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mm/gup: allow to react to fatal signals

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The existing gup code does not react to the fatal signals in many code
paths.  For example, in one retry path of gup we're still using
down_read() rather than down_read_killable().  Also, when doing page
faults we don't pass in FAULT_FLAG_KILLABLE as well, which means that
within the faulting process we'll wait in non-killable way as well.  These
were spotted by Linus during the code review of some other patches.

Let's allow the gup code to react to fatal signals to improve the
responsiveness of threads when during gup and being killed.

Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Brian Geffon <bgeffon@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Bobby Powers <bobbypowers@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Denis Plotnikov <dplotnikov@virtuozzo.com>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Martin Cracauer <cracauer@cons.org>
Cc: Marty McFadden <mcfadden8@llnl.gov>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Maya Gokhale <gokhale2@llnl.gov>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Link: http://lkml.kernel.org/r/20200220160256.9887-1-peterx@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Peter Xu 2020-04-01 21:08:53 -07:00 committed by Linus Torvalds
parent 4426e945df
commit 71335f37c5
2 changed files with 11 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
mm/gup.c
View File

@ -864,7 +864,7 @@ static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma,
if (*flags & FOLL_REMOTE)
fault_flags |= FAULT_FLAG_REMOTE;
if (locked)
fault_flags |= FAULT_FLAG_ALLOW_RETRY;
fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
if (*flags & FOLL_NOWAIT)
fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT;
if (*flags & FOLL_TRIED) {
@ -1207,7 +1207,7 @@ int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm,
address = untagged_addr(address);
if (unlocked)
fault_flags |= FAULT_FLAG_ALLOW_RETRY;
fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
retry:
vma = find_extend_vma(mm, address);
@ -1329,7 +1329,13 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk,
break;
*locked = 1;
down_read(&mm->mmap_sem);
ret = down_read_killable(&mm->mmap_sem);
if (ret) {
BUG_ON(ret > 0);
if (!pages_done)
pages_done = ret;
break;
}
ret = __get_user_pages(tsk, mm, start, 1, flags | FOLL_TRIED,
pages, NULL, locked);

3
mm/hugetlb.c
View File

@ -4344,7 +4344,8 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
if (flags & FOLL_WRITE)
fault_flags |= FAULT_FLAG_WRITE;
if (locked)
fault_flags |= FAULT_FLAG_ALLOW_RETRY;
fault_flags |= FAULT_FLAG_ALLOW_RETRY |
FAULT_FLAG_KILLABLE;
if (flags & FOLL_NOWAIT)
fault_flags |= FAULT_FLAG_ALLOW_RETRY |
FAULT_FLAG_RETRY_NOWAIT;