
Linux 5.1 Arrives - CrankyBear
https://www.zdnet.com/article/linux-5-1-arrives/
======
kjeetgill
One of the coolest new features was just on HN: Efficient IO with io_uring,
the new async I/O interface in Linux 5.1
[https://news.ycombinator.com/item?id=19843464](https://news.ycombinator.com/item?id=19843464)

Personally I'm most excited for "Safe signal delivery in presence of PID
reuse". I think the kernel/syscall boundary has so many cracks when it comes
to race-conditions. It really shows how much has changed with respect to
concurrency.

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jolmg
> The first of these is Linux now supports persistent memory as RAM. Sure,
> non-volatile memory (NVM) isn't as fast as good old RAM, but on newer
> systems it gives you the option of expanding your memory.

That sounds like swap. What's the difference?

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vbezhenar
I think that this article explains it somewhat:
[https://lwn.net/Articles/777212/](https://lwn.net/Articles/777212/)

Basically there's Intel Optane DIMM which costs less than DRAM and offers good
enough performance, so you can use Optane with DRAM as a cache and those
patches provide proper Linux support for that scheme.

~~~
jolmg
Isn't swap basically expanded memory while using DRAM as cache? It seems like
this could be just a different way of operating that cache.

I wonder if this new feature would be used with swapon/swapoff or if it would
need a different interface.

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robbyt
Intel have a fork of Redis that uses Optane storage instead of RAM. The end
result is a persistent DB that can operate at the speed of Redis.

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andrius4669
[https://kernelnewbies.org/LinuxChanges](https://kernelnewbies.org/LinuxChanges)
more detailed changelog

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wyld_one
Hm storage as RAM. Sounds like what IBM AS/400 was doing like 30 years ago for
mini-frame machines.

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yellowapple
A lot of the current server trends are basically reinventing wheels that were
already spinning on mainframes multiple decades ago.

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kawsper
Whats the current status of the situation between the ZFS-on-Linux project and
Linux 5.1+?

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burtonator
How is ZFS in general vs btrfs?

ZFS is basically killed by Oracle right?

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ComputerGuru
btrfs is a dumpster truck on fire and everyone serious about their data has
switched to ZoL or is holding out in hopes that bcachefs won't be a similar
clusterfsck (which shouldn't be too hard to do).

~~~
jolmg
Btrfs has such a bad rep right now, but because such comments like yours lack
any specifics I don't know if I should worry if all my systems with a simple
btrfs root partition are going to spontaneously corrupt one day. Can anyone
give concrete examples of what's wrong with btrfs?

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silversconfused
Lilo doesn't support it. Other than that I have no problem with it. I think it
had some problems with being declared "prod ready" by some vendors with some
certain kernel version, and then a bunch of redhat users went off and tried it
with ancient kernels and lost data.

To me, this is just ext4 all over again. That filesystem was _terrible_ in the
early days. Ext4 is pretty ok now, just slow...

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zelly
It also has the Spectre/Meltdown mitigations, which happen to significantly
decrease performance.

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thaumaturgy
Oh goodie, I get a new kernel version to compile repeatedly for the next few
days.

If any of you are successfully rocking Linux on an LG Gram (especially the
17Z990), and you have decent ACPI support, I'd loooooooove to see your kernel
config file. Please.

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silversconfused
Posting your current config would allow others to see if their own is
relevantly different. Sorry I can't help though, I'll be building this for an
arm chromebook, not a pc, so my configs will be nothing helpful.

