lkml.org 
[lkml]   [2019]   [Aug]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v4 2/2] uprobe: collapse THP pmd after removing all uprobes
Date
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().

Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Song Liu <songliubraving@fb.com>
---
kernel/events/uprobes.c | 9 +++++++++
1 file changed, 9 insertions(+)

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 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
/* 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 @@ int uprobe_write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm,
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;
}

--
2.17.1
\
 
 \ /
  Last update: 2019-08-03 01:20    [W:0.047 / U:1.596 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site