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| author |   Christian Borntraeger <borntraeger@de.ibm.com> | 2016-02-03 10:18:41 +0100 |
|---|---|---|
| committer | Christian Borntraeger <borntraeger@de.ibm.com> | 2016-02-10 13:12:56 +0100 |
| commit | ab99a1cc7a405fed5148cf6a6fc26eec75b8a7a7 (patch) | |
| tree | e14e35351435069a1879d3868f8ea9b8c851837b /tools/perf/scripts/python/stackcollapse.py | |
| parent | KVM: s390: usage hint for adapter mappings (diff) | |
| download | linux-dev-ab99a1cc7a405fed5148cf6a6fc26eec75b8a7a7.tar.xz linux-dev-ab99a1cc7a405fed5148cf6a6fc26eec75b8a7a7.zip | |
KVM: s390: do not take mmap_sem on dirty log query
Dirty log query can take a long time for huge guests.
Holding the mmap_sem for very long times can cause some unwanted
latencies.
Turns out that we do not need to hold the mmap semaphore.
We hold the slots_lock for gfn->hva translation and walk the page
tables with that address, so no need to look at the VMAs. KVM also
holds a reference to the mm, which should prevent other things
going away. During the walk we take the necessary ptl locks.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Diffstat (limited to 'tools/perf/scripts/python/stackcollapse.py')
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