Re: [PATCH] Don't inherit swiotlb parameter form 1st kernel by default

[Kairui Song]

On Fri, May 29, 2020 at 10:16 AM piliu <piliu(a)redhat.com&gt; wrote:
>  On 05/17/2020 10:48 PM, Kairui Song wrote:
>  > Usually kdump kernel don't need a swiotlb. There are two cases known
>  > common case a swiotlb is needed:
>  >
>  >  - SEV/SME is active.
>  >  - crashkernel high reservation is used, or there are crashkernel memory
>  >    above 4G.
>  >
>  > For both case, if swiotlb is set to a large value in first kernel, kdump
>  > kernel will likely to fail with OOM. So don't inherit swiotlb parameter
>  > by default.
>
>  Then is it OK for the two aforementioned cases? Just leave them fixed by
>  user? 
No worry, the swiotlb is not disabled, just not inheriting the size
from first kernel. If swiotlb is required, kernel will enabled it
using default size (64M).

>  Thanks,
>  Pingfan
>  >
>  > Signed-off-by: Kairui Song <kasong(a)redhat.com&gt;
>  > ---
>  >  kdump.sysconfig         | 2 +-
>  >  kdump.sysconfig.aarch64 | 2 +-
>  >  kdump.sysconfig.i386    | 2 +-
>  >  kdump.sysconfig.ppc64   | 2 +-
>  >  kdump.sysconfig.ppc64le | 2 +-
>  >  kdump.sysconfig.s390x   | 2 +-
>  >  kdump.sysconfig.x86_64  | 2 +-
>  >  7 files changed, 7 insertions(+), 7 deletions(-)
>  >
>  > diff --git a/kdump.sysconfig b/kdump.sysconfig
>  > index df518d6..d8b301c 100644
>  > --- a/kdump.sysconfig
>  > +++ b/kdump.sysconfig
>  > @@ -17,7 +17,7 @@ KDUMP_COMMANDLINE=""
>  >  # This variable lets us remove arguments from the current kdump commandline
>  >  # as taken from either KDUMP_COMMANDLINE above, or from /proc/cmdline
>  >  # NOTE: some arguments such as crashkernel will always be removed
>  > -KDUMP_COMMANDLINE_REMOVE="hugepages hugepagesz slub_debug quiet"
>  > +KDUMP_COMMANDLINE_REMOVE="hugepages hugepagesz slub_debug quiet swiotlb"
>  >
>  >  # This variable lets us append arguments to the current kdump commandline
>  >  # after processed by KDUMP_COMMANDLINE_REMOVE
>  > diff --git a/kdump.sysconfig.aarch64 b/kdump.sysconfig.aarch64
>  > index d5d7624..bcb4a37 100644
>  > --- a/kdump.sysconfig.aarch64
>  > +++ b/kdump.sysconfig.aarch64
>  > @@ -17,7 +17,7 @@ KDUMP_COMMANDLINE=""
>  >  # This variable lets us remove arguments from the current kdump commandline
>  >  # as taken from either KDUMP_COMMANDLINE above, or from /proc/cmdline
>  >  # NOTE: some arguments such as crashkernel will always be removed
>  > -KDUMP_COMMANDLINE_REMOVE="hugepages hugepagesz slub_debug quiet"
>  > +KDUMP_COMMANDLINE_REMOVE="hugepages hugepagesz slub_debug quiet swiotlb"
>  >
>  >  # This variable lets us append arguments to the current kdump commandline
>  >  # after processed by KDUMP_COMMANDLINE_REMOVE
>  > diff --git a/kdump.sysconfig.i386 b/kdump.sysconfig.i386
>  > index c31a8cb..650e405 100644
>  > --- a/kdump.sysconfig.i386
>  > +++ b/kdump.sysconfig.i386
>  > @@ -17,7 +17,7 @@ KDUMP_COMMANDLINE=""
>  >  # This variable lets us remove arguments from the current kdump commandline
>  >  # as taken from either KDUMP_COMMANDLINE above, or from /proc/cmdline
>  >  # NOTE: some arguments such as crashkernel will always be removed
>  > -KDUMP_COMMANDLINE_REMOVE="hugepages hugepagesz slub_debug quiet"
