Re: [LTP] [PATCH v1] swapoff01.c: Adjust blocks size base on pagesize

[Wei Gao via ltp <ltp@lists.linux.it>]

On Thu, Feb 22, 2024 at 09:39:43AM +0100, Cyril Hrubis wrote:
> Hi!
> > The make_swapfile function will encounter no space error if pagesize
> > is bigger then 4096, such as ppc64 system use default pagesize 65535.
>                                                                     ^
> 								 65536?
Yes
> 
> Isn't this more about Btrfs though? Looking at the make_swapfile() we do
> use statvfs to get filesystem block size and if that is Btrfs with 64k
> blocks we end up with swapfile of a size of 4GB that sounds like a bit
> too much I guess.
> 

Sorry for confusing. It should caused by block size instead of page size.
The code change should change like following, but i suppose you will not agree
on this solution, correct?

--- a/testcases/kernel/syscalls/swapoff/swapoff01.c
+++ b/testcases/kernel/syscalls/swapoff/swapoff01.c
@@ -12,6 +12,7 @@
 #include <unistd.h>
 #include <errno.h>
 #include <stdlib.h>
+#include <sys/statvfs.h>

 #include "tst_test.h"
 #include "lapi/syscalls.h"
@@ -44,8 +45,21 @@ static void setup(void)
 {
        is_swap_supported(TEST_FILE);

-       if (make_swapfile(SWAP_FILE, 65536, 1))
+       struct statvfs fs_info;
+       unsigned long blk_size;
+       if (statvfs(".", &fs_info) == -1)
+               tst_brk(TBROK, "Failed to get statvfs info");
+
+       blk_size = fs_info.f_bsize;
+
+       int blocks = 65535;
+
+       if (blk_size > 4096)
+               blocks = 65535 * 4096 / blk_size;
+
+       if (make_swapfile(SWAP_FILE, blocks, 1))
                tst_brk(TBROK, "Failed to create file for swap");
+
 }


> > Signed-off-by: Wei Gao <wegao@suse.com>
> > ---
> >  testcases/kernel/syscalls/swapoff/swapoff01.c | 7 ++++++-
> >  1 file changed, 6 insertions(+), 1 deletion(-)
> > 
> > diff --git a/testcases/kernel/syscalls/swapoff/swapoff01.c b/testcases/kernel/syscalls/swapoff/swapoff01.c
> > index c303588df..71d6c6c04 100644
> > --- a/testcases/kernel/syscalls/swapoff/swapoff01.c
> > +++ b/testcases/kernel/syscalls/swapoff/swapoff01.c
> > @@ -44,7 +44,12 @@ static void setup(void)
> >  {
> >  	is_swap_supported(TEST_FILE);
> >  
> > -	if (make_swapfile(SWAP_FILE, 65536, 1))
> > +	int blocks = 65535;
> > +
> > +	if (getpagesize() > 4096)
> > +		blocks = 65535 * 4096 / getpagesize();
> > +
> > +	if (make_swapfile(SWAP_FILE, blocks, 1))
> >  		tst_brk(TBROK, "Failed to create file for swap");
> 
> 
> I do not think that this is a right solution though. Is there any reason
> why we pass number of blocks to the make_swapfile instead of megabytes?
> 
@Li Wang, could you give some clue for above question(for why pass number of blocks instead of megabytes)?

Thanks all for comments!

> >  }
> >  
> > -- 
> > 2.35.3
> > 
> > 
> > -- 
> > Mailing list info: https://lists.linux.it/listinfo/ltp
> 
> -- 
> Cyril Hrubis
> chrubis@suse.cz

-- 
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