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Feature #5880

closed

Increase IOV_MAX to at least 1024

Added by Robert Mustacchi over 7 years ago. Updated over 2 years ago.

Status:
Closed
Priority:
Normal
Assignee:
Jerry Jelinek
Category:
kernel
Start date:
2015-04-29
Due date:
% Done:

100%

Estimated time:
Difficulty:
Medium
Tags:
Gerrit CR:

Description

Today IOV_MAX on most other platforms is 1024; however, on illumos it is 16. This is properly informed by the value of IOV_MAX. However, there are applications out there (HVM-815) that don't even think to check IOV_MAX and just go to town. We should consider increasing ours to make life for parts of the lx brand easier (OS-3404) and for ourselves.

Today iovectors are declared by the kernel on the stack. If we have a smaller number of I/O vectors, then we continue to allocate them on the stack, otherwise we switch to a kmem allocation.

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 #1

Updated by John Levon over 2 years ago

This has been in use at Joyent forever.

In addition this has been unit tested via http://cr.illumos.org/~webrev/jlevon/12365/usr/src/test/os-tests/tests/writev/writev_test.c.html

as well as Jerry's original testing.

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 #2

Updated by Dan McDonald over 2 years ago

This has also been in OmniOS since the LX port, i.e. 2016.

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 #3

Updated by Electric Monk over 2 years ago

  • Status changed from New to Closed

git commit 8e9352593f28b1a84101b11e1c6db6aabf187a1c

commit  8e9352593f28b1a84101b11e1c6db6aabf187a1c
Author: Bryan Cantrill <bryan@joyent.com>
Date:   2020-03-12T09:44:29.000Z

    5880 Increase IOV_MAX to at least 1024
    Portions contributed by: Jerry Jelinek <jerry.jelinek@joyent.com>
    Reviewed by: Andy Fiddaman <andy@omniosce.org>
    Reviewed by: Yuri Pankov <ypankov@fastmail.com>
    Approved by: Dan McDonald <danmcd@joyent.com>

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