>  > +KDUMP_COMMANDLINE_REMOVE="hugepages hugepagesz slub_debug quiet swiotlb"
>  >
>  >  # This variable lets us append arguments to the current kdump commandline
>  >  # after processed by KDUMP_COMMANDLINE_REMOVE
>  > diff --git a/kdump.sysconfig.ppc64 b/kdump.sysconfig.ppc64
>  > index 1f95452..03fde14 100644
>  > --- a/kdump.sysconfig.ppc64
>  > +++ b/kdump.sysconfig.ppc64
>  > @@ -17,7 +17,7 @@ KDUMP_COMMANDLINE=""
>  >  # This variable lets us remove arguments from the current kdump commandline
>  >  # as taken from either KDUMP_COMMANDLINE above, or from /proc/cmdline
>  >  # NOTE: some arguments such as crashkernel will always be removed
>  > -KDUMP_COMMANDLINE_REMOVE="hugepages hugepagesz slub_debug quiet"
>  > +KDUMP_COMMANDLINE_REMOVE="hugepages hugepagesz slub_debug quiet swiotlb"
>  >
>  >  # This variable lets us append arguments to the current kdump commandline
>  >  # after processed by KDUMP_COMMANDLINE_REMOVE
>  > diff --git a/kdump.sysconfig.ppc64le b/kdump.sysconfig.ppc64le
>  > index 1f95452..03fde14 100644
>  > --- a/kdump.sysconfig.ppc64le
>  > +++ b/kdump.sysconfig.ppc64le
>  > @@ -17,7 +17,7 @@ KDUMP_COMMANDLINE=""
>  >  # This variable lets us remove arguments from the current kdump commandline
>  >  # as taken from either KDUMP_COMMANDLINE above, or from /proc/cmdline
>  >  # NOTE: some arguments such as crashkernel will always be removed
>  > -KDUMP_COMMANDLINE_REMOVE="hugepages hugepagesz slub_debug quiet"
>  > +KDUMP_COMMANDLINE_REMOVE="hugepages hugepagesz slub_debug quiet swiotlb"
>  >
>  >  # This variable lets us append arguments to the current kdump commandline
>  >  # after processed by KDUMP_COMMANDLINE_REMOVE
>  > diff --git a/kdump.sysconfig.s390x b/kdump.sysconfig.s390x
>  > index abd45a2..6effd6d 100644
>  > --- a/kdump.sysconfig.s390x
>  > +++ b/kdump.sysconfig.s390x
>  > @@ -17,7 +17,7 @@ KDUMP_COMMANDLINE=""
>  >  # This variable lets us remove arguments from the current kdump commandline
>  >  # as taken from either KDUMP_COMMANDLINE above, or from /proc/cmdline
>  >  # NOTE: some arguments such as crashkernel will always be removed
>  > -KDUMP_COMMANDLINE_REMOVE="hugepages hugepagesz slub_debug quiet"
>  > +KDUMP_COMMANDLINE_REMOVE="hugepages hugepagesz slub_debug quiet swiotlb"
>  >
>  >  # This variable lets us append arguments to the current kdump commandline
>  >  # after processed by KDUMP_COMMANDLINE_REMOVE
>  > diff --git a/kdump.sysconfig.x86_64 b/kdump.sysconfig.x86_64
>  > index a43a970..7b3c68c 100644
>  > --- a/kdump.sysconfig.x86_64
>  > +++ b/kdump.sysconfig.x86_64
>  > @@ -17,7 +17,7 @@ KDUMP_COMMANDLINE=""
>  >  # This variable lets us remove arguments from the current kdump commandline
>  >  # as taken from either KDUMP_COMMANDLINE above, or from /proc/cmdline
>  >  # NOTE: some arguments such as crashkernel will always be removed
>  > -KDUMP_COMMANDLINE_REMOVE="hugepages hugepagesz slub_debug quiet"
>  > +KDUMP_COMMANDLINE_REMOVE="hugepages hugepagesz slub_debug quiet swiotlb"
>  >
>  >  # This variable lets us append arguments to the current kdump commandline
>  >  # after processed by KDUMP_COMMANDLINE_REMOVE
>  >
>  

--
Best Regards,
Kairui Song