Messages in this thread | | | Date | Thu, 17 Oct 2019 13:48:15 +0100 | From | Russell King - ARM Linux admin <> | Subject | Re: [RFC PATCH 0/3] watchdog servicing during decompression |
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On Thu, Oct 17, 2019 at 02:34:52PM +0200, Rasmus Villemoes wrote: > On 17/10/2019 14.03, Russell King - ARM Linux admin wrote: > > We used to have this on ARM - it was called from the decompressor > > code via an arch_decomp_wdog() hook. > > > > That code got removed because it is entirely unsuitable for a multi- > > platform kernel. This looks like it takes an address for the watchdog > > from the Kconfig, and builds that into the decompressor, making the > > decompressor specific to that board or platform. > > > > I'm not sure distros are going to like that given where we are with > > multiplatform kernels. > > This is definitely not for multiplatform kernels or general distros, > it's for kernels that are built as part of a BSP for a specific board - > hence the "Say N unless you know you need this.". > > I didn't know it used to exist. But I do know that something like this > is carried out-of-tree for lots of boards, so I thought I'd try to get > upstream support.
Sorry, it does still exist, just been moved around a bit.
See lib/inflate.c:
STATIC int INIT inflate(void) { ... #ifdef ARCH_HAS_DECOMP_WDOG arch_decomp_wdog(); #endif
Given that it still exists, maybe this hook name should be used for this same issue in the LZ4 code?
> The first two patches, or something like them, would be nice on their > own, as that would minimize the conflicts when forward-porting the > board-specific patch. But such a half-implemented feature that requires > out-of-tree patches to actually do anything useful of course won't fly. > > I'm not really a big fan of the third patch, even though it does work > for all the cases I've encountered so far - I'm sure there would be > boards where a much more complicated solution would be needed. Another > method I thought of was to just supply a __weak no-op > decompress_keepalive(), and then have a config option to point at an > extra object file to link into the compressed/vmlinux (similar to the > initramfs_source option that also points to some external resource). > > But if the mainline kernel doesn't want anything like this > re-introduced, that's also fine, that just means a bit of job security.
Well, we'll see whether the arm-soc people have anything to add...
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