The patch titled
Subject: uprobe: use FOLL_SPLIT_PMD instead of FOLL_SPLIT
has been added to the -mm tree. Its filename is
uprobe-use-foll_split_pmd-instead-of-foll_split.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/uprobe-use-foll_split_pmd-instead-of-foll_split.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/uprobe-use-foll_split_pmd-instead-of-foll_split.patch
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------------------------------------------------------
From: Song Liu <songliubraving@xxxxxx>
Subject: uprobe: use FOLL_SPLIT_PMD instead of FOLL_SPLIT
Use the newly added FOLL_SPLIT_PMD in uprobe. This preserves the huge
page when the uprobe is enabled. When the uprobe is disabled, newer
instances of the same application could still benefit from huge page.
For the next step, we will enable khugepaged to regroup the pmd, so that
existing instances of the application could also benefit from huge page
after the uprobe is disabled.
Link: http://lkml.kernel.org/r/20190815164525.1848545-5-songliubraving@xxxxxx
Signed-off-by: Song Liu <songliubraving@xxxxxx>
Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Reviewed-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/events/uprobes.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
--- a/kernel/events/uprobes.c~uprobe-use-foll_split_pmd-instead-of-foll_split
+++ a/kernel/events/uprobes.c
@@ -155,7 +155,7 @@ static int __replace_page(struct vm_area
{
struct mm_struct *mm = vma->vm_mm;
struct page_vma_mapped_walk pvmw = {
- .page = old_page,
+ .page = compound_head(old_page),
.vma = vma,
.address = addr,
};
@@ -166,8 +166,6 @@ static int __replace_page(struct vm_area
mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm, addr,
addr + PAGE_SIZE);
- VM_BUG_ON_PAGE(PageTransHuge(old_page), old_page);
-
if (new_page) {
err = mem_cgroup_try_charge(new_page, vma->vm_mm, GFP_KERNEL,
&memcg, false);
@@ -481,7 +479,7 @@ int uprobe_write_opcode(struct arch_upro
retry:
/* Read the page with vaddr into memory */
ret = get_user_pages_remote(NULL, mm, vaddr, 1,
- FOLL_FORCE | FOLL_SPLIT, &old_page, &vma, NULL);
+ FOLL_FORCE | FOLL_SPLIT_PMD, &old_page, &vma, NULL);
if (ret <= 0)
return ret;
_
Patches currently in -mm which might be from songliubraving@xxxxxx are
filemap-check-compound_headpage-mapping-in-filemap_fault.patch
filemap-check-compound_headpage-mapping-in-pagecache_get_page.patch
filemap-update-offset-check-in-filemap_fault.patch
mmthp-stats-for-file-backed-thp.patch
khugepaged-rename-collapse_shmem-and-khugepaged_scan_shmem.patch
mmthp-add-read-only-thp-support-for-non-shmem-fs.patch
mmthp-add-read-only-thp-support-for-non-shmem-fs-fix.patch
mmthp-add-read-only-thp-support-for-non-shmem-fs-fix-2.patch
mmthp-avoid-writes-to-file-with-thp-in-pagecache.patch
mm-move-memcmp_pages-and-pages_identical.patch
uprobe-use-original-page-when-all-uprobes-are-removed.patch
mm-thp-introduce-foll_split_pmd.patch
uprobe-use-foll_split_pmd-instead-of-foll_split.patch
khugepaged-enable-collapse-pmd-for-pte-mapped-thp.patch
uprobe-collapse-thp-pmd-after-removing-all-uprobes.patch
