From nobody Fri Jan 2 01:31:39 2026 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 53DA3CDB474 for ; Tue, 17 Oct 2023 15:45:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344131AbjJQPpZ (ORCPT ); Tue, 17 Oct 2023 11:45:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42314 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235034AbjJQPpW (ORCPT ); Tue, 17 Oct 2023 11:45:22 -0400 Received: from out-206.mta1.migadu.com (out-206.mta1.migadu.com [95.215.58.206]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E173095 for ; Tue, 17 Oct 2023 08:45:20 -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=1697557519; 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=k+bY4oHxBRtJWcNO+Gp7uU0LbPEc1T0Re1GRoZLORj4=; b=CcmfhoGdDV5iQ65rv3mmqcXetcW5trAeYkwUs1YW3F3rWasU7mQ1KysL674T5DLYaL+6bY hvlmkEqgAGs6ijxn+CaFmKHMdHwEHXZOjokAKPisHp+6bsfBg24xWmR06X5Sv+xRkXOR31 /Kyv+0b/9DHODnwMzhKPyqiEic4J/bc= From: chengming.zhou@linux.dev To: cl@linux.com, penberg@kernel.org Cc: rientjes@google.com, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org, vbabka@suse.cz, 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 1/5] slub: Introduce on_partial() Date: Tue, 17 Oct 2023 15:44:35 +0000 Message-Id: <20231017154439.3036608-2-chengming.zhou@linux.dev> In-Reply-To: <20231017154439.3036608-1-chengming.zhou@linux.dev> References: <20231017154439.3036608-1-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 We change slab->__unused to slab->flags to use it as SLUB_FLAGS, which now only include SF_NODE_PARTIAL flag. It indicates whether or not the slab is on node partial list. The following patches will change to don't freeze slab when moving it from node partial list to cpu partial list. So we can't rely on frozen bit to see if we should manipulate the slab->slab_list. Instead we will rely on this SF_NODE_PARTIAL flag, which is protected by node list_lock. Signed-off-by: Chengming Zhou --- mm/slab.h | 2 +- mm/slub.c | 28 ++++++++++++++++++++++++++++ 2 files changed, 29 insertions(+), 1 deletion(-) diff --git a/mm/slab.h b/mm/slab.h index 8cd3294fedf5..11e9c9a0f648 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -89,7 +89,7 @@ struct slab { }; struct rcu_head rcu_head; }; - unsigned int __unused; + unsigned int flags; =20 #else #error "Unexpected slab allocator configured" diff --git a/mm/slub.c b/mm/slub.c index 63d281dfacdb..e5356ad14951 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1993,6 +1993,12 @@ static inline bool shuffle_freelist(struct kmem_cach= e *s, struct slab *slab) } #endif /* CONFIG_SLAB_FREELIST_RANDOM */ =20 +enum SLUB_FLAGS { + SF_INIT_VALUE =3D 0, + SF_EXIT_VALUE =3D -1, + SF_NODE_PARTIAL =3D 1 << 0, +}; + static struct slab *allocate_slab(struct kmem_cache *s, gfp_t flags, int n= ode) { struct slab *slab; @@ -2031,6 +2037,7 @@ static struct slab *allocate_slab(struct kmem_cache *= s, gfp_t flags, int node) slab->objects =3D oo_objects(oo); slab->inuse =3D 0; slab->frozen =3D 0; + slab->flags =3D SF_INIT_VALUE; =20 account_slab(slab, oo_order(oo), s, flags); =20 @@ -2077,6 +2084,7 @@ static void __free_slab(struct kmem_cache *s, struct = slab *slab) int order =3D folio_order(folio); int pages =3D 1 << order; =20 + slab->flags =3D SF_EXIT_VALUE; __slab_clear_pfmemalloc(slab); folio->mapping =3D NULL; /* Make the mapping reset visible before clearing the flag */ @@ -2119,9 +2127,28 @@ static void discard_slab(struct kmem_cache *s, struc= t slab *slab) /* * Management of partially allocated slabs. */ +static void ___add_partial(struct kmem_cache_node *n, struct slab *slab) +{ + lockdep_assert_held(&n->list_lock); + slab->flags |=3D SF_NODE_PARTIAL; +} + +static void ___remove_partial(struct kmem_cache_node *n, struct slab *slab) +{ + lockdep_assert_held(&n->list_lock); + slab->flags &=3D ~SF_NODE_PARTIAL; +} + +static inline bool on_partial(struct kmem_cache_node *n, struct slab *slab) +{ + lockdep_assert_held(&n->list_lock); + return slab->flags & SF_NODE_PARTIAL; +} + static inline void __add_partial(struct kmem_cache_node *n, struct slab *slab, int tail) { + ___add_partial(n, slab); n->nr_partial++; if (tail =3D=3D DEACTIVATE_TO_TAIL) list_add_tail(&slab->slab_list, &n->partial); @@ -2142,6 +2169,7 @@ static inline void remove_partial(struct kmem_cache_n= ode *n, lockdep_assert_held(&n->list_lock); list_del(&slab->slab_list); n->nr_partial--; + ___remove_partial(n, slab); } =20 /* --=20 2.40.1