PROBLEM: selftest/vm/cow.c failed to compile (‘MADV_PAGEOUT’ undeclared)

PROBLEM: selftest/vm/cow.c failed to compile (‘MADV_PAGEOUT’ undeclared)

[Mirsad Goran Todorovac]

Hi all,

During "make kselftest" there is an error in selftest/vm/cow.c compilation on
platform:

- Lenovo desktop 10TX000VCR (LENOVO_MT_10TX_BU_Lenovo_FM_V530S-07ICB)
- AlmaLinux 8.7 (CentOS fork)
- gcc 8.5.0 20210514 (Red Hat 8.5.0-15)
- vanilla kernel 6.2-rc2 from the torvalds mainline tree.

Compilation fails to find "#define MADV_PAGEOUT":

[root@pc-mtodorov vm]# make
gcc -Wall -I /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/../../.. -I /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/../../../usr/include  -isystem /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/../../../usr/include -no-pie     cow.c vm_util.c -lrt -lpthread  -o /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/vm/cow
cow.c: In function ‘do_run_with_base_page’:
cow.c:755:26: error: ‘MADV_PAGEOUT’ undeclared (first use in this function); did you mean ‘MADV_RANDOM’?
   madvise(mem, pagesize, MADV_PAGEOUT);
                          ^~~~~~~~~~~~
                          MADV_RANDOM
cow.c:755:26: note: each undeclared identifier is reported only once for each function it appears in
cow.c: In function ‘do_run_with_thp’:
cow.c:914:22: error: ‘MADV_PAGEOUT’ undeclared (first use in this function); did you mean ‘MADV_RANDOM’?
   madvise(mem, size, MADV_PAGEOUT);
                      ^~~~~~~~~~~~
                      MADV_RANDOM
make: *** [../lib.mk:145: /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/vm/cow] Error 1
[root@pc-mtodorov vm]# 

MADV_PAGEOUT is defined in #include <asm-generic/mman-common.h> :

[root@pc-mtodorov vm]# grep MADV_PAGEOUT -r /usr/include
/usr/include/asm-generic/mman-common.h:#define MADV_PAGEOUT     21              /* reclaim these pages */
[root@pc-mtodorov vm]# grep MADV_PAGEOUT -r ../../../../usr/include
../../../../usr/include/asm-generic/mman-common.h:#define MADV_PAGEOUT  21              /* reclaim these pages */
[root@pc-mtodorov vm]# 

However, gcc -E shows that asm-generic/mman-common.h is somehow never included:

---------------------------------------------------------------------------------------------
[root@pc-mtodorov vm]# gcc -Wall -E -I /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/../../.. -I /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/../../../usr/include  -isystem /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/../../../usr/include -no-pie     cow.c | cat -s | less
# 1 "/usr/include/sys/mman.h" 1 3 4
# 25 "/usr/include/sys/mman.h" 3 4
# 1 "/usr/lib/gcc/x86_64-redhat-linux/8/include/stddef.h" 1 3 4
# 26 "/usr/include/sys/mman.h" 2 3 4
# 41 "/usr/include/sys/mman.h" 3 4
# 1 "/usr/include/bits/mman.h" 1 3 4
# 49 "/usr/include/bits/mman.h" 3 4
# 1 "/usr/include/bits/mman-linux.h" 1 3 4
# 117 "/usr/include/bits/mman-linux.h" 3 4
# 1 "/usr/include/bits/mman-shared.h" 1 3 4
# 42 "/usr/include/bits/mman-shared.h" 3 4

int memfd_create (const char *__name, unsigned int __flags) __attribute__ ((__nothrow__ , __leaf__));
int mlock2 (const void *__addr, size_t __length, unsigned int __flags) __attribute__ ((__nothrow__ , __leaf__));
int pkey_alloc (unsigned int __flags, unsigned int __access_rights) __attribute__ ((__nothrow__ , __leaf__));
int pkey_set (int __key, unsigned int __access_rights) __attribute__ ((__nothrow__ , __leaf__));
int pkey_get (int __key) __attribute__ ((__nothrow__ , __leaf__));
int pkey_free (int __key) __attribute__ ((__nothrow__ , __leaf__));
int pkey_mprotect (void *__addr, size_t __len, int __prot, int __pkey) __attribute__ ((__nothrow__ , __leaf__));

