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authorHugh Dickins <hugh.dickins@tiscali.co.uk>2009-09-21 20:01:57 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-22 10:17:31 -0400
commitf8af4da3b4c14e7267c4ffb952079af3912c51c5 (patch)
tree17b0cfbd2d3d9abf9008f69e7fee5369cec7afa5 /kernel
parentd19f352484467a5e518639ddff0554669c10ffab (diff)
ksm: the mm interface to ksm
This patch presents the mm interface to a dummy version of ksm.c, for better scrutiny of that interface: the real ksm.c follows later. When CONFIG_KSM is not set, madvise(2) reject MADV_MERGEABLE and MADV_UNMERGEABLE with EINVAL, since that seems more helpful than pretending that they can be serviced. But when CONFIG_KSM=y, accept them even if KSM is not currently running, and even on areas which KSM will not touch (e.g. hugetlb or shared file or special driver mappings). Like other madvices, report ENOMEM despite success if any area in the range is unmapped, and use EAGAIN to report out of memory. Define vma flag VM_MERGEABLE to identify an area on which KSM may try merging pages: leave it to ksm_madvise() to decide whether to set it. Define mm flag MMF_VM_MERGEABLE to identify an mm which might contain VM_MERGEABLE areas, to minimize callouts when forking or exiting. Based upon earlier patches by Chris Wright and Izik Eidus. Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Chris Wright <chrisw@redhat.com> Signed-off-by: Izik Eidus <ieidus@redhat.com> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Avi Kivity <avi@redhat.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/fork.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index d4638c8cc19e..73a442b7be6d 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -49,6 +49,7 @@
49#include <linux/ftrace.h> 49#include <linux/ftrace.h>
50#include <linux/profile.h> 50#include <linux/profile.h>
51#include <linux/rmap.h> 51#include <linux/rmap.h>
52#include <linux/ksm.h>
52#include <linux/acct.h> 53#include <linux/acct.h>
53#include <linux/tsacct_kern.h> 54#include <linux/tsacct_kern.h>
54#include <linux/cn_proc.h> 55#include <linux/cn_proc.h>
@@ -299,6 +300,9 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
299 rb_link = &mm->mm_rb.rb_node; 300 rb_link = &mm->mm_rb.rb_node;
300 rb_parent = NULL; 301 rb_parent = NULL;
301 pprev = &mm->mmap; 302 pprev = &mm->mmap;
303 retval = ksm_fork(mm, oldmm);
304 if (retval)
305 goto out;
302 306
303 for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) { 307 for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) {
304 struct file *file; 308 struct file *file;
@@ -435,7 +439,8 @@ static struct mm_struct * mm_init(struct mm_struct * mm, struct task_struct *p)
435 atomic_set(&mm->mm_count, 1); 439 atomic_set(&mm->mm_count, 1);
436 init_rwsem(&mm->mmap_sem); 440 init_rwsem(&mm->mmap_sem);
437 INIT_LIST_HEAD(&mm->mmlist); 441 INIT_LIST_HEAD(&mm->mmlist);
438 mm->flags = (current->mm) ? current->mm->flags : default_dump_filter; 442 mm->flags = (current->mm) ?
443 (current->mm->flags & MMF_INIT_MASK) : default_dump_filter;
439 mm->core_state = NULL; 444 mm->core_state = NULL;
440 mm->nr_ptes = 0; 445 mm->nr_ptes = 0;
441 set_mm_counter(mm, file_rss, 0); 446 set_mm_counter(mm, file_rss, 0);
@@ -496,6 +501,7 @@ void mmput(struct mm_struct *mm)
496 501
497 if (atomic_dec_and_test(&mm->mm_users)) { 502 if (atomic_dec_and_test(&mm->mm_users)) {
498 exit_aio(mm); 503 exit_aio(mm);
504 ksm_exit(mm);
499 exit_mmap(mm); 505 exit_mmap(mm);
500 set_mm_exe_file(mm, NULL); 506 set_mm_exe_file(mm, NULL);
501 if (!list_empty(&mm->mmlist)) { 507 if (!list_empty(&mm->mmlist)) {