Remove #include <sys/lock.h> from tmpfs.h.

Add in the next planned change - the fix of the max_free test cases at the start of SPLAY_{LEFT,RIGHT}_STEP.

In D21964#500501, @neel_neelc.org wrote:

Sounds good, lets go with your patch then.

I closed my merge request on the GNOME GitLab.

In D21964#500456, @neel_neelc.org wrote:

@dougm Your patch surely does look cleaner than mine (I just needed something to unbreak the build), but are you sure it will work on 12.x and 11.x? If so, lets go with yours.

I built my patch to (hopefully) be compatible with 12.x and 11.x, so that's why it looks ugly, it has #ifdefs. I don't know if 12.x and below has vm_map_entry_read_succ().

In D21964#500392, @neel_neelc.org wrote:

I integrated your changes. Would the updated Ports/GNOME changes work?

In D21964#500356, @neel_neelc.org wrote:

I sent an updated patch to the GNOME people here: https://gitlab.gnome.org/GNOME/libgtop/merge_requests/12

I also have an fixed Bugzilla patch here: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=242533

In D21964#500073, @pkubaj wrote:

This change broke devel/libgtop on powerpc64 (I didn't try amd64, it could also break there). The error is:

procmap.c:282:39: error: no member named 'next' in 'struct vm_map_entry'
        first = vmspace.vm_map.header.next;

A similar problem arose in lib/libprocstat/libprocstat.c and was
addressed in the most recent change to that file.  I'll look at this
problem tonight, and expect to find that a similar solution will suffice.

Rework the path compression so that there's no need to consider entries not strictly between entry and next_entry (or prev_entry).

Carefully pick the end-of-list marker before starting the walk toward a successor in clip_end.

Fix failure to update map->nentries. Fix problem updating max_free when entry and successor/predecessor are parent and child in the tree. Do path-halving when taking more than one step to find the successor/predecessor to avoid walking long paths when the same entry is clipped one piece at a time repeatedly.

Apply reviewer's suggestions.

Resolve merge conflicts.

Completing the threading of the vm_map splay tree makes this pointless.

In D22324#490910, @kib wrote:

I am somewhat curious how much does the upgrade succeed. Did you measured it ? E.g. the counters of total vm_pager_page_unswapped calls during buildworld vs. the number of times the lock needs to be upgraded vs. the number of successfull upgrades.

Make more clear that the new function is not used by the kernel.

In D22728#497480, @kib wrote:

I was bitten by use of seemingly kernel-only headers in userspace too many times. I believe that it is much better to not try to adapt vm/vm_map.h inlines to userspace, but have separate code in libprocstat, as Mark suggested.

Add comment. Change vm_map_entry_read_succ so that it leaves the next entry in vmentry, and doesn't only return the pointer to that entry.

In D22728#497468, @markj wrote:

I don't have an objection to this approach, but it's kind of unusual when compared with other routines which use libkvm. That is, I would just implement entry_read_succ directly in libprocstat. With this patch, libprocstat still embed details of the implementation (such as the fact that iteration terminates after visiting the header) so we still do not get a clean separation between userspace and the kernel, and vm_map_entry_read_succ() is harder to understand because of the indirection through "reader".

Fix compilation errors.

Update base to r355439. Stop passing dereferenced pointers to SPLAY_{LEFT,RIGHT}_STEP macros, since it seems that the compiler can't avoid extra operations for possible aliasing.

In D21964#496486, @markj wrote:

Thanks. To be clear, "old" is unmodified sources, "new" is the patch but with next and prev pointers retained, and "new, thread-only" is this patch?

In D21964#495950, @markj wrote:

How are you collecting performance counters in your benchmark? Would it also be possible to collect branch miss and CPI statistics?

With the attached simple test program, compiled with -O3, the results without and with DM defined are:

Apply reviewer suggestions. Modify SPLAY_{LEFT,RIGHT}_STEP to address performance issues. Update timing results. More than have the time lost is recovered. The rest is likely due to the cost of successor and predecessor.

Update to account for the fact that several parts originally in this patch have now been checked in. They were the parts that let me show a little time improvement, and what's left here, about nothing but threading the tree, will probably give back some of that time saved. I'll update the timing results and cache miss results in a while.

Incrementing the nupdates counter, which matters only when DIAGNOSTICS is #defined, fell out of the previous version. Add it back in, in a new and better place.

In D22544#493747, @alc wrote:

Can you explain why this change reduces the number of L1 data cache misses?

Go ahead and make findnext and findprev look less weird.

Stop trying to insert 'found' into the splay search code.

Replace the macros with __always_inline functions, which preserves, and perhaps slightly enhances the performance benefit.

Just tidying up.

Restore gap_end variable to fix findspace problem.

Reconsider a pessimization to vm_map_findspace.

Remove the bits that have been checked in separately.

Take out the parts that have been check in separately. Leave in the renaming parts from a patch awaiting review. Macro-size some splay-helper functions to help improve performance.

Add a missing underscore.

Reorder operations to avoid reading the word past the end of the bitstring, and ignoring it.

Revert half of the previous change. Only _value needs initialization based on _start, and _offset does not.

Address a problem of finding a match at the start when start!=0.