# 117 "/usr/include/bits/mman-linux.h" 2 3 4
# 49 "/usr/include/bits/mman.h" 2 3 4
# 42 "/usr/include/sys/mman.h" 2 3 4

# 57 "/usr/include/sys/mman.h" 3 4
extern void *mmap (void *__addr, size_t __len, int __prot,
     int __flags, int __fd, __off_t __offset) __attribute__ ((__nothrow__ , __leaf__));
# 70 "/usr/include/sys/mman.h" 3 4
extern void *mmap64 (void *__addr, size_t __len, int __prot,
       int __flags, int __fd, __off64_t __offset) __attribute__ ((__nothrow__ , __leaf__));

extern int munmap (void *__addr, size_t __len) __attribute__ ((__nothrow__ , __leaf__));
extern int mprotect (void *__addr, size_t __len, int __prot) __attribute__ ((__nothrow__ , __leaf__));
extern int msync (void *__addr, size_t __len, int __flags);
extern int madvise (void *__addr, size_t __len, int __advice) __attribute__ ((__nothrow__ , __leaf__));
extern int posix_madvise (void *__addr, size_t __len, int __advice) __attribute__ ((__nothrow__ , __leaf__));
extern int mlock (const void *__addr, size_t __len) __attribute__ ((__nothrow__ , __leaf__));
extern int munlock (const void *__addr, size_t __len) __attribute__ ((__nothrow__ , __leaf__));
extern int mlockall (int __flags) __attribute__ ((__nothrow__ , __leaf__));
extern int munlockall (void) __attribute__ ((__nothrow__ , __leaf__));
extern int mincore (void *__start, size_t __len, unsigned char *__vec)
     __attribute__ ((__nothrow__ , __leaf__));

# 133 "/usr/include/sys/mman.h" 3 4

extern void *mremap (void *__addr, size_t __old_len, size_t __new_len,
       int __flags, ...) __attribute__ ((__nothrow__ , __leaf__));
extern int remap_file_pages (void *__start, size_t __size, int __prot,
        size_t __pgoff, int __flags) __attribute__ ((__nothrow__ , __leaf__));
extern int shm_open (const char *__name, int __oflag, mode_t __mode);
extern int shm_unlink (const char *__name);
-------------------------------------------------------------------------------------------------------

FYI:

On the platform:

- Ubuntu 22.10 kinetic kudu
- gcc 12.2.0
- same 6.2-rc2

, MADV_PAGEOUT is also defined in bits/mmap-linux.h, so the compile passes.

root@marvin-IdeaPad-3-15ITL6:/home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/vm# grep MADV_PAGEOUT -r /usr/include
/usr/include/asm-generic/mman-common.h:#define MADV_PAGEOUT	21		/* reclaim these pages */
/usr/include/x86_64-linux-gnu/bits/mman-linux.h:# define MADV_PAGEOUT     21	/* Reclaim these pages.  */
root@marvin-IdeaPad-3-15ITL6:/home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/vm# grep MADV_PAGEOUT -r ../../../../usr/include
../../../../usr/include/asm-generic/mman-common.h:#define MADV_PAGEOUT	21		/* reclaim these pages */
root@marvin-IdeaPad-3-15ITL6:/home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/vm# 

