Ensure that grequestx continuously make progress

[devreal]

The handling of the grequest extensions is missing the release of the in_progress guard, causing requests not being polled after the first invocation.

Signed-off-by: Joseph Schuchart [email protected]

[bosilca]

Nice catch.

[jsquyres]

Does this mean that grequests were, in general, broken? (i.e., never being advanced)

[bosilca]

yup.

[jsquyres]

This is NEWS-worthy, then...

[jsquyres]

@devreal Can you cherry-pick to the appropriate branches?

[devreal]

@jsquyres :

Does this mean that grequests were, in general, broken? (i.e., never being advanced)

I think only the extended grequests (see #24) were affected, the ones that come with a progress function. that are not in the MPI standard. AFAICS they are used internally by ROMIO but are not exposed to the user (unlike MPICH). The regular grequests should not be affected.

I will cherry-pick to the release branches.

[jsquyres]

Oh, if there's no way for the user to be exposed to this bug, then it's not worth cherry-picking.

Specifically: are we using the extended grequests functionality in ROMIO?

[bosilca]

indeed, the normal grequest are having their query function called as expected. I wonder how is ROMIO working if we don't progress their requests as expected ? If this functionality used in the current code ?

[devreal]

@bosilca Grepping through the romio code it seems that extended grequests are only used when a working aio library is found, for example here. Not sure how often this configuration is used.