Re: [PATCH] check kernel version for io_method

From: Andreas Karlsson <andreas(at)proxel(dot)se>
Sent: Wednesday, January 14, 2026 09:07
To: Pierre <pierre(dot)forstmann(at)gmail(dot)com>; pgsql-hackers(at)lists(dot)postgresql(dot)org <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: [PATCH] check kernel version for io_method

On 1/13/26 11:05 PM, Pierre wrote:
> Please find a patch proposal for bug BUG #19369: Not documented that
> io_uring on kernel versions between 5.1 and below 5.6 does not work.
Wouldn't it make more sense to use io_uring_get_probe_ring() and
io_uring_opcode_supported() to actually check for the required opcode?
Then if someone uses a Kernel with the required features backported
everything will still work.

Andreas

+1
It would be more reliable to check the availability of io_uring feature than to check OS version.

BTW, the error message in the following code block is wrong as it locates in branch that IO_URING is not enabled.

#else
+ if (*newval == IOMETHOD_WORKER || *newval == IOMETHOD_SYNC)
+ {
+ /*
+ * OK
+ */
+ }
+ else
+ {
+ GUC_check_errdetail("io_uring requires Linux kernel 5.6 or later.");
+ return false;
+ }

Thanks,
Steven