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mm: huge_memory: refactor anon_enabled_store() with set_anon_enabled_mode()

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Consolidate the repeated spin_lock/set_bit/clear_bit pattern in
anon_enabled_store() into a new set_anon_enabled_mode() helper that loops
over an orders[] array, setting the bit for the selected mode and clearing
the others.

Introduce enum anon_enabled_mode and anon_enabled_mode_strings[] for the
per-order anon THP setting.

Use sysfs_match_string() with the anon_enabled_mode_strings[] table to
replace the if/else chain of sysfs_streq() calls.

The helper uses __test_and_set_bit()/__test_and_clear_bit() to track
whether the state actually changed, so start_stop_khugepaged() is only
called when needed.  When the mode is unchanged,
set_recommended_min_free_kbytes() is called directly to preserve the
watermark recalculation behavior of the original code.

Link: https://lkml.kernel.org/r/20260317-thp_logs-v7-2-31eb98fa5a8b@debian.org
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Breno Leitao 2026-03-17 08:33:57 -07:00 committed by Andrew Morton
parent c82aade08c
commit 82d9ff648c
1 changed files with 52 additions and 32 deletions
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84
mm/huge_memory.c
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@ -316,6 +316,20 @@ static ssize_t enabled_show(struct kobject *kobj,
return sysfs_emit(buf, "%s\n", output);
}
enum anon_enabled_mode {
ANON_ENABLED_ALWAYS = 0,
ANON_ENABLED_INHERIT = 1,
ANON_ENABLED_MADVISE = 2,
ANON_ENABLED_NEVER = 3,
};
static const char * const anon_enabled_mode_strings[] = {
[ANON_ENABLED_ALWAYS] = "always",
[ANON_ENABLED_INHERIT] = "inherit",
[ANON_ENABLED_MADVISE] = "madvise",
[ANON_ENABLED_NEVER] = "never",
};
static ssize_t enabled_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
@ -515,48 +529,54 @@ static ssize_t anon_enabled_show(struct kobject *kobj,
return sysfs_emit(buf, "%s\n", output);
}
static bool set_anon_enabled_mode(int order, enum anon_enabled_mode mode)
{
static unsigned long *enabled_orders[] = {
&huge_anon_orders_always,
&huge_anon_orders_inherit,
&huge_anon_orders_madvise,
};
enum anon_enabled_mode m;
bool changed = false;
spin_lock(&huge_anon_orders_lock);
for (m = 0; m < ARRAY_SIZE(enabled_orders); m++) {
if (m == mode)
changed |= !__test_and_set_bit(order, enabled_orders[m]);
else
changed |= __test_and_clear_bit(order, enabled_orders[m]);
}
spin_unlock(&huge_anon_orders_lock);
return changed;
}
static ssize_t anon_enabled_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
int order = to_thpsize(kobj)->order;
ssize_t ret = count;
int mode;
if (sysfs_streq(buf, "always")) {
spin_lock(&huge_anon_orders_lock);
clear_bit(order, &huge_anon_orders_inherit);
clear_bit(order, &huge_anon_orders_madvise);
set_bit(order, &huge_anon_orders_always);
spin_unlock(&huge_anon_orders_lock);
} else if (sysfs_streq(buf, "inherit")) {
spin_lock(&huge_anon_orders_lock);
clear_bit(order, &huge_anon_orders_always);
clear_bit(order, &huge_anon_orders_madvise);
set_bit(order, &huge_anon_orders_inherit);
spin_unlock(&huge_anon_orders_lock);
} else if (sysfs_streq(buf, "madvise")) {
spin_lock(&huge_anon_orders_lock);
clear_bit(order, &huge_anon_orders_always);
clear_bit(order, &huge_anon_orders_inherit);
set_bit(order, &huge_anon_orders_madvise);
spin_unlock(&huge_anon_orders_lock);
} else if (sysfs_streq(buf, "never")) {
spin_lock(&huge_anon_orders_lock);
clear_bit(order, &huge_anon_orders_always);
clear_bit(order, &huge_anon_orders_inherit);
clear_bit(order, &huge_anon_orders_madvise);
spin_unlock(&huge_anon_orders_lock);
} else
ret = -EINVAL;
mode = sysfs_match_string(anon_enabled_mode_strings, buf);
if (mode < 0)
return -EINVAL;
if (ret > 0) {
int err;
if (set_anon_enabled_mode(order, mode)) {
int err = start_stop_khugepaged();
err = start_stop_khugepaged();
if (err)
ret = err;
return err;
} else {
/*
* Recalculate watermarks even when the mode didn't
* change, as the previous code always called
* start_stop_khugepaged() which does this internally.
*/
set_recommended_min_free_kbytes();
}
return ret;
return count;
}
static struct kobj_attribute anon_enabled_attr =