However, mman-common.h from ../../../../usr/include/asm-generic/mman-common.h is also not included,
as of "gcc -E", but only bits/mman-linux.h:

root@marvin-IdeaPad-3-15ITL6:/home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/vm# gcc -Wall -E -I /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/../../.. -I /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/../../../usr/include  -isystem /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/../../../usr/include -no-pie     cow.c | grep mman-common.h
root@marvin-IdeaPad-3-15ITL6:/home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/vm# gcc -Wall -E -I /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/../../.. -I /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/../../../usr/include  -isystem /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/../../../usr/include -no-pie     cow.c | grep mman-linux.h
# 1 "/usr/include/x86_64-linux-gnu/bits/mman-linux.h" 1 3 4
# 119 "/usr/include/x86_64-linux-gnu/bits/mman-linux.h" 3 4
# 120 "/usr/include/x86_64-linux-gnu/bits/mman-linux.h" 2 3 4
root@marvin-IdeaPad-3-15ITL6:/home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/vm# 

I hope this is enough information for you to debug the issue.

I am standing by for any additional diagnostics needed.

Regards,
Mirsad

-- 
Mirsad Goran Todorovac
Sistem inženjer
Grafički fakultet | Akademija likovnih umjetnosti
Sveučilište u Zagrebu
 
System engineer
Faculty of Graphic Arts | Academy of Fine Arts
University of Zagreb, Republic of Croatia
The European Union

Re: PROBLEM: selftest/vm/cow.c failed to compile (‘MADV_PAGEOUT’ undeclared)

[David Hildenbrand]

