high_memory is the virtual address of the 'highest physical address' in the system. But __va(get_num_physpages() << PAGE_SHIFT) is not what we want because there may be holes in the physical address space. On the other hand, max_low_pfn is calculated from memblock_end_of_DRAM(), which is exactly corresponding to the highest physical address, so use it for high_memory calculation.
Cc: stable@vger.kernel.org Signed-off-by: Chong Qiao qiaochong@loongson.cn Signed-off-by: Huacai Chen chenhuacai@loongson.cn --- arch/loongarch/kernel/numa.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/loongarch/kernel/numa.c b/arch/loongarch/kernel/numa.c index c7d33c489e04..6e65ff12d5c7 100644 --- a/arch/loongarch/kernel/numa.c +++ b/arch/loongarch/kernel/numa.c @@ -436,7 +436,7 @@ void __init paging_init(void)
void __init mem_init(void) { - high_memory = (void *) __va(get_num_physpages() << PAGE_SHIFT); + high_memory = (void *) __va(max_low_pfn << PAGE_SHIFT); memblock_free_all(); }
On 9/26/23 20:10, Huacai Chen wrote:
high_memory is the virtual address of the 'highest physical address' in the system. But __va(get_num_physpages() << PAGE_SHIFT) is not what we want because there may be holes in the physical address space. On the other hand, max_low_pfn is calculated from memblock_end_of_DRAM(), which is exactly corresponding to the highest physical address, so use it for high_memory calculation.
Which commit is this patch intended to amend? A "Fixes:" tag may be helpful for stable backporting.
Signed-off-by: Chong Qiao qiaochong@loongson.cn Signed-off-by: Huacai Chen chenhuacai@loongson.cn
arch/loongarch/kernel/numa.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/loongarch/kernel/numa.c b/arch/loongarch/kernel/numa.c index c7d33c489e04..6e65ff12d5c7 100644 --- a/arch/loongarch/kernel/numa.c +++ b/arch/loongarch/kernel/numa.c @@ -436,7 +436,7 @@ void __init paging_init(void) void __init mem_init(void) {
- high_memory = (void *) __va(get_num_physpages() << PAGE_SHIFT);
- high_memory = (void *) __va(max_low_pfn << PAGE_SHIFT); memblock_free_all(); }
On Tue, Sep 26, 2023 at 11:26 PM WANG Xuerui kernel@xen0n.name wrote:
On 9/26/23 20:10, Huacai Chen wrote:
high_memory is the virtual address of the 'highest physical address' in the system. But __va(get_num_physpages() << PAGE_SHIFT) is not what we want because there may be holes in the physical address space. On the other hand, max_low_pfn is calculated from memblock_end_of_DRAM(), which is exactly corresponding to the highest physical address, so use it for high_memory calculation.
Which commit is this patch intended to amend? A "Fixes:" tag may be helpful for stable backporting.
OK, I will add a Fixes: tag.
Huacai
Signed-off-by: Chong Qiao qiaochong@loongson.cn Signed-off-by: Huacai Chen chenhuacai@loongson.cn
arch/loongarch/kernel/numa.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/loongarch/kernel/numa.c b/arch/loongarch/kernel/numa.c index c7d33c489e04..6e65ff12d5c7 100644 --- a/arch/loongarch/kernel/numa.c +++ b/arch/loongarch/kernel/numa.c @@ -436,7 +436,7 @@ void __init paging_init(void)
void __init mem_init(void) {
high_memory = (void *) __va(get_num_physpages() << PAGE_SHIFT);
high_memory = (void *) __va(max_low_pfn << PAGE_SHIFT); memblock_free_all();-- WANG "xen0n" Xuerui
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Huacai Chen -
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