kevin/linux
1
Fork 0
Code

mm: multi-gen LRU: rename lrugen->lists[] to lrugen->folios[]

Browse Source 
lru_gen_folio will be chained into per-node lists by the coming
lrugen->list.

Link: https://lkml.kernel.org/r/20221222041905.2431096-3-yuzhao@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michael Larabel <Michael@MichaelLarabel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Yu Zhao 2022-12-21 21:19:00 -07:00 committed by Andrew Morton
parent 391655fe08
commit 6df1b22129
4 changed files with 20 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
Documentation/mm/multigen_lru.rst
View File

@ -89,15 +89,15 @@ variables are monotonically increasing.
Generation numbers are truncated into ``order_base_2(MAX_NR_GENS+1)``
bits in order to fit into the gen counter in ``folio->flags``. Each
truncated generation number is an index to ``lrugen->lists[]``. The
truncated generation number is an index to ``lrugen->folios[]``. The
sliding window technique is used to track at least ``MIN_NR_GENS`` and
at most ``MAX_NR_GENS`` generations. The gen counter stores a value
within ``[1, MAX_NR_GENS]`` while a page is on one of
``lrugen->lists[]``; otherwise it stores zero.
``lrugen->folios[]``; otherwise it stores zero.
Each generation is divided into multiple tiers. A page accessed ``N``
times through file descriptors is in tier ``order_base_2(N)``. Unlike
generations, tiers do not have dedicated ``lrugen->lists[]``. In
generations, tiers do not have dedicated ``lrugen->folios[]``. In
contrast to moving across generations, which requires the LRU lock,
moving across tiers only involves atomic operations on
``folio->flags`` and therefore has a negligible cost. A feedback loop
@ -127,7 +127,7 @@ page mapped by this PTE to ``(max_seq%MAX_NR_GENS)+1``.
Eviction
--------
The eviction consumes old generations. Given an ``lruvec``, it
increments ``min_seq`` when ``lrugen->lists[]`` indexed by
increments ``min_seq`` when ``lrugen->folios[]`` indexed by
``min_seq%MAX_NR_GENS`` becomes empty. To select a type and a tier to
evict from, it first compares ``min_seq[]`` to select the older type.
If both types are equally old, it selects the one whose first tier has

4
include/linux/mm_inline.h
View File

@ -256,9 +256,9 @@ static inline bool lru_gen_add_folio(struct lruvec *lruvec, struct folio *folio,
lru_gen_update_size(lruvec, folio, -1, gen);
/* for folio_rotate_reclaimable() */
if (reclaiming)
list_add_tail(&folio->lru, &lrugen->lists[gen][type][zone]);
list_add_tail(&folio->lru, &lrugen->folios[gen][type][zone]);
else
list_add(&folio->lru, &lrugen->lists[gen][type][zone]);
list_add(&folio->lru, &lrugen->folios[gen][type][zone]);
return true;
}

8
include/linux/mmzone.h
View File

@ -312,7 +312,7 @@ enum lruvec_flags {
* They form a sliding window of a variable size [MIN_NR_GENS, MAX_NR_GENS]. An
* offset within MAX_NR_GENS, i.e., gen, indexes the LRU list of the
* corresponding generation. The gen counter in folio->flags stores gen+1 while
* a page is on one of lrugen->lists[]. Otherwise it stores 0.
* a page is on one of lrugen->folios[]. Otherwise it stores 0.
*
* A page is added to the youngest generation on faulting. The aging needs to
* check the accessed bit at least twice before handing this page over to the
@ -324,8 +324,8 @@ enum lruvec_flags {
* rest of generations, if they exist, are considered inactive. See
* lru_gen_is_active().
*
* PG_active is always cleared while a page is on one of lrugen->lists[] so that
* the aging needs not to worry about it. And it's set again when a page
* PG_active is always cleared while a page is on one of lrugen->folios[] so
* that the aging needs not to worry about it. And it's set again when a page
* considered active is isolated for non-reclaiming purposes, e.g., migration.
* See lru_gen_add_folio() and lru_gen_del_folio().
*
@ -412,7 +412,7 @@ struct lru_gen_folio {
/* the birth time of each generation in jiffies */
unsigned long timestamps[MAX_NR_GENS];
/* the multi-gen LRU lists, lazily sorted on eviction */
struct list_head lists[MAX_NR_GENS][ANON_AND_FILE][MAX_NR_ZONES];
struct list_head folios[MAX_NR_GENS][ANON_AND_FILE][MAX_NR_ZONES];
/* the multi-gen LRU sizes, eventually consistent */
long nr_pages[MAX_NR_GENS][ANON_AND_FILE][MAX_NR_ZONES];
/* the exponential moving average of refaulted */

