[PATCH 4/4] xfs: use separate btree cursor slab for each btree type

Darrick J. Wong
2021-09-24T01:28:01Z

From: Darrick J. Wong <djwong@kernel.org>

Now that we have the infrastructure to track the max possible height of
each btree type, we can create a separate slab zone for cursors of each
type of btree. For smaller indices like the free space btrees, this
means that we can pack more cursors into a slab page, improving slab
utilization.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
fs/xfs/libxfs/xfs_btree.c | 12 ++++++------
fs/xfs/libxfs/xfs_btree.h | 9 +--------
fs/xfs/xfs_super.c | 33 ++++++++++++++++++++++++---------
3 files changed, 31 insertions(+), 23 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
index 120280c998f8..3131de9ae631 100644
--- a/fs/xfs/libxfs/xfs_btree.c
+++ b/fs/xfs/libxfs/xfs_btree.c
@@ -26,7 +26,6 @@
/*
* Cursor allocation zone.
*/
-kmem_zone_t *xfs_btree_cur_zone;
struct xfs_btree_cur_zone xfs_btree_cur_zones[XFS_BTNUM_MAX] = {
[XFS_BTNUM_BNO] = { .name = "xfs_alloc_btree_cur" },
[XFS_BTNUM_INO] = { .name = "xfs_ialloc_btree_cur" },
@@ -364,6 +363,7 @@ xfs_btree_del_cursor(
struct xfs_btree_cur *cur, /* btree cursor */
int error) /* del because of error */
{
+ struct xfs_btree_cur_zone *bczone = &xfs_btree_cur_zones[cur->bc_btnum];
int i; /* btree level */

/*
@@ -386,10 +386,10 @@ xfs_btree_del_cursor(
kmem_free(cur->bc_ops);
if (!(cur->bc_flags & XFS_BTREE_LONG_PTRS) && cur->bc_ag.pag)
xfs_perag_put(cur->bc_ag.pag);
- if (cur->bc_maxlevels > XFS_BTREE_CUR_ZONE_MAXLEVELS)
+ if (cur->bc_maxlevels > bczone->maxlevels)
kmem_free(cur);
else
- kmem_cache_free(xfs_btree_cur_zone, cur);
+ kmem_cache_free(bczone->zone, cur);
}

/*
@@ -5021,12 +5021,12 @@ xfs_btree_alloc_cursor(
{
struct xfs_btree_cur *cur;
unsigned int maxlevels = xfs_btree_maxlevels(mp, btnum);
+ struct xfs_btree_cur_zone *bczone = &xfs_btree_cur_zones[btnum];

- if (maxlevels > XFS_BTREE_CUR_ZONE_MAXLEVELS)
+ if (maxlevels > bczone->maxlevels)
cur = kmem_zalloc(xfs_btree_cur_sizeof(maxlevels), KM_NOFS);
else
- cur = kmem_cache_zalloc(xfs_btree_cur_zone,
- GFP_NOFS | __GFP_NOFAIL);
+ cur = kmem_cache_zalloc(bczone->zone, GFP_NOFS | __GFP_NOFAIL);
cur->bc_tp = tp;
cur->bc_mp = mp;
cur->bc_btnum = btnum;
diff --git a/fs/xfs/libxfs/xfs_btree.h b/fs/xfs/libxfs/xfs_btree.h
index 5bebd26f8b2c..854235a8adac 100644
--- a/fs/xfs/libxfs/xfs_btree.h
+++ b/fs/xfs/libxfs/xfs_btree.h
@@ -13,8 +13,6 @@ struct xfs_trans;
struct xfs_ifork;
struct xfs_perag;

-extern kmem_zone_t *xfs_btree_cur_zone;
-
/*
* Generic key, ptr and record wrapper structures.
*
@@ -92,12 +90,6 @@ uint32_t xfs_btree_magic(int crc, xfs_btnum_t btnum);
#define XFS_BTREE_STATS_ADD(cur, stat, val) \
XFS_STATS_ADD_OFF((cur)->bc_mp, (cur)->bc_statoff + __XBTS_ ## stat, val)

-/*
- * The btree cursor zone hands out cursors that can handle up to this many
- * levels. This is the known maximum for all btree types.
- */
-#define XFS_BTREE_CUR_ZONE_MAXLEVELS (9)
-
struct xfs_btree_ops {
/* size of the key and record structures */
size_t key_len;
@@ -588,6 +580,7 @@ void xfs_btree_absolute_minrecs(unsigned int *minrecs, unsigned int bc_flags,

struct xfs_btree_cur_zone {
const char *name;
+ kmem_zone_t *zone;
unsigned int maxlevels;
};

diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 83abe9bfe3ef..426dcba213ac 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1969,7 +1969,14 @@ xfs_init_btree_zones(void)
z[XFS_BTNUM_REFC].maxlevels = xfs_refcountbt_absolute_maxlevels();

for_each_xfs_btnum(btnum) {
- ASSERT(z[btnum].maxlevels <= XFS_BTREE_CUR_ZONE_MAXLEVELS);
+ if (z[btnum].name == NULL)
+ continue;
+ ASSERT(z[btnum].maxlevels >= 1);
+ z[btnum].zone = kmem_cache_create(z[btnum].name,
+ xfs_btree_cur_sizeof(z[btnum].maxlevels),
+ 0, 0, NULL);
+ if (!z[btnum].zone)
+ return -ENOMEM;
}

/* struct copies for btree types that share zones */
@@ -1979,6 +1986,20 @@ xfs_init_btree_zones(void)
return 0;
}

+STATIC void
+xfs_destroy_btree_zones(void)
+{
+ struct xfs_btree_cur_zone *z = xfs_btree_cur_zones;
+ xfs_btnum_t btnum;
+
+ /* don't free shared zones */
+ z[XFS_BTNUM_CNT].zone = NULL;
+ z[XFS_BTNUM_FINO].zone = NULL;
+
+ for_each_xfs_btnum(btnum)
+ kmem_cache_destroy(z[btnum].zone);
+}
+
STATIC int __init
xfs_init_zones(void)
{
@@ -2000,12 +2021,6 @@ xfs_init_zones(void)
if (error)
goto out_destroy_bmap_free_item_zone;

- xfs_btree_cur_zone = kmem_cache_create("xfs_btree_cur",
- xfs_btree_cur_sizeof(XFS_BTREE_CUR_ZONE_MAXLEVELS),
- 0, 0, NULL);
- if (!xfs_btree_cur_zone)
- goto out_destroy_bmap_free_item_zone;
-
xfs_da_state_zone = kmem_cache_create("xfs_da_state",
sizeof(struct xfs_da_state),
0, 0, NULL);
@@ -2141,7 +2156,7 @@ xfs_init_zones(void)
out_destroy_da_state_zone:
kmem_cache_destroy(xfs_da_state_zone);
out_destroy_btree_cur_zone:
- kmem_cache_destroy(xfs_btree_cur_zone);
+ xfs_destroy_btree_zones();
out_destroy_bmap_free_item_zone:
kmem_cache_destroy(xfs_bmap_free_item_zone);
out_destroy_log_ticket_zone:
@@ -2173,7 +2188,7 @@ xfs_destroy_zones(void)
kmem_cache_destroy(xfs_trans_zone);
kmem_cache_destroy(xfs_ifork_zone);
kmem_cache_destroy(xfs_da_state_zone);
- kmem_cache_destroy(xfs_btree_cur_zone);
+ xfs_destroy_btree_zones();
kmem_cache_destroy(xfs_bmap_free_item_zone);
kmem_cache_destroy(xfs_log_ticket_zone);
}