Re: [PATCH v4 1/2] xen: replace complicated tlbflush check with an inline function

["Jan Beulich" <JBeulich@suse.com>]

>>> On 15.09.16 at 08:47, <dongli.zhang@oracle.com> wrote:
>> > I rewrite the inline function in xen/include/xen/mm.h to:
>> > 
>> > +#include <asm/flushtlb.h>
>> > +
>> > +static inline bool accumulate_tlbflush(bool need_tlbflush,
>> > +                                       const struct page_info *page,
>> > +                                       uint32_t tlbflush_timestamp)
>> > +{
>> > +    return page->u.free.need_tlbflush &&
>> > +           page->tlbflush_timestamp <= tlbflush_current_time() &&
>> > +           (!need_tlbflush ||
>> > +            page->tlbflush_timestamp > tlbflush_timestamp);
>> > +}
>> > 
>> > However, to use tlbflush_current_time and "asm/flushtlb.h" would lead
>> > to the following compiling error:
>> > 
>> >>>>>>>>>>>>>>>>>>>>>>>>>>>>
>> > In file included from 
>> > /home/zhang/test/mainline-xen/xen/include/asm/flushtlb.h:14:0,
>> >                  from suspend.c:13:
>> > /home/zhang/test/mainline-xen/xen/include/xen/mm.h: In function 
>> > ‘accumulate_tlbflush’:
>> > /home/zhang/test/mainline-xen/xen/include/xen/mm.h:577:12: error: implicit 
>> > declaration of function ‘tlbflush_current_time’ 
>> > [-Werror=implicit-function-declaration]
>> >             page->tlbflush_timestamp <= tlbflush_current_time() &&
>> >             ^
>> > /home/zhang/test/mainline-xen/xen/include/xen/mm.h:577:12: error: nested 
>> > extern declaration of ‘tlbflush_current_time’ [-Werror=nested-externs]
>> > cc1: all warnings being treated as errors
>> > make[4]: *** [suspend.o] Error 1
>> >>>>>>>>>>>>>>>>>>>>>>>>>>>>
>> > 
>> > I can workaround the issue by removing "#include <asm/flushtlb.h>" from
>> > xen/arch/x86/acpi/suspend.c and then everything works fine.
> 
>> Removing? You should _add_ asm/tlbflush.h inclusion to xen/mm.h.
> 
> As mentioned in previous email, there was a compiling error from 
> suspend.c:13
> even after asm/tlbflush.h is added to xen/mm.h
> 
> The compiling error is bypassed if I remove the include of asm/flushtlb.h 
> from
> suspend.c. 
> 
> The following patch can make the inline function work while avoiding 
> compiling
> error. Since asm/flushtlb.h depends on get_order_from_bytes in xen/mm.h, it 
> is
> included after get_order_from_bytes in xen/mm.h.

Ah - that wasn't mentioned in your earlier mail.

> If removing asm/flushtlb.h in suspend.c is not preferred, the other two 
> options

I don't mind it being removed, it just needs to be clear why.

Jan

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