Messages in this thread | | | From | John Ogness <> | Subject | Re: [PATCH 4/4] fs/dcache: Avoid the try_lock loops in dentry_kill() | Date | Sat, 17 Feb 2018 00:49:35 +0100 |
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On 2018-02-17, Linus Torvalds <torvalds@linux-foundation.org> wrote: >> dentry_kill() calls both dentry_lock_inode() and lock_parent() in the >> common case. So by changing the semantics of lock_parent(), I am >> removing two "recheck in case I dropped" in the common case rather >> than just the one you pointed out. > > Ok, that would be lovely, but doesn't that end up being a nasty patch?
After reading your initial feedback my idea was to change both lock_parent() and dentry_lock_inode() to not only communicate _if_ the lock was successful, but also if d_lock was dropped in the process. (For example, with a tristate rather than boolean return value.) Then callers would know if they needed to recheck the dentry contents.
> So it may be that my dislike of the "re-check after possibly dropping > the lock" is not really about the re-checking, but about just how it > made that function look much more complicated.
I understand what you are saying and I appreciate the comments. I will code up some variations for myself and try to pick the one that is the least complicated for my v2.
John Ogness
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