* [PATCH v3] memory hotplug: update the variables after memory removed [not found] <1406633598-27910-1-git-send-email-zhenzhang.zhang@huawei.com> @ 2014-07-29 11:35 ` Zhang Zhen 0 siblings, 0 replies; 4+ messages in thread From: Zhang Zhen @ 2014-07-29 11:35 UTC (permalink / raw) To: tglx, Ingo Molnar, hpa, Andrew Morton, Dave Hansen, David Rientjes Cc: wangnan0, x86, linux-kernel, Linux MM Commit ea0854170c95 ("memory hotplug: fix a bug on /dev/mem for 64-bit kernels") added a fuction update_end_of_memory_vars() to update high_memory, max_pfn and max_low_pfn. Here we may access wrong memory via /dev/mem after memory remove without this patch. I modified the function and call it in arch_remove_memory() to update these variables too. Change v1->v2: - according to Dave Hansen and David Rientjes's suggestions modified update_end_of_memory_vars(). change v2->v3: - remove the extra space before the function identifier of update_end_of_memory_vars(). - remove the end_pfn and use start_pfn + nr_pages in the conditional. Signed-off-by: Zhang Zhen <zhenzhang.zhang@huawei.com> --- arch/x86/mm/init_64.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index df1a992..d16368e 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -673,15 +673,11 @@ void __init paging_init(void) * After memory hotplug the variables max_pfn, max_low_pfn and high_memory need * updating. */ -static void update_end_of_memory_vars(u64 start, u64 size) +static void update_end_of_memory_vars(u64 end_pfn) { - unsigned long end_pfn = PFN_UP(start + size); - - if (end_pfn > max_pfn) { - max_pfn = end_pfn; - max_low_pfn = end_pfn; - high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1; - } + max_pfn = end_pfn; + max_low_pfn = end_pfn; + high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1; } /* @@ -694,6 +690,7 @@ int arch_add_memory(int nid, u64 start, u64 size) struct zone *zone = pgdat->node_zones + ZONE_NORMAL; unsigned long start_pfn = start >> PAGE_SHIFT; unsigned long nr_pages = size >> PAGE_SHIFT; + unsigned long end_pfn; int ret; init_memory_mapping(start, start + size); @@ -702,7 +699,9 @@ int arch_add_memory(int nid, u64 start, u64 size) WARN_ON_ONCE(ret); /* update max_pfn, max_low_pfn and high_memory */ - update_end_of_memory_vars(start, size); + end_pfn = start_pfn + nr_pages; + if (end_pfn > max_pfn) + update_end_of_memory_vars(end_pfn); return ret; } @@ -1025,6 +1024,10 @@ int __ref arch_remove_memory(u64 start, u64 size) ret = __remove_pages(zone, start_pfn, nr_pages); WARN_ON_ONCE(ret); + /* update max_pfn, max_low_pfn and high_memory */ + if ((max_pfn >= start_pfn) && (max_pfn < (start_pfn + nr_pages))) + update_end_of_memory_vars(start_pfn); + return ret; } #endif -- 1.8.1.2 . -- 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: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH v3] memory hotplug: update the variables after memory removed @ 2014-07-29 11:35 ` Zhang Zhen 0 siblings, 0 replies; 4+ messages in thread From: Zhang Zhen @ 2014-07-29 11:35 UTC (permalink / raw) To: tglx, Ingo Molnar, hpa, Andrew Morton, Dave Hansen, David Rientjes Cc: wangnan0, x86, linux-kernel, Linux MM Commit ea0854170c95 ("memory hotplug: fix a bug on /dev/mem for 64-bit kernels") added a fuction update_end_of_memory_vars() to update high_memory, max_pfn and max_low_pfn. Here we may access wrong memory via /dev/mem after memory remove without this patch. I modified the function and call it in arch_remove_memory() to update these variables too. Change v1->v2: - according to Dave Hansen and David Rientjes's suggestions modified update_end_of_memory_vars(). change v2->v3: - remove the extra space before the function identifier of update_end_of_memory_vars(). - remove the end_pfn and use start_pfn + nr_pages in the conditional. Signed-off-by: Zhang Zhen <zhenzhang.zhang@huawei.com> --- arch/x86/mm/init_64.