[RFC PATCH 3/9] mm: zswap: refactor limit checking from zswap_store()

Yosry Ahmed
2024-03-25T23:50:25Z

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@google.com>
---
mm/zswap.c | 32 ++++++++++++++++----------------
1 file changed, 16 insertions(+), 16 deletions(-)

diff --git a/mm/zswap.c b/mm/zswap.c
index ff1975afb7e3d..6b890c8590ef7 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -1415,6 +1415,21 @@ static void zswap_fill_page(void *ptr, unsigned long value)
memset_l(page, value, PAGE_SIZE / sizeof(unsigned long));
}

+static bool zswap_check_limit(void)
+{
+ unsigned long cur_pages = zswap_total_pages();
+ unsigned long thr = zswap_accept_thr_pages();
+ unsigned long max_pages = zswap_max_pages();
+
+ if (cur_pages >= max_pages) {
+ zswap_pool_limit_hit++;
+ zswap_pool_reached_full = true;
+ } else if (zswap_pool_reached_full && cur_pages <= thr) {
+ zswap_pool_reached_full = false;
+ }
+ return !zswap_pool_reached_full;
+}
+
bool zswap_store(struct folio *folio)
{
swp_entry_t swp = folio->swap;
@@ -1422,7 +1437,6 @@ bool zswap_store(struct folio *folio)
struct xarray *tree = swap_zswap_tree(swp);
struct obj_cgroup *objcg = NULL;
struct mem_cgroup *memcg = NULL;
- unsigned long max_pages, cur_pages;
struct zswap_entry *entry;

VM_WARN_ON_ONCE(!folio_test_locked(folio));
@@ -1446,22 +1460,8 @@ bool zswap_store(struct folio *folio)
mem_cgroup_put(memcg);
}

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

/* allocate entry */
entry = zswap_entry_cache_alloc(GFP_KERNEL, folio_nid(folio));
--
2.44.0.396.g6e790dbe36-goog