Re: [PATCH v1 2/4] memblock: allow to specify flags with memblock_add_node()
On Mon, Sep 27, 2021 at 5:05 PM David Hildenbrand wrote:
> We want to specify flags when hotplugging memory. Let's prepare to pass
> flags to memblock_add_node() by adjusting all existing users.
>
> Note that when hotplugging memory the system is already up and running
> and we don't want to add the memory first and apply flags later: it
> should happen within one memblock call.
>
> Signed-off-by: David Hildenbrand
> arch/m68k/mm/mcfmmu.c| 3 ++-
> arch/m68k/mm/motorola.c | 6 --
Acked-by: Geert Uytterhoeven
Gr{oetje,eeting}s,
Geert
--
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In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
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Re: [PATCH v1 0/4] mm/memory_hotplug: full support for
Intended subject was "[PATCH v1 0/4] mm/memory_hotplug: full support for add_memory_driver_managed() with CONFIG_ARCH_KEEP_MEMBLOCK" -- Thanks, David / dhildenb ___ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
[PATCH v1 2/4] memblock: allow to specify flags with memblock_add_node()
We want to specify flags when hotplugging memory. Let's prepare to pass
flags to memblock_add_node() by adjusting all existing users.
Note that when hotplugging memory the system is already up and running
and we don't want to add the memory first and apply flags later: it
should happen within one memblock call.
Signed-off-by: David Hildenbrand
---
arch/arc/mm/init.c | 4 ++--
arch/ia64/mm/contig.c| 2 +-
arch/ia64/mm/init.c | 2 +-
arch/m68k/mm/mcfmmu.c| 3 ++-
arch/m68k/mm/motorola.c | 6 --
arch/mips/loongson64/init.c | 4 +++-
arch/mips/sgi-ip27/ip27-memory.c | 3 ++-
arch/s390/kernel/setup.c | 3 ++-
include/linux/memblock.h | 3 ++-
include/linux/mm.h | 2 +-
mm/memblock.c| 9 +
mm/memory_hotplug.c | 2 +-
12 files changed, 26 insertions(+), 17 deletions(-)
diff --git a/arch/arc/mm/init.c b/arch/arc/mm/init.c
index 699ecf119641..110eb69e9bee 100644
--- a/arch/arc/mm/init.c
+++ b/arch/arc/mm/init.c
@@ -59,13 +59,13 @@ void __init early_init_dt_add_memory_arch(u64 base, u64
size)
low_mem_sz = size;
in_use = 1;
- memblock_add_node(base, size, 0);
+ memblock_add_node(base, size, 0, MEMBLOCK_NONE);
} else {
#ifdef CONFIG_HIGHMEM
high_mem_start = base;
high_mem_sz = size;
in_use = 1;
- memblock_add_node(base, size, 1);
+ memblock_add_node(base, size, 1, MEMBLOCK_NONE);
memblock_reserve(base, size);
#endif
}
diff --git a/arch/ia64/mm/contig.c b/arch/ia64/mm/contig.c
index 42e025cfbd08..24901d809301 100644
--- a/arch/ia64/mm/contig.c
+++ b/arch/ia64/mm/contig.c
@@ -153,7 +153,7 @@ find_memory (void)
efi_memmap_walk(find_max_min_low_pfn, NULL);
max_pfn = max_low_pfn;
- memblock_add_node(0, PFN_PHYS(max_low_pfn), 0);
+ memblock_add_node(0, PFN_PHYS(max_low_pfn), 0, MEMBLOCK_NONE);
find_initrd();
diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
index 5c6da8d83c1a..5d165607bf35 100644
--- a/arch/ia64/mm/init.c
+++ b/arch/ia64/mm/init.c
@@ -378,7 +378,7 @@ int __init register_active_ranges(u64 start, u64 len, int
nid)
#endif
if (start < end)
- memblock_add_node(__pa(start), end - start, nid);
+ memblock_add_node(__pa(start), end - start, nid, MEMBLOCK_NONE);
return 0;
}
diff --git a/arch/m68k/mm/mcfmmu.c b/arch/m68k/mm/mcfmmu.c
index eac9dde65193..6f1f25125294 100644
--- a/arch/m68k/mm/mcfmmu.c
+++ b/arch/m68k/mm/mcfmmu.c
@@ -174,7 +174,8 @@ void __init cf_bootmem_alloc(void)
m68k_memory[0].addr = _rambase;
m68k_memory[0].size = _ramend - _rambase;
- memblock_add_node(m68k_memory[0].addr, m68k_memory[0].size, 0);
