x86/mm: Pre-allocate P4D/PUD pages for vmalloc area

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Pre-allocate the page-table pages for the vmalloc area at the level
which needs synchronization on x86-64, which is P4D for 5-level and
PUD for 4-level paging.

Doing this at boot makes sure no synchronization of that area is
necessary at runtime. The synchronization takes the pgd_lock and
iterates over all page-tables in the system, so it can take quite long
and is better avoided.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Link: https://lore.kernel.org/r/20200721095953.6218-2-joro@8bytes.org

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Joerg Roedel 2020-07-21 11:59:51 +02:00 • committed by Ingo Molnar

parent 92ed301919

commit 6eb82f9940

1 changed files with 52 additions and 0 deletions

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arch/x86/mm/init_64.c

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