Messages in this thread | | | From | Mel Gorman <> | Subject | [PATCH 0/4] Verification and debugging of memory initialisation V3 | Date | Tue, 22 Apr 2008 19:31:33 +0100 (IST) |
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Other than a rebase to the latest -mm, there are not many big changes. Credit goes to Christoph Lameter, an off-list reviewer and in particular Ingo Molnar for helping bash this into shape.
Changelog since V2 o (Mel) Rebase to 2.6.25-mm1 and rewrite zonelist dump o (Mel) Depend on DEBUG_VM instead of DEBUG_KERNEL o (Mel) Use __meminitdata instead of __initdata for logging level o (Christoph) Get rid of FLAGS_RESERVED references o (Christoph) Print out flag usage information o (Ingo) Default do the verifications on DEBUG_VM and instead control the level of verbose logging with mminit_loglevel= instead of mminit_debug_level= o (Anon) Log at KERN_DEBUG level o (Anon) Optimisation to the mminit_debug_printk macro
Changelog since V1 o (Ingo) Make memory initialisation verification a DEBUG option depending on DEBUG_KERNEL option. By default it will then to verify structures but tracing can be enabled via the command-line. Without the CONFIG option, checks will still be made on PFN ranges passed by the architecture-specific code and a warning printed once if a problem is encountered o (Ingo) WARN_ON_ONCE when PFNs from the architecture violate SPARSEMEM limitations. The warning should be "harmless" as the system will boot regardless but it acts as a reminder that bad input is being used. o (Anon) Convert mminit_debug_printk() to a macro o (Anon) Spelling mistake corrections o (Anon) Use of KERN_CONT properly for multiple printks o (Mel) Reshuffle the patches so that the zonelist printing is at the end of the patchset. This is because -mm requires a different patch to print zonelists and this allows the end patch to be temporarily dropped when testing against -mm o (Mel) Rebase on top of Ingo's sparsemem fix for easier testing o (Mel) Document mminit_debug_level= o (Mel) Fix check on pageflags where the masks were not being shifted o (Mel) The zone ID should should have used page_zonenum not page_zone_id o (Mel) Iterate all zonelists correctly o (Mel) Correct typo of SECTIONS_SHIFT
Boot initialisation has always been a bit of a mess with a number of ugly points. While significant amounts of the initialisation is architecture-independent, it trusts of the data received from the architecture layer. This was a mistake in retrospect as it has resulted in a number of difficult-to-diagnose bugs.
This patchset adds some validation and tracing to memory initialisation when CONFIG_DEBUG_VM is set. The configuration option can be explicitly disabled for embedded systems. It also introduces a few basic defencive measures and depending on a boot parameter, will perform additional tests for errors "that should never occur". The intention is that additional checks are added over time that would have identified mysterious boot failures faster.
-- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab
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