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From: Vlastimil Babka <vbabka@suse.cz>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: kernel test robot <oliver.sang@intel.com>,
	Alexei Starovoitov <ast@kernel.org>,
	oe-lkp@lists.linux.dev, kbuild test robot <lkp@intel.com>,
	Michal Hocko <mhocko@suse.com>,
	Shakeel Butt <shakeel.butt@linux.dev>,
	"open list:CONTROL GROUP (CGROUP)" <cgroups@vger.kernel.org>,
	linux-mm <linux-mm@kvack.org>
Subject: Re: [linux-next:master] [memcg] 01d37228d3: netperf.Throughput_Mbps 37.9% regression
Date: Mon, 10 Mar 2025 11:34:51 +0100	[thread overview]
Message-ID: <a30e2c60-e01b-4eac-8a40-e7a73abebfd3@suse.cz> (raw)
In-Reply-To: <CAADnVQ+NKZtNxS+jBW=tMnmca18S2jfuGCR+ap1bPHYyhxy6HQ@mail.gmail.com>

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 !!



  reply	other threads:[~2025-03-10 10:34 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-03-10  5:50 kernel test robot
2025-03-10  9:55 ` Vlastimil Babka
2025-03-10 10:18   ` Alexei Starovoitov
2025-03-10 10:34     ` Vlastimil Babka [this message]
2025-03-10 10:56       ` Alexei Starovoitov
2025-03-10 11:03         ` Vlastimil Babka

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