On 08.01.23 11:58, Mirsad Goran Todorovac wrote:
> Hi all,
> 
> During "make kselftest" there is an error in selftest/vm/cow.c compilation on
> platform:
> 
> - Lenovo desktop 10TX000VCR (LENOVO_MT_10TX_BU_Lenovo_FM_V530S-07ICB)
> - AlmaLinux 8.7 (CentOS fork)
> - gcc 8.5.0 20210514 (Red Hat 8.5.0-15)
> - vanilla kernel 6.2-rc2 from the torvalds mainline tree.
> 
> Compilation fails to find "#define MADV_PAGEOUT":
> 
> [root@pc-mtodorov vm]# make
> gcc -Wall -I /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/../../.. -I /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/../../../usr/include  -isystem /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/../../../usr/include -no-pie     cow.c vm_util.c -lrt -lpthread  -o /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/vm/cow
> cow.c: In function ‘do_run_with_base_page’:
> cow.c:755:26: error: ‘MADV_PAGEOUT’ undeclared (first use in this function); did you mean ‘MADV_RANDOM’?
>     madvise(mem, pagesize, MADV_PAGEOUT);
>                            ^~~~~~~~~~~~
>                            MADV_RANDOM
> cow.c:755:26: note: each undeclared identifier is reported only once for each function it appears in
> cow.c: In function ‘do_run_with_thp’:
> cow.c:914:22: error: ‘MADV_PAGEOUT’ undeclared (first use in this function); did you mean ‘MADV_RANDOM’?
>     madvise(mem, size, MADV_PAGEOUT);
>                        ^~~~~~~~~~~~
>                        MADV_RANDOM
> make: *** [../lib.mk:145: /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/vm/cow] Error 1
> [root@pc-mtodorov vm]#
> 
> MADV_PAGEOUT is defined in #include <asm-generic/mman-common.h> :
> 
> [root@pc-mtodorov vm]# grep MADV_PAGEOUT -r /usr/include
> /usr/include/asm-generic/mman-common.h:#define MADV_PAGEOUT     21              /* reclaim these pages */
> [root@pc-mtodorov vm]# grep MADV_PAGEOUT -r ../../../../usr/include
> ../../../../usr/include/asm-generic/mman-common.h:#define MADV_PAGEOUT  21              /* reclaim these pages */
> [root@pc-mtodorov vm]#
> 
> However, gcc -E shows that asm-generic/mman-common.h is somehow never included:
> 
> ---------------------------------------------------------------------------------------------
> [root@pc-mtodorov vm]# gcc -Wall -E -I /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/../../.. -I /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/../../../usr/include  -isystem /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/../../../usr/include -no-pie     cow.c | cat -s | less
> # 1 "/usr/include/sys/mman.h" 1 3 4
> # 25 "/usr/include/sys/mman.h" 3 4
> # 1 "/usr/lib/gcc/x86_64-redhat-linux/8/include/stddef.h" 1 3 4
> # 26 "/usr/include/sys/mman.h" 2 3 4
> # 41 "/usr/include/sys/mman.h" 3 4
> # 1 "/usr/include/bits/mman.h" 1 3 4
> # 49 "/usr/include/bits/mman.h" 3 4
> # 1 "/usr/include/bits/mman-linux.h" 1 3 4
> # 117 "/usr/include/bits/mman-linux.h" 3 4
> # 1 "/usr/include/bits/mman-shared.h" 1 3 4
> # 42 "/usr/include/bits/mman-shared.h" 3 4
> 
> int memfd_create (const char *__name, unsigned int __flags) __attribute__ ((__nothrow__ , __leaf__));
> int mlock2 (const void *__addr, size_t __length, unsigned int __flags) __attribute__ ((__nothrow__ , __leaf__));
> int pkey_alloc (unsigned int __flags, unsigned int __access_rights) __attribute__ ((__nothrow__ , __leaf__));
> int pkey_set (int __key, unsigned int __access_rights) __attribute__ ((__nothrow__ , __leaf__));
> int pkey_get (int __key) __attribute__ ((__nothrow__ , __leaf__));
> int pkey_free (int __key) __attribute__ ((__nothrow__ , __leaf__));
> int pkey_mprotect (void *__addr, size_t __len, int __prot, int __pkey) __attribute__ ((__nothrow__ , __leaf__));
> 
> # 117 "/usr/include/bits/mman-linux.h" 2 3 4
> # 49 "/usr/include/bits/mman.h" 2 3 4
> # 42 "/usr/include/sys/mman.h" 2 3 4
> 
> # 57 "/usr/include/sys/mman.h" 3 4
> extern void *mmap (void *__addr, size_t __len, int __prot,
>       int __flags, int __fd, __off_t __offset) __attribute__ ((__nothrow__ , __leaf__));
> # 70 "/usr/include/sys/mman.h" 3 4
> extern void *mmap64 (void *__addr, size_t __len, int __prot,
>         int __flags, int __fd, __off64_t __offset) __attribute__ ((__nothrow__ , __leaf__));
> 
> extern int munmap (void *__addr, size_t __len) __attribute__ ((__nothrow__ , __leaf__));
> extern int mprotect (void *__addr, size_t __len, int __prot) __attribute__ ((__nothrow__ , __leaf__));
> extern int msync (void *__addr, size_t __len, int __flags);
> extern int madvise (void *__addr, size_t __len, int __advice) __attribute__ ((__nothrow__ , __leaf__));
> extern int posix_madvise (void *__addr, size_t __len, int __advice) __attribute__ ((__nothrow__ , __leaf__));
> extern int mlock (const void *__addr, size_t __len) __attribute__ ((__nothrow__ , __leaf__));
> extern int munlock (const void *__addr, size_t __len) __attribute__ ((__nothrow__ , __leaf__));
> extern int mlockall (int __flags) __attribute__ ((__nothrow__ , __leaf__));
> extern int munlockall (void) __attribute__ ((__nothrow__ , __leaf__));
> extern int mincore (void *__start, size_t __len, unsigned char *__vec)
>       __attribute__ ((__nothrow__ , __leaf__));
> 
> # 133 "/usr/include/sys/mman.h" 3 4
> 
> extern void *mremap (void *__addr, size_t __old_len, size_t __new_len,
>         int __flags, ...) __attribute__ ((__nothrow__ , __leaf__));
> extern int remap_file_pages (void *__start, size_t __size, int __prot,
>          size_t __pgoff, int __flags) __attribute__ ((__nothrow__ , __leaf__));
> extern int shm_open (const char *__name, int __oflag, mode_t __mode);
> extern int shm_unlink (const char *__name);
> -------------------------------------------------------------------------------------------------------
> 
> FYI:
> 
> On the platform:
> 
> - Ubuntu 22.10 kinetic kudu
> - gcc 12.2.0
> - same 6.2-rc2
> 
> , MADV_PAGEOUT is also defined in bits/mmap-linux.h, so the compile passes.
> 
> root@marvin-IdeaPad-3-15ITL6:/home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/vm# grep MADV_PAGEOUT -r /usr/include
> /usr/include/asm-generic/mman-common.h:#define MADV_PAGEOUT	21		/* reclaim these pages */
> /usr/include/x86_64-linux-gnu/bits/mman-linux.h:# define MADV_PAGEOUT     21	/* Reclaim these pages.  */
> root@marvin-IdeaPad-3-15ITL6:/home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/vm# grep MADV_PAGEOUT -r ../../../../usr/include
> ../../../../usr/include/asm-generic/mman-common.h:#define MADV_PAGEOUT	21		/* reclaim these pages */
> root@marvin-IdeaPad-3-15ITL6:/home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/vm#
> 
> However, mman-common.h from ../../../../usr/include/asm-generic/mman-common.h is also not included,
> as of "gcc -E", but only bits/mman-linux.h:
> 
> root@marvin-IdeaPad-3-15ITL6:/home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/vm# gcc -Wall -E -I /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/../../.. -I /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/../../../usr/include  -isystem /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/../../../usr/include -no-pie     cow.c | grep mman-common.h
> root@marvin-IdeaPad-3-15ITL6:/home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/vm# gcc -Wall -E -I /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/../../.. -I /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/../../../usr/include  -isystem /home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/../../../usr/include -no-pie     cow.c | grep mman-linux.h
> # 1 "/usr/include/x86_64-linux-gnu/bits/mman-linux.h" 1 3 4
> # 119 "/usr/include/x86_64-linux-gnu/bits/mman-linux.h" 3 4
> # 120 "/usr/include/x86_64-linux-gnu/bits/mman-linux.h" 2 3 4
> root@marvin-IdeaPad-3-15ITL6:/home/marvin/linux/kernel/linux_torvalds/tools/testing/selftests/vm#
> 
> I hope this is enough information for you to debug the issue.
> 
> I am standing by for any additional diagnostics needed.

