From nobody Wed Dec 31 18:16:58 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4BE7FC4332F for ; Tue, 31 Oct 2023 14:09:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233271AbjJaOJO (ORCPT ); Tue, 31 Oct 2023 10:09:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34474 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231286AbjJaOJL (ORCPT ); Tue, 31 Oct 2023 10:09:11 -0400 Received: from out-181.mta1.migadu.com (out-181.mta1.migadu.com [IPv6:2001:41d0:203:375::b5]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 492E9F1 for ; Tue, 31 Oct 2023 07:09:08 -0700 (PDT) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1698761346; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=A++jOVGS7LIP72VwRB52HksoP76pYwnYqPVPh8XlVaY=; b=e0oJj347aPZSwbHKIh3vXLsSkKARGwrOKNnsPyGmHd3T7kZSTXQX3ogXWfbcaQarI3N9T+ K6a8+/g2w/Lvo1/fNOwaYaNltKZM0McSUApZ+72CI1R6rJaPoGntDGGb/xG8G5fgvNBo8e 6XB8zAf1SLuL1e087s8VurnX6PJPY5s= From: chengming.zhou@linux.dev To: vbabka@suse.cz, cl@linux.com, penberg@kernel.org, willy@infradead.org Cc: rientjes@google.com, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org, roman.gushchin@linux.dev, 42.hyeyoo@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, chengming.zhou@linux.dev, Chengming Zhou Subject: [RFC PATCH v4 3/9] slub: Keep track of whether slub is on the per-node partial list Date: Tue, 31 Oct 2023 14:07:35 +0000 Message-Id: <20231031140741.79387-4-chengming.zhou@linux.dev> In-Reply-To: <20231031140741.79387-1-chengming.zhou@linux.dev> References: <20231031140741.79387-1-chengming.zhou@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Chengming Zhou Now we rely on the "frozen" bit to see if we should manipulate the slab->slab_list, which will be changed in the following patch. Instead we introduce another way to keep track of whether slub is on the per-node partial list, here we reuse the PG_workingset bit. We use __set_bit and __clear_bit directly instead of the atomic version for better performance and it's safe since it's protected by the slub node list_lock. Suggested-by: Matthew Wilcox Signed-off-by: Chengming Zhou Reviewed-by: Vlastimil Babka --- mm/slub.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/mm/slub.c b/mm/slub.c index 03384cd965c5..eed8ae0dbaf9 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2116,6 +2116,25 @@ static void discard_slab(struct kmem_cache *s, struc= t slab *slab) free_slab(s, slab); } =20 +/* + * SLUB reuses PG_workingset bit to keep track of whether it's on + * the per-node partial list. + */ +static inline bool slab_test_node_partial(const struct slab *slab) +{ + return folio_test_workingset((struct folio *)slab_folio(slab)); +} + +static inline void slab_set_node_partial(struct slab *slab) +{ + __set_bit(PG_workingset, folio_flags(slab_folio(slab), 0)); +} + +static inline void slab_clear_node_partial(struct slab *slab) +{ + __clear_bit(PG_workingset, folio_flags(slab_folio(slab), 0)); +} + /* * Management of partially allocated slabs. */ @@ -2127,6 +2146,7 @@ __add_partial(struct kmem_cache_node *n, struct slab = *slab, int tail) list_add_tail(&slab->slab_list, &n->partial); else list_add(&slab->slab_list, &n->partial); + slab_set_node_partial(slab); } =20 static inline void add_partial(struct kmem_cache_node *n, @@ -2141,6 +2161,7 @@ static inline void remove_partial(struct kmem_cache_n= ode *n, { lockdep_assert_held(&n->list_lock); list_del(&slab->slab_list); + slab_clear_node_partial(slab); n->nr_partial--; } =20 @@ -4833,6 +4854,7 @@ static int __kmem_cache_do_shrink(struct kmem_cache *= s) =20 if (free =3D=3D slab->objects) { list_move(&slab->slab_list, &discard); + slab_clear_node_partial(slab); n->nr_partial--; dec_slabs_node(s, node, slab->objects); } else if (free <=3D SHRINK_PROMOTE_MAX) --=20 2.20.1