Re: [linux-next:master] [memcg] 01d37228d3: netperf.Throughput_Mbps 37.9% regression

[Vlastimil Babka <vbabka@suse.cz>]

On 3/10/25 11:18, Alexei Starovoitov wrote:
>> because this will affect the refill even if consume_stock() fails not due to
>> a trylock failure (which should not be happening), but also just because the
>> stock was of a wrong memcg or depleted. So in the nowait context we deny the
>> refill even if we have the memory. Attached patch could be used to see if it
>> if fixes things. I'm not sure about the testcases where it doesn't look like
>> nowait context would be used though, let's see.
> 
> Not quite.
> GFP_NOWAIT includes __GFP_KSWAPD_RECLAIM,
> so gfpflags_allow_spinning() will return true.

Uh right, it's the new gfpflags_allow_spinning(), not the
gfpflags_allow_blocking() I'm used to and implicitly assumed, sorry.

But then it's very simple because it has a bug:
gfpflags_allow_spinning() does

return !(gfp_flags & __GFP_RECLAIM);

should be !!