0003571: mmaped bigarrays over NFS

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0003571

OCaml

OCaml general

public

2005-03-31 21:18

2012-04-09 12:25

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administrator

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Priority

normal

Severity

minor

Reproducibility

always

Status

resolved

Resolution

fixed

Platform

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Target Version

Fixed in Version

4.00.0+dev

Summary

0003571: mmaped bigarrays over NFS

Description

Bonjour,

je viens de lire ceci sur la page du serveur NFS linux :

,----[ http://nfs.sourceforge.net/#faq_d8 [^] ]
| Although some implementations of munmap(2) happen to write dirty pages
| to local file systems, the NFS version of munmap(2) does not. An
| msync(2) call is always required to guarantee that dirty mapped data
| is written to permanent storage.
`----

il y a donc problème d'intégrité des données pour les bigarrays créés
avec Genarray.map_file en mode "shared". Rajouter un msync() juste
avant le munmap() n'est même pas suffisant puisque munmap est appelé
pendant la finalisation. Il faudrait donc rajouter une function
sync_file aux modules de Bigarray ...

--
Olivier

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Notes
(0006350) xleroy (administrator) 2011-12-17 09:38	I've been sleeping on this PR for years, so I'm un-assigning it for me just in case someone is willing to pick it. Can anyone confirm that the issue mentioned by Olivier is still there? If so, providing a wrapper around msync() in Bigarrays is a good idea. One thing to check, though, is whether msync() needs an existence test in configure, or whether it can safely be assumed to be there if we've found mmap and munmap.

(0007298) xleroy (administrator) 2012-04-09 12:25	Added call to msync() before munmap(). Commit 12326 in version/4.00, 12327 in trunk.

Issue History
Date Modified	Username	Field	Change
2005-11-18 10:14	administrator	New Issue
2005-12-15 15:24	doligez	Assigned To	=> xleroy
2005-12-15 15:24	doligez	Description Updated
2011-12-17 09:38	xleroy	Note Added: 0006350
2011-12-17 09:38	xleroy	Assigned To	xleroy =>
2012-04-09 12:25	xleroy	Note Added: 0007298
2012-04-09 12:25	xleroy	Status	acknowledged => resolved
2012-04-09 12:25	xleroy	Resolution	open => fixed
2012-04-09 12:25	xleroy	Fixed in Version	=> 4.00.0+dev