Re: [PATCH 0/9] Clean up alloc_cache allocations

[Jens Axboe <axboe@kernel.dk>]

On 11/18/24 6:22 PM, Gabriel Krisman Bertazi wrote:
> Jens, Pavel,
> 
> The allocation paths that use alloc_cache duplicate the same code
> pattern, sometimes in a quite convoluted way.  This series cleans up
> that code by folding the allocation into the cache code itself, making
> it just an allocator function, and keeping the cache policy invisible to
> callers.  A bigger justification for doing this, beyond code simplicity,
> is that it makes it trivial to test the impact of disabling the cache
> and using slab directly, which I've used for slab improvement
> experiments.  I think this is one step forward in the direction
> eventually lifting the alloc_cache into a proper magazine layer in slab
> out of io_uring.

Nice!

Patchset looks good, from a quick look, even from just a cleanup
perspective. We're obviously inside the merge window right now, so it's
a 6.14 target at this point. I'll take some timer to review it a bit
closer later this week.

> It survived liburing testsuite, and when microbenchmarking the
> read-write path with mmtests and fio, I didn't observe any significant
> performance variation (there was actually a 2% gain, but that was
> within the variance of the test runs, making it not signficant and
> surely test noise).
> 
> I'm specifically interested, and happy to do so, if there are specific
> benchmarks you'd like me to run it against.

In general, running the liburing test suite with various types of files
and devices and with KASAN and LOCKDEP turned on is a good test of not
having messed something up, in a big way at least. But maybe you already
ran that too?

-- 
Jens Axboe