation.
+ *
+ * If the iterator was referencing index 0, this function wraps
+ * around to %ULONG_MAX.
+ *
+ * Return: The entry at the new index. This may be %NULL or an internal
+ * entry.
+ */
+static inline void *xas_prev(struct xa_state *xas)
+{
+ struct xa_node *node = xas->xa_node;
+
+ if (unlikely(xas_not_node(node) || node->shift ||
+ xas->xa_offset == 0))
+ return __xas_prev(xas);
+
+ xas->xa_index--;
+ xas->xa_offset--;
+ return xa_entry(xas->xa, node, xas->xa_offset);
+}
+
+/**
+ * xas_next() - Move state to next index.
+ * @xas: XArray operation state.
+ *
+ * If the @xas was in an error state, it will remain in an error state
+ * and this function will return %NULL. If the @xas has never been walked,
+ * it will have the effect of calling xas_load(). Otherwise one will be
+ * added to the index and the state will be walked to the correct
+ * location in the array for the next operation.
+ *
+ * If the iterator was referencing index %ULONG_MAX, this function wraps
+ * around to 0.
+ *
+ * Return: The entry at the new index. This may be %NULL or an internal
+ * entry.
+ */
+static inline void *xas_next(struct xa_state *xas)
+{
+ struct xa_node *node = xas->xa_node;
+
+ if (unlikely(xas_not_node(node) || node->shift ||
+ xas->xa_offset == XA_CHUNK_MASK))
+ return __xas_next(xas);
+
+ xas->xa_index++;
+ xas->xa_offset++;
+ return xa_entry(xas->xa, node, xas->xa_offset);
+}
+
/* Internal functions, mostly shared between radix-tree.c, xarray.c and idr.c */
void xas_destroy(struct xa_state *);
diff --git a/lib/test_xarray.c b/lib/test_xarray.c
index a6a3705165ca..e74ade12c663 100644
--- a/lib/test_xarray.c
+++ b/lib/test_xarray.c
@@ -384,6 +384,114 @@ static void check_find(struct xarray *xa)
check_multi_find(xa);
}
+static void check_move_small(struct xarray *xa, unsigned long idx)
+{
+ XA_STATE(xas, xa, 0);
+ unsigned long i;
+
+ xa_store_value(xa, 0, GFP_KERNEL);
+ xa_store_value(xa, idx, GFP_KERNEL);
+
+ for (i = 0; i < idx * 4; i++) {
+ void *entry = xas_next(&xas);
+ if (i <= idx)
+ XA_BUG_ON(xa, xas.xa_node == XAS_RESTART);
+ XA_BUG_ON(xa, xas.xa_index != i);
+ if (i == 0 || i == idx)
+ XA_BUG_ON(xa, entry != xa_mk_value(i));
+ else
+ XA_BUG_ON(xa, entry != NULL);
+ }
+ xas_next(&xas);
+ XA_BUG_ON(xa, xas.xa_index != i);
+
+ do {
+ void *entry = xas_prev(&xas);
+ i--;
+ if (i <= idx)
+ XA_BUG_ON(xa, xas.xa_node == XAS_RESTART);
+ XA_BUG_ON(xa, xas.xa_index != i);
+ if (i == 0 || i == idx)
+ XA_BUG_ON(xa, entry != xa_mk_value(i));
+ else
+ XA_BUG_ON(xa, entry != NULL);
+ } while (i > 0);
+
+ xas_set(&xas, ULONG_MAX);
+ XA_BUG_ON(xa, xas_next(&xas) != NULL);
+ XA_BUG_ON(xa, xas.xa_index != ULONG_MAX);
+ XA_BUG_ON(xa, xas_next(&xas) != xa_mk_value(0));
+ XA_BUG_ON(xa, xas.xa_index != 0);
+ XA_BUG_ON(xa, xas_prev(&xas) != NULL);
+ XA_BUG_ON(xa, xas.xa_index != ULONG_MAX);
+
+ xa_erase_value(xa, 0);