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index df1a992..d16368e 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -673,15 +673,11 @@ void __init paging_init(void) * After memory hotplug the variables max_pfn, max_low_pfn and high_memory need * updating. */ -static void update_end_of_memory_vars(u64 start, u64 size) +static void update_end_of_memory_vars(u64 end_pfn) { - unsigned long end_pfn = PFN_UP(start + size); - - if (end_pfn > max_pfn) { - max_pfn = end_pfn; - max_low_pfn = end_pfn; - high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1; - } + max_pfn = end_pfn; + max_low_pfn = end_pfn; + high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1; } /* @@ -694,6 +690,7 @@ int arch_add_memory(int nid, u64 start, u64 size) struct zone *zone = pgdat->node_zones + ZONE_NORMAL; unsigned long start_pfn = start >> PAGE_SHIFT; unsigned long nr_pages = size >> PAGE_SHIFT; + unsigned long end_pfn; int ret; init_memory_mapping(start, start + size); @@ -702,7 +699,9 @@ int arch_add_memory(int nid, u64 start, u64 size) WARN_ON_ONCE(ret); /* update max_pfn, max_low_pfn and high_memory */ - update_end_of_memory_vars(start, size); + end_pfn = start_pfn + nr_pages; + if (end_pfn > max_pfn) + update_end_of_memory_vars(end_pfn); return ret; } @@ -1025,6 +1024,10 @@ int __ref arch_remove_memory(u64 start, u64 size) ret = __remove_pages(zone, start_pfn, nr_pages); WARN_ON_ONCE(ret); + /* update max_pfn, max_low_pfn and high_memory */ + if ((max_pfn >= start_pfn) && (max_pfn < (start_pfn + nr_pages))) + update_end_of_memory_vars(start_pfn); + return ret; } #endif -- 1.8.1.2 . ^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH v3] memory hotplug: update the variables after memory removed 2014-07-29 11:35 ` Zhang Zhen @ 2014-07-29 11:39 ` Zhang Zhen -1 siblings, 0 replies; 4+ messages in thread From: Zhang Zhen @ 2014-07-29 11:39 UTC (permalink / raw) To: tglx, Ingo Molnar, hpa, Andrew Morton, Dave Hansen, David Rientjes Cc: wangnan0, x86, linux-kernel, Linux MM Commit ea0854170c95 ("memory hotplug: fix a bug on /dev/mem for 64-bit kernels") added a fuction update_end_of_memory_vars() to update high_memory, max_pfn and max_low_pfn. Here we may access wrong memory via /dev/mem after memory remove without this patch. I modified the function and call it in arch_remove_memory() to update these variables too. Change v1->v2: - according to Dave Hansen and David Rientjes's suggestions modified update_end_of_memory_vars(). change v2->v3: - remove the extra space before the function identifier of update_end_of_memory_vars(). - remove the end_pfn and use start_pfn + nr_pages in the conditional. Signed-off-by: Zhang Zhen <zhenzhang.zhang@huawei.com> Acked-by: David Rientjes <rientjes@google.com> --- arch/x86/mm/init_64.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index df1a992..d16368e 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -673,15 +673,11 @@ void __init paging_init(void) * After memory hotplug the variables max_pfn, max_low_pfn and high_memory need * updating. */ -static void update_end_of_memory_vars(u64 start, u64 size) +static void update_end_of_memory_vars(u64 end_pfn) { - unsigned long end_pfn = PFN_UP(start + size); - - if (end_pfn > max_pfn) { - max_pfn = end_pfn; - max_low_pfn = end_pfn; - high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1; - } + max_pfn = end_pfn; + max_low_pfn = end_pfn; + high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1; } /* @@ -694,6 +690,7 @@ int arch_add_memory(int nid, u64 start, u64 size) struct zone *zone = pgdat->node_zones + ZONE_NORMAL; unsigned long start_pfn = start >> PAGE_SHIFT; unsigned long nr_pages = size >> PAGE_SHIFT; + unsigned long end_pfn; int ret; init_memory_mapping(start, start + size); @@ -702,7 +699,9 @@ int arch_add_memory(int