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| author | Hugh Dickins <hugh.dickins@tiscali.co.uk> | 2009-09-21 17:02:23 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-22 07:17:32 -0700 |
| commit | 2ffd8679c8e4ec226718bff58b50b226dd477015 (patch) | |
| tree | 5e58b19da86defa012613a850c6f57dd69ab51f3 | |
| parent | 1c2fb7a4c2ca7a958b02bc1e615d0254990bba8d (diff) | |
| download | lwn-2ffd8679c8e4ec226718bff58b50b226dd477015.tar.gz lwn-2ffd8679c8e4ec226718bff58b50b226dd477015.zip | |
ksm: sysfs and defaults
At present KSM is just a waste of space if you don't have CONFIG_SYSFS=y
to provide the /sys/kernel/mm/ksm files to tune and activate it.
Make KSM depend on SYSFS? Could do, but it might be better to provide
some defaults so that KSM works out-of-the-box, ready for testers to
madvise MADV_MERGEABLE, even without SYSFS.
Though anyone serious is likely to want to retune the numbers to their
taste once they have experience; and whether these settings ever reach
2.6.32 can be discussed along the way.
Save 1kB from tiny kernels by #ifdef'ing the SYSFS side of it.
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/ksm.c | 26 |
1 files changed, 19 insertions, 7 deletions
@@ -163,18 +163,18 @@ static unsigned long ksm_pages_unshared; static unsigned long ksm_rmap_items; /* Limit on the number of unswappable pages used */ -static unsigned long ksm_max_kernel_pages; +static unsigned long ksm_max_kernel_pages = 2000; /* Number of pages ksmd should scan in one batch */ -static unsigned int ksm_thread_pages_to_scan; +static unsigned int ksm_thread_pages_to_scan = 200; /* Milliseconds ksmd should sleep between batches */ -static unsigned int ksm_thread_sleep_millisecs; +static unsigned int ksm_thread_sleep_millisecs = 20; #define KSM_RUN_STOP 0 #define KSM_RUN_MERGE 1 #define KSM_RUN_UNMERGE 2 -static unsigned int ksm_run; +static unsigned int ksm_run = KSM_RUN_MERGE; static DECLARE_WAIT_QUEUE_HEAD(ksm_thread_wait); static DEFINE_MUTEX(ksm_thread_mutex); @@ -506,6 +506,10 @@ static int unmerge_ksm_pages(struct vm_area_struct *vma, return err; } +#ifdef CONFIG_SYSFS +/* + * Only called through the sysfs control interface: + */ static int unmerge_and_remove_all_rmap_items(void) { struct mm_slot *mm_slot; @@ -563,6 +567,7 @@ error: spin_unlock(&ksm_mmlist_lock); return err; } +#endif /* CONFIG_SYSFS */ static u32 calc_checksum(struct page *page) { @@ -1454,6 +1459,11 @@ void __ksm_exit(struct mm_struct *mm) } } +#ifdef CONFIG_SYSFS +/* + * This all compiles without CONFIG_SYSFS, but is a waste of space. + */ + #define KSM_ATTR_RO(_name) \ static struct kobj_attribute _name##_attr = __ATTR_RO(_name) #define KSM_ATTR(_name) \ @@ -1636,6 +1646,7 @@ static struct attribute_group ksm_attr_group = { .attrs = ksm_attrs, .name = "ksm", }; +#endif /* CONFIG_SYSFS */ static int __init ksm_init(void) { @@ -1657,16 +1668,17 @@ static int __init ksm_init(void) goto out_free2; } +#ifdef CONFIG_SYSFS err = sysfs_create_group(mm_kobj, &ksm_attr_group); if (err) { printk(KERN_ERR "ksm: register sysfs failed\n"); - goto out_free3; + kthread_stop(ksm_thread); + goto out_free2; } +#endif /* CONFIG_SYSFS */ return 0; -out_free3: - kthread_stop(ksm_thread); out_free2: mm_slots_hash_free(); out_free1: |