+ xa_erase_value(xa, idx);
+ XA_BUG_ON(xa, !xa_empty(xa));
+}
+
+static void check_move(struct xarray *xa)
+{
+ XA_STATE(xas, xa, (1 << 16) - 1);
+ unsigned long i;
+
+ for (i = 0; i < (1 << 16); i++)
+ XA_BUG_ON(xa, xa_store_value(xa, i, GFP_KERNEL) != NULL);
+
+ do {
+ void *entry = xas_prev(&xas);
+ i--;
+ XA_BUG_ON(xa, entry != xa_mk_value(i));
+ XA_BUG_ON(xa, i != xas.xa_index);
+ } while (i != 0);
+
+ XA_BUG_ON(xa, xas_prev(&xas) != NULL);
+ XA_BUG_ON(xa, xas.xa_index != ULONG_MAX);
+
+ do {
+ void *entry = xas_next(&xas);
+ XA_BUG_ON(xa, entry != xa_mk_value(i));
+ XA_BUG_ON(xa, i != xas.xa_index);
+ i++;
+ } while (i < (1 << 16));
+
+ for (i = (1 << 8); i < (1 << 15); i++)
+ xa_erase_value(xa, i);
+
+ i = xas.xa_index;
+
+ do {
+ void *entry = xas_prev(&xas);
+ i--;
+ if ((i < (1 << 8)) || (i >= (1 << 15)))
+ XA_BUG_ON(xa, entry != xa_mk_value(i));
+ else
+ XA_BUG_ON(xa, entry != NULL);
+ XA_BUG_ON(xa, i != xas.xa_index);
+ } while (i != 0);
+
+ XA_BUG_ON(xa, xas_prev(&xas) != NULL);
+ XA_BUG_ON(xa, xas.xa_index != ULONG_MAX);
+
+ do {
+ void *entry = xas_next(&xas);
+ if ((i < (1 << 8)) || (i >= (1 << 15)))
+ XA_BUG_ON(xa, entry != xa_mk_value(i));
+ else
+ XA_BUG_ON(xa, entry != NULL);
+ XA_BUG_ON(xa, i != xas.xa_index);
+ i++;
+ } while (i < (1 << 16));
+
+ xa_destroy(xa);
+
+ for (i = 0; i < 16; i++)
+ check_move_small(xa, 1UL << i);
+
+ for (i = 2; i < 16; i++)
+ check_move_small(xa, (1UL << i) - 1);
+}
+
static int xarray_checks(void)
{
DEFINE_XARRAY(array);
@@ -397,6 +505,7 @@ static int xarray_checks(void)
check_cmpxchg(&array);
check_multi_store(&array);
check_find(&array);
+ check_move(&array);
printk("XArray: %u of %u tests passed\n", tests_passed, tests_run);
return (tests_run != tests_passed) ? 0 : -EINVAL;
diff --git a/lib/xarray.c b/lib/xarray.c
index e90ba76404ae..ab1b6786711e 100644
--- a/lib/xarray.c
+++ b/lib/xarray.c
@@ -863,6 +863,80 @@ void xas_pause(struct xa_state *xas)
}
EXPORT_SYMBOL_GPL(xas_pause);
+/*
+ * __xas_prev() - Find the previous entry in the XArray.
+ * @xas: XArray operation state.
+ *
+ * Helper function for xas_prev() which handles all the complex cases
+ * out of line.
+ */
+void *__xas_prev(struct xa_state *xas)
+{
+ void *entry;
+
+ if (!xas_frozen(xas->xa_node))
+ xas->xa_index--;
+ if (xas_not_node(xas->xa_node))
+ return xas_load(xas);
+
+ if (xas->xa_offset != get_offset(xas->xa_index, xas->xa_node))
+ xas->xa_offset--;
+
+ while (xas->xa_offset == 255) {
+ xas->xa_offset = xas->xa_node->offset - 1;
+ xas->xa_node = xa_parent(xas->xa, xas->xa_node);
+ if (!xas->xa_node)
+ return set_bounds(xas);
+ }
+
+ for (;;) {
+ entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset);
+ if (!xa_is_node(entry))
+ return entry;
+
+ xas->xa_node = xa_to_node(entry);
+ xas_set_offset(xas);
+ }
+}
+EXPORT_SYMBOL_GPL(__xas_prev);
+
+/*
+ * __xas_next() - Find the next entry in the XArray.
