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Date: Mon, 15 Apr 2019 22:09:42 +0300
From: Mike Rapoport <rppt@...ux.ibm.com>
To: Chen Zhou <chenzhou10@...wei.com>
Cc: tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
ebiederm@...ssion.com, catalin.marinas@....com,
will.deacon@....com, akpm@...ux-foundation.org,
ard.biesheuvel@...aro.org, horms@...ge.net.au,
takahiro.akashi@...aro.org, linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org, kexec@...ts.infradead.org,
linux-mm@...ck.org, wangkefeng.wang@...wei.com
Subject: Re: [PATCH v4 3/5] memblock: add memblock_cap_memory_ranges for
multiple ranges
Hi,
On Mon, Apr 15, 2019 at 06:57:23PM +0800, Chen Zhou wrote:
> The memblock_cap_memory_range() removes all the memory except the
> range passed to it. Extend this function to receive memblock_type
> with the regions that should be kept.
>
> Enable this function in arm64 for reservation of multiple regions
> for the crash kernel.
>
> Signed-off-by: Chen Zhou <chenzhou10@...wei.com>
> Signed-off-by: Mike Rapoport <rppt@...ux.ibm.com>
I didn't work on this version, please drop the signed-off.
> ---
> include/linux/memblock.h | 1 +
> mm/memblock.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 46 insertions(+)
>
> diff --git a/include/linux/memblock.h b/include/linux/memblock.h
> index 47e3c06..180877c 100644
> --- a/include/linux/memblock.h
> +++ b/include/linux/memblock.h
> @@ -446,6 +446,7 @@ 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_cap_memory_ranges(struct memblock_type *regions_to_keep);
> void memblock_mem_limit_remove_map(phys_addr_t limit);
> bool memblock_is_memory(phys_addr_t addr);
> bool memblock_is_map_memory(phys_addr_t addr);
> diff --git a/mm/memblock.c b/mm/memblock.c
> index f315eca..9661807 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -1697,6 +1697,51 @@ void __init memblock_cap_memory_range(phys_addr_t base, phys_addr_t size)
> base + size, PHYS_ADDR_MAX);
> }
>
> +void __init memblock_cap_memory_ranges(struct memblock_type *regions_to_keep)
> +{
> + int start_rgn[INIT_MEMBLOCK_REGIONS], end_rgn[INIT_MEMBLOCK_REGIONS];
> + int i, j, ret, nr = 0;
> + struct memblock_region *regs = regions_to_keep->regions;
> +
> + for (i = 0; i < regions_to_keep->cnt; i++) {
> + ret = memblock_isolate_range(&memblock.memory, regs[i].base,
> + regs[i].size, &start_rgn[i], &end_rgn[i]);
> + if (ret)
> + break;
> + nr++;
> + }
> + if (!nr)
> + return;
> +
> + /* remove all the MAP regions */
> + for (i = memblock.memory.cnt - 1; i >= end_rgn[nr - 1]; i--)
> + if (!memblock_is_nomap(&memblock.memory.regions[i]))
> + memblock_remove_region(&memblock.memory, i);
> +
> + for (i = nr - 1; i > 0; i--)
> + for (j = start_rgn[i] - 1; j >= end_rgn[i - 1]; j--)
> + if (!memblock_is_nomap(&memblock.memory.regions[j]))
> + memblock_remove_region(&memblock.memory, j);
> +
> + for (i = start_rgn[0] - 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, regs[0].base);
> +
> + for (i = nr - 1; i > 0; i--) {
> + phys_addr_t remove_base = regs[i - 1].base + regs[i - 1].size;
> + phys_addr_t remove_size = regs[i].base - remove_base;
> +
> + memblock_remove_range(&memblock.reserved, remove_base,
> + remove_size);
> + }
> +
> + memblock_remove_range(&memblock.reserved,
> + regs[nr - 1].base + regs[nr - 1].size, PHYS_ADDR_MAX);
> +}
> +
I've double-checked and I see no problem with using
for_each_mem_range_rev() iterators for removing some ranges. And with them
this functions becomes much clearer and more efficient.
Can you please check if the below patch works for you?
>From e25e6c9cd94a01abac124deacc66e5d258fdbf7c Mon Sep 17 00:00:00 2001
From: Mike Rapoport <rppt@...ux.ibm.com>
Date: Wed, 10 Apr 2019 16:02:32 +0300
Subject: [PATCH] memblock: extend memblock_cap_memory_range to multiple ranges
The memblock_cap_memory_range() removes all the memory except the range
passed to it. Extend this function to receive an array of memblock_regions
that should be kept. This allows switching to simple iteration over
memblock arrays with 'for_each_mem_range_rev' to remove the unneeded memory.