Won't userfaultfd.c fail in a similar way?

Anyhow, khugepaged.c jas

#ifndef MADV_PAGEOUT
#define MADV_PAGEOUT 21
#endif

So most probably we should do the same.

-- 
Thanks,

David / dhildenb

Re: PROBLEM: selftest/vm/cow.c failed to compile (‘MADV_PAGEOUT’ undeclared)

[Mirsad Goran Todorovac]

On 1/9/2023 5:42 PM, David Hildenbrand wrote:

Hi, thank you for your reply.

>> I hope this is enough information for you to debug the issue.
>>
>> I am standing by for any additional diagnostics needed.
> 
> Won't userfaultfd.c fail in a similar way?
> 
> Anyhow, khugepaged.c jas
> 
> #ifndef MADV_PAGEOUT
> #define MADV_PAGEOUT 21
> #endif
> 
> So most probably we should do the same.

Actually, David, it turned out that userfaultfd.c compiled 
out-of-the-box, and side-by-side comparison showed that it also included 
"/home/marvin/linux/kernel/linux_torvalds/usr/include/asm-generic/mman-common.h"

The only remaining difference was including <linux/mman.h>, which fixed 
the issue w/o #ifdef ... #endif

Hope this helps.

Please find the following diff.

Regards,
Mirsad

------------------------------------------------------------------------------
diff --git a/tools/testing/selftests/vm/cow.c 
b/tools/testing/selftests/vm/cow.c
index 26f6ea3079e2..dd8cf12c6776 100644
--- a/tools/testing/selftests/vm/cow.c
+++ b/tools/testing/selftests/vm/cow.c
@@ -16,6 +16,7 @@
  #include <fcntl.h>
  #include <dirent.h>
  #include <assert.h>
+#include <linux/mman.h>
  #include <sys/mman.h>
  #include <sys/ioctl.h>
  #include <sys/wait.h>




