RE: [PATCH 1/1] get page size using sysconf (_SC_PAGESIZE) instead of PAGE_SIZE

["Metzger, Markus T" <markus.t.metzger@intel.com>]

Hello Zied,


Please check the return value.  You may just error out but we should

detect errors, at least.
[Zied] according to man pages the returned values should not be below 1. I will check against it and write a warning message.

I’m referring to: “
On  error,  -1 is returned and errno is set to indicate the cause of the error
“.



  struct perf_event_mmap_page *header = (struct perf_event_mmap_page *)

    data.get ();

-  data_offset = PAGE_SIZE;

+  data_offset = page_size;



Hmmm, I would have expected a compiler warning, here, since PAGE_SIZE is

now long and DATA_OFFSET is __u64.

[Zied] I go a clean compilation on my machine. here is the outcome:

"build_intel/gdb$ make
  CXX    nat/linux-btrace.o
  GEN    init.c
  CXXLD  gdb
"

Do you recommend casting page_size to a __u64?
You may need to enable warnings.    I’m configuring with “
--enable-build-warnings --enable-gdb-build-warnings --enable-werror
“ but I have not checked this case myself.

The original PAGE_SIZE macro is defined as (1UL << PAGE_SHIFT).  After checking for errors, we
should probably cast it to an appropriate unsigned type.

Regards,
Markus.

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