Differential D21984

vfs: reduce failing trylock attempts in mnt_vnode_next_active
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Authored by mjg on Oct 11 2019, 6:45 PM.

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Summary

When doing poudriere -j 104, after 4 minutes of tracing:

kernel`mnt_vnode_next_active                        _mtx_trylock_flags_int                                            1          1683089
kernel`mnt_vnode_next_active                        _mtx_trylock_flags_int                                            0          4781020

That is, majority of attempts to trylock has failed.

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Repository

rS FreeBSD src repository - subversion

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Buildable 26991

Event Timeline

mjg created this revision.Oct 11 2019, 6:45 PM

Herald added a subscriber: imp. · View Herald TranscriptOct 11 2019, 6:45 PM

Harbormaster completed remote builds in B26991: Diff 63158.Oct 11 2019, 6:45 PM

mjg retitled this revision from vfs: reduce failing trylock attempts in nt_vnode_next_active to vfs: reduce failing trylock attempts in mnt_vnode_next_active.Oct 11 2019, 6:45 PM

This cannot go in without explanation why mtx_owner is checked, in the comment above. But it should not go in regardless, if such check is useful perhaps it should be added to VI_TRYLOCK, or mtx_trylock, or another version of VI_TRYLOCK created.

add VI_TRYLOCK_CONTENDED

kib accepted this revision.Oct 11 2019, 8:56 PM

This revision is now accepted and ready to land.Oct 11 2019, 8:56 PM

With filtering support (D22690) this should not be needed

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sys/

kern/

vfs_subr.c

2 lines

Diff 63158

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vfs: reduce failing trylock attempts in mnt_vnode_next_activeAbandonedPublicActions