| Message ID | 20180421021600.17549-1-liwang@redhat.com |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [v3,1/2] include: add an exponential backoff macro for function repeat | expand |
Hi! > +#define TST_RETRY_FN_EXP_BACKOFF(FUNC, ERET, MAX_DELAY) \ > +({ int tst_delay = 1; \ > + for (;;) { \ > + typeof(FUNC) ret = FUNC; \ ^ I prefixed this variable with tst_ and even added _ suffix to make sure that it will not alias either. > + if (ret == ERET) \ > + break; \ > + if (tst_delay < MAX_DELAY * 1000000) { \ > + tst_res(TINFO, \ > + #FUNC" returned %i, retrying" \ > + " in %ius", ret, tst_delay); \ > + usleep(tst_delay); \ > + tst_delay *= 2; \ > + } else { \ > + tst_brk(TBROK, #FUNC" failed"); \ > + } \ > + } \ > + ERET; \ > +}) And pushed, thanks. I know that the documentation is there in the comment but we should probably add a note about the macro into the test-writing-guidelines.txt as well...
Cyril Hrubis wrote: > hi! > > +#define tst_retry_fn_exp_backoff(func, eret, max_delay) \ > > +({ int tst_delay = 1; \ > > + for (;;) { \ > > + typeof(FUNC) ret = FUNC; \ > ^ > I prefixed this variable with tst_ and even added _ > suffix to make sure that it will not alias either. Good catch. > > > + if (ret == ERET) \ > > + break; \ > > + if (tst_delay < MAX_DELAY * 1000000) { \ > > + tst_res(TINFO, \ > > + #FUNC" returned %i, retrying" \ > > + " in %ius", ret, tst_delay); \ > > + usleep(tst_delay); \ > > + tst_delay *= 2; \ > > + } else { \ > > + tst_brk(TBROK, #FUNC" failed"); \ > > + } \ > > + } \ > > + ERET; \ > > +}) > > And pushed, thanks. > > I know that the documentation is there in the comment but we should > probably add a note about the macro into the test-writing-guidelines.txt > as well... Yes, we should. I will do that when I'm free. Thanks for reviewing. Li Wang
diff --git a/include/tst_common.h b/include/tst_common.h index e4466d5..32adb74 100644 --- a/include/tst_common.h +++ b/include/tst_common.h @@ -35,4 +35,37 @@ #define LTP_ALIGN(x, a) __LTP_ALIGN_MASK(x, (typeof(x))(a) - 1) #define __LTP_ALIGN_MASK(x, mask) (((x) + (mask)) & ~(mask)) +/** + * TST_RETRY_FUNC() - Repeatedly retry a function with an increasing delay. + * @FUNC - The function which will be retried + * @ERET - The value returned from @FUNC on success + * + * This macro will call @FUNC in a loop with a delay between retries. If @FUNC + * returns @ERET then the loop exits. The delay between retries starts at one + * micro second and is then doubled each iteration until it exceeds one second + * (the total time sleeping will be aproximately one second as well). When the + * delay exceeds one second tst_brk() is called. + */ +#define TST_RETRY_FUNC(FUNC, ERET) \ + TST_RETRY_FN_EXP_BACKOFF(FUNC, ERET, 1) + +#define TST_RETRY_FN_EXP_BACKOFF(FUNC, ERET, MAX_DELAY) \ +({ int tst_delay = 1; \ + for (;;) { \ + typeof(FUNC) ret = FUNC; \ + if (ret == ERET) \ + break; \ + if (tst_delay < MAX_DELAY * 1000000) { \ + tst_res(TINFO, \ + #FUNC" returned %i, retrying" \ + " in %ius", ret, tst_delay); \ + usleep(tst_delay); \ + tst_delay *= 2; \ + } else { \ + tst_brk(TBROK, #FUNC" failed"); \ + } \ + } \ + ERET; \ +}) + #endif /* TST_COMMON_H__ */
Signed-off-by: Li Wang <liwang@redhat.com> Cc: Richard Palethorpe <rpalethorpe@suse.de> Cc: Cyril Hrubis <chrubis@suse.cz> --- include/tst_common.h | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+)