On Mon, Jan 14, 2019 at 12:24 PM Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote: > > Hi, > > Just fix a few of the commit log comments... > > On 1/13/19 7:15 PM, Pingfan Liu wrote: > > People reported a bug on a high end server with many pcie devices, where > > kernel bootup with crashkernel=384M, and kaslr is enabled. Even > > though we still see much memory under 896 MB, the finding still failed > > intermittently. Because currently we can only find region under 896 MB, > > if w/0 ',high' specified. Then KASLR breaks 896 MB into several parts > > if w/o > or preferably: > if without > > > randomly, and crashkernel reservation need be aligned to 128 MB, that's > > why failure is found. It raises confusion to the end user that sometimes > > crashkernel=X works while sometimes fails. > > If want to make it succeed, customer can change kernel option to > > "crashkernel=384M, high". Just this give "crashkernel=xx@yy" a very > > no space? just > "crashkernel=384M,high" > > > limited space to behave even though its grammer looks more generic. > > grammar > Thanks for your review, will cc you in next version. Regards, Pingfan > > And we can't answer questions raised from customer that confidently: > > 1) why it doesn't succeed to reserve 896 MB; > > 2) what's wrong with memory region under 4G; > > 3) why I have to add ',high', I only require 384 MB, not 3840 MB. > > This patch tries to get memory region from 896 MB firstly, then [896MB,4G], > > finally above 4G. > > Dave Young sent the original post, and I just re-post it with commit log > > improvement as his requirement. > > http://lists.infradead.org/pipermail/kexec/2017-October/019571.html > > There was an old discussion below (previously posted by Chao Wang): > > https://lkml.org/lkml/2013/10/15/601 > > > > Signed-off-by: Pingfan Liu <kernelfans@xxxxxxxxx> > > Cc: Dave Young <dyoung@xxxxxxxxxx> > > Cc: Baoquan He <bhe@xxxxxxxxxx> > > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > > Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx> > > Cc: yinghai@xxxxxxxxxx, > > Cc: vgoyal@xxxxxxxxxx > > --- > > v5 -> v6 > > discard bottom-up allocation, just repost dyoung's original patch with commit log improved > > --- > > arch/x86/kernel/setup.c | 16 ++++++++++++++++ > > 1 file changed, 16 insertions(+) > > > > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c > > index 3d872a5..fa62c81 100644 > > --- a/arch/x86/kernel/setup.c > > +++ b/arch/x86/kernel/setup.c > > @@ -551,6 +551,22 @@ static void __init reserve_crashkernel(void) > > high ? CRASH_ADDR_HIGH_MAX > > : CRASH_ADDR_LOW_MAX, > > crash_size, CRASH_ALIGN); > > +#ifdef CONFIG_X86_64 > > + /* > > + * crashkernel=X reserve below 896M fails? Try below 4G > > + */ > > + if (!high && !crash_base) > > + crash_base = memblock_find_in_range(CRASH_ALIGN, > > + (1ULL << 32), > > + crash_size, CRASH_ALIGN); > > + /* > > + * crashkernel=X reserve below 4G fails? Try MAXMEM > > + */ > > + if (!high && !crash_base) > > + crash_base = memblock_find_in_range(CRASH_ALIGN, > > + CRASH_ADDR_HIGH_MAX, > > + crash_size, CRASH_ALIGN); > > +#endif > > if (!crash_base) { > > pr_info("crashkernel reservation failed - No suitable area found.\n"); > > return; > > > > ciao. > -- > ~Randy _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
