From: Marc Herbert <marc.herbert@linux.intel.com>
To: Dan Williams <dan.j.williams@intel.com>,
"ruansy.fnst" <ruansy.fnst@fujitsu.com>,
linux-cxl@vger.kernel.org
Cc: vishal.l.verma@intel.com, sunfishho12@gmail.com
Subject: Re: [PATCH] test/cxl-xor-region.sh: remove redundant waitting
Date: Mon, 19 May 2025 18:00:19 -0700 [thread overview]
Message-ID: <d9b62e78-52df-4283-9004-18c0bc01f73a@linux.intel.com> (raw)
In-Reply-To: <682bba2f9ce2b_1626e100dd@dwillia2-xfh.jf.intel.com.notmuch>
On 2025-05-19 16:09, Dan Williams wrote:
> Marc Herbert wrote:
>> PS: while... waiting for such a fast/no-wait/unstable option, I see no
>> reason why systemd would not work.
>
> It does not work due to circular dependency deadlock.
I just had a quick chat with Dan about this.
A local, systemd indirection _workaround_ would avoid the
deadlock. systemd is dealing with processes than "hang" by design:
daemons! And with even more complex and difficult processes and
services. udev routinely sends messages and triggers systemd, yet
systemd has never blocked udev in return, no matter what happens.
When you connect a USB printer, udev and systemd start the ipp-usb
process which "hangs" forever. This does not block udev.
On the other hand, in
https://lore.kernel.org/linux-cxl/ef46edd7-b492-4124-9cf9-0db104175eac@linux.intel.com/
I never meant to suggest systemd as a "permanent" solution for every
user of the cxl command! I was only suggesting systemd as a "private"
workaround, part of some specific test suite currently stuck with this
deadlock.
Hope this clarifies.
next prev parent reply other threads:[~2025-05-20 1:00 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-14 11:20 [PATCH] test/cxl-xor-region.sh: remove redundant waitting ruansy.fnst
2025-05-16 21:36 ` Alison Schofield
2025-05-20 3:54 ` Shiyang Ruan
2025-05-16 23:50 ` cxl <-> udev deadlock? Marc Herbert
2025-05-17 0:23 ` [PATCH] test/cxl-xor-region.sh: remove redundant waitting dan.j.williams
2025-05-19 21:47 ` Marc Herbert
2025-05-19 23:09 ` Dan Williams
2025-05-20 1:00 ` Marc Herbert [this message]
2025-05-20 3:38 ` Shiyang Ruan
2025-05-20 5:26 ` Marc Herbert
2025-05-28 20:49 ` Alison Schofield
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