(12/28/11 11:36 PM), Hugh Dickins wrote:
scan_mapping_unevictable_pages() is used to make SysV SHM_LOCKed pages
evictable again once the shared memory is unlocked or destroyed (the
latter seems rather a waste of time, but meets internal expectations).
It does pagevec_lookup()s across the whole object: methinks a
cond_resched() every PAGEVEC_SIZE pages would be worthwhile.
Signed-off-by: Hugh Dickins<hughd@xxxxxxxxxx>
---
mm/vmscan.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- mmotm.orig/mm/vmscan.c 2011-12-28 16:49:36.000000000 -0800
+++ mmotm/mm/vmscan.c 2011-12-28 17:03:07.647220248 -0800
@@ -3583,8 +3583,8 @@ void scan_mapping_unevictable_pages(stru
pagevec_release(&pvec);
count_vm_events(UNEVICTABLE_PGSCANNED, pg_scanned);
+ cond_resched();
}
Hmm...
scan_mapping_unevictable_pages() is always under spinlock?
int shmem_lock(struct file *file, int lock, struct user_struct *user)
{
spin_lock(&info->lock);
(snip)
smp_mb__after_clear_bit();
scan_mapping_unevictable_pages(file->f_mapping);
(snip)
out_nomem:
spin_unlock(&info->lock);
return retval;
}
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