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 0ED97C433EF for ; Fri, 1 Apr 2022 16:28:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243414AbiDAQaY (ORCPT ); Fri, 1 Apr 2022 12:30:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38552 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348557AbiDAQ16 (ORCPT ); Fri, 1 Apr 2022 12:27:58 -0400 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 2EB0E13F89 for ; Fri, 1 Apr 2022 08:59:26 -0700 (PDT) Received: from [192.168.4.54] (cpe-70-95-196-11.san.res.rr.com [70.95.196.11]) by linux.microsoft.com (Postfix) with ESMTPSA id 267D920DEEBF; Fri, 1 Apr 2022 08:59:25 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 267D920DEEBF DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1648828765; bh=4U2yibKauUx9VepxeUJ4omwk1df4H2DqEYX73pyN2jU=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=cJfgF5guqfuH2XAMLI4R332Jmgro/dAyFeCQw/usoUMHx5Tu/aaSgNhhP14UOAdv2 nIpTkdNy0+ME3YhEd1tfhJRFWjGkYeEDbocixtfiWuGm4LFn+QVmvSUgK+PYlStRZV urQmxT+RTEHnW8ILrxgzj4iSgTp0Dyvo6WSYjlPA= Message-ID: <69c1e722-33ea-95cf-de84-aed3022cb042@linux.microsoft.com> Date: Fri, 1 Apr 2022 08:59:24 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: [PATCH v2 resend 1/3] arm64: mm: Do not defer reserve_crashkernel() if only ZONE_DMA32 Content-Language: en-US To: Kefeng Wang , catalin.marinas@arm.com, will@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: f.fainelli@gmail.com, Pasha Tatashin References: <20220331074055.125824-1-wangkefeng.wang@huawei.com> <20220331074055.125824-2-wangkefeng.wang@huawei.com> From: Vijay Balakrishna In-Reply-To: <20220331074055.125824-2-wangkefeng.wang@huawei.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/31/2022 12:40 AM, Kefeng Wang wrote: > The kernel could be benefit due to BLOCK_MAPPINGS, see commit > 031495635b46 ("arm64: Do not defer reserve_crashkernel() for > platforms with no DMA memory zones"), if only with ZONE_DMA32, > set arm64_dma_phys_limit to max_zone_phys(32) earlier in > arm64_memblock_init(), so platforms with just ZONE_DMA32 config > enabled will be benefit. nit -- - "will be benefit" => will benefit On further look I feel we can getaway without dma32_phys_limit static global and replace with two separate calls to max_zone_phys(32)? Just a thought. If you decide to keep it then a better location would be immediately above arm64_memblock_init() definition where it is initialized can improve code readability. Thanks, Vijay > > Cc: Vijay Balakrishna > Cc: Pasha Tatashin > Cc: Will Deacon > Reviewed-by: Vijay Balakrishna > Signed-off-by: Kefeng Wang > --- > arch/arm64/mm/init.c | 23 +++++++++++++---------- > arch/arm64/mm/mmu.c | 6 ++---- > 2 files changed, 15 insertions(+), 14 deletions(-) > > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c > index 8ac25f19084e..fb01eb489fa9 100644 > --- a/arch/arm64/mm/init.c > +++ b/arch/arm64/mm/init.c > @@ -65,8 +65,9 @@ EXPORT_SYMBOL(memstart_addr); > * Memory reservation for crash kernel either done early or deferred > * depending on DMA memory zones configs (ZONE_DMA) -- > * > - * In absence of ZONE_DMA configs arm64_dma_phys_limit initialized > - * here instead of max_zone_phys(). This lets early reservation of > + * In absence of ZONE_DMA and ZONE_DMA32 configs arm64_dma_phys_limit > + * initialized here and if only