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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