--
Mirsad Todorovac
Sistem inženjer
Grafički fakultet | Akademija likovnih umjetnosti
Sveučilište u Zagrebu
-- 
System engineer
Faculty of Graphic Arts | Academy of Fine Arts
University of Zagreb, Republic of Croatia
tel. +385 (0)1 3711 451
mob. +385 91 57 88 355

Re: PROBLEM: selftest/vm/cow.c failed to compile (‘MADV_PAGEOUT’ undeclared)

[David Hildenbrand]

On 09.01.23 22:41, Mirsad Goran Todorovac wrote:
> On 1/9/2023 5:42 PM, David Hildenbrand wrote:
> 
> Hi, thank you for your reply.
> 
>>> I hope this is enough information for you to debug the issue.
>>>
>>> I am standing by for any additional diagnostics needed.
>>
>> Won't userfaultfd.c fail in a similar way?
>>
>> Anyhow, khugepaged.c jas
>>
>> #ifndef MADV_PAGEOUT
>> #define MADV_PAGEOUT 21
>> #endif
>>
>> So most probably we should do the same.
> 
> Actually, David, it turned out that userfaultfd.c compiled
> out-of-the-box, and side-by-side comparison showed that it also included
> "/home/marvin/linux/kernel/linux_torvalds/usr/include/asm-generic/mman-common.h"
> 
> The only remaining difference was including <linux/mman.h>, which fixed
> the issue w/o #ifdef ... #endif
> 
> Hope this helps.
> 
> Please find the following diff.
> 
> Regards,
> Mirsad
> 
> ------------------------------------------------------------------------------
> diff --git a/tools/testing/selftests/vm/cow.c
> b/tools/testing/selftests/vm/cow.c
> index 26f6ea3079e2..dd8cf12c6776 100644
> --- a/tools/testing/selftests/vm/cow.c
> +++ b/tools/testing/selftests/vm/cow.c
> @@ -16,6 +16,7 @@
>    #include <fcntl.h>
>    #include <dirent.h>
>    #include <assert.h>
> +#include <linux/mman.h>
>    #include <sys/mman.h>
>    #include <sys/ioctl.h>
>    #include <sys/wait.h>
>

I already sent a different fix [1]. I suspect when including
linux/mman.h, it would still be problematic with older kernel
headers that lack MADV_PAGEOUT (< v5.4).


But yeah, I saw that userfaultfd.c was fixed that way:

commit b773827e361952b3f53ac6fa4c4e39ccd632102e
Author: Chengming Zhou <zhouchengming@bytedance.com>
Date:   Fri Mar 4 20:29:04 2022 -0800

     kselftest/vm: fix tests build with old libc
     
     The error message when I build vm tests on debian10 (GLIBC 2.28):
     
         userfaultfd.c: In function `userfaultfd_pagemap_test':
         userfaultfd.c:1393:37: error: `MADV_PAGEOUT' undeclared (first use
         in this function); did you mean `MADV_RANDOM'?
           if (madvise(area_dst, test_pgsize, MADV_PAGEOUT))
                                              ^~~~~~~~~~~~
                                              MADV_RANDOM
     
     This patch includes these newer definitions from UAPI linux/mman.h, is
     useful to fix tests build on systems without these definitions in glibc
     sys/mman.h.


[1] https://lkml.kernel.org/r/20230109171255.488749-1-david@redhat.com

-- 
Thanks,

David / dhildenb

Re: PROBLEM: selftest/vm/cow.c failed to compile (‘MADV_PAGEOUT’ undeclared)

[Mirsad Todorovac]

