From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4E7B7480DD1 for ; Thu, 2 Jul 2026 12:50:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782996606; cv=none; b=mhjh7hkvYttXCpZ4jtEpJsU7XGstdYDpSlqR7bUpU7d/bGSRUF72LxH7CSfOpykz7ukv5ydsyXG/7yYk0KjU7w2ItC7yyQO/QeTTpq2mGu4UbY/3eubD06LnrmntUjO0onn7qaA1c+Puw8nnjvT5DKBKX3iqUOvmq7eJyV/SosI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782996606; c=relaxed/simple; bh=aDFGKLrJyONBobW5+ctgGWqbIHfLDgwoKcQsseKJw9g=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=eCUHisVX9Qmvq54IF3BWgXAstrEZrP+6l87VMJsVTG3IJGHXr7eQl8DfzDNbHh05Ztj5BRv+WdFscPL4432tY1RIMt6ouSaTZnlHNQG8EDxvM25Rb83RdHcBr4j67VFX0j10Swkub5Dj2axIUfMfbG7ZDxbnhR5IBZbV9GZvhJ8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=T8DHv3d8; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="T8DHv3d8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5128B1F000E9; Thu, 2 Jul 2026 12:49:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782996600; bh=tZi5/PxPDHPTvkcO5bl7EKgvWFiIsWID58nlNnwaQfo=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=T8DHv3d8UB5SYbQ7X8E936a47Cf8KKIU9qWB0eDMFtMWJKi3lgZn8n+XWRnPih70V +I8sJQqVN02vy2zTNH8lhBpfuKfbSj6JAZfJf9AkuP8W2f7rDD3LIYUeD+DJUU1lj0 o3vAnSWsELO55LGD1Uy7BBpPb6+rbIHLIMk7u+v1xcD7PXb+u6EPDnJTJ0sAB0ryA2 nbAS+ggnexoEE/9RmNLfAfeIIp+4hpI4y0Lamu0zQ+XplqQSK7DmBUHpu5+t7crzFZ 51vu3bRBZrhPDa9DJLr8nGvkNrgvdlird8co7vg+XZpU+RLiNpY5wTJbGqWbMsZ8xW BbK2GuEsscHNg== Message-ID: Date: Thu, 2 Jul 2026 14:49:57 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC hotfixes 1/2] mm/slab: decouple SLAB_NO_SHEAVES from SLAB_NO_OBJ_EXT Content-Language: en-US To: "Harry Yoo (Oracle)" , Andrew Morton , Hao Li , Christoph Lameter , David Rientjes , Roman Gushchin , Suren Baghdasaryan , Hao Ge , Kees Cook , Pedro Falcato , Shakeel Butt , Danielle Constantino Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20260702-kmalloc-no-objext-v1-0-167175008538@kernel.org> <20260702-kmalloc-no-objext-v1-1-167175008538@kernel.org> From: "Vlastimil Babka (SUSE)" Autocrypt: addr=vbabka@kernel.org; keydata= xsFNBFZdmxYBEADsw/SiUSjB0dM+vSh95UkgcHjzEVBlby/Fg+g42O7LAEkCYXi/vvq31JTB KxRWDHX0R2tgpFDXHnzZcQywawu8eSq0LxzxFNYMvtB7sV1pxYwej2qx9B75qW2plBs+7+YB 87tMFA+u+L4Z5xAzIimfLD5EKC56kJ1CsXlM8S/LHcmdD9Ctkn3trYDNnat0eoAcfPIP2OZ+ 9oe9IF/R28zmh0ifLXyJQQz5ofdj4bPf8ecEW0rhcqHfTD8k4yK0xxt3xW+6Exqp9n9bydiy tcSAw/TahjW6yrA+6JhSBv1v2tIm+itQc073zjSX8OFL51qQVzRFr7H2UQG33lw2QrvHRXqD Ot7ViKam7v0Ho9wEWiQOOZlHItOOXFphWb2yq3nzrKe45oWoSgkxKb97MVsQ+q2SYjJRBBH4 8qKhphADYxkIP6yut/eaj9ImvRUZZRi0DTc8xfnvHGTjKbJzC2xpFcY0DQbZzuwsIZ8OPJCc LM4S7mT25NE5kUTG/TKQCk922vRdGVMoLA7dIQrgXnRXtyT61sg8PG4wcfOnuWf8577aXP1x 6mzw3/jh3F+oSBHb/GcLC7mvWreJifUL2gEdssGfXhGWBo6zLS3qhgtwjay0Jl+kza1lo+Cv