+ memblock_add_node(m68k_memory[0].addr, m68k_memory[0].size, 0,
+ MEMBLOCK_NONE);
/* compute total pages in system */
num_pages = PFN_DOWN(_ramend - _rambase);
diff --git a/arch/m68k/mm/motorola.c b/arch/m68k/mm/motorola.c
index 3a653f0a4188..e80c5d7e6728 100644
--- a/arch/m68k/mm/motorola.c
+++ b/arch/m68k/mm/motorola.c
@@ -410,7 +410,8 @@ void __init paging_init(void)
min_addr = m68k_memory[0].addr;
max_addr = min_addr + m68k_memory[0].size;
- memblock_add_node(m68k_memory[0].addr, m68k_memory[0].size, 0);
+ memblock_add_node(m68k_memory[0].addr, m68k_memory[0].size, 0,
+ MEMBLOCK_NONE);
for (i = 1; i < m68k_num_memory;) {
if (m68k_memory[i].addr < min_addr) {
printk("Ignoring memory chunk at 0x%lx:0x%lx before the
first chunk\n",
@@ -421,7 +422,8 @@ void __init paging_init(void)
(m68k_num_memory - i) * sizeof(struct
m68k_mem_info));
continue;
}
- memblock_add_node(m68k_memory[i].addr, m68k_memory[i].size, i);
+ memblock_add_node(m68k_memory[i].addr, m68k_memory[i].size, i,
+ MEMBLOCK_NONE);
addr = m68k_memory[i].addr + m68k_memory[i].size;
if (addr > max_addr)
max_addr = addr;
diff --git a/arch/mips/loongson64/init.c b/arch/mips/loongson64/init.c
index 76e0a9636a0e..4ac5ba80bbf6 100644
--- a/arch/mips/loongson64/init.c
+++ b/arch/mips/loongson64/init.c
@@ -77,7 +77,9 @@ void __init szmem(unsigned int node)
(u32)node_id, mem_type, mem_start, mem_size);
pr_info(" start_pfn:0x%llx, end_pfn:0x%llx,
num_physpages:0x%lx\n",
start_pfn, end_pfn, num_physpages);
- memblock_add_node(PFN_PHYS(start_pfn),
PFN_PHYS(node_psize), node);
+ memblock_add_node(PFN_PHYS(start_pfn),
+
[PATCH v1 3/4] memblock: add MEMBLOCK_DRIVER_MANAGED to mimic IORESOURCE_SYSRAM_DRIVER_MANAGED
Let's add a flag that corresponds to IORESOURCE_SYSRAM_DRIVER_MANAGED.
Similar to MEMBLOCK_HOTPLUG, most infrastructure has to treat such memory
like ordinary MEMBLOCK_NONE memory -- for example, when selecting memory
regions to add to the vmcore for dumping in the crashkernel via
for_each_mem_range().
However, especially kexec_file is not supposed to select such memblocks via
for_each_free_mem_range() / for_each_free_mem_range_reverse() to place
kexec images, similar to how we handle IORESOURCE_SYSRAM_DRIVER_MANAGED
without CONFIG_ARCH_KEEP_MEMBLOCK.
Let's document why kexec_walk_memblock() won't try placing images on
areas marked MEMBLOCK_DRIVER_MANAGED -- similar to
IORESOURCE_SYSRAM_DRIVER_MANAGED handling in locate_mem_hole_callback()
via kexec_walk_resources().
We'll make sure that memory hotplug code sets the flag where applicable
(IORESOURCE_SYSRAM_DRIVER_MANAGED) next. This prepares architectures
that need CONFIG_ARCH_KEEP_MEMBLOCK, such as arm64, for virtio-mem
support.
Signed-off-by: David Hildenbrand
---
include/linux/memblock.h | 16 ++--
kernel/kexec_file.c | 5 +
mm/memblock.c| 4
3 files changed, 23 insertions(+), 2 deletions(-)
diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index b49a58f621bc..7d8d656d5082 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -33,12 +33,17 @@ extern unsigned long long max_possible_pfn;
* @MEMBLOCK_NOMAP: don't add to kernel direct mapping and treat as
* reserved in the memory map; refer to memblock_mark_nomap() description
* for further details
+ * @MEMBLOCK_DRIVER_MANAGED: memory region that is always detected via a
driver,
+ * corresponding to IORESOURCE_SYSRAM_DRIVER_MANAGED in the kernel resource
+ * tree. Especially kexec should never use this memory for placing images and
+ * shouldn't expose this memory to the second kernel.
