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authorSong Liu <songliubraving@fb.com>2019-09-23 15:38:33 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-09-24 15:54:11 -0700
commitf385cb85a42fc4ba92464c2bfd2e2049d65353d3 (patch)
treeecbb1588dd56f195f28fd76740e384096284e1dd /kernel
parent27e1f8273113adec0e98bf513e4091636b27cc2a (diff)
downloadlinux-f385cb85a42fc4ba92464c2bfd2e2049d65353d3.tar.bz2
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 <songliubraving@fb.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: kbuild test robot <lkp@intel.com> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/events/uprobes.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 27b596f14463..94d38a39d72e 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -26,6 +26,7 @@
#include <linux/percpu-rwsem.h>
#include <linux/task_work.h>
#include <linux/shmem_fs.h>
+#include <linux/khugepaged.h>
#include <linux/uprobes.h>
@@ -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;
}