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 5D884C74A5B for ; Mon, 27 Mar 2023 01:26:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231717AbjC0B0w (ORCPT ); Sun, 26 Mar 2023 21:26:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49696 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229456AbjC0B0u (ORCPT ); Sun, 26 Mar 2023 21:26:50 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2B41340E3 for ; Sun, 26 Mar 2023 18:26:49 -0700 (PDT) Received: from dggpemm500006.china.huawei.com (unknown [172.30.72.57]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4PlFSL5pXMzSpGF; Mon, 27 Mar 2023 09:23:14 +0800 (CST) Received: from [10.174.178.55] (10.174.178.55) by dggpemm500006.china.huawei.com (7.185.36.236) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.21; Mon, 27 Mar 2023 09:26:46 +0800 Subject: Re: [PATCH v2 3/3] arm64: kdump: defer the crashkernel reservation for platforms with no DMA memory zones To: Baoquan He , CC: , , , , , , , References: <20230324131838.409996-1-bhe@redhat.com> <20230324131838.409996-4-bhe@redhat.com> From: "Leizhen (ThunderTown)" Message-ID: Date: Mon, 27 Mar 2023 09:26:46 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.178.55] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpemm500006.china.huawei.com (7.185.36.236) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023/3/26 21:02, Baoquan He wrote: > In commit 031495635b46 ("arm64: Do not defer reserve_crashkernel() for > platforms with no DMA memory zones"), reserve_crashkernel() is called > much earlier in arm64_memblock_init() to avoid causing base apge > mapping on platforms with no DMA meomry zones. > > With taking off protection on crashkernel memory region, no need to call > reserve_crashkernel() specially in advance. The deferred invocation of > reserve_crashkernel() in bootmem_init() can cover all cases. So revert > the commit 031495635b46 now. > > Signed-off-by: Baoquan He > --- > v1->v2: > - When trying to revert commit 031495635b46, two hunks were missed in v1 > post. Remove them in v2. Thanks to Leizhen for pointing out this. > - Remove code comment above arm64_dma_phys_limit definition added > in commit 031495635b46; > - Move the arm64_dma_phys_limit assignment back into zone_sizes_init() > when both CONFIG_ZONE_DMA and CONFIG_ZONE_DMA32 are not enabled. Reviewed-by: Zhen Lei > > arch/arm64/include/asm/memory.h | 5 ----- > arch/arm64/mm/init.c | 34 +++------------------------------ > 2 files changed, 3 insertions(+), 36 deletions(-) > > diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h > index 78e5163836a0..efcd68154a3a 100644 > --- a/arch/arm64/include/asm/memory.h > +++ b/arch/arm64/include/asm/memory.h > @@ -374,11 +374,6 @@ static inline void *phys_to_virt(phys_addr_t x) > }) > > void dump_mem_limit(void); > - > -static inline bool defer_reserve_crashkernel(void) > -{ > - return IS_ENABLED(CONFIG_ZONE_DMA) || IS_ENABLED(CONFIG_ZONE_DMA32); > -} > #endif /* !ASSEMBLY */ > > /* > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c > index 58a0bb2c17f1..66e70ca47680 100644 > --- a/arch/arm64/mm/init.c > +++ b/arch/arm64/mm/init.c > @@ -61,34 +61,8 @@ EXPORT_SYMBOL(memstart_addr); > * unless restricted on specific platforms (e.g. 30-bit on Raspberry Pi 4). > * In such case, ZONE_DMA32 covers the rest of the 32-bit addressable memory, > * otherwise it is empty. > - * > - * 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 > - * 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. > - * In this scheme a comparatively quicker boot is observed. > - * > - * If ZONE_DMA configs are defined, crash kernel memory reservation > - * is delayed until DMA zone memory range size initialization performed in > - * zone_sizes_init(). The defer is necessary to steer clear of DMA zone > - * memory range to avoid overlap allocation. So crash kernel memory boundaries > - * are not known when mapping all bank memory ranges, which otherwise means > - * not possible to exclude crash kernel range from creating block mappings > - * so page-granularity mappings are created for the entire memory range. > - * Hence a slightly slower boot is observed. > - * > - * Note: Page-granularity mappings are necessary for crash kernel memory > - * range for shrinking its size via /sys/kernel/kexec_crash_size interface. > */ > -#if IS_ENABLED(CONFIG_ZONE_DMA) || IS_ENABLED(CONFIG_ZONE_DMA32) > phys_addr_t __ro_after_init arm64_dma_phys_limit; > -#else > -phys_addr_t __ro_after_init arm64_dma_phys_limit = PHYS_MASK + 1; > -#endif > > /* Current arm64 boot protocol requires 2MB alignment */ > #define CRASH_ALIGN SZ_2M > @@ -248,6 +222,8 @@ static void __init zone_sizes_init(void) > if (!arm64_dma_phys_limit) > arm64_dma_phys_limit = dma32_phys_limit; > #endif > + if (!arm64_dma_phys_limit) > + arm64_dma_phys_limit = PHYS_MASK + 1; > max_zone_pfns[ZONE_NORMAL] = max_pfn; > > free_area_init(max_zone_pfns); > @@ -408,9 +384,6 @@ void __init arm64_memblock_init(void) > > early_init_fdt_scan_reserved_mem(); > > - if (!defer_reserve_crashkernel()) > - reserve_crashkernel(); > - > high_memory = __va(memblock_end_of_DRAM() - 1) + 1; > } > > @@ -457,8 +430,7 @@ void __init bootmem_init(void) > * request_standard_resources() depends on crashkernel's memory being > * reserved, so do it here. > */ > - if (defer_reserve_crashkernel()) > - reserve_crashkernel(); > + reserve_crashkernel(); > > memblock_dump_all(); > } > -- Regards, Zhen Lei