Swapfile

[Franck666666]

Hi there,

just created an 18Gb Swapfile on an ext4 Fs to make sure no Holes are in. Moved to the bcachefs Partition and mounted it as a loop Device. Works until this Point just normal.

But when i compile the Kernel or other with Full Lto the System freezes at Swapfile Use beginning mostly at 4GB use as u can see f.e with btop. Sometime at 6, Sometimes at 9 Gb Use.

In lets say 30 Attempts only 1 compile Process endet with Sucess.

While when i use an Swapfile from the ext4 Partion ALL Compiles works but needs more Time.

Any Ideas u have ?

Sincerly, Franck

[koverstreet]

If that was you on IRC I just missed you

On Fri, Jul 18, 2025 at 5:26 AM Franck6666 @.***> wrote:

Franck6666 created an issue (koverstreet/bcachefs#923) https://github.com/koverstreet/bcachefs/issues/923

Hi there,

just created an 18Gb Swapfile on an ext4 Fs to make sure no Holes are in. Moved to the bcachefs Partition and mounted it as a loop Device. Works until this Point just normal.

But when i compile the Kernel or other with Full Lto the System freezes at Swapfile Use beginning mostly at 4GB use as u can see f.e with btop. Sometime at 6, Sometimes at 9 Gb Use.

In lets say 30 Attempts only 1 compile Process endet with Sucess.

While when i use an Swapfile from the ext4 Partion ALL Compiles works but needs more Time.

Any Ideas u have ?

Sincerly, Franck

— Reply to this email directly, view it on GitHub https://github.com/koverstreet/bcachefs/issues/923, or unsubscribe https://github.com/notifications/unsubscribe-auth/AAPGX3URLIRL23SQJASKDKT3JC4VDAVCNFSM6AAAAACB2E2CMGVHI2DSMVQWIX3LMV43ASLTON2WKOZTGI2DENJWHA4DQNQ . You are receiving this because you are subscribed to this thread.Message ID: @.***>

[Franck666666]

Pardon ?

[devZer0]

i know swap on zfs or btrfs is problematic , too.

for example on btrfs, you need NODATACOW for using swap ( https://btrfs.readthedocs.io/en/latest/Swapfile.html )

swap on zfs will deadlock: https://github.com/openzfs/zfs/issues/7734

so , is there an offical status yet regarding swap on top of bcachefs ?

and isn't this ticket a duplicate as we also have https://github.com/koverstreet/bcachefs/issues/368 ?

[koverstreet]

can't get to it yet, but it's a good wishlist item