From: Kefeng Wang <wangkefeng.wang@huawei.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: <linux-mm@kvack.org>, Chengming Zhou <chengming.zhou@linux.dev>,
Johannes Weiner <hannes@cmpxchg.org>,
Kairui Song <kasong@tencent.com>, Nhat Pham <nphamcs@gmail.com>,
Yosry Ahmed <yosryahmed@google.com>,
Kefeng Wang <wangkefeng.wang@huawei.com>
Subject: [PATCH v2 3/4] mm: zswap: avoid unnecessary xarray lookup in zswap_store()
Date: Thu, 10 Sep 2026 17:54:48 +0800 [thread overview]
Message-ID: <20260910095449.715183-4-wangkefeng.wang@huawei.com> (raw)
In-Reply-To: <20260910095449.715183-1-wangkefeng.wang@huawei.com>
zswap_store() falls through to check_old and walks the swap xarray
even when zswap is disabled. Add a zswap_never_enabled() early return
matching zswap_load() to avoid unnecessary xarray lookup.
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
mm/zswap.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/mm/zswap.c b/mm/zswap.c
index 2c06e4e0e130..6197aa71e33c 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -1492,6 +1492,9 @@ bool zswap_store(struct folio *folio)
VM_WARN_ON_ONCE(!folio_test_locked(folio));
VM_WARN_ON_ONCE(!folio_test_swapcache(folio));
+ if (zswap_never_enabled())
+ return false;
+
if (!zswap_enabled)
goto check_old;
--
2.55.0
next prev parent reply other threads:[~2026-09-10 9:55 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-10 9:54 [PATCH v2 0/4] mm: zswap: misc optimizations Kefeng Wang
2026-09-10 9:54 ` [PATCH v2 1/4] mm: zswap: pass type and offset to zswap_invalidate() directly Kefeng Wang
2026-09-10 10:26 ` Yosry Ahmed
2026-09-10 17:57 ` Nhat Pham
2026-09-10 19:27 ` Johannes Weiner
2026-09-10 9:54 ` [PATCH v2 2/4] mm: zswap: reuse zswap_invalidate() in zswap_store() check_old path Kefeng Wang
2026-09-10 10:27 ` Yosry Ahmed
2026-09-10 19:27 ` Johannes Weiner
2026-09-10 9:54 ` Kefeng Wang [this message]
2026-09-10 10:28 ` [PATCH v2 3/4] mm: zswap: avoid unnecessary xarray lookup in zswap_store() Yosry Ahmed
2026-09-10 9:54 ` [PATCH v2 4/4] mm: zswap: skip zswap_invalidate() in swap_range_free() when zswap is unused Kefeng Wang
2026-09-10 10:29 ` Yosry Ahmed
2026-09-10 11:10 ` Kefeng Wang
2026-09-10 11:12 ` Yosry Ahmed
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