mm: rearrange madvise code to allow for reuse

Patch series "mm: rearrange madvise code to allow for reuse", v11.

Avoid performance regression of the new anon vma name field refcounting it.

I checked the image sizes with allnoconfig builds:

  unpatched Linus' ToT
     text    data     bss     dec     hex filename
  1324759      32   73928 1398719 1557bf vmlinux

  After the first patch is applied (madvise refactoring)
     text    data     bss     dec     hex filename
  1322346      32   73928 1396306 154e52 vmlinux
  >>> 2413 bytes decrease vs ToT <<<

  After all patches applied with CONFIG_ANON_VMA_NAME=n
     text    data     bss     dec     hex filename
  1322337      32   73928 1396297 154e49 vmlinux
  >>> 2422 bytes decrease vs ToT <<<

  After all patches applied with CONFIG_ANON_VMA_NAME=y
     text    data     bss     dec     hex filename
  1325228      32   73928 1399188 155994 vmlinux
  >>> 469 bytes increase vs ToT <<<

This patch (of 3):

Refactor the madvise syscall to allow for parts of it to be reused by a
prctl syscall that affects vmas.

Move the code that walks vmas in a virtual address range into a function
that takes a function pointer as a parameter.  The only caller for now
is sys_madvise, which uses it to call madvise_vma_behavior on each vma,
but the next patch will add an additional caller.

Move handling all vma behaviors inside madvise_behavior, and rename it
to madvise_vma_behavior.

Move the code that updates the flags on a vma, including splitting or
merging the vma as necessary, into a new function called
madvise_update_vma.  The next patch will add support for updating a new
anon_name field as well.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Colin Cross <[email protected]>
Signed-off-by: Suren Baghdasaryan <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: "Eric W. Biederman" <[email protected]>
Cc: Jan Glauber <[email protected]>
Cc: John Stultz <[email protected]>
Cc: Rob Landley <[email protected]>
Cc: Cyrill Gorcunov <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: "Serge E. Hallyn" <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Shaohua Li <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Minchan Kim <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions