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Commit 20652ed6 authored by Ingo Molnar's avatar Ingo Molnar
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Merge branch 'for-mingo' of... 

Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu

Pull RCU fixes from Paul E. McKenney:

"This series adds a pair of commits that move function definitions
 from include/linux/rcu_segcblist.h to new kernel/rcu/rcu_segcblist.h
 and kernel/rcu/rcu_segcblist.c files, thus greatly decreasing the
 size of the externally visible include/linux/rcu_segcblist.h file."
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parents b5fe223a 933dfbd7
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include/linux/rcu_segcblist.h
View file @ 20652ed6
...@@ -20,8 +20,8 @@ ...@@ -20,8 +20,8 @@
* Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com> * Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
*/ */
#ifndef __KERNEL_RCU_SEGCBLIST_H #ifndef __INCLUDE_LINUX_RCU_SEGCBLIST_H
#define __KERNEL_RCU_SEGCBLIST_H #define __INCLUDE_LINUX_RCU_SEGCBLIST_H
/* Simple unsegmented callback lists. */ /* Simple unsegmented callback lists. */
struct rcu_cblist { struct rcu_cblist {
...@@ -33,102 +33,6 @@ struct rcu_cblist { ...@@ -33,102 +33,6 @@ struct rcu_cblist {
#define RCU_CBLIST_INITIALIZER(n) { .head = NULL, .tail = &n.head } #define RCU_CBLIST_INITIALIZER(n) { .head = NULL, .tail = &n.head }
/* Initialize simple callback list. */
static inline void rcu_cblist_init(struct rcu_cblist *rclp)
{
rclp->head = NULL;
rclp->tail = &rclp->head;
rclp->len = 0;
rclp->len_lazy = 0;
}
/* Is simple callback list empty? */
static inline bool rcu_cblist_empty(struct rcu_cblist *rclp)
{
return !rclp->head;
}
/* Return number of callbacks in simple callback list. */
static inline long rcu_cblist_n_cbs(struct rcu_cblist *rclp)
{
return rclp->len;
}
/* Return number of lazy callbacks in simple callback list. */
static inline long rcu_cblist_n_lazy_cbs(struct rcu_cblist *rclp)
{
return rclp->len_lazy;
}
/*
* Debug function to actually count the number of callbacks.
* If the number exceeds the limit specified, return -1.
*/
static inline long rcu_cblist_count_cbs(struct rcu_cblist *rclp, long lim)
{
int cnt = 0;
struct rcu_head **rhpp = &rclp->head;
for (;;) {
if (!*rhpp)
return cnt;
if (++cnt > lim)
return -1;
rhpp = &(*rhpp)->next;
}
}
/*
* Dequeue the oldest rcu_head structure from the specified callback
* list. This function assumes that the callback is non-lazy, but
* the caller can later invoke rcu_cblist_dequeued_lazy() if it
* finds otherwise (and if it cares about laziness). This allows
* different users to have different ways of determining laziness.
*/
static inline struct rcu_head *rcu_cblist_dequeue(struct rcu_cblist *rclp)
{
struct rcu_head *rhp;
rhp = rclp->head;
if (!rhp)
return NULL;
rclp->len--;
rclp->head = rhp->next;
if (!rclp->head)
rclp->tail = &rclp->head;
return rhp;
}
/*
* Account for the fact that a previously dequeued callback turned out
* to be marked as lazy.
*/
static inline void rcu_cblist_dequeued_lazy(struct rcu_cblist *rclp)
{
rclp->len_lazy--;
}
/*
* Interim function to return rcu_cblist head pointer. Longer term, the
* rcu_cblist will be used more pervasively, removing the need for this
* function.
*/
static inline struct rcu_head *rcu_cblist_head(struct rcu_cblist *rclp)
{
return rclp->head;
}
/*
* Interim function to return rcu_cblist head pointer. Longer term, the
* rcu_cblist will be used more pervasively, removing the need for this
* function.
*/
static inline struct rcu_head **rcu_cblist_tail(struct rcu_cblist *rclp)
{
WARN_ON_ONCE(rcu_cblist_empty(rclp));
return rclp->tail;
}
/* Complicated segmented callback lists. ;-) */ /* Complicated segmented callback lists. ;-) */
/* /*
...@@ -183,530 +87,4 @@ struct rcu_segcblist { ...@@ -183,530 +87,4 @@ struct rcu_segcblist {
.tails[RCU_NEXT_TAIL] = &n.head, \ .tails[RCU_NEXT_TAIL] = &n.head, \
} }
/* #endif /* __INCLUDE_LINUX_RCU_SEGCBLIST_H */
* Initialize an rcu_segcblist structure.
*/
static inline void rcu_segcblist_init(struct rcu_segcblist *rsclp)
{
int i;
BUILD_BUG_ON(RCU_NEXT_TAIL + 1 != ARRAY_SIZE(rsclp->gp_seq));
BUILD_BUG_ON(ARRAY_SIZE(rsclp->tails) != ARRAY_SIZE(rsclp->gp_seq));
rsclp->head = NULL;
for (i = 0; i < RCU_CBLIST_NSEGS; i++)
rsclp->tails[i] = &rsclp->head;
rsclp->len = 0;
rsclp->len_lazy = 0;
}
/*
* Is the specified rcu_segcblist structure empty?
*
* But careful! The fact that the ->head field is NULL does not