nid, u64 start, u64 size) WARN_ON_ONCE(ret); /* update max_pfn, max_low_pfn and high_memory */ - update_end_of_memory_vars(start, size); + end_pfn = start_pfn + nr_pages; + if (end_pfn > max_pfn) + update_end_of_memory_vars(end_pfn); return ret; } @@ -1025,6 +1024,10 @@ int __ref arch_remove_memory(u64 start, u64 size) ret = __remove_pages(zone, start_pfn, nr_pages); WARN_ON_ONCE(ret); + /* update max_pfn, max_low_pfn and high_memory */ + if ((max_pfn >= start_pfn) && (max_pfn < (start_pfn + nr_pages))) + update_end_of_memory_vars(start_pfn); + return ret; } #endif -- 1.8.1.2 . -- 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: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH v3] memory hotplug: update the variables after memory removed @ 2014-07-29 11:39 ` Zhang Zhen 0 siblings, 0 replies; 4+ messages in thread From: Zhang Zhen @ 2014-07-29 11:39 UTC (permalink / raw) To: tglx, Ingo Molnar, hpa, Andrew Morton, Dave Hansen, David Rientjes Cc: wangnan0, x86, linux-kernel, Linux MM Commit ea0854170c95 ("memory hotplug: fix a bug on /dev/mem for 64-bit kernels") added a fuction update_end_of_memory_vars() to update high_memory, max_pfn and max_low_pfn. Here we may access wrong memory via /dev/mem after memory remove without this patch. I modified the function and call it in arch_remove_memory() to update these variables too. Change v1->v2: - according to Dave Hansen and David Rientjes's suggestions modified update_end_of_memory_vars(). change v2->v3: - remove the extra space before the function identifier of update_end_of_memory_vars(). - remove the end_pfn and use start_pfn + nr_pages in the conditional. Signed-off-by: Zhang Zhen <zhenzhang.zhang@huawei.com> Acked-by: David Rientjes <rientjes@google.com> --- arch/x86/mm/init_64.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index df1a992..d16368e 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -673,15 +673,11 @@ void __init paging_init(void) * After memory hotplug the variables max_pfn, max_low_pfn and high_memory need * updating. */ -static void update_end_of_memory_vars(u64 start, u64 size) +static void update_end_of_memory_vars(u64 end_pfn) { - unsigned long end_pfn = PFN_UP(start + size); - - if (end_pfn > max_pfn) { - max_pfn = end_pfn; - max_low_pfn = end_pfn; - high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1; - } + max_pfn = end_pfn; + max_low_pfn = end_pfn; + high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1; } /* @@ -694,6 +690,7 @@ int arch_add_memory(int nid, u64 start, u64 size) struct zone *zone = pgdat->node_zones + ZONE_NORMAL; unsigned long start_pfn = start >> PAGE_SHIFT; unsigned long nr_pages = size >> PAGE_SHIFT; + unsigned long end_pfn; int ret; init_memory_mapping(start, start + size); @@ -702,7 +699,9 @@ int arch_add_memory(int nid, u64 start, u64 size) WARN_ON_ONCE(ret); /* update max_pfn, max_low_pfn and high_memory */ - update_end_of_memory_vars(start, size); + end_pfn = start_pfn + nr_pages; + if (end_pfn > max_pfn) + update_end_of_memory_vars(end_pfn); return ret; } @@ -1025,6 +1024,10 @@ int __ref arch_remove_memory(u64 start, u64 size) ret = __remove_pages(zone, start_pfn, nr_pages); WARN_ON_ONCE(ret); + /* update max_pfn, max_low_pfn and high_memory */ + if ((max_pfn >= start_pfn) && (max_pfn < (start_pfn + nr_pages))) + update_end_of_memory_vars(start_pfn); + return ret; } #endif -- 1.8.1.2 . ^ permalink raw reply related [flat|nested] 4+ messages in thread
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[not found] <1406633598-27910-1-git-send-email-zhenzhang.zhang@huawei.com>
2014-07-29 11:35 ` [PATCH v3] memory hotplug: update the variables after memory removed Zhang Zhen
2014-07-29 11:35 ` Zhang Zhen
2014-07-29 11:39 ` Zhang Zhen
2014-07-29 11:39 ` Zhang Zhen
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