+ * @xas: XArray operation state.
+ *
+ * Helper function for xas_next() which handles all the complex cases
+ * out of line.
+ */
+void *__xas_next(struct xa_state *xas)
+{
+ void *entry;
+
+ if (!xas_frozen(xas->xa_node))
+ xas->xa_index++;
+ if (xas_not_node(xas->xa_node))
+ return xas_load(xas);
+
+ if (xas->xa_offset != get_offset(xas->xa_index, xas->xa_node))
+ xas->xa_offset++;
+
+ while (xas->xa_offset == XA_CHUNK_SIZE) {
+ xas->xa_offset = xas->xa_node->offset + 1;
+ xas->xa_node = xa_parent(xas->xa, xas->xa_node);
+ if (!xas->xa_node)
+ return set_bounds(xas);
+ }
+
+ for (;;) {
+ entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset);
+ if (!xa_is_node(entry))
+ return entry;
+
+ xas->xa_node = xa_to_node(entry);
+ xas_set_offset(xas);
+ }
+}
+EXPORT_SYMBOL_GPL(__xas_next);
+
/**
* xas_find() - Find the next present entry in the XArray.
* @xas: XArray operation state.
--
2.17.1
next prev parent reply other threads:[~2018-06-17 2:01 UTC|newest]
Thread overview: 90+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-17 1:59 [PATCH v14 00/74] Convert page cache to XArray Matthew Wilcox
2018-06-17 1:59 ` [PATCH v14 01/74] Update email address Matthew Wilcox
2018-06-17 1:59 ` [PATCH v14 02/74] radix tree test suite: Enable ubsan Matthew Wilcox
2018-06-17 1:59 ` [PATCH v14 03/74] dax: Fix use of zero page Matthew Wilcox
2018-06-17 1:59 ` [PATCH v14 04/74] xarray: Replace exceptional entries Matthew Wilcox
2018-06-17 1:59 ` [PATCH v14 05/74] xarray: Change definition of sibling entries Matthew Wilcox
2018-06-17 1:59 ` [PATCH v14 06/74] xarray: Add definition of struct xarray Matthew Wilcox
2018-06-17 1:59 ` [PATCH v14 07/74] xarray: Define struct xa_node Matthew Wilcox
2018-06-17 1:59 ` [PATCH v14 08/74] xarray: Add documentation Matthew Wilcox
2018-06-17 1:59 ` [PATCH v14 09/74] xarray: Add XArray load operation Matthew Wilcox
2018-06-17 1:59 ` [PATCH v14 10/74] xarray: Add XArray tags Matthew Wilcox
2018-06-17 1:59 ` [PATCH v14 11/74] xarray: Add XArray unconditional store operations Matthew Wilcox
2018-06-17 1:59 ` [PATCH v14 12/74] xarray: Add XArray conditional " Matthew Wilcox
2018-06-17 1:59 ` [PATCH v14 13/74] xarray: Add XArray iterators Matthew Wilcox
2018-06-17 1:59 ` [PATCH v14 14/74] xarray: Extract entries from an XArray Matthew Wilcox
2018-06-17 1:59 ` [PATCH v14 15/74] xarray: Destroy " Matthew Wilcox
2018-06-17 1:59 ` Matthew Wilcox [this message]
2018-06-17 1:59 ` [PATCH v14 17/74] xarray: Add xas_for_each_conflict Matthew Wilcox
2018-06-17 1:59 ` [PATCH v14 18/74] xarray: Add xas_create_range Matthew Wilcox
2018-06-17 1:59 ` [PATCH v14 19/74] xarray: Add MAINTAINERS entry Matthew Wilcox
2018-06-17 1:59 ` [PATCH v14 20/74] page cache: Rearrange address_space Matthew Wilcox
2018-06-17 1:59 ` [PATCH v14 21/74] page cache: Convert hole search to XArray Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 22/74] page cache: Add and replace pages using the XArray Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 23/74] page cache: Convert page deletion to XArray Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 24/74] page cache: Convert find_get_entry " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 25/74] page cache: Convert find_get_entries " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 26/74] page cache: Convert find_get_pages_range " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 27/74] page cache: Convert find_get_pages_contig " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 28/74] page cache; Convert find_get_pages_range_tag " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 29/74] page cache: Convert find_get_entries_tag " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 30/74] page cache: Convert filemap_map_pages " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 31/74] radix tree test suite: Convert regression1 " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 32/74] page cache: Convert delete_batch " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 33/74] page cache: Remove stray radix comment Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 34/74] page cache: Convert filemap_range_has_page to XArray Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 35/74] mm: Convert page-writeback " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 