尝试分配更多共享 memory 时“驱动器上没有剩余空间”

Question

MacOS. 16GB RAM

I'm running code (which other users are running on similar hardware) allocating shared memory. It gets halfway through, then dies with the message:

Error allocating shared memory:: No space left on device

I've checked:

sysctl -A | grep shm               
kern.sysv.shmall: 1024
kern.sysv.shmmax: 4194304
kern.sysv.shmmin: 1
kern.sysv.shmmni: 32
kern.sysv.shmseg: 128
security.mac.posixshm_enforce: 1
security.mac.sysvshm_enforce: 1

I tried to increase shmall but kept getting:

sysctl: unknown oid 'kern.sysv.shmall:'

Anyone know how to fix this?

Answer 1

This looks like a duplicate of https://unix.stackexchange.com/questions/689295/values-from-sysctl-a-dont-match-etc-sysctl-conf-even-after-restart/710645 .

I can copy/paste my answer here, but not sure if that's double dipping haha. The tl;dr is you'll need to create a LaunchDaemon after disabling SIP :

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<!-- DISABLE SIP TO USE: macOS Recovery > Utilities > Terminal > `csrutil disable` > Reboot -->
<plist version="1.0">
    <dict>
        <key>Label</key>
        <string>com.startup.sysctl</string>
        <key>LaunchOnlyOnce</key>
        <true/>
        <key>StandardErrorPath</key>
            <string>/private/tmp/sysctl.err</string>
        <key>StandardOutPath</key>
            <string>/private/tmp/sysctl.out</string>
        <key>ProgramArguments</key>
        <array>
            <string>/usr/sbin/sysctl</string>
            <string>-w</string>
            <string>kern.sysv.shmmax=4194304</string>
            <string>kern.sysv.shmmin=1</string>
            <string>kern.sysv.shmmni=32</string>
            <string>kern.sysv.shmseg=128</string>
            <string>kern.sysv.shmall=1024</string>
        </array>
        <key>RunAtLoad</key>
        <true/>
    </dict>
</plist>

Then load with sudo launchctl bootstrap system /Library/LaunchDaemons/com.startup.sysctl.plist

Output looks like this:

λ tail -f /tmp/sysctl.out
kern.sysv.shmmax: 16777216 -> 4194304
kern.sysv.shmmin: 1 -> 1
kern.sysv.shmmni: 4096
kern.sysv.shmseg: 512 -> 128
kern.sysv.shmall: 4096 -> 1024