On Thu, Aug 08, 2024 at 03:56:35PM +0800, Jinjie Ruan wrote: > On 2024/8/7 3:34, Catalin Marinas wrote: > > On Tue, Aug 06, 2024 at 08:10:30PM +0100, Catalin Marinas wrote: > >> On Fri, Aug 02, 2024 at 06:11:01PM +0800, Baoquan He wrote: > >>> And I don't like the idea crashkernel=,high failure will fallback to > >>> attempt in low area, so this looks good to me. > >> > >> Well, I kind of liked this behaviour. One can specify ,high as a > >> preference rather than forcing a range. The arm64 land has different > >> platforms with some constrained memory layouts. Such fallback works well > >> as a default command line option shipped with distros without having to > >> guess the SoC memory layout. > > > > I haven't tried but it's possible that this patch also breaks those > > arm64 platforms with all RAM above 4GB when CRASH_ADDR_LOW_MAX is > > memblock_end_of_DRAM(). Here all memory would be low and in the absence > > of no fallback, it fails to allocate. > > > > So, my strong preference would be to re-instate the current behaviour > > and work around the infinite loop in a different way. > > Hi, baoquan, What's your opinion? > > Only this patch should be re-instate or all the 3 dead loop fix patch? Only the riscv64 patch that that removes the ,high reservation fallback to ,low. From this series: https://lore.kernel.org/r/20240719095735.1912878-1-ruanjinjie@xxxxxxxxxx/ the first two fixes look fine (x86_32). The third one (arm32), not sure why it's in the series called "crash: Fix x86_32 memory reserve dead loop bug". Does it fix a problem on arm32? Anyway, I'm not against it getting merged but I'm not maintaining arm32. If the first two patches could be merged for 6.11, I think the arm32 one is more of a 6.12 material (unless it does fix something). On the riscv64 patch removing the high->low fallback to avoid the infinite loop, I'd rather replace it with something similar to the x86_32 fix in the series above. I suggested something in the main if block but, looking at the x86_32 fix, for consistency, I think it would look better as something like: diff --git a/kernel/crash_reserve.c b/kernel/crash_reserve.c index d3b4cd12bdd1..64d44a52c011 100644 --- a/kernel/crash_reserve.c +++ b/kernel/crash_reserve.c @@ -423,7 +423,8 @@ void __init reserve_crashkernel_generic(char *cmdline, if (high && search_end == CRASH_ADDR_HIGH_MAX) { search_end = CRASH_ADDR_LOW_MAX; search_base = 0; - goto retry; + if (search_end != CRASH_ADDR_HIGH_MAX) + goto retry; } pr_warn("cannot allocate crashkernel (size:0x%llx)\n", crash_size); In summary, just replace the riscv64 fix with something along the lines of the diff above (or pick whatever you prefer that still keeps the fallback). Thanks. -- Catalin _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
