From 6bd92a8dc1a2c796121ea4c63d6e49c8266821bc Mon Sep 17 00:00:00 2001 From: Song Liu Date: Mon, 23 Sep 2019 15:38:33 -0700 Subject: [PATCH] uprobe: collapse THP pmd after removing all uprobes After all uprobes are removed from the huge page (with PTE pgtable), it is possible to collapse the pmd and benefit from THP again. This patch does the collapse by calling collapse_pte_mapped_thp(). Link: http://lkml.kernel.org/r/20190815164525.1848545-7-songliubraving@fb.com Signed-off-by: Song Liu Acked-by: Kirill A. Shutemov Reported-by: kbuild test robot Reviewed-by: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/events/uprobes.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index 27b596f14463a..94d38a39d72ec 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -26,6 +26,7 @@ #include #include #include +#include #include @@ -472,6 +473,7 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm, struct page *old_page, *new_page; struct vm_area_struct *vma; int ret, is_register, ref_ctr_updated = 0; + bool orig_page_huge = false; is_register = is_swbp_insn(&opcode); uprobe = container_of(auprobe, struct uprobe, arch); @@ -529,6 +531,9 @@ retry: /* let go new_page */ put_page(new_page); new_page = NULL; + + if (PageCompound(orig_page)) + orig_page_huge = true; } put_page(orig_page); } @@ -547,6 +552,10 @@ put_old: if (ret && is_register && ref_ctr_updated) update_ref_ctr(uprobe, mm, -1); + /* try collapse pmd for compound page */ + if (!ret && orig_page_huge) + collapse_pte_mapped_thp(mm, vaddr); + return ret; } -- 2.39.5