| Message ID | 20200915125947.26204-21-songmuchun@bytedance.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mm/hugetlb: Free some vmemmap pages of hugetlb page | expand |
Hi, Please see comments below. On 9/15/20 5:59 AM, Muchun Song wrote: > 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 <songmuchun@bytedance.com> > --- > .../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 feature disable > + > hung_task_panic= > [KNL] Should the hung task detector generate panics. > Format: 0 | 1 > diff --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. insert blank line here. > +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.
On Wed, Sep 16, 2020 at 10:11 AM Randy Dunlap <rdunlap@infradead.org> wrote: > > Hi, > Please see comments below. > > On 9/15/20 5:59 AM, Muchun Song wrote: > > 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 <songmuchun@bytedance.com> > > --- > > .../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 feature > > disable > > > + > > hung_task_panic= > > [KNL] Should the hung task detector generate panics. > > Format: 0 | 1 > > diff --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. > > insert blank line here. > > > +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. > Thanks for your comments. > > -- > ~Randy >
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 + each HugeTLB page. + Format: { on (default) | off } + + on: enable the feature + off: dosable the feature + hung_task_panic= [KNL] Should the hung task detector generate panics. Format: 0 | 1 diff --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. +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. diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 56c0bf2370ed..28c154679838 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1310,6 +1310,8 @@ static void __free_hugepage(struct hstate *h, struct page *page); (__boundary - 1 < (end) - 1) ? __boundary : (end); \ }) +static bool hugetlb_free_vmemmap_disabled __initdata; + static inline unsigned int nr_free_vmemmap(struct hstate *h) { return h->nr_free_vmemmap_pages; @@ -1457,6 +1459,13 @@ static void __init hugetlb_vmemmap_init(struct hstate *h) unsigned int order = huge_page_order(h); unsigned int vmemmap_pages; + if (hugetlb_free_vmemmap_disabled) { + h->nr_free_vmemmap_pages = 0; + pr_info("HugeTLB: disable free vmemmap pages for %s\n", + h->name); + return; + } + vmemmap_pages = ((1 << order) * sizeof(struct page)) >> PAGE_SHIFT; /* * The head page and the first tail page not free to buddy system, @@ -1867,6 +1876,20 @@ static inline void clear_subpage_hwpoison(struct page *head) { set_page_private(head + 4, 0); } + +static int __init early_hugetlb_free_vmemmap_param(char *buf) +{ + if (!buf) + return -EINVAL; + + if (!strcmp(buf, "off")) + hugetlb_free_vmemmap_disabled = true; + else if (strcmp(buf, "on")) + return -EINVAL; + + return 0; +} +early_param("hugetlb_free_vmemmap", early_hugetlb_free_vmemmap_param); #else static inline void hugetlb_vmemmap_init(struct hstate *h) {
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 <songmuchun@bytedance.com> --- .../admin-guide/kernel-parameters.txt | 9 ++++++++ Documentation/admin-guide/mm/hugetlbpage.rst | 3 +++ mm/hugetlb.c | 23 +++++++++++++++++++ 3 files changed, 35 insertions(+)