On 31/05/18 16:49, Andrew Cooper wrote: > On 31/05/18 15:14, Juergen Gross wrote: >> On 31/05/18 15:05, Marcello Seri wrote: >>> When xenstore was updated to support safe-string, some unnecessary >>> copies were introduced. A further patch reduced the copies at the price >>> of many calls to unsafe conversions between bytes and strings. In the >>> port we also did not notice that some C stubs were still incorrectly >>> using ocaml strings as mutable payload. >>> >>> This set of patches updates the C stubs that use mutable payloads passed >>> from ocaml, and reduces the amount of unsafe conversions where possible >>> without further increasing the number of copies. >>> >>> This seems also to fix some unclear instabilities that appeared after >>> the former patch introducing the unsafe conversion with some version of >>> the ocaml compiler. >> This is rather vague. >> >> Can you confirm that oxenstored is now as stable as it was without the >> safe-string patches? >> >> Could you please mention the commit of the patch you are fixing in the >> related commit message? I'd like to know which of the two patches is >> the real fix and which is "only" some improvement of code. >> >> We are rather close to the release, so I'm hesitating to accept cleanup >> patches now. > > So far, these changes do appear to have fixed the issues XenRT first > noticed. Unfortunately the failures are very hard to quantify, but seem > to amount to "some operations seem to get dropped" (as there is no > obvious corruption), but the issues are rare and takes an large quantity > of machine hours to encounter.
Did you try multiple concurrent runs of "xs-test -r <seconds>" to reproduce the problem? This has helped me a lot to find problems in xenstore. > I can't comment for exact changes, but the bug being fixed by patch 1 is > not passing a buffer (which the Ocaml runtime thinks is immutable) to > the C stubs to be written into. AFAICT, it is consequence of the very > first attempt to move from mutable to immutable strings. So patch 2 is more kind of a cleanup? Or is it needed for the fix, too? Juergen _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
