[LTP] [PATCH] swapon01: swapon01: prevent OOM happening in swap process

[Li Wang]

On Tue, Mar 19, 2024 at 1:43 PM Li Wang <liwang@redhat.com> wrote:

>
>
> On Tue, Mar 19, 2024 at 1:04 PM Petr Vorel <pvorel@suse.cz> wrote:
>
>> > On Mon, Mar 18, 2024 at 8:40 PM Wei Gao <wegao@suse.com> wrote:
>>
>>
>>
>>
>> > > > That's because the available swapfile on your SUT is too small,
>> > > > you can adjust it (then retest it) by yourself to find a proper
>> size.
>>
>> > > > This is fine as long as the swapfile size is less than 300MB,
>> > > > otherwise we need to set .dev_min_size like what we did
>> > > > for swapoff01.c.
>>
>> > > > And, on the other side, we can't guarantee the system SwapCached
>> > > > happened every time, it depends on the system's configuration.
>>
>>
>> > > 100M is good enough for current system, could you help check following
>> > > patch?
>>
>>
>> > Can we rewrite the make_swapfile() API to support passing MB size for
>> > making the swapfile?
>>
>> I guess it would be desirable (but keep also possible to pass that 10
>> blocks,
>> therefore maybe use flag to distinguish between MB and blocks?).
>>
>
> That's fine but a bit complex for users to distinguish flags.
>
> Or, what about making the function use the flag as static, and
> export two additional functions with MB and blocks?
>
> enum swapfile_method {
>     SWAPFILE_BY_SIZE,
>     SWAPFILE_BY_BLOCKS
> };
>
> static int make_swapfile(const char *swapfile, unsigned int para, int
> safe, enum swapfile_method method) {
>     // The main logic to achieve the swapfile-making process
>     // ...
> }
>
> int make_swapfile_size(const char *swapfile, unsigned int size, int safe) {
>     return make_swapfile(swapfile, size, safe, SWAPFILE_BY_SIZE);
> }
>
> int make_swapfile_blks(const char *swapfile, unsigned int blocks, int
> safe) {
>     return make_swapfile(swapfile, blocks, safe, SWAPFILE_BY_BLOCKS);
> }
>

Even simpler to define two macros with one make_swapfile():

#define MAKE_SWAPFILE_SIZE(swapfile, size, safe) \
    make_swapfile(swapfile, size, safe, SWAPFILE_BY_SIZE)

#define MAKE_SWAPFILE_BLKS(swapfile, blocks, safe) \
    make_swapfile(swapfile, blocks, safe, SWAPFILE_BY_BLOCKS)



-- 
Regards,
Li Wang