Re: [RFC PATCH 20/24] mm/hugetlb: Add a kernel parameter hugetlb_free_vmemmap
From: Randy Dunlap <rdunlap@infradead.org>
Date: 2020-09-16 02:11:26
Also in:
linux-fsdevel, linux-mm, lkml
Hi, Please see comments below. On 9/15/20 5:59 AM, Muchun Song wrote:
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Add a kernel parameter hugetlb_free_vmemmap to disable the feature of freeing unused vmemmap pages associated with each hugetlb page on boot. Signed-off-by: Muchun Song <redacted> --- .../admin-guide/kernel-parameters.txt | 9 ++++++++ Documentation/admin-guide/mm/hugetlbpage.rst | 3 +++ mm/hugetlb.c | 23 +++++++++++++++++++ 3 files changed, 35 insertions(+)diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 5debfe238027..69d18ef6f66b 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt@@ -1551,6 +1551,15 @@ Documentation/admin-guide/mm/hugetlbpage.rst. Format: size[KMG] + hugetlb_free_vmemmap= + [KNL] When CONFIG_HUGETLB_PAGE_FREE_VMEMMAP is set, + this disables freeing unused vmemmap pages associated
this controls
+ each HugeTLB page.
with each HugeTLB page.
+ Format: { on (default) | off }
+
+ on: enable the feature
+ off: dosable the featuredisable
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+ hung_task_panic= [KNL] Should the hung task detector generate panics. Format: 0 | 1diff --git a/Documentation/admin-guide/mm/hugetlbpage.rst b/Documentation/admin-guide/mm/hugetlbpage.rst index f7b1c7462991..7d6129ee97dd 100644 --- a/Documentation/admin-guide/mm/hugetlbpage.rst +++ b/Documentation/admin-guide/mm/hugetlbpage.rst@@ -145,6 +145,9 @@ default_hugepagesz will all result in 256 2M huge pages being allocated. Valid default huge page size is architecture dependent.
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+hugetlb_free_vmemmap + When CONFIG_HUGETLB_PAGE_FREE_VMEMMAP is set, this disables freeing + unused vmemmap pages associated each HugeTLB page. When multiple huge page sizes are supported, ``/proc/sys/vm/nr_hugepages`` indicates the current number of pre-allocated huge pages of the default size.
-- ~Randy