BB2T79D4WGdDuVa4eOrQ02TxqGN7G0Biz5ZLRSFzQSQwLn8fbwARAQABzSNWbGFzdGltaWwg QmFia2EgPHZiYWJrYUBrZXJuZWwub3JnPsLBsAQTAQoAWhYhBKlA1DSZLC6OmRA9UCJPp+fM gqZkBQJqFFy6GxSAAAAAAAQADm1hbnUyLDIuNSsxLjEyLDIsMgIbAwUJGtCBUAULCQgHAwUV CgkICwUWAgMBAAIeBQIXgAAKCRAiT6fnzIKmZJIUEADFx/tREzUImHrEwVHeSvDFmA7tJysI UVrlvrM09E7GIuzphzv7jYmo8n3ANpCczLEVr4G0syYQdTigaZgv3+FQDIIzhKih1IHhu1Ei XHlywNWKnQxxQEUNi5Mwx43wQz5XVw9F1A7gtKBKNtfogO511hAbrzagrYajyQacEJ/+sfhZ 9Da8ltHIXD8pcYaHUfQgEusCgmEd9+KrUwrTbckFKmYq5chuE6yJ4J0EmWknL096jIE6CnzF FRslQ3B1UKDjxVsm1ZHfir5NeWszLkTvGFsddFaWTgh8UycESG6VQzKXjjewXu2pG7YQYRpj QKm1W5X2TkwWkXRBZTmfmbhxIUMh3+zf5wQ463rSmDN/8v81tdqBtAW6rH/kzg1GvkaTHXn0 507yEHFzBksk2viAuIxxr7km8+/KARYLIdGtx30EG8cKzAUZOK6WqxtNCsXUJNrVE8CWrCaD icoNu7Fs1c5hmPHdSTnU48ce67449DdnO4neLSNhRiGlMHJgfJUmgrxu/hcYeOZ3haWmEQ2w uW1Mh01OHi8QZHCEyAbABrPs9GUgccc/4eYXX9hIgxfSkYzn8f+8NuIFPWl/0uTvjgqU29FQ SbzOLxHq9439Ox40G5mS5eZXRGxITYR+6TXvRGI6P/264jvflnr/pDGUttaikU+0W+1uxgKH cmYbEc7ATQRbGTU1AQgAn0H6UrFiWcovkh6EXVcl+SeqyO6JHOPm+e9Wu0Vw+VIUvXZVUVVQ La1PQDUi6j00ChlcR66g9/V0sPIcSutacPKfdKYOBvzd4rlhL8rfrdEsQw5ApZxrA8kYZVMh FmBRKAa6wos25moTlMKpCWzTH84+WO5+ziCTsTUZASAToz3RdunTD+vQcHj0GqNTPAHK63sf bAB2I0BslZkXkY1RLb/YhuA6E7JyEd2pilZOrIuBGl/5q2qSakgnAVFWFBR/DO27JuAksYnq +aH8vI0xGvwn75KqSk4UzAkDzWSmO4ZHuahKtQgZNsMYV+PGayRBX9b9zbldzopoLBdqHc4n jQARAQABwsF8BBgBCgAmAhsMFiEEqUDUNJksLo6ZED1QIk+n58yCpmQFAmfIHFQFCRYU6J8A CgkQIk+n58yCpmS2PA//bqN1LfcotmArgElsa+0EGZSQlYgK48pm8WAeTXTngudP9IJ4SuKY HR5RNjHcBeqN+Me0zxRqYzRb8nGanHEkDyf4Im8DQM8d6vbyU+FcPmG4skud4kgS1zMHnlVd SXfSIwKC/hKgdHG8aBV7545Lz9X6Iohea+94wneD0aw/hqF+QWewGZhWJriWAZtvEkzNjQOi 4U9F/trLten/x7bpphDSnDMKJtITbtzATT1Dq7o7VpIUK1nCTQALMuMjKCdi8OdU/+V+R3O4 0PXWvX8qrvqYapVbZ+9KqT74FsuB0Ya9uXwgBF2Q6cRuETZk5vqaqKxzqoQZCO8AOz/58j6O 2RHNy/mZEN+7tJ5Tsq42zVJ4jxsT8b9YplavCMsnBgDeRWhcbYhCyttoL7nYISyWg4kQYZ/P wIV3OuNv2f8iKYsxNsRuClOAF82+gvqOy1/1pprFjy8uo2pkoOrb63aOP3vO5VHnRKgra6dq NcaZ+c6J4H+nEJGi2SkHAUJz5oBzuThvPudLvPA/SK8sKoM01IRxSihev/S/5WLazXB1PGem OCbvzC1IjWJJraxiDJ5IygokapUa2RP7+WBR22skQ3SSl6G107QgWKSyTOGWEaRmV53vxQLV jXuCmzSSasTL60zq5yGrT4/DYQVSNEUiUbG4pYekxJujNeEDkUlky0Y= In-Reply-To: <20260702-kmalloc-no-objext-v1-1-167175008538@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 7/2/26 06:09, Harry Yoo (Oracle) wrote: > Bootstrap caches are created with SLAB_NO_OBJ_EXT to disallow sheaves > and obj_exts. > > To allow disabling obj_exts while allowing sheaves, decouple > SLAB_NO_SHEAVES from SLAB_NO_OBJ_EXT. Bootstrap caches now have both > SLAB_NO_SHEAVES and SLAB_NO_OBJ_EXT. > > No functional change intended. > > Cc: stable@vger.kernel.org > Fixes: e47c897a2949 ("slab: add sheaves to most caches") > Signed-off-by: