]> pilppa.com Git - linux-2.6-omap-h63xx.git/commit
[PATCH] msync: check pte dirty earlier
authorAbhijit Karmarkar <abhijitk@veritas.com>
Wed, 22 Jun 2005 00:15:13 +0000 (17:15 -0700)
committerLinus Torvalds <torvalds@ppc970.osdl.org>
Wed, 22 Jun 2005 01:46:21 +0000 (18:46 -0700)
commitb4955ce3dd0818b56da532a16c9a4a3804a558ee
tree6e01667181bfc495b56e39748783ad2235a4f56e
parentc475a8ab625d567eacf5e30ec35d6d8704558062
[PATCH] msync: check pte dirty earlier

It's common practice to msync a large address range regularly, in which
often only a few ptes have actually been dirtied since the previous pass.

sync_pte_range then goes much faster if it tests whether pte is dirty
before locating and accessing each struct page cacheline; and it is hardly
slowed by ptep_clear_flush_dirty repeating that test in the opposite case,
when every pte actually is dirty.

But beware, s390's pte_dirty always says false, since its dirty bit is kept
in the storage key, located via the struct page address.  So skip this
optimization in its case: use a pte_maybe_dirty macro which just says true
if page_test_and_clear_dirty is implemented.

Signed-off-by: Abhijit Karmarkar <abhijitk@veritas.com>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
include/asm-generic/pgtable.h
mm/msync.c