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| author | Alexey Perevalov <a.perevalov@samsung.com> | 2017-09-06 16:23:56 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-09-06 17:27:29 -0700 |
| commit | 9d4ac934829ac58c5109c49e6dfe677300e5e652 (patch) | |
| tree | 95d3de228e2d3f34ef777b7674f27adcf075c84a /fs | |
| parent | 2376dd7ceddae67432db055ff3f2b7f4122a919d (diff) | |
| download | linux-9d4ac934829ac58c5109c49e6dfe677300e5e652.tar.bz2 | |
userfaultfd: provide pid in userfault msg
It could be useful for calculating downtime during postcopy live
migration per vCPU. Side observer or application itself will be
informed about proper task's sleep during userfaultfd processing.
Process's thread id is being provided when user requeste it by setting
UFFD_FEATURE_THREAD_ID bit into uffdio_api.features.
Link: http://lkml.kernel.org/r/20170802165145.22628-6-aarcange@redhat.com
Signed-off-by: Alexey Perevalov <a.perevalov@samsung.com>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/userfaultfd.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 5fd4d846691f..665bf7a930b2 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -178,7 +178,8 @@ static inline void msg_init(struct uffd_msg *msg) static inline struct uffd_msg userfault_msg(unsigned long address, unsigned int flags, - unsigned long reason) + unsigned long reason, + unsigned int features) { struct uffd_msg msg; msg_init(&msg); @@ -202,6 +203,8 @@ static inline struct uffd_msg userfault_msg(unsigned long address, * write protect fault. */ msg.arg.pagefault.flags |= UFFD_PAGEFAULT_FLAG_WP; + if (features & UFFD_FEATURE_THREAD_ID) + msg.arg.pagefault.ptid = task_pid_vnr(current); return msg; } @@ -422,7 +425,8 @@ int handle_userfault(struct vm_fault *vmf, unsigned long reason) init_waitqueue_func_entry(&uwq.wq, userfaultfd_wake_function); uwq.wq.private = current; - uwq.msg = userfault_msg(vmf->address, vmf->flags, reason); + uwq.msg = userfault_msg(vmf->address, vmf->flags, reason, + ctx->features); uwq.ctx = ctx; uwq.waken = false; |