From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-f70.google.com (mail-it0-f70.google.com [209.85.214.70]) by kanga.kvack.org (Postfix) with ESMTP id CBD372806CB for ; Tue, 28 Mar 2017 05:48:43 -0400 (EDT) Received: by mail-it0-f70.google.com with SMTP id 133so10517115itu.17 for ; Tue, 28 Mar 2017 02:48:43 -0700 (PDT) Received: from mail-it0-x229.google.com (mail-it0-x229.google.com. [2607:f8b0:4001:c0b::229]) by mx.google.com with ESMTPS id t12si2613663ite.96.2017.03.28.02.48.43 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 28 Mar 2017 02:48:43 -0700 (PDT) Received: by mail-it0-x229.google.com with SMTP id 190so12333973itm.0 for ; Tue, 28 Mar 2017 02:48:43 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20170328065033.15966-2-takahiro.akashi@linaro.org> References: <20170328064831.15894-1-takahiro.akashi@linaro.org> <20170328065033.15966-2-takahiro.akashi@linaro.org> From: Ard Biesheuvel Date: Tue, 28 Mar 2017 10:48:42 +0100 Message-ID: Subject: Re: [PATCH v34 02/14] memblock: add memblock_cap_memory_range() Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: AKASHI Takahiro Cc: Catalin Marinas , Will Deacon , Andrew Morton , James Morse , Geoff Levand , Thiago Jung Bauermann , Dave Young , Mark Rutland , Pratyush Anand , Sameer Goel , David Woodhouse , "kexec@lists.infradead.org" , "linux-arm-kernel@lists.infradead.org" , "linux-mm@kvack.org" On 28 March 2017 at 07:50, AKASHI Takahiro wrote: > Add memblock_cap_memory_range() which will remove all the memblock regions > except the memory range specified in the arguments. In addition, rework is > done on memblock_mem_limit_remove_map() to re-implement it using > memblock_cap_memory_range(). > > This function, like memblock_mem_limit_remove_map(), will not remove > memblocks with MEMMAP_NOMAP attribute as they may be mapped and accessed > later as "device memory." > See the commit a571d4eb55d8 ("mm/memblock.c: add new infrastructure to > address the mem limit issue"). > > This function is used, in a succeeding patch in the series of arm64 kdump > suuport, to limit the range of usable memory, or System RAM, on crash dump > kernel. > (Please note that "mem=" parameter is of little use for this purpose.) > > Signed-off-by: AKASHI Takahiro > Reviewed-by: Will Deacon > Acked-by: Catalin Marinas > Acked-by: Dennis Chen > Cc: linux-mm@kvack.org > Cc: Andrew Morton Reviewed-by: Ard Biesheuvel > --- > include/linux/memblock.h | 1 + > mm/memblock.c | 44 +++++++++++++++++++++++++++++--------------- > 2 files changed, 30 insertions(+), 15 deletions(-) > > diff --git a/include/linux/memblock.h b/include/linux/memblock.h > index e82daffcfc44..4ce24a376262 100644 > --- a/include/linux/memblock.h > +++ b/include/linux/memblock.h > @@ -336,6 +336,7 @@ phys_addr_t memblock_mem_size(unsigned long limit_pfn); > phys_addr_t memblock_start_of_DRAM(void); > phys_addr_t memblock_end_of_DRAM(void); > void memblock_enforce_memory_limit(phys_addr_t memory_limit); > +void memblock_cap_memory_range(phys_addr_t base, phys_addr_t size); > void memblock_mem_limit_remove_map(phys_addr_t limit); > bool memblock_is_memory(phys_addr_t addr); > int memblock_is_map_memory(phys_addr_t addr); > diff --git a/mm/memblock.c b/mm/memblock.c > index 2f4ca8104ea4..b049c9b2dba8 100644 > --- a/mm/memblock.c > +++ b/mm/memblock.c > @@ -1543,11 +1543,37 @@ void __init memblock_enforce_memory_limit(phys_addr_t limit) > (phys_addr_t)ULLONG_MAX); > } > > +void __init memblock_cap_memory_range(phys_addr_t base, phys_addr_t size) > +{ > + int start_rgn, end_rgn; > + int i, ret; > + > + if (!size) > + return; > + > + ret = memblock_isolate_range(&memblock.memory, base, size, > + &start_rgn, &end_rgn); > + if (ret) > + return; > + > + /* remove all the MAP regions */ > + for (i = memblock.memory.cnt - 1; i >= end_rgn; i--) > + if (!memblock_is_nomap(&memblock.memory.regions[i])) > + memblock_remove_region(&memblock.memory, i); > + > + for (i = start_rgn - 1; i >= 0; i--) > + if (!memblock_is_nomap(&memblock.memory.regions[i])) > + memblock_remove_region(&memblock.memory, i); > + > + /* truncate the reserved regions */ > + memblock_remove_range(&memblock.reserved, 0, base); > + memblock_remove_range(&memblock.reserved, > + base + size, (phys_addr_t)ULLONG_MAX); > +} > + > void __init memblock_mem_limit_remove_map(phys_addr_t limit) > { > - struct memblock_type *type = &memblock.memory; > phys_addr_t max_addr; > - int i, ret, start_rgn, end_rgn; > > if (!limit) > return; > @@ -1558,19 +1584,7 @@ void __init memblock_mem_limit_remove_map(phys_addr_t limit) > if (max_addr == (phys_addr_t)ULLONG_MAX) > return; > > - ret = memblock_isolate_range(type, max_addr, (phys_addr_t)ULLONG_MAX, > - &start_rgn, &end_rgn); > - if (ret) > - return; > - > - /* remove all the MAP regions above the limit */ > - for (i = end_rgn - 1; i >= start_rgn; i--) { > - if (!memblock_is_nomap(&type->regions[i])) > - memblock_remove_region(type, i); > - } > - /* truncate the reserved regions */ > - memblock_remove_range(&memblock.reserved, max_addr, > - (phys_addr_t)ULLONG_MAX); > + memblock_cap_memory_range(0, max_addr); > } > > static int __init_memblock memblock_search(struct memblock_type *type, phys_addr_t addr) > -- > 2.11.1 > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org