mremap: don't do uneccesary checks if new_len == old_len

[cascardo/linux.git] / mm / Kconfig

diff --git a/mm/Kconfig b/mm/Kconfig
index c180af8..d4e6495 100644 (file)
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -299,15 +299,9 @@ config BOUNCE
 # On the 'tile' arch, USB OHCI needs the bounce pool since tilegx will often
 # have more than 4GB of memory, but we don't currently use the IOTLB to present
 # a 32-bit address to OHCI.  So we need to use a bounce pool instead.
-#
-# We also use the bounce pool to provide stable page writes for jbd.  jbd
-# initiates buffer writeback without locking the page or setting PG_writeback,
-# and fixing that behavior (a second time; jbd2 doesn't have this problem) is
-# a major rework effort.  Instead, use the bounce buffer to snapshot pages
-# (until jbd goes away).  The only jbd user is ext3.
 config NEED_BOUNCE_POOL
        bool
-       default y if (TILE && USB_OHCI_HCD) || (BLK_DEV_INTEGRITY && JBD)
+       default y if TILE && USB_OHCI_HCD
 
 config NR_QUICK
        int
@@ -636,3 +630,21 @@ config MAX_STACK_SIZE_MB
          changed to a smaller value in which case that is used.
 
          A sane initial value is 80 MB.
+
+# For architectures that support deferred memory initialisation
+config ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT
+       bool
+
+config DEFERRED_STRUCT_PAGE_INIT
+       bool "Defer initialisation of struct pages to kswapd"
+       default n
+       depends on ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT
+       depends on MEMORY_HOTPLUG
+       help
+         Ordinarily all struct pages are initialised during early boot in a
+         single thread. On very large machines this can take a considerable
+         amount of time. If this option is set, large machines will bring up
+         a subset of memmap at boot and then initialise the rest in parallel
+         when kswapd starts. This has a potential performance impact on
+         processes running early in the lifetime of the systemm until kswapd
+         finishes the initialisation.