* necessarily imply that there are no callbacks associated with
* this structure. When callbacks are being invoked, they are
* removed as a group. If callback invocation must be preempted,
* the remaining callbacks will be added back to the list. Either
* way, the counts are updated later.
*
* So it is often the case that rcu_segcblist_n_cbs() should be used
* instead.
*/
static inline bool rcu_segcblist_empty(struct rcu_segcblist *rsclp)
{
return !rsclp->head;
}
/* Return number of callbacks in segmented callback list. */
static inline long rcu_segcblist_n_cbs(struct rcu_segcblist *rsclp)
{
return READ_ONCE(rsclp->len);
}
/* Return number of lazy callbacks in segmented callback list. */
static inline long rcu_segcblist_n_lazy_cbs(struct rcu_segcblist *rsclp)
{
return rsclp->len_lazy;
}
/* Return number of lazy callbacks in segmented callback list. */
static inline long rcu_segcblist_n_nonlazy_cbs(struct rcu_segcblist *rsclp)
{
return rsclp->len - rsclp->len_lazy;
}
/*
* Is the specified rcu_segcblist enabled, for example, not corresponding
* to an offline or callback-offloaded CPU?
*/
static inline bool rcu_segcblist_is_enabled(struct rcu_segcblist *rsclp)
{
return !!rsclp->tails[RCU_NEXT_TAIL];
}
/*
* Disable the specified rcu_segcblist structure, so that callbacks can
* no longer be posted to it. This structure must be empty.
*/
static inline void rcu_segcblist_disable(struct rcu_segcblist *rsclp)
{
WARN_ON_ONCE(!rcu_segcblist_empty(rsclp));
WARN_ON_ONCE(rcu_segcblist_n_cbs(rsclp));
WARN_ON_ONCE(rcu_segcblist_n_lazy_cbs(rsclp));
rsclp->tails[RCU_NEXT_TAIL] = NULL;
}
/*
* Is the specified segment of the specified rcu_segcblist structure
* empty of callbacks?
*/
static inline bool rcu_segcblist_segempty(struct rcu_segcblist *rsclp, int seg)
{
if (seg == RCU_DONE_TAIL)
return &rsclp->head == rsclp->tails[RCU_DONE_TAIL];
return rsclp->tails[seg - 1] == rsclp->tails[seg];
}
/*
* Are all segments following the specified segment of the specified
* rcu_segcblist structure empty of callbacks? (The specified
* segment might well contain callbacks.)
*/
static inline bool rcu_segcblist_restempty(struct rcu_segcblist *rsclp, int seg)
{
return !*rsclp->tails[seg];
}
/*
* Does the specified rcu_segcblist structure contain callbacks that
* are ready to be invoked?
*/
static inline bool rcu_segcblist_ready_cbs(struct rcu_segcblist *rsclp)
{
return rcu_segcblist_is_enabled(rsclp) &&
&rsclp->head != rsclp->tails[RCU_DONE_TAIL];
}
/*
* Does the specified rcu_segcblist structure contain callbacks that
* are still pending, that is, not yet ready to be invoked?
*/
static inline bool rcu_segcblist_pend_cbs(struct rcu_segcblist *rsclp)
{
return rcu_segcblist_is_enabled(rsclp) &&
!rcu_segcblist_restempty(rsclp, RCU_DONE_TAIL);
}
/*
* Dequeue and return the first ready-to-invoke callback. If there
* are no ready-to-invoke callbacks, return NULL. Disables interrupts
* to avoid interference. Does not protect from interference from other
* CPUs or tasks.
*/
static inline struct rcu_head *
rcu_segcblist_dequeue(struct rcu_segcblist *rsclp)
{
unsigned long flags;
int i;
struct rcu_head *rhp;
local_irq_save(flags);
if (!rcu_segcblist_ready_cbs(rsclp)) {
local_irq_restore(flags);
return NULL;
}
rhp = rsclp->head;
BUG_ON(!rhp);
rsclp->head = rhp->next;
for (i = RCU_DONE_TAIL; i < RCU_CBLIST_NSEGS; i++) {
if (rsclp->tails[i] != &rhp->next)
break;
rsclp->tails[i] = &rsclp->head;
}
smp_mb(); /* Dequeue before decrement for rcu_barrier(). */
WRITE_ONCE(rsclp->len, rsclp->len - 1);
local_irq_restore(flags);
return rhp;
}
/*
* Account for the fact that a previously dequeued callback turned out
* to be marked as lazy.
*/
static inline void rcu_segcblist_dequeued_lazy(struct rcu_segcblist *rsclp)
{
unsigned long flags;
local_irq_save(flags);
rsclp->len_lazy--;
local_irq_restore(flags);
}
/*
* Return a pointer to the first callback in the specified rcu_segcblist
* structure. This is useful for diagnostics.
*/
static inline struct rcu_head *
rcu_segcblist_first_cb(struct rcu_segcblist *rsclp)
{
if (rcu_segcblist_is_enabled(rsclp))
return rsclp->head;
return NULL;
}
/*
* Return a pointer to the first pending callback in the specified
* rcu_segcblist structure. This is useful just after posting a given
* callback -- if that callback is the first pending callback, then
* you cannot rely on someone else having already started up the required
* grace period.
*/
static inline struct rcu_head *