From mboxrd@z Thu Jan 1 00:00:00 1970 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 D2824C83F19 for ; Mon, 28 Aug 2023 07:49:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229818AbjH1Hsf (ORCPT ); Mon, 28 Aug 2023 03:48:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49920 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229798AbjH1HsG (ORCPT ); Mon, 28 Aug 2023 03:48:06 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C9B19F3 for ; Mon, 28 Aug 2023 00:48:03 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 4E77C617C4 for ; Mon, 28 Aug 2023 07:48:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A8FA7C433C9; Mon, 28 Aug 2023 07:47:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1693208882; bh=CFNiuixnb3UYTeuKjM3Rt3BAiDuLmUsszcQ+qqgsBa4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Nkkvo6kaqwdfZYBHZaowW7k4gkQpMKWajPDj6R8aWMQPxZuFKru2HpZflXqXJ5Hzh P15Z6c8TFZ6KKMlWYbPPvjxbbqDIqXk/m5O16S01HOrCRiCxpv3J2KV+XrDA5CvfcP iJJXnBepDYMe0yGnpwVbJDbafVKwfHybH61cJjUlBozUlkzTgwqrWcM88kMcZu3kOM KpK4bsGCVK5DY2Vn39dUkZ8YAhn1WxZjjKjKcdjkQ0ZmoCndjQpq2MW1Qr+DbyOHmr 36fkCyXJ2KPjOpD3193v/wCZ5HcaJBmMDFXvdlGpBz1BmamrJTlpsrPzvzEeLfwQm9 gv9IXuZwUfZiQ== Date: Mon, 28 Aug 2023 10:47:29 +0300 From: Mike Rapoport To: Usama Arif Cc: linux-mm@kvack.org, muchun.song@linux.dev, mike.kravetz@oracle.com, linux-kernel@vger.kernel.org, songmuchun@bytedance.com, fam.zheng@bytedance.com, liangma@liangbit.com, punit.agrawal@bytedance.com Subject: Re: [v3 3/4] memblock: introduce MEMBLOCK_RSRV_NOINIT_VMEMMAP flag Message-ID: <20230828074729.GC3223@kernel.org> References: <20230825111836.1715308-1-usama.arif@bytedance.com> <20230825111836.1715308-4-usama.arif@bytedance.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230825111836.1715308-4-usama.arif@bytedance.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 25, 2023 at 12:18:35PM +0100, Usama Arif wrote: > For reserved memory regions marked with this flag, > reserve_bootmem_region is not called during memmap_init_reserved_pages. > This can be used to avoid struct page initialization for > regions which won't need them, for e.g. hugepages with > HVO enabled. > > Signed-off-by: Usama Arif > --- > include/linux/memblock.h | 10 ++++++++++ > mm/memblock.c | 32 +++++++++++++++++++++++++++----- > 2 files changed, 37 insertions(+), 5 deletions(-) > > diff --git a/include/linux/memblock.h b/include/linux/memblock.h > index f71ff9f0ec81..6d681d053880 100644 > --- a/include/linux/memblock.h > +++ b/include/linux/memblock.h > @@ -40,6 +40,8 @@ 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_VMEMMAP: memory region for which struct pages are > + * not initialized (only for reserved regions). > */ > enum memblock_flags { > MEMBLOCK_NONE = 0x0, /* No special request */ > @@ -47,6 +49,8 @@ enum memblock_flags { > MEMBLOCK_MIRROR = 0x2, /* mirrored region */ > MEMBLOCK_NOMAP = 0x4, /* don't add to kernel direct mapping */ > MEMBLOCK_DRIVER_MANAGED = 0x8, /* always detected via a driver */ > + /* don't initialize struct pages associated with this reserver memory block */ > + MEMBLOCK_RSRV_NOINIT_VMEMMAP = 0x10, The flag means that struct page shouldn't be initialized, it may be used not only by vmemmap optimizations. Please drop _VMEMMAP. And I agree with Muchun's remarks about the comments. > }; > > /** > @@ -125,6 +129,7 @@ int memblock_clear_hotplug(phys_addr_t base, phys_addr_t size); > int memblock_mark_mirror(phys_addr_t base, phys_addr_t size); > int memblock_mark_nomap(phys_addr_t base, phys_addr_t size); > int memblock_clear_nomap(phys_addr_t base, phys_addr_t size); > +int memblock_reserved_mark_noinit_vmemmap(phys_addr_t base, phys_addr_t size); memblock does not care about vmemmap, please drop _vmemmap here and below as well. > void memblock_free_all(void); > void memblock_free(void *ptr, size_t size); > @@ -259,6 +264,11 @@ static inline bool memblock_is_nomap(struct memblock_region *m) > return m->flags & MEMBLOCK_NOMAP; > } > > +static inline bool memblock_is_noinit_vmemmap(struct memblock_region *m) memblock_is_reserved_noinit please. > +{ > + return m->flags & MEMBLOCK_RSRV_NOINIT_VMEMMAP; > +} > + > static inline bool memblock_is_driver_managed(struct memblock_region *m) > { > return m->flags & MEMBLOCK_DRIVER_MANAGED; > diff --git a/mm/memblock.c b/mm/memblock.c > index 43cb4404d94c..a9782228c840 100644 > --- a/mm/memblock.c > +++ b/mm/memblock.c > @@ -991,6 +991,23 @@ int __init_memblock memblock_clear_nomap(phys_addr_t base, phys_addr_t size) > return memblock_setclr_flag(&memblock.memory, base, size, 0, MEMBLOCK_NOMAP); > } > > +/** > + * memblock_reserved_mark_noinit_vmemmap - Mark a reserved memory region with flag > + * MEMBLOCK_RSRV_NOINIT_VMEMMAP. this should be about what marking RSRV_NOINIT does, not what flag it uses > + * @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_VMEMMAP. > + * > + * Return: 0 on success, -errno on failure. > + */ > +int __init_memblock memblock_reserved_mark_noinit_vmemmap(phys_addr_t base, phys_addr_t size) > +{ > + return memblock_setclr_flag(&memblock.reserved, base, size, 1, > + MEMBLOCK_RSRV_NOINIT_VMEMMAP); > +} > + > static bool should_skip_region(struct memblock_type *type, > struct memblock_region *m, > int nid, int flags) > @@ -2107,13 +2124,18 @@ static void __init memmap_init_reserved_pages(void) > memblock_set_node(start, end, &memblock.reserved, nid); > } > > - /* initialize struct pages for the reserved regions */ > + /* > + * initialize struct pages for reserved regions that don't have > + * the MEMBLOCK_RSRV_NOINIT_VMEMMAP flag set > + */ > for_each_reserved_mem_region(region) { > - nid = memblock_get_region_node(region); > - start = region->base; > - end = start + region->size; > + if (!memblock_is_noinit_vmemmap(region)) { > + nid = memblock_get_region_node(region); > + start = region->base; > + end = start + region->size; > > - reserve_bootmem_region(start, end, nid); > + reserve_bootmem_region(start, end, nid); > + } > } > } > > -- > 2.25.1 > -- Sincerely yours, Mike.