On Wed, Apr 08, 2020 at 08:15:19AM -0700, Matthew Wilcox wrote:

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 config ZSMALLOC_PGTABLE_MAPPING
 	bool "Use page table mapping to access object in zsmalloc"
-	depends on ZSMALLOC
+	depends on ZSMALLOC=y

It's a bool so this shouldn't matter... not needed.

My mm/Kconfig has:

config ZSMALLOC
	tristate "Memory allocator for compressed pages"
	depends on MMU

which I think means it can be modular, no?

Randy means that ZSMALLOC_PGTABLE_MAPPING is a bool, so I think hch's patch
is wrong ... if ZSMALLOC is 'm' then ZSMALLOC_PGTABLE_MAPPING would become
'n' instead of 'y'.

In Linus' tree you can select PGTABLE_MAPPING=y with ZSMALLOC=m,
and that fits my understanding of the kbuild language.  With this
patch I can't anymore.