6:31 a.m.
We may meet a large folio at two cases:
1.) when height is 1, the real data layout may looks like this:
--------------------------------------------
crash> p *(struct xa_node*)0xffff889883a6a910
$5 = {
shift = 0 '\000',
offset = 0 '\000',
count = 64 '@',
nr_values = 0 '\000',
.................
slots = { 0xffffea0061d21000, 0x2, 0x2, 0x2,
0xffffea0121d85c00, 0x12, 0x12, 0x12,
0xffffea0121d9f400, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22,
0xffffea0121583800, 0x42, 0x42, 0x42, 0x42, 0x42, 0x42, 0x42,
0xffffea0121833e00, 0x62, 0x62, 0x62, 0x62, 0x62, 0x62, 0x62,
0xffffea0121eb3800, 0x82, 0x82, 0x82, 0x82, 0x82, 0x82, 0x82,
0x82, 0x82, 0x82, 0x82, 0x82, 0x82, 0x82,
0x82, 0x82, 0x82, 0x82, 0x82, 0x82, 0x82,
0x82, 0x82, 0x82, 0x82, 0x82, 0x82, 0x82,
0x82, 0x82, 0x82
},
.................
}
--------------------------------------------
The page orders for above folios:
0xffffea0061d21000 --> order 2
0xffffea0121d85c00 --> order 2
0xffffea0121d9f400 --> order 3
0xffffea0121583800 --> order 3
0xffffea0121833e00 --> order 3
0xffffea0121eb3800 --> order 5
2.) when height is not 1, the real data layout may looks like this:
--------------------------------------------
slot: { 0xffff8a2c866b745a, 0xffff8a2c866b16d2, 0xfffff9fcc4ea4000,
0xfffff9fcc4eb9000, ..}
--------------------------------------------
The 0xffff8a2c866b745a and 0xffff8a2c866b16d2 is a internal node, not a folio.
The page orders for above folios:
0xfffff9fcc4ea4000 --> order 6
Current code does not work correctly with large folio page cache.
This patch adds the large folio support with following:
1.) Add XARRAY_TYPE_PAGE_CACHE flag for do_xarray().
2.) Add update_count hook for do_xarray_info{},
add update_off hook for xarray_ops{}.
3.) changed the do_xarray_iter() to check the update_off
at proper place (height == 1 and height > 1).
4.) Implement the folio_update_count/folio_xarray_update_off
hooks for large folio page cache.
Signed-off-by: Huang Shijie <huangsj(a)hygon.cn>
---
defs.h | 5 +++++
filesys.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++-----
tools.c | 15 +++++++++++++--
3 files changed, 64 insertions(+), 7 deletions(-)
diff --git a/defs.h b/defs.h
index bd996ef..e7e97e7 100644
--- a/defs.h
+++ b/defs.h
@@ -5689,6 +5689,9 @@ int do_radix_tree_traverse(ulong ptr, int is_root, struct
radix_tree_ops *ops);
struct xarray_ops {
void (*entry)(ulong node, ulong slot, const char *path,
ulong index, void *private);
+ uint (*update_off)(ulong node, uint height, char *path, ulong index,
+ ulong slot, uint off, ulong shift, struct xarray_ops *ops,
+ bool *should_continue);
uint radix;
void *private;
};
@@ -6003,6 +6006,8 @@ ulong do_xarray(ulong, int, struct list_pair *);
#define XARRAY_DUMP_CB (5)
#define XARRAY_TAG_MASK (3UL)
#define XARRAY_TAG_INTERNAL (2UL)
+#define XARRAY_TYPE_PAGE_CACHE 0x8
+extern ulong XA_CHUNK_SHIFT;
int folio_order(ulong folio);
diff --git a/filesys.c b/filesys.c
index 34944e2..35d55a5 100644
--- a/filesys.c
+++ b/filesys.c
@@ -2289,7 +2289,7 @@ dump_inode_page_cache_info(ulong inode)
if (root_rnode)
count = do_radix_tree(root_rnode, RADIX_TREE_DUMP_CB, &lp);
else if (xarray)
- count = do_xarray(xarray, XARRAY_DUMP_CB, &lp);
+ count = do_xarray(xarray, XARRAY_DUMP_CB | XARRAY_TYPE_PAGE_CACHE, &lp);