Harry Yoo (Oracle) Reviewed-by: Vlastimil Babka (SUSE) > --- > include/linux/slab.h | 13 +++++++++++-- > mm/slub.c | 10 ++++++---- > 2 files changed, 17 insertions(+), 6 deletions(-) > > diff --git a/include/linux/slab.h b/include/linux/slab.h > index 51f03f18c9a7..08d7b6c9c4d6 100644 > --- a/include/linux/slab.h > +++ b/include/linux/slab.h > @@ -58,10 +58,13 @@ enum _slab_flag_bits { > #endif > _SLAB_OBJECT_POISON, > _SLAB_CMPXCHG_DOUBLE, > +#ifdef CONFIG_SLAB_OBJ_EXT > _SLAB_NO_OBJ_EXT, > -#if defined(CONFIG_SLAB_OBJ_EXT) && defined(CONFIG_64BIT) > +#ifdef CONFIG_64BIT > _SLAB_OBJ_EXT_IN_OBJ, > #endif > +#endif > + _SLAB_NO_SHEAVES, > _SLAB_FLAGS_LAST_BIT > }; > > @@ -239,8 +242,14 @@ enum _slab_flag_bits { > #endif > #define SLAB_TEMPORARY SLAB_RECLAIM_ACCOUNT /* Objects are short-lived */ > > -/* Slab created using create_boot_cache */ > +/* Slab caches without obj_exts array */ > +#ifdef CONFIG_SLAB_OBJ_EXT > #define SLAB_NO_OBJ_EXT __SLAB_FLAG_BIT(_SLAB_NO_OBJ_EXT) > +#else > +#define SLAB_NO_OBJ_EXT __SLAB_FLAG_UNUSED > +#endif > + > +#define SLAB_NO_SHEAVES __SLAB_FLAG_BIT(_SLAB_NO_SHEAVES) > > #if defined(CONFIG_SLAB_OBJ_EXT) && defined(CONFIG_64BIT) > #define SLAB_OBJ_EXT_IN_OBJ __SLAB_FLAG_BIT(_SLAB_OBJ_EXT_IN_OBJ) > diff --git a/mm/slub.c b/mm/slub.c > index 9f754cf1c187..efc85053ae84 100644 > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -7777,12 +7777,12 @@ static unsigned int calculate_sheaf_capacity(struct kmem_cache *s, > return 0; > > /* > - * Bootstrap caches can't have sheaves for now (SLAB_NO_OBJ_EXT). > + * Bootstrap caches can't have sheaves for now (SLAB_NO_SHEAVES). > * SLAB_NOLEAKTRACE caches (e.g., kmemleak's object_cache) must not > * have sheaves to avoid recursion when sheaf allocation triggers > * kmemleak tracking. > */ > - if (s->flags & (SLAB_NO_OBJ_EXT | SLAB_NOLEAKTRACE)) > + if (s->flags & (SLAB_NO_SHEAVES | SLAB_NOLEAKTRACE)) > return 0; > > /* > @@ -8559,7 +8559,8 @@ void __init kmem_cache_init(void) > > create_boot_cache(kmem_cache_node, "kmem_cache_node", > sizeof(struct kmem_cache_node), > - SLAB_HWCACHE_ALIGN | SLAB_NO_OBJ_EXT, 0, 0); > + SLAB_HWCACHE_ALIGN | SLAB_NO_SHEAVES | SLAB_NO_OBJ_EXT, > + 0, 0); > > hotplug_node_notifier(slab_memory_callback, SLAB_CALLBACK_PRI); > > @@ -8569,7 +8570,8 @@ void __init kmem_cache_init(void) > create_boot_cache(kmem_cache, "kmem_cache", > offsetof(struct kmem_cache, per_node) + > nr_node_ids * sizeof(struct kmem_cache_per_node_ptrs), > - SLAB_HWCACHE_ALIGN | SLAB_NO_OBJ_EXT, 0, 0); > + SLAB_HWCACHE_ALIGN | SLAB_NO_SHEAVES | SLAB_NO_OBJ_EXT, > + 0, 0); > > kmem_cache = bootstrap(&boot_kmem_cache); > kmem_cache_node = bootstrap(&boot_kmem_cache_node); >