[PATCH RFC 10/32] mm: replace folio_test_workingset with folio_is_workingset
From: Kairui Song via B4 Relay
Date: Fri May 01 2026 - 17:07:52 EST
From: Kairui Song <kasong@xxxxxxxxxxx>
With the new folio LRU refs tracking API, a folio is considered a
workingset folio if its referenced count > 1. This is compatible and
reasonable in many ways:
The PG_referenced and PG_workingset are used as the lower bits of the
LRU refs counter, and MGLRU will make use of extra bits as higher bits.
So when MGLRU is disabled, all higher bits are always 0, making the
check bit-wise equal to the old behavior. Active/inactive LRU sets
PG_workingset explicitly for folios moved from active list to inactive
list, and that makes the LRU refs tracking API (folio_is_workingset)
report a referenced number > 1. Clearing PG_workingset will always
return a value <= 1.
When MGLRU is enabled, a folio referenced twice is considered a
workingset folio, which is basically the same as how active/inactive LRU
used to promote a file page to the active list. Note for
active/inactive, the folio has to be marked inactive and PG_workingset
before eviction, but MGLRU doesn't have a demotion process, so this
simplified check ensures we have a stable definition and accurate
readings in PSI and readaheads just like before.
Signed-off-by: Kairui Song <kasong@xxxxxxxxxxx>
---
fs/btrfs/compression.c | 3 ++-
mm/filemap.c | 10 +++++-----
mm/page_io.c | 3 ++-
mm/readahead.c | 8 ++++----
mm/workingset.c | 2 +-
5 files changed, 14 insertions(+), 12 deletions(-)
diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index b2393a48a8fe..ac7bfb0017c6 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -21,6 +21,7 @@
#include <linux/sched/mm.h>
#include <linux/log2.h>
#include <linux/shrinker.h>
+#include <linux/mm_inline.h>
#include "misc.h"
#include "ctree.h"
#include "fs.h"
@@ -461,7 +462,7 @@ static noinline int add_ra_bio_pages(struct inode *inode,
continue;
}
- if (!*memstall && folio_test_workingset(folio)) {
+ if (!*memstall && folio_is_workingset(folio)) {
psi_memstall_enter(pflags);
*memstall = 1;
}
diff --git a/mm/filemap.c b/mm/filemap.c
index 4e636647100c..50897ca1d74e 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1254,7 +1254,7 @@ static inline int folio_wait_bit_common(struct folio *folio, int bit_nr,
bool in_thrashing;
if (bit_nr == PG_locked &&
- !folio_test_uptodate(folio) && folio_test_workingset(folio)) {
+ !folio_test_uptodate(folio) && folio_is_workingset(folio)) {
delayacct_thrashing_start(&in_thrashing);
psi_memstall_enter(&pflags);
thrashing = true;
@@ -1409,7 +1409,7 @@ void softleaf_entry_wait_on_locked(softleaf_t entry, spinlock_t *ptl)
struct folio *folio = softleaf_to_folio(entry);
q = folio_waitqueue(folio);
- if (!folio_test_uptodate(folio) && folio_test_workingset(folio)) {
+ if (!folio_test_uptodate(folio) && folio_is_workingset(folio)) {
delayacct_thrashing_start(&in_thrashing);
psi_memstall_enter(&pflags);
thrashing = true;
@@ -2492,7 +2492,7 @@ static void filemap_get_read_batch(struct address_space *mapping,
static int filemap_read_folio(struct file *file, filler_t filler,
struct folio *folio)
{
- bool workingset = folio_test_workingset(folio);
+ bool workingset = folio_is_workingset(folio);
unsigned long pflags;
int error;
@@ -3787,7 +3787,7 @@ static vm_fault_t filemap_map_folio_range(struct vm_fault *vmf,
* Don't decrease mmap_miss in this scenario to make sure
* we can stop read-ahead.
*/
- if (!folio_test_workingset(folio))
+ if (!folio_is_workingset(folio))
(*mmap_miss)++;
/*
@@ -3845,7 +3845,7 @@ static vm_fault_t filemap_map_order0_folio(struct vm_fault *vmf,
goto out;
/* See comment of filemap_map_folio_range() */
- if (!folio_test_workingset(folio))
+ if (!folio_is_workingset(folio))
(*mmap_miss)++;
/*
diff --git a/mm/page_io.c b/mm/page_io.c
index 70cea9e24d2f..a78a4e753650 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -25,6 +25,7 @@
#include <linux/sched/task.h>
#include <linux/delayacct.h>
#include <linux/zswap.h>
+#include <linux/mm_inline.h>
#include "swap.h"
static void __end_swap_bio_write(struct bio *bio)
@@ -614,7 +615,7 @@ void swap_read_folio(struct folio *folio, struct swap_iocb **plug)
{
struct swap_info_struct *sis = __swap_entry_to_info(folio->swap);
bool synchronous = sis->flags & SWP_SYNCHRONOUS_IO;
- bool workingset = folio_test_workingset(folio);
+ bool workingset = folio_is_workingset(folio);
unsigned long pflags;
bool in_thrashing;
diff --git a/mm/readahead.c b/mm/readahead.c
index 7b05082c89ea..f3b03d6e7828 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -291,7 +291,7 @@ void page_cache_ra_unbounded(struct readahead_control *ractl,
}
if (i == mark)
folio_set_readahead(folio);
- ractl->_workingset |= folio_test_workingset(folio);
+ ractl->_workingset |= folio_is_workingset(folio);
ractl->_nr_pages += min_nrpages;
i += min_nrpages;
}
@@ -460,7 +460,7 @@ static inline int ra_alloc_folio(struct readahead_control *ractl, pgoff_t index,
}
ractl->_nr_pages += 1UL << order;
- ractl->_workingset |= folio_test_workingset(folio);
+ ractl->_workingset |= folio_is_workingset(folio);
return 0;
}
@@ -797,7 +797,7 @@ void readahead_expand(struct readahead_control *ractl,
folio_put(folio);
return;
}
- if (unlikely(folio_test_workingset(folio)) &&
+ if (unlikely(folio_is_workingset(folio)) &&
!ractl->_workingset) {
ractl->_workingset = true;
psi_memstall_enter(&ractl->_pflags);
@@ -826,7 +826,7 @@ void readahead_expand(struct readahead_control *ractl,
folio_put(folio);
return;
}
- if (unlikely(folio_test_workingset(folio)) &&
+ if (unlikely(folio_is_workingset(folio)) &&
!ractl->_workingset) {
ractl->_workingset = true;
psi_memstall_enter(&ractl->_pflags);
diff --git a/mm/workingset.c b/mm/workingset.c
index bdee91f54e61..fa644948c80e 100644
--- a/mm/workingset.c
+++ b/mm/workingset.c
@@ -415,7 +415,7 @@ void *workingset_eviction(struct folio *folio, struct mem_cgroup *target_memcg)
eviction >>= bucket_order[file];
workingset_age_nonresident(lruvec, folio_nr_pages(folio));
return pack_shadow(memcgid, pgdat, eviction,
- folio_test_workingset(folio), file);
+ folio_is_workingset(folio), file);
}
/**
--
2.54.0