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From: takahiro.akashi@linaro.org (AKASHI Takahiro)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v35 02/14] memblock: add memblock_cap_memory_range()
Date: Mon,  3 Apr 2017 11:23:55 +0900	[thread overview]
Message-ID: <20170403022355.12463-2-takahiro.akashi@linaro.org> (raw)
In-Reply-To: <20170403022139.12383-1-takahiro.akashi@linaro.org>

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 <takahiro.akashi@linaro.org>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Dennis Chen <dennis.chen@arm.com>
Cc: linux-mm at kvack.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 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

  parent reply	other threads:[~2017-04-03  2:23 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-03  2:21 [PATCH v35 00/14] arm64: add kdump support AKASHI Takahiro
2017-04-03  2:23 ` [PATCH v35 01/14] memblock: add memblock_clear_nomap() AKASHI Takahiro
2017-04-03  2:23 ` AKASHI Takahiro [this message]
2017-04-05 17:20   ` [PATCH v35 02/14] memblock: add memblock_cap_memory_range() Catalin Marinas
2017-04-03  2:24 ` [PATCH v35 03/14] arm64: limit memory regions based on DT property, usable-memory-range AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 04/14] arm64: kdump: reserve memory for crash dump kernel AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 05/14] arm64: mm: add set_memory_valid() AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 06/14] arm64: kdump: protect crash dump kernel memory AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 07/14] arm64: hibernate: preserve kdump image around hibernation AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 08/14] arm64: kdump: implement machine_crash_shutdown() AKASHI Takahiro
2017-04-03  9:21   ` David Woodhouse
2017-04-04  7:29     ` AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 09/14] arm64: kdump: add VMCOREINFO's for user-space tools AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 10/14] arm64: kdump: provide /proc/vmcore file AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 11/14] arm64: kdump: enable kdump in defconfig AKASHI Takahiro
2017-04-03  2:24 ` [PATCH v35 12/14] Documentation: kdump: describe arm64 port AKASHI Takahiro
2017-04-03  2:26 ` [PATCH v35 13/14] Documentation: dt: chosen properties for arm64 kdump AKASHI Takahiro
2017-04-03  2:26 ` [PATCH v35 14/14] efi/libstub/arm*: Set default address and size cells values for an empty dtb AKASHI Takahiro
2017-05-22  0:25 ` [PATCH v35 00/14] arm64: add kdump support AKASHI Takahiro

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