36/74] mm: Convert workingset " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 37/74] mm: Convert truncate " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 38/74] mm: Convert add_to_swap_cache " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 39/74] mm: Convert delete_from_swap_cache " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 40/74] mm: Convert __do_page_cache_readahead " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 41/74] mm: Convert page migration " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 42/74] mm: Convert huge_memory " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 43/74] mm: Convert collapse_shmem " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 44/74] mm: Convert khugepaged_scan_shmem " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 45/74] mm: Convert is_page_cache_freeable " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 46/74] pagevec: Use xa_tag_t Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 47/74] shmem: Convert shmem_radix_tree_replace to XArray Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 48/74] shmem: Convert shmem_confirm_swap " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 49/74] shmem: Convert find_swap_entry " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 50/74] shmem: Convert shmem_add_to_page_cache " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 51/74] shmem: Convert shmem_alloc_hugepage " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 52/74] shmem: Convert shmem_free_swap " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 53/74] shmem: Convert shmem_partial_swap_usage " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 54/74] memfd: Convert memfd_wait_for_pins " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 55/74] memfd: Convert memfd_tag_pins " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 56/74] shmem: Comment fixups Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 57/74] btrfs: Convert page cache to XArray Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 58/74] fs: Convert buffer " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 59/74] fs: Convert writeback " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 60/74] nilfs2: Convert " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 61/74] f2fs: " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 62/74] dax: Rename some functions Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 63/74] dax: Hash on XArray instead of mapping Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 64/74] dax: Convert dax_insert_pfn_mkwrite to XArray Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 65/74] dax: Convert dax_layout_busy_page " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 66/74] dax: Convert __dax_invalidate_entry " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 67/74] dax: Convert dax writeback " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 68/74] dax: Convert dax_lock_page " Matthew Wilcox
2018-06-29 17:30 ` Ross Zwisler
2018-07-06 11:54 ` [PATCH] fs/dax: remove unused function Anders Roxell
2018-07-06 13:04 ` [PATCH v14 68/74] dax: Convert dax_lock_page to XArray Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 69/74] dax: Convert page fault handlers " Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 70/74] page cache: Finish XArray conversion Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 71/74] radix tree: Remove radix_tree_update_node_t Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 72/74] radix tree: Remove split/join code Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 73/74] radix tree: Remove radix_tree_maybe_preload_order Matthew Wilcox
2018-06-17 2:00 ` [PATCH v14 74/74] radix tree: Remove radix_tree_clear_tags Matthew Wilcox
2018-06-19 3:12 ` [PATCH v14 00/74] Convert page cache to XArray Ross Zwisler
2018-06-19 9:22 ` Matthew Wilcox
2018-06-19 16:40 ` Ross Zwisler
2018-06-19 17:16 ` Matthew Wilcox
2018-06-27 11:05 ` Matthew Wilcox
2018-06-27 19:44 ` Ross Zwisler
2018-06-28 8:39 ` Matthew Wilcox
2018-06-28 16:30 ` Ross Zwisler
2018-07-25 21:03 ` Matthew Wilcox
2018-07-25 21:12 ` Ross Zwisler
2018-07-27 17:20 ` Ross Zwisler
2018-07-30 15:43 ` Matthew Wilcox
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