*/
enum memblock_flags {
MEMBLOCK_NONE = 0x0, /* No special request */
MEMBLOCK_HOTPLUG= 0x1, /* hotpluggable region */
MEMBLOCK_MIRROR = 0x2, /* mirrored region */
MEMBLOCK_NOMAP = 0x4, /* don't add to kernel direct mapping */
+ MEMBLOCK_DRIVER_MANAGED = 0x8, /* always detected via a driver */
};
/**
@@ -209,7 +214,8 @@ static inline void __next_physmem_range(u64 *idx, struct
memblock_type *type,
*/
#define for_each_mem_range(i, p_start, p_end) \
__for_each_mem_range(i, &memblock.memory, NULL, NUMA_NO_NODE, \
-MEMBLOCK_HOTPLUG, p_start, p_end, NULL)
+MEMBLOCK_HOTPLUG | MEMBLOCK_DRIVER_MANAGED, \
+p_start, p_end, NULL)
/**
* for_each_mem_range_rev - reverse iterate through memblock areas from
@@ -220,7 +226,8 @@ static inline void __next_physmem_range(u64 *idx, struct
memblock_type *type,
*/
#define for_each_mem_range_rev(i, p_start, p_end) \
__for_each_mem_range_rev(i, &memblock.memory, NULL, NUMA_NO_NODE, \
-MEMBLOCK_HOTPLUG, p_start, p_end, NULL)
+MEMBLOCK_HOTPLUG | MEMBLOCK_DRIVER_MANAGED,\
+p_start, p_end, NULL)
/**
* for_each_reserved_mem_range - iterate over all reserved memblock areas
@@ -250,6 +257,11 @@ static inline bool memblock_is_nomap(struct
memblock_region *m)
return m->flags & MEMBLOCK_NOMAP;
}
+static inline bool memblock_is_driver_managed(struct memblock_region *m)
+{
+ return m->flags & MEMBLOCK_DRIVER_MANAGED;
+}
+
int memblock_search_pfn_nid(unsigned long pfn, unsigned long *start_pfn,
unsigned long *end_pfn);
void __next_mem_pfn_range(int *idx, int nid, unsigned long *out_start_pfn,
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 33400ff051a8..8347fc158d2b 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -556,6 +556,11 @@ static int kexec_walk_memblock(struct kexec_buf *kbuf,
if (kbuf->image->type == KEXEC_TYPE_CRASH)
return func(&crashk_res, kbuf);
+ /*
+* Using MEMBLOCK_NONE will properly skip MEMBLOCK_DRIVER_MANAGED. See
+* IORESOURCE_SYSRAM_DRIVER_MANAGED handling in
+* locate_mem_hole_callback().
+*/
if (kbuf->top_down) {
for_each_free_mem_range_reverse(i, NUMA_NO_NODE, MEMBLOCK_NONE,
&mstart, &mend, NULL) {
diff --git a/mm/memblock.c b/mm/memblock.c
index 47a56b223141..540a35317fb0 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -979,6 +979,10 @@ static bool should_skip_region(struct memblock_type *type,
if (!(flags & MEMBLOCK_NOMAP) && memblock_is_nomap(m))
return true;
+ /* skip driver-managed memory unless we were asked for it explicitly */
+ if (!(flags & MEMBLOCK_DRIVER_MANAGED) && memblock_is_driver_managed(m))
+ return true;
+
[PATCH v1 0/4] mm/memory_hotplug: full support for
Architectures that require CONFIG_ARCH_KEEP_MEMBLOCK=y, such as arm64,
don't cleanly support add_memory_driver_managed() yet. Most prominently,
kexec_file can still end up placing images on such driver-managed memory,
resulting in undesired behavior.
Teaching kexec to not place images on driver-managed memory is especially
relevant for virtio-mem. Details can be found in commit 7b7b27214bba
("mm/memory_hotplug: introduce add_memory_driver_managed()").
Extend memblock with a new flag and set it from memory hotplug code
when applicable. This is required to fully support virtio-mem on
arm64, making also kexec_file behave like on x86-64.
Alternative A: Extend kexec_walk_memblock() to consult the kernel resource
tree whether IORESOURCE_SYSRAM_DRIVER_MANAGED is set. This feels wrong,
because the goal was to rely on memblock and not the resource tree.
Alternative B: Reuse MEMBLOCK_HOTPLUG. MEMBLOCK_HOTPLUG serves a different
purpose, though.
