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| author |   Matthew Wilcox <willy@infradead.org> | 2017-11-03 13:30:42 -0400 |
|---|---|---|
| committer | Matthew Wilcox <willy@infradead.org> | 2018-09-29 22:47:49 -0400 |
| commit | 3159f943aafdbacb2f94c38fdaadabf2bbde2a14 (patch) | |
| tree | 7e06823a1ab7e90774535d17a217a939bdddda3b /mm/workingset.c | |
| parent | idr: Permit any valid kernel pointer to be stored (diff) | |
| download | linux-dev-3159f943aafdbacb2f94c38fdaadabf2bbde2a14.tar.xz linux-dev-3159f943aafdbacb2f94c38fdaadabf2bbde2a14.zip | |
xarray: Replace exceptional entries
Introduce xarray value entries and tagged pointers to replace radix
tree exceptional entries. This is a slight change in encoding to allow
the use of an extra bit (we can now store BITS_PER_LONG - 1 bits in a
value entry). It is also a change in emphasis; exceptional entries are
intimidating and different. As the comment explains, you can choose
to store values or pointers in the xarray and they are both first-class
citizens.
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Diffstat (limited to 'mm/workingset.c')
| -rw-r--r-- | mm/workingset.c | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/mm/workingset.c b/mm/workingset.c index 4516dd790129..bb109b3afac2 100644 --- a/mm/workingset.c +++ b/mm/workingset.c @@ -155,8 +155,8 @@ * refault distance will immediately activate the refaulting page. */ -#define EVICTION_SHIFT (RADIX_TREE_EXCEPTIONAL_ENTRY + \ - NODES_SHIFT + \ +#define EVICTION_SHIFT ((BITS_PER_LONG - BITS_PER_XA_VALUE) + \ + NODES_SHIFT + \ MEM_CGROUP_ID_SHIFT) #define EVICTION_MASK (~0UL >> EVICTION_SHIFT) @@ -173,20 +173,19 @@ static unsigned int bucket_order __read_mostly; static void *pack_shadow(int memcgid, pg_data_t *pgdat, unsigned long eviction) { eviction >>= bucket_order; + eviction &= EVICTION_MASK; eviction = (eviction << MEM_CGROUP_ID_SHIFT) | memcgid; eviction = (eviction << NODES_SHIFT) | pgdat->node_id; - eviction = (eviction << RADIX_TREE_EXCEPTIONAL_SHIFT); - return (void *)(eviction | RADIX_TREE_EXCEPTIONAL_ENTRY); + return xa_mk_value(eviction); } static void unpack_shadow(void *shadow, int *memcgidp, pg_data_t **pgdat, unsigned long *evictionp) { - unsigned long entry = (unsigned long)shadow; + unsigned long entry = xa_to_value(shadow); int memcgid, nid; - entry >>= RADIX_TREE_EXCEPTIONAL_SHIFT; nid = entry & ((1UL << NODES_SHIFT) - 1); entry >>= NODES_SHIFT; memcgid = entry & ((1UL << MEM_CGROUP_ID_SHIFT) - 1); @@ -453,7 +452,7 @@ static enum lru_status shadow_lru_isolate(struct list_head *item, goto out_invalid; for (i = 0; i < RADIX_TREE_MAP_SIZE; i++) { if (node->slots[i]) { - if (WARN_ON_ONCE(!radix_tree_exceptional_entry(node->slots[i]))) + if (WARN_ON_ONCE(!xa_is_value(node->slots[i]))) goto out_invalid; if (WARN_ON_ONCE(!node->exceptional)) goto out_invalid; |