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[45.249.212.191]) by mx.google.com with ESMTPS id x25si5436290uar.209.2019.04.08.08.38.55 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 08 Apr 2019 08:38:56 -0700 (PDT) Received-SPF: pass (google.com: domain of chenzhou10@huawei.com designates 45.249.212.191 as permitted sender) client-ip=45.249.212.191; Authentication-Results: mx.google.com; spf=pass (google.com: domain of chenzhou10@huawei.com designates 45.249.212.191 as permitted sender) smtp.mailfrom=chenzhou10@huawei.com Received: from DGGEMS405-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id 6796C636F9A6EFFFA345; Mon, 8 Apr 2019 23:38:49 +0800 (CST) Received: from [127.0.0.1] (10.177.131.64) by DGGEMS405-HUB.china.huawei.com (10.3.19.205) with Microsoft SMTP Server id 14.3.408.0; Mon, 8 Apr 2019 23:38:42 +0800 Subject: Re: [PATCH 2/3] arm64: kdump: support more than one crash kernel regions To: Mike Rapoport References: <20190403030546.23718-1-chenzhou10@huawei.com> <20190403030546.23718-3-chenzhou10@huawei.com> <20190403112929.GA7715@rapoport-lnx> <20190404144408.GA6433@rapoport-lnx> <783b8712-ddb1-a52b-81ee-0c6a216e5b7d@huawei.com> <4b188535-c12d-e05b-9154-2c2d580f903b@huawei.com> <20190408065711.GA8403@rapoport-lnx> <3fc772a2-292b-9c2a-465f-eabe86961dfd@huawei.com> CC: , , , , , , , , , From: Chen Zhou Message-ID: <2aadfb89-4ac0-a9a9-e157-a23d686cb374@huawei.com> Date: Mon, 8 Apr 2019 23:38:41 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.7.1 MIME-Version: 1.0 In-Reply-To: <3fc772a2-292b-9c2a-465f-eabe86961dfd@huawei.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.131.64] X-CFilter-Loop: Reflected X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Hi Mike, On 2019/4/8 16:39, Chen Zhou wrote: >>> >>> Sorry, just ignore my previous reply, I got that wrong. >>> >>> I think it carefully, we can cap the memory range for [min(regs[*].start, max(regs[*].end)] >>> firstly. But how to remove the middle ranges, we still can't use memblock_cap_memory_range() >>> directly and the extra remove operation may be complex. >>> >>> For more than one regions, i think add a new memblock_cap_memory_ranges() may be better. >>> Besides, memblock_cap_memory_ranges() is also applicable for one region. >>> >>> How about replace memblock_cap_memory_range() with memblock_cap_memory_ranges()? >> >> arm64 is the only user of both MEMBLOCK_NOMAP and memblock_cap_memory_range() >> and I don't expect other architectures will use these interfaces. >> It seems that capping the memory for arm64 crash kernel the way I've >> suggested can be implemented in fdt_enforce_memory_region(). If we'd ever >> need such functionality elsewhere or CRASH_MAX_USABLE_RANGES will need to >> grow we'll rethink the solution. > > Ok, i will implement that in fdt_enforce_memory_region() in next version. > And we will support at most two crash kernel regions now. > > Thanks, > Chen Zhou > I implement that in fdt_enforce_memory_region() simply as below. You have a look at if it is the way you suggested. diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index f9fa5f8..52bd69db 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -65,6 +65,11 @@ phys_addr_t arm64_dma_phys_limit __ro_after_init; #ifdef CONFIG_KEXEC_CORE +/* at most two crash kernel regions, low_region and high_region */ +#define CRASH_MAX_USABLE_RANGES 2 +#define LOW_REGION_IDX 0 +#define HIGH_REGION_IDX 1 + /* * reserve_crashkernel() - reserves memory for crash kernel * @@ -296,8 +301,8 @@ static int __init early_init_dt_scan_usablemem(unsigned long node, const char *uname, int depth, void *data) { struct memblock_region *usablemem = data; - const __be32 *reg; - int len; + const __be32 *reg, *endp; + int len, nr = 0; if (depth != 1 || strcmp(uname, "chosen") != 0) return 0; @@ -306,22 +311,62 @@ static int __init early_init_dt_scan_usablemem(unsigned long node, if (!reg || (len < (dt_root_addr_cells + dt_root_size_cells))) return 1; - usablemem->base = dt_mem_next_cell(dt_root_addr_cells, ®); - usablemem->size = dt_mem_next_cell(dt_root_size_cells, ®); + endp = reg + (len / sizeof(__be32)); + while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) { + usablemem[nr].base = dt_mem_next_cell(dt_root_addr_cells, ®); + usablemem[nr].size = dt_mem_next_cell(dt_root_size_cells, ®); + + if (++nr >= CRASH_MAX_USABLE_RANGES) + break; + } return 1; } static void __init fdt_enforce_memory_region(void) { - struct memblock_region reg = { - .size = 0, - }; + int i, cnt = 0; + struct memblock_region regs[CRASH_MAX_USABLE_RANGES]; + + memset(regs, 0, sizeof(regs)); + of_scan_flat_dt(early_init_dt_scan_usablemem, regs); + + for (i = 0; i < CRASH_MAX_USABLE_RANGES; i++) + if (regs[i].size) + cnt++; + else + break; + + if (cnt - 1 == LOW_REGION_IDX) + memblock_cap_memory_range(regs[LOW_REGION_IDX].base, + regs[LOW_REGION_IDX].size); + else if (cnt - 1 == HIGH_REGION_IDX) { + /* + * Two crash kernel regions, cap the memory range + * [regs[LOW_REGION_IDX].base, regs[HIGH_REGION_IDX].end] + * and then remove the memory range in the middle. + */ + int start_rgn, end_rgn, i, ret; + phys_addr_t mid_base, mid_size; + + mid_base = regs[LOW_REGION_IDX].base + regs[LOW_REGION_IDX].size; + mid_size = regs[HIGH_REGION_IDX].base - mid_base; + ret = memblock_isolate_range(&memblock.memory, mid_base, mid_size, + &start_rgn, &end_rgn); - of_scan_flat_dt(early_init_dt_scan_usablemem, ®); + if (ret) + return; - if (reg.size) - memblock_cap_memory_range(reg.base, reg.size); + memblock_cap_memory_range(regs[LOW_REGION_IDX].base, + regs[HIGH_REGION_IDX].base - regs[LOW_REGION_IDX].base + + regs[HIGH_REGION_IDX].size); + for (i = end_rgn - 1; i >= start_rgn; i--) { + if (!memblock_is_nomap(&memblock.memory.regions[i])) + memblock_remove_region(&memblock.memory, i); + } + memblock_remove_range(&memblock.reserved, mid_base, + mid_base + mid_size); + } } void __init arm64_memblock_init(void) diff --git a/include/linux/memblock.h b/include/linux/memblock.h index 294d5d8..787d252 100644 --- a/include/linux/memblock.h +++ b/include/linux/memblock.h @@ -110,9 +110,15 @@ void memblock_discard(void); phys_addr_t memblock_find_in_range(phys_addr_t start, phys_addr_t end, phys_addr_t size, phys_addr_t align); +void memblock_remove_region(struct memblock_type *type, unsigned long r); void memblock_allow_resize(void); int memblock_add_node(phys_addr_t base, phys_addr_t size, int nid); int memblock_add(phys_addr_t base, phys_addr_t size); +int memblock_isolate_range(struct memblock_type *type, + phys_addr_t base, phys_addr_t size, + int *start_rgn, int *end_rgn); +int memblock_remove_range(struct memblock_type *type, + phys_addr_t base, phys_addr_t size); int memblock_remove(phys_addr_t base, phys_addr_t size); int memblock_free(phys_addr_t base, phys_addr_t size); int memblock_reserve(phys_addr_t base, phys_addr_t size); diff --git a/mm/memblock.c b/mm/memblock.c index e7665cf..7130c3a 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -357,7 +357,7 @@ phys_addr_t __init_memblock memblock_find_in_range(phys_addr_t start, return ret; } -static void __init_memblock memblock_remove_region(struct memblock_type *type, unsigned long r) +void __init_memblock memblock_remove_region(struct memblock_type *type, unsigned long r) { type->total_size -= type->regions[r].size; memmove(&type->regions[r], &type->regions[r + 1], @@ -724,7 +724,7 @@ int __init_memblock memblock_add(phys_addr_t base, phys_addr_t size) * Return: * 0 on success, -errno on failure. */ -static int __init_memblock memblock_isolate_range(struct memblock_type *type, +int __init_memblock memblock_isolate_range(struct memblock_type *type, phys_addr_t base, phys_addr_t size, int *start_rgn, int *end_rgn) { @@ -784,7 +784,7 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type, return 0; } -static int __init_memblock memblock_remove_range(struct memblock_type *type, +int __init_memblock memblock_remove_range(struct memblock_type *type, phys_addr_t base, phys_addr_t size) { int start_rgn, end_rgn; Thanks, Chen Zhou > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > > . >