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Memory dumping and restoring (edit)

Revision as of 19:09, 21 October 2012

803 bytes removed , 19:09, 21 October 2012

→‎Problems

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== Problems ==

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~~=== Shared memory dump ===~~

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~~When dumping a vma for a task its consents is dumped regardless of whether a mapping is shared. Thus for e.g. 2 tasks with shared region we'll have 2 images with the same contents.~~

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~~Another problem is that a shared memory region may have different mincore() reports from different tasks. Thus neither of them is suitable for dumping the shmem with current technique.~~

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~~=== Mincore report is bad ===~~

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~~The existing mincore bit is not enough for several reasons.~~

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~~# Swapped out memory is not reported and this is a BUG. Plan is to propose the MINCORE_SWAP bit.~~

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~~# File pages are reported as present if they are in page cache regardless of whether they are mapped or not.~~

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~~# When a page from private file mapping is not cow-ed (i.e. was read only) it's not necessary to dump it.~~

=== Non linear mappings ===

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Currently ~~there~~'~~s no way to detect this mapping and~~ dump ~~one carefully.~~

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Currently we don't support non-linear mappings (fail dump if present)

Xemul

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