On 1/10/23 11:05, David Hildenbrand wrote:
> On 09.01.23 22:41, Mirsad Goran Todorovac wrote:
>> On 1/9/2023 5:42 PM, David Hildenbrand wrote:
>>
>> Hi, thank you for your reply.
>>
>>>> I hope this is enough information for you to debug the issue.
>>>>
>>>> I am standing by for any additional diagnostics needed.
>>>
>>> Won't userfaultfd.c fail in a similar way?
>>>
>>> Anyhow, khugepaged.c jas
>>>
>>> #ifndef MADV_PAGEOUT
>>> #define MADV_PAGEOUT 21
>>> #endif
>>>
>>> So most probably we should do the same.
>>
>> Actually, David, it turned out that userfaultfd.c compiled
>> out-of-the-box, and side-by-side comparison showed that it also included
>> "/home/marvin/linux/kernel/linux_torvalds/usr/include/asm-generic/mman-common.h"
>>
>> The only remaining difference was including <linux/mman.h>, which fixed
>> the issue w/o #ifdef ... #endif
>>
>> Hope this helps.
>>
>> Please find the following diff.
>>
>> Regards,
>> Mirsad
>>
>> ------------------------------------------------------------------------------
>> diff --git a/tools/testing/selftests/vm/cow.c
>> b/tools/testing/selftests/vm/cow.c
>> index 26f6ea3079e2..dd8cf12c6776 100644
>> --- a/tools/testing/selftests/vm/cow.c
>> +++ b/tools/testing/selftests/vm/cow.c
>> @@ -16,6 +16,7 @@
>>    #include <fcntl.h>
>>    #include <dirent.h>
>>    #include <assert.h>
>> +#include <linux/mman.h>
>>    #include <sys/mman.h>
>>    #include <sys/ioctl.h>
>>    #include <sys/wait.h>
>>
> 
> I already sent a different fix [1]. I suspect when including
> linux/mman.h, it would still be problematic with older kernel
> headers that lack MADV_PAGEOUT (< v5.4).

I see your point.

> But yeah, I saw that userfaultfd.c was fixed that way:
> 
> commit b773827e361952b3f53ac6fa4c4e39ccd632102e
> Author: Chengming Zhou <zhouchengming@bytedance.com>
> Date:   Fri Mar 4 20:29:04 2022 -0800
> 
>      kselftest/vm: fix tests build with old libc
>      The error message when I build vm tests on debian10 (GLIBC 2.28):
>          userfaultfd.c: In function `userfaultfd_pagemap_test':
>          userfaultfd.c:1393:37: error: `MADV_PAGEOUT' undeclared (first use
>          in this function); did you mean `MADV_RANDOM'?
>            if (madvise(area_dst, test_pgsize, MADV_PAGEOUT))
>                                               ^~~~~~~~~~~~
>                                               MADV_RANDOM
>      This patch includes these newer definitions from UAPI linux/mman.h, is
>      useful to fix tests build on systems without these definitions in 
> glibc
>      sys/mman.h.
> 
> 
> [1] https://lkml.kernel.org/r/20230109171255.488749-1-david@redhat.com

You're the boss :)

However, IMHO, having MADV_PAGEOUT defined in three or four places could
make like miserable. OK, it is unlikely to change value, but something
tells me that the right way to do it is to guarantee that the macro
definition is unique.

I don't know what would be the right thing to do in pre-5.4 kernels
w/o MADV_PAGEOUT defined.

Probably then the "(madvise(area_dst, test_pgsize, MADV_PAGEOUT)" gives
EINVAL or is undefined?

-- 
Mirsad Goran Todorovac
Sistem inženjer
Grafički fakultet | Akademija likovnih umjetnosti
Sveučilište u Zagrebu

System engineer
Faculty of Graphic Arts | Academy of Fine Arts
University of Zagreb, Republic of Croatia

Re: PROBLEM: selftest/vm/cow.c failed to compile (‘MADV_PAGEOUT’ undeclared)

[David Hildenbrand]

