Re: [PATCH 04/17] block: split bio_kmalloc from bio_alloc_bioset

[Matthew Wilcox <willy-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>]

On Tue, Jan 26, 2021 at 03:52:34PM +0100, Christoph Hellwig wrote:
> bio_kmalloc shares almost no logic with the bio_set based fast path
> in bio_alloc_bioset.  Split it into an entirely separate implementation.
> 
> Signed-off-by: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>
> ---
>  block/bio.c         | 167 ++++++++++++++++++++++----------------------
>  include/linux/bio.h |   6 +-
>  2 files changed, 86 insertions(+), 87 deletions(-)

This patch causes current linux-next to OOM for me when running xfstests
after about ten minutes.  Haven't looked into why yet, this is just the
results of a git bisect.

The qemu command line is:

qemu-system-x86_64 -nodefaults -nographic -cpu host -machine accel=kvm,nvdimm -m 2G,slots=8,maxmem=1T -smp 6 -kernel /home/willy/kernel/folio/.build_test_kernel-x86_64/kpgk/vmlinuz -append console=hvc0 root=/dev/sda rw log_buf_len=8M ktest.dir=/home/willy/kernel/ktest ktest.env=/tmp/build-test-kernel-nJO6QgxOmo/env quiet systemd.show_status=0 systemd.log-target=journal crashkernel=128M no_console_suspend -device virtio-serial -chardev stdio,id=console -device virtconsole,chardev=console -serial unix:/tmp/build-test-kernel-nJO6QgxOmo/vm-kgdb,server,nowait -monitor unix:/tmp/build-test-kernel-nJO6QgxOmo/vm-mon,server,nowait -gdb unix:/tmp/build-test-kernel-nJO6QgxOmo/vm-gdb,server,nowait -device virtio-rng-pci -virtfs local,path=/,mount_tag=host,security_model=none -device virtio-scsi-pci,id
 =hba -nic user,model=virtio,hostfwd=tcp:127.0.0.1:24674-:22 -drive if=none,format=raw,id=disk0,file=/var/lib/ktest/root.amd64,snapshot=on -device scsi-hd,bus=hba.0,drive=disk0 -drive if=none
 ,format=raw,id=disk1,file=/tmp/build-test-kernel-nJO6QgxOmo/dev-1,cache=unsafe -device scsi-hd,bus=hba.0,drive=disk1 -drive if=none,format=raw,id=disk2,file=/tmp/build-test-kernel-nJO6QgxOmo/dev-2,cache=unsafe -device scsi-hd,bus=hba.0,drive=disk2 -drive if=none,format=raw,id=disk3,file=/tmp/build-test-kernel-nJO6QgxOmo/dev-3,cache=unsafe -device scsi-hd,bus=hba.0,drive=disk3