if (count != nrpages)
error(INFO, "%s page count: %ld nrpages: %ld\n",
@@ -4217,12 +4217,46 @@ struct do_xarray_info {
ulong maxcount;
ulong count;
void *data;
+ ulong (*update_count)(ulong);
};
+
+static ulong
+folio_update_count(ulong slot)
+{
+ return 1 << folio_order(slot);
+}
+
+static uint folio_xarray_update_off(ulong node, uint height, char *path, ulong index,
+ ulong slot, uint off, ulong shift, struct xarray_ops *ops, bool *should_continue)
+{
+ uint order;
+
+ *should_continue = false;
+
+ if (height == 1) {
+ order = folio_order(slot) % XA_CHUNK_SHIFT;
+ return 1 << order;
+ }
+
+ /* height > 1 */
+ if ((slot & XARRAY_TAG_MASK) == 0) {
+ ops->entry(node, slot, path, index | off, ops->private);
+ *should_continue = true;
+ order = folio_order(slot) % XA_CHUNK_SHIFT;
+ return 1 << order;
+ }
+ return 1;
+}
+
static void do_xarray_count(ulong node, ulong slot, const char *path,
ulong index, void *private)
{
struct do_xarray_info *info = private;
- info->count++;
+
+ if (info->update_count)
+ info->count += info->update_count(slot);
+ else
+ info->count++;
}
static void do_xarray_search(ulong node, ulong slot, const char *path,
ulong index, void *private)
@@ -4239,8 +4273,9 @@ static void do_xarray_dump(ulong node, ulong slot, const char
*path,
ulong index, void *private)
{
struct do_xarray_info *info = private;
+
fprintf(fp, "[%ld] %lx\n", index, slot);
- info->count++;
+ do_xarray_count(node, slot, path, index, private);
}
static void do_xarray_gather(ulong node, ulong slot, const char *path,
ulong index, void *private)
@@ -4274,7 +4309,8 @@ static void do_xarray_dump_cb(ulong node, ulong slot, const char
*path,
"operation failed: entry: %ld item: %lx\n",
info->count, slot);
}
- info->count++;
+
+ do_xarray_count(node, slot, path, index, private);
}
/*
@@ -4318,7 +4354,12 @@ do_xarray(ulong root, int flag, struct list_pair *xp)
.private = &info,
};
- switch (flag)
+ if (flag & XARRAY_TYPE_PAGE_CACHE) {
+ info.update_count = folio_update_count;
+ ops.update_off = folio_xarray_update_off;
+ }
+
+ switch (flag & 0x7)
{
case XARRAY_COUNT:
ops.entry = do_xarray_count;
diff --git a/tools.c b/tools.c
index 69250c4..7dc11ae 100644
--- a/tools.c
+++ b/tools.c
@@ -4728,7 +4728,7 @@ error_height:
return -1;
}
-static ulong XA_CHUNK_SHIFT = UNINITIALIZED;
+ulong XA_CHUNK_SHIFT = UNINITIALIZED;
static ulong XA_CHUNK_SIZE = UNINITIALIZED;
static ulong XA_CHUNK_MASK = UNINITIALIZED;
@@ -4737,21 +4737,32 @@ do_xarray_iter(ulong node, uint height, char *path,
ulong index, struct xarray_ops *ops)
{
uint off;
+ uint update_off;
+ bool should_continue;
if (!hq_enter(node))
error(FATAL,
"\nduplicate tree node: %lx\n", node);
- for (off = 0; off < XA_CHUNK_SIZE; off++) {
+ for (off = 0; off < XA_CHUNK_SIZE; off += update_off) {
ulong slot;
ulong shift = (height - 1) * XA_CHUNK_SHIFT;
+ update_off = 1;
+
readmem(node + OFFSET(xa_node_slots) +
sizeof(void *) * off, KVADDR, &slot, sizeof(void *),
"xa_node.slots[off]", FAULT_ON_ERROR);
if (!slot)
continue;
+ if (ops->update_off) {
+ update_off = ops->update_off(node, height, path, index,
+ slot, off, shift, ops, &should_continue);
+ if (should_continue)
+ continue;
+ }
+
if ((slot & XARRAY_TAG_MASK) == XARRAY_TAG_INTERNAL)
slot &= ~XARRAY_TAG_INTERNAL;
--
2.53.0