On 10.01.23 13:25, Mirsad Todorovac wrote:
> On 1/10/23 11:05, David Hildenbrand wrote:
>> On 09.01.23 22:41, Mirsad Goran Todorovac wrote:
>>> On 1/9/2023 5:42 PM, David Hildenbrand wrote:
>>>
>>> Hi, thank you for your reply.
>>>
>>>>> I hope this is enough information for you to debug the issue.
>>>>>
>>>>> I am standing by for any additional diagnostics needed.
>>>>
>>>> Won't userfaultfd.c fail in a similar way?
>>>>
>>>> Anyhow, khugepaged.c jas
>>>>
>>>> #ifndef MADV_PAGEOUT
>>>> #define MADV_PAGEOUT 21
>>>> #endif
>>>>
>>>> So most probably we should do the same.
>>>
>>> Actually, David, it turned out that userfaultfd.c compiled
>>> out-of-the-box, and side-by-side comparison showed that it also included
>>> "/home/marvin/linux/kernel/linux_torvalds/usr/include/asm-generic/mman-common.h"
>>>
>>> The only remaining difference was including <linux/mman.h>, which fixed
>>> the issue w/o #ifdef ... #endif
>>>
>>> Hope this helps.
>>>
>>> Please find the following diff.
>>>
>>> Regards,
>>> Mirsad
>>>
>>> ------------------------------------------------------------------------------
>>> diff --git a/tools/testing/selftests/vm/cow.c
>>> b/tools/testing/selftests/vm/cow.c
>>> index 26f6ea3079e2..dd8cf12c6776 100644
>>> --- a/tools/testing/selftests/vm/cow.c
>>> +++ b/tools/testing/selftests/vm/cow.c
>>> @@ -16,6 +16,7 @@
>>>     #include <fcntl.h>
>>>     #include <dirent.h>
>>>     #include <assert.h>
>>> +#include <linux/mman.h>
>>>     #include <sys/mman.h>
>>>     #include <sys/ioctl.h>
>>>     #include <sys/wait.h>
>>>
>>
>> I already sent a different fix [1]. I suspect when including
>> linux/mman.h, it would still be problematic with older kernel
>> headers that lack MADV_PAGEOUT (< v5.4).
> 
> I see your point.
> 
>> But yeah, I saw that userfaultfd.c was fixed that way:
>>
>> commit b773827e361952b3f53ac6fa4c4e39ccd632102e
>> Author: Chengming Zhou <zhouchengming@bytedance.com>
>> Date:   Fri Mar 4 20:29:04 2022 -0800
>>
>>       kselftest/vm: fix tests build with old libc
>>       The error message when I build vm tests on debian10 (GLIBC 2.28):
>>           userfaultfd.c: In function `userfaultfd_pagemap_test':
>>           userfaultfd.c:1393:37: error: `MADV_PAGEOUT' undeclared (first use
>>           in this function); did you mean `MADV_RANDOM'?
>>             if (madvise(area_dst, test_pgsize, MADV_PAGEOUT))
>>                                                ^~~~~~~~~~~~
>>                                                MADV_RANDOM
>>       This patch includes these newer definitions from UAPI linux/mman.h, is
>>       useful to fix tests build on systems without these definitions in
>> glibc
>>       sys/mman.h.
>>
>>
>> [1] https://lkml.kernel.org/r/20230109171255.488749-1-david@redhat.com
> 
> You're the boss :)

Heh, no I'm not :) I'm just raising that this turned out to be 
problematic unfortunately.

> 
> However, IMHO, having MADV_PAGEOUT defined in three or four places could
> make like miserable. OK, it is unlikely to change value, but something
> tells me that the right way to do it is to guarantee that the macro
> definition is unique.
> 
> I don't know what would be the right thing to do in pre-5.4 kernels
> w/o MADV_PAGEOUT defined.
> 
> Probably then the "(madvise(area_dst, test_pgsize, MADV_PAGEOUT)" gives
> EINVAL or is undefined?

Yes. The expectation is that it fails with ENOSYS or EINVAL if the 
kernel doesn't support it. The kernel might be different to the 
installed kernel headers.

In an ideal world, we'd be using the in-tree headers -- they are 
guaranteed to define what we need. So far, I failed to make it work (I 
thought it would work as expected before I had to do above mentioned 
fix). Maybe that can be made working?

-- 
Thanks,

David / dhildenb