[PATCH v2 3/5] mm: zswap: refactor limit checking from zswap_store()

From: Yosry Ahmed
Date: Fri Apr 05 2024 - 01:36:04 EST


Refactor limit and acceptance threshold checking outside of
zswap_store(). This code will be moved around in a following patch, so
it would be cleaner to move a function call around.

Signed-off-by: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
---
mm/zswap.c | 29 +++++++++++++++--------------
1 file changed, 15 insertions(+), 14 deletions(-)

diff --git a/mm/zswap.c b/mm/zswap.c
index 832e3f56232f0..ab3cd43cdfc9d 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -1444,6 +1444,20 @@ static void zswap_fill_page(void *ptr, unsigned long value)
memset_l(page, value, PAGE_SIZE / sizeof(unsigned long));
}

+static bool zswap_check_full(void)
+{
+ unsigned long cur_pages = zswap_total_pages();
+
+ if (cur_pages >= READ_ONCE(zswap_max_pages)) {
+ zswap_pool_limit_hit++;
+ zswap_pool_reached_full = true;
+ } else if (zswap_pool_reached_full &&
+ cur_pages <= READ_ONCE(zswap_accept_thr_pages)) {
+ zswap_pool_reached_full = false;
+ }
+ return zswap_pool_reached_full;
+}
+
bool zswap_store(struct folio *folio)
{
swp_entry_t swp = folio->swap;
@@ -1452,7 +1466,6 @@ bool zswap_store(struct folio *folio)
struct zswap_entry *entry, *old;
struct obj_cgroup *objcg = NULL;
struct mem_cgroup *memcg = NULL;
- unsigned long max_pages, cur_pages;

VM_WARN_ON_ONCE(!folio_test_locked(folio));
VM_WARN_ON_ONCE(!folio_test_swapcache(folio));
@@ -1475,20 +1488,8 @@ bool zswap_store(struct folio *folio)
mem_cgroup_put(memcg);
}

- /* Check global limits */
- cur_pages = zswap_total_pages();
- if (cur_pages >= READ_ONCE(zswap_max_pages)) {
- zswap_pool_limit_hit++;
- zswap_pool_reached_full = true;
+ if (zswap_check_full())
goto reject;
- }
-
- if (zswap_pool_reached_full) {
- if (cur_pages > READ_ONCE(zswap_accept_thr_pages))
- goto reject;
- else
- zswap_pool_reached_full = false;
- }

/* allocate entry */
entry = zswap_entry_cache_alloc(GFP_KERNEL, folio_nid(folio));
--
2.44.0.478.gd926399ef9-goog