Re: [PATCH] crash_core: export vmemmap when CONFIG_SPARSEMEM_VMEMMAP is enabled

[Shijie Huang]

在 2023/11/27 10:51, Baoquan He 写道:
> Hi,
>
> On 11/27/23 at 10:07am, Huang Shijie wrote:
> > In memory_model.h, if CONFIG_SPARSEMEM_VMEMMAP is configed,
> > kernel will use vmemmap to do the __pfn_to_page/page_to_pfn,
> > and kernel will not use the "classic sparse" to do the
> > __pfn_to_page/page_to_pfn.
> >
> > So export the vmemmap when CONFIG_SPARSEMEM_VMEMMAP is configed.
> > This makes the user applications (crash, etc) get faster
> > pfn_to_page/page_to_pfn operations too.
> Are there Crash or makedupfile patches posted yet to make use of this?

I have patches for Crash to use the 'vmemmap', but after this patch is 
merged, I will send it out.

(I think Kazu will not merge a crash patch which depends on a kernel 
patch which is not merged.)


Thanks

Huang Shijie


> > Signed-off-by: Huang Shijie <shijie@xxxxxxxxxxxxxxxxxxxxxx>
> > ---
> >   kernel/crash_core.c | 3 +++
> >   1 file changed, 3 insertions(+)
> >
> > diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> > index efe87d501c8c..9653c4177191 100644
> > --- a/kernel/crash_core.c
> > +++ b/kernel/crash_core.c
> > @@ -765,6 +765,9 @@ static int __init crash_save_vmcoreinfo_init(void)
> >   	VMCOREINFO_SYMBOL(mem_map);
> >   	VMCOREINFO_SYMBOL(contig_page_data);
> >   #endif
> > +#ifdef CONFIG_SPARSEMEM_VMEMMAP
> > +	VMCOREINFO_SYMBOL_ARRAY(vmemmap);
> > +#endif
> >   #ifdef CONFIG_SPARSEMEM
> >   	VMCOREINFO_SYMBOL_ARRAY(mem_section);
> >   	VMCOREINFO_LENGTH(mem_section, NR_SECTION_ROOTS);
> > --
> > 2.40.1