20
mm/vmscan.c
View File

@ -4271,7 +4271,7 @@ static bool inc_min_seq(struct lruvec *lruvec, int type, bool can_swap)
/* prevent cold/hot inversion if force_scan is true */
for (zone = 0; zone < MAX_NR_ZONES; zone++) {
struct list_head *head = &lrugen->lists[old_gen][type][zone];
struct list_head *head = &lrugen->folios[old_gen][type][zone];
while (!list_empty(head)) {
struct folio *folio = lru_to_folio(head);
@ -4282,7 +4282,7 @@ static bool inc_min_seq(struct lruvec *lruvec, int type, bool can_swap)
VM_WARN_ON_ONCE_FOLIO(folio_zonenum(folio) != zone, folio);
new_gen = folio_inc_gen(lruvec, folio, false);
list_move_tail(&folio->lru, &lrugen->lists[new_gen][type][zone]);
list_move_tail(&folio->lru, &lrugen->folios[new_gen][type][zone]);
if (!--remaining)
return false;
@ -4310,7 +4310,7 @@ static bool try_to_inc_min_seq(struct lruvec *lruvec, bool can_swap)
gen = lru_gen_from_seq(min_seq[type]);
for (zone = 0; zone < MAX_NR_ZONES; zone++) {
if (!list_empty(&lrugen->lists[gen][type][zone]))
if (!list_empty(&lrugen->folios[gen][type][zone]))
goto next;
}
@ -4775,7 +4775,7 @@ static bool sort_folio(struct lruvec *lruvec, struct folio *folio, int tier_idx)
/* promoted */
if (gen != lru_gen_from_seq(lrugen->min_seq[type])) {
list_move(&folio->lru, &lrugen->lists[gen][type][zone]);
list_move(&folio->lru, &lrugen->folios[gen][type][zone]);
return true;
}
@ -4784,7 +4784,7 @@ static bool sort_folio(struct lruvec *lruvec, struct folio *folio, int tier_idx)
int hist = lru_hist_from_seq(lrugen->min_seq[type]);
gen = folio_inc_gen(lruvec, folio, false);
list_move_tail(&folio->lru, &lrugen->lists[gen][type][zone]);
list_move_tail(&folio->lru, &lrugen->folios[gen][type][zone]);
WRITE_ONCE(lrugen->protected[hist][type][tier - 1],
lrugen->protected[hist][type][tier - 1] + delta);
@ -4796,7 +4796,7 @@ static bool sort_folio(struct lruvec *lruvec, struct folio *folio, int tier_idx)
if (folio_test_locked(folio) || folio_test_writeback(folio) ||
(type == LRU_GEN_FILE && folio_test_dirty(folio))) {
gen = folio_inc_gen(lruvec, folio, true);
list_move(&folio->lru, &lrugen->lists[gen][type][zone]);
list_move(&folio->lru, &lrugen->folios[gen][type][zone]);
return true;
}
@ -4863,7 +4863,7 @@ static int scan_folios(struct lruvec *lruvec, struct scan_control *sc,
for (zone = sc->reclaim_idx; zone >= 0; zone--) {
LIST_HEAD(moved);
int skipped = 0;
struct list_head *head = &lrugen->lists[gen][type][zone];
struct list_head *head = &lrugen->folios[gen][type][zone];
while (!list_empty(head)) {
struct folio *folio = lru_to_folio(head);
@ -5264,7 +5264,7 @@ static bool __maybe_unused state_is_valid(struct lruvec *lruvec)
int gen, type, zone;
for_each_gen_type_zone(gen, type, zone) {
if (!list_empty(&lrugen->lists[gen][type][zone]))
if (!list_empty(&lrugen->folios[gen][type][zone]))
return false;
}
}
@ -5309,7 +5309,7 @@ static bool drain_evictable(struct lruvec *lruvec)
int remaining = MAX_LRU_BATCH;
for_each_gen_type_zone(gen, type, zone) {
struct list_head *head = &lruvec->lrugen.lists[gen][type][zone];
struct list_head *head = &lruvec->lrugen.folios[gen][type][zone];
while (!list_empty(head)) {
bool success;
@ -5843,7 +5843,7 @@ void lru_gen_init_lruvec(struct lruvec *lruvec)
lrugen->timestamps[i] = jiffies;
for_each_gen_type_zone(gen, type, zone)
INIT_LIST_HEAD(&lrugen->lists[gen][type][zone]);
INIT_LIST_HEAD(&lrugen->folios[gen][type][zone]);
lruvec->mm_state.seq = MIN_NR_GENS;
init_waitqueue_head(&lruvec->mm_state.wait);