Commit 12b98044 authored by KAMEZAWA Hiroyuki's avatar KAMEZAWA Hiroyuki Committed by Linus Torvalds

res_counter: limit change support ebusy

Add an interface to set limit.  This is necessary to memory resource
controller because it shrinks usage at set limit.

Other controllers may not need this interface to shrink usage because
shrinking is not necessary or impossible.
Acked-by: default avatarBalbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: default avatarPavel Emelyanov <xemul@openvz.org>
Signed-off-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent cede86ac
...@@ -158,4 +158,20 @@ static inline void res_counter_reset_failcnt(struct res_counter *cnt) ...@@ -158,4 +158,20 @@ static inline void res_counter_reset_failcnt(struct res_counter *cnt)
cnt->failcnt = 0; cnt->failcnt = 0;
spin_unlock_irqrestore(&cnt->lock, flags); spin_unlock_irqrestore(&cnt->lock, flags);
} }
static inline int res_counter_set_limit(struct res_counter *cnt,
unsigned long long limit)
{
unsigned long flags;
int ret = -EBUSY;
spin_lock_irqsave(&cnt->lock, flags);
if (cnt->usage < limit) {
cnt->limit = limit;
ret = 0;
}
spin_unlock_irqrestore(&cnt->lock, flags);
return ret;
}
#endif #endif
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