Enable use of this function in arm64 for reservation of multiple regions for
the crash kernel.
Signed-off-by: Mike Rapoport <rppt@...ux.ibm.com>
---
arch/arm64/mm/init.c | 34 ++++++++++++++++++++++++----------
include/linux/memblock.h | 2 +-
mm/memblock.c | 44 ++++++++++++++++++++------------------------
3 files changed, 45 insertions(+), 35 deletions(-)
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 6bc1350..8665d29 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -64,6 +64,10 @@ EXPORT_SYMBOL(memstart_addr);
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
+
/*
* reserve_crashkernel() - reserves memory for crash kernel
*
@@ -280,9 +284,9 @@ early_param("mem", early_mem);
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;
+ struct memblock_type *usablemem = data;
+ const __be32 *reg, *endp;
+ int len, nr = 0;
if (depth != 1 || strcmp(uname, "chosen") != 0)
return 0;
@@ -291,22 +295,32 @@ 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)) {
+ unsigned long base = dt_mem_next_cell(dt_root_addr_cells, ®);
+ unsigned long size = dt_mem_next_cell(dt_root_size_cells, ®);
+ if (memblock_add_range(usablemem, base, size, NUMA_NO_NODE,
+ MEMBLOCK_NONE))
+ return 0;
+ if (++nr >= CRASH_MAX_USABLE_RANGES)
+ break;
+ }
return 1;
}
static void __init fdt_enforce_memory_region(void)
{
- struct memblock_region reg = {
- .size = 0,
+ struct memblock_region usable_regions[CRASH_MAX_USABLE_RANGES];
+ struct memblock_type usablemem = {
+ .max = CRASH_MAX_USABLE_RANGES,
+ .regions = usable_regions,
};
- of_scan_flat_dt(early_init_dt_scan_usablemem, ®);
+ of_scan_flat_dt(early_init_dt_scan_usablemem, &usablemem);
- if (reg.size)
- memblock_cap_memory_range(reg.base, reg.size);
+ if (usablemem.cnt)
+ memblock_cap_memory_ranges(usablemem.regions, usablemem.cnt);
}
void __init arm64_memblock_init(void)
diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index 294d5d8..f5c029b 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -404,7 +404,7 @@ 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_cap_memory_ranges(struct memblock_region *regions, int count);
void memblock_mem_limit_remove_map(phys_addr_t limit);
bool memblock_is_memory(phys_addr_t addr);
bool memblock_is_map_memory(phys_addr_t addr);
diff --git a/mm/memblock.c b/mm/memblock.c
index e7665cf..8d4d060 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -1605,36 +1605,31 @@ void __init memblock_enforce_memory_limit(phys_addr_t limit)
PHYS_ADDR_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);
+void __init memblock_cap_memory_ranges(struct memblock_region *regions,
+ int count)
+{
+ struct memblock_type regions_to_keep = {
+ .max = count,
+ .cnt = count,
+ .regions = regions,
+ };
+ phys_addr_t start, end;
+ u64 i;
- for (i = start_rgn - 1; i >= 0; i--)
- if (!memblock_is_nomap(&memblock.memory.regions[i]))
- memblock_remove_region(&memblock.memory, i);
+ /* truncate memory while skipping NOMAP regions */
+ for_each_mem_range_rev(i, &memblock.memory, ®ions_to_keep,
+ NUMA_NO_NODE, MEMBLOCK_NONE, &start, &end, NULL)
+ memblock_remove(start, end);
/* truncate the reserved regions */
- memblock_remove_range(&memblock.reserved, 0, base);
- memblock_remove_range(&memblock.reserved,
- base + size, PHYS_ADDR_MAX);
+ for_each_mem_range_rev(i, &memblock.reserved, ®ions_to_keep,
+ NUMA_NO_NODE, MEMBLOCK_NONE, &start, &end, NULL)
+ memblock_remove_range(&memblock.reserved, start, end);
}
void __init memblock_mem_limit_remove_map(phys_addr_t limit)
{
+ struct memblock_region region = { 0 };
phys_addr_t max_addr;
if (!limit)
@@ -1646,7 +1641,8 @@ void __init memblock_mem_limit_remove_map(phys_addr_t limit)
if (max_addr == PHYS_ADDR_MAX)
return;
- memblock_cap_memory_range(0, max_addr);
+ region.size = max_addr;
+ memblock_cap_memory_ranges(®ion, 1);
}
static int __init_memblock memblock_search(struct memblock_type *type, phys_addr_t addr)
--
2.7.4
--
Sincerely yours,
Mike.
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