From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 C68651DBB2E; Mon, 25 Aug 2025 16:58:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756141108; cv=none; b=R8UNt0Gtt5Qur9wDRPBQgiUGucLXVycA+kb6Eiw1bJjkMH50XYLypMN+kWmkZ6WdgCecCYQDloTqP1CZ2zLOrFGsLOU7Z4lwhZfk2YwKPUff5H4xCUorV1v3pDHOO2VZZgFNs5j0dZcBDZBdmD7U07aCCynib2F3FpQ5V7anG2U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756141108; c=relaxed/simple; bh=5Xs4ClQrBNPUK24yQ8tvJo62CGzQ+OUCbyk/7pv7K6g=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=QgQWpbJWBzKj1a7SGWEa7yiJVbyEsh6QfFcjr6FB5I1pwO1WfiT8/uFaFVx6gWLTFQRkxS+wNhE7g6Fyui1pXkyyXnYAxEYOOZzOjKauT+7dz50o0FGODdFKhMUV1kmI3JjzzXBcFOZPuunyhfYRHFDPIaVNZWvqRyS3rrMc/xw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=K8EPeL9r; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="K8EPeL9r" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AF37AC4CEED; Mon, 25 Aug 2025 16:58:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1756141107; bh=5Xs4ClQrBNPUK24yQ8tvJo62CGzQ+OUCbyk/7pv7K6g=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=K8EPeL9rFMK2+nBscZ78BHN9AXOnwLlio8wCQA9T4HPI2M7JTseek460vnzI7LqJC TDu4NzXeMpXS8jhUa/iSAcIvRfHFDSrWxcvq7/PwB+bucaEQsHAodSxeBqU3oHbYQw JfnmUaXpTgDVr5GNOQRbyvPuO31dhRIGQUncZS3uv95CJi5KIRjBjS37ASsfqMbjJV FaVoAzebuKQA21fTHdob2rVKAkh6oJNsI5NIl49si6OGRBanVCOrvFPYRUxz3E2h7U H5t70EO0n4A9bkEljsMG6VtFtoS+dKBxf5ZFl9Bmc3Iax0SvbwLHZzXF+Oj3qlKigt vsahqKXPodl2Q== Date: Mon, 25 Aug 2025 19:58:10 +0300 From: Mike Rapoport To: David Hildenbrand Cc: Mika =?iso-8859-1?Q?Penttil=E4?= , linux-kernel@vger.kernel.org, Alexander Potapenko , Andrew Morton , Brendan Jackman , Christoph Lameter , Dennis Zhou , Dmitry Vyukov , dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, iommu@lists.linux.dev, io-uring@vger.kernel.org, Jason Gunthorpe , Jens Axboe , Johannes Weiner , John Hubbard , kasan-dev@googlegroups.com, kvm@vger.kernel.org, "Liam R. Howlett" , Linus Torvalds , linux-arm-kernel@axis.com, linux-arm-kernel@lists.infradead.org, linux-crypto@vger.kernel.org, linux-ide@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mips@vger.kernel.org, linux-mmc@vger.kernel.org, linux-mm@kvack.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org, Lorenzo Stoakes , Marco Elver , Marek Szyprowski , Michal Hocko , Muchun Song , netdev@vger.kernel.org, Oscar Salvador , Peter Xu , Robin Murphy , Suren Baghdasaryan , Tejun Heo , virtualization@lists.linux.dev, Vlastimil Babka , wireguard@lists.zx2c4.com, x86@kernel.org, Zi Yan Subject: update kernel-doc for MEMBLOCK_RSRV_NOINIT (was: Re: [PATCH RFC 10/35] mm/hugetlb: cleanup hugetlb_folio_init_tail_vmemmap()) Message-ID: References: <9156d191-9ec4-4422-bae9-2e8ce66f9d5e@redhat.com> <7077e09f-6ce9-43ba-8f87-47a290680141@redhat.com> Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Mon, Aug 25, 2025 at 06:23:48PM +0200, David Hildenbrand wrote: > > I don't quite understand the interaction with PG_Reserved and why anybody > using this function should care. > > So maybe you can rephrase in a way that is easier to digest, and rather > focuses on what callers of this function are supposed to do vs. have the > liberty of not doing? How about diff --git a/include/linux/memblock.h b/include/linux/memblock.h index b96746376e17..fcda8481de9a 100644 --- a/include/linux/memblock.h +++ b/include/linux/memblock.h @@ -40,8 +40,9 @@ extern unsigned long long max_possible_pfn; * via a driver, and never indicated in the firmware-provided memory map as * system RAM. This corresponds to IORESOURCE_SYSRAM_DRIVER_MANAGED in the * kernel resource tree. - * @MEMBLOCK_RSRV_NOINIT: memory region for which struct pages are - * not initialized (only for reserved regions). + * @MEMBLOCK_RSRV_NOINIT: reserved memory region for which struct pages are not + * fully initialized. Users of this flag are responsible to properly initialize + * struct pages of this region * @MEMBLOCK_RSRV_KERN: memory region that is reserved for kernel use, * either explictitly with memblock_reserve_kern() or via memblock * allocation APIs. All memblock allocations set this flag. diff --git a/mm/memblock.c b/mm/memblock.c index 154f1d73b61f..46b411fb3630 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -1091,13 +1091,20 @@ int __init_memblock memblock_clear_nomap(phys_addr_t base, phys_addr_t size) /** * memblock_reserved_mark_noinit - Mark a reserved memory region with flag - * MEMBLOCK_RSRV_NOINIT which results in the struct pages not being initialized - * for this region. + * MEMBLOCK_RSRV_NOINIT + * * @base: the base phys addr of the region * @size: the size of the region * - * struct pages will not be initialized for reserved memory regions marked with - * %MEMBLOCK_RSRV_NOINIT. + * The struct pages for the reserved regions marked %MEMBLOCK_RSRV_NOINIT will + * not be fully initialized to allow the caller optimize their initialization. + * + * When %CONFIG_DEFERRED_STRUCT_PAGE_INIT is enabled, setting this flag + * completely bypasses the initialization of struct pages for such region. + * + * When %CONFIG_DEFERRED_STRUCT_PAGE_INIT is disabled, struct pages in this + * region will be initialized with default values but won't be marked as + * reserved. * * Return: 0 on success, -errno on failure. */ > -- > Cheers > > David / dhildenb > -- Sincerely yours, Mike.