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[Qemu-devel] [PATCH 0/1] FOLL_NOWAIT and get_user_pages_unlocked
From: |
Andrea Arcangeli |
Subject: |
[Qemu-devel] [PATCH 0/1] FOLL_NOWAIT and get_user_pages_unlocked |
Date: |
Fri, 2 Mar 2018 18:43:42 +0100 |
Hello,
KVM is hanging on postcopy live migration.
David tracked it down to commit
ce53053ce378c21e7ffc45241fd67d6ee79daa2b and the problem is pretty
obvious then.
Either we teach get_user_pages_locked/unlocked to handle FOLL_NOWAIT
(so faultin_nopage works right even when the nonblocking pointer is
not NULL) or we need to revert part of commit
ce53053ce378c21e7ffc45241fd67d6ee79daa2b and keep using FOLL_NOWAIT
only as parameter to get_user_pages (which won't ever set nonblocking
pointer to non-NULL). I suppose the former approach is preferred to be
more robust.
Thanks,
Andrea
Andrea Arcangeli (1):
mm: gup: teach get_user_pages_unlocked to handle FOLL_NOWAIT
mm/gup.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
- [Qemu-devel] [PATCH 0/1] FOLL_NOWAIT and get_user_pages_unlocked,
Andrea Arcangeli <=