with ZONE_DMA32 arm64_dma_phys_limit > + * initialised to dma32_phys_limit. This lets early reservation of > * crash kernel memory which has a dependency on arm64_dma_phys_limit. > * Reserving memory early for crash kernel allows linear creation of block > * mappings (greater than page-granularity) for all the memory bank rangs. > @@ -84,6 +85,7 @@ EXPORT_SYMBOL(memstart_addr); > * Note: Page-granularity mapppings are necessary for crash kernel memory > * range for shrinking its size via /sys/kernel/kexec_crash_size interface. > */ > +static phys_addr_t __ro_after_init dma32_phys_limit; > #if IS_ENABLED(CONFIG_ZONE_DMA) || IS_ENABLED(CONFIG_ZONE_DMA32) > phys_addr_t __ro_after_init arm64_dma_phys_limit; > #else > @@ -160,11 +162,10 @@ static phys_addr_t __init max_zone_phys(unsigned int zone_bits) > static void __init zone_sizes_init(unsigned long min, unsigned long max) > { > unsigned long max_zone_pfns[MAX_NR_ZONES] = {0}; > - unsigned int __maybe_unused acpi_zone_dma_bits; > - unsigned int __maybe_unused dt_zone_dma_bits; > - phys_addr_t __maybe_unused dma32_phys_limit = max_zone_phys(32); > - > #ifdef CONFIG_ZONE_DMA > + unsigned int acpi_zone_dma_bits; > + unsigned int dt_zone_dma_bits; > + > acpi_zone_dma_bits = fls64(acpi_iort_dma_get_max_cpu_address()); > dt_zone_dma_bits = fls64(of_dma_get_max_cpu_address(NULL)); > zone_dma_bits = min3(32U, dt_zone_dma_bits, acpi_zone_dma_bits); > @@ -173,8 +174,6 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max) > #endif > #ifdef CONFIG_ZONE_DMA32 > max_zone_pfns[ZONE_DMA32] = PFN_DOWN(dma32_phys_limit); > - if (!arm64_dma_phys_limit) > - arm64_dma_phys_limit = dma32_phys_limit; > #endif > max_zone_pfns[ZONE_NORMAL] = max; > > @@ -336,8 +335,12 @@ void __init arm64_memblock_init(void) > > early_init_fdt_scan_reserved_mem(); > > - if (!IS_ENABLED(CONFIG_ZONE_DMA) && !IS_ENABLED(CONFIG_ZONE_DMA32)) > + dma32_phys_limit = max_zone_phys(32); > + if (!IS_ENABLED(CONFIG_ZONE_DMA)) { > + if (IS_ENABLED(CONFIG_ZONE_DMA32)) > + arm64_dma_phys_limit = dma32_phys_limit; > reserve_crashkernel(); > + } > > high_memory = __va(memblock_end_of_DRAM() - 1) + 1; > } > @@ -385,7 +388,7 @@ void __init bootmem_init(void) > * request_standard_resources() depends on crashkernel's memory being > * reserved, so do it here. > */ > - if (IS_ENABLED(CONFIG_ZONE_DMA) || IS_ENABLED(CONFIG_ZONE_DMA32)) > + if (IS_ENABLED(CONFIG_ZONE_DMA)) > reserve_crashkernel(); > > memblock_dump_all(); > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index 626ec32873c6..23734481318a 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -529,8 +529,7 @@ static void __init map_mem(pgd_t *pgdp) > > #ifdef CONFIG_KEXEC_CORE > if (crash_mem_map) { > - if (IS_ENABLED(CONFIG_ZONE_DMA) || > - IS_ENABLED(CONFIG_ZONE_DMA32)) > + if (IS_ENABLED(CONFIG_ZONE_DMA)) > flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; > else if (crashk_res.end) > memblock_mark_nomap(crashk_res.start, > @@ -571,8 +570,7 @@ static void __init map_mem(pgd_t *pgdp) > * through /sys/kernel/kexec_crash_size interface. > */ > #ifdef CONFIG_KEXEC_CORE > - if (crash_mem_map && > - !IS_ENABLED(CONFIG_ZONE_DMA) && !IS_ENABLED(CONFIG_ZONE_DMA32)) { > + if (crash_mem_map && !IS_ENABLED(CONFIG_ZONE_DMA)) { > if (crashk_res.end) { > __map_memblock(pgdp, crashk_res.start, > crashk_res.end + 1,