Cc: Andrew Morton
Cc: Mike Rapoport
Cc: Michal Hocko
Cc: Oscar Salvador
Cc: Jianyong Wu
Cc: Aneesh Kumar K.V
Cc: Vineet Gupta
Cc: Geert Uytterhoeven
Cc: Huacai Chen
Cc: Jiaxun Yang
Cc: Thomas Bogendoerfer
Cc: Heiko Carstens
Cc: Vasily Gorbik
Cc: Christian Borntraeger
Cc: Eric Biederman
Cc: Arnd Bergmann
Cc: linux-snps-...@lists.infradead.org
Cc: linux-i...@vger.kernel.org
Cc: linux-m...@lists.linux-m68k.org
Cc: linux-m...@vger.kernel.org
Cc: linux-s...@vger.kernel.org
Cc: linux...@kvack.org
Cc: kexec@lists.infradead.org
David Hildenbrand (4):
mm/memory_hotplug: handle memblock_add_node() failures in
add_memory_resource()
memblock: allow to specify flags with memblock_add_node()
memblock: add MEMBLOCK_DRIVER_MANAGED to mimic
IORESOURCE_SYSRAM_DRIVER_MANAGED
mm/memory_hotplug: indicate MEMBLOCK_DRIVER_MANAGED with
IORESOURCE_SYSRAM_DRIVER_MANAGED
arch/arc/mm/init.c | 4 ++--
arch/ia64/mm/contig.c| 2 +-
arch/ia64/mm/init.c | 2 +-
arch/m68k/mm/mcfmmu.c| 3 ++-
arch/m68k/mm/motorola.c | 6 --
arch/mips/loongson64/init.c | 4 +++-
arch/mips/sgi-ip27/ip27-memory.c | 3 ++-
arch/s390/kernel/setup.c | 3 ++-
include/linux/memblock.h | 19 ---
include/linux/mm.h | 2 +-
kernel/kexec_file.c | 5 +
mm/memblock.c| 13 +
mm/memory_hotplug.c | 11 +--
13 files changed, 57 insertions(+), 20 deletions(-)
base-commit: 5816b3e6577eaa676ceb00a848f0fd65fe2adc29
--
2.31.1
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[PATCH v1 1/4] mm/memory_hotplug: handle memblock_add_node() failures in add_memory_resource()
If memblock_add_node() fails, we're most probably running out of memory.
While this is unlikely to happen, it can happen and having memory added
without a memblock can be problematic for architectures that use
memblock to detect valid memory. Let's fail in a nice way instead of
silently ignoring the error.
Signed-off-by: David Hildenbrand
---
mm/memory_hotplug.c | 8 ++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 9fd0be32a281..917b3528636d 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1384,8 +1384,11 @@ int __ref add_memory_resource(int nid, struct resource
*res, mhp_t mhp_flags)
mem_hotplug_begin();
- if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
- memblock_add_node(start, size, nid);
+ if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) {
+ ret = memblock_add_node(start, size, nid);
+ if (ret)
+ goto error_mem_hotplug_end;
+ }
ret = __try_online_node(nid, false);
if (ret < 0)
@@ -1458,6 +1461,7 @@ int __ref add_memory_resource(int nid, struct resource
*res, mhp_t mhp_flags)
rollback_node_hotadd(nid);
if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
memblock_remove(start, size);
+error_mem_hotplug_end:
mem_hotplug_done();
return ret;
}
--
2.31.1
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[PATCH v1 4/4] mm/memory_hotplug: indicate MEMBLOCK_DRIVER_MANAGED with IORESOURCE_SYSRAM_DRIVER_MANAGED
Let's communicate driver-managed regions to memblock, to properly
teach kexec_file with CONFIG_ARCH_KEEP_MEMBLOCK to not place images on
these memory regions.
Signed-off-by: David Hildenbrand
---
mm/memory_hotplug.c | 5 -
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 5f873e7f5b29..6d90818d4ce8 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1357,6 +1357,7 @@ bool mhp_supports_memmap_on_memory(unsigned long size)
int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags)
{
struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) };
+ enum memblock_flags memblock_flags = MEMBLOCK_NONE;
struct vmem_altmap mhp_altmap = {};
struct memory_group *group = NULL;
u64 start, size;
@@ -1385,7 +1386,9 @@ int __ref add_memory_resource(int nid, struct resource
*res, mhp_t mhp_flags)
mem_hotplug_begin();
if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) {
- ret = memblock_add_node(start, size, nid, MEMBLOCK_NONE);
+ if (res->flags & IORESOURCE_SYSRAM_DRIVER_MANAGED)
+ memblock_flags = MEMBLOCK_DRIVER_MANAGED;
+ ret = memblock_add_node(start, size, nid, memblock_flags);
if (ret)
goto error_mem_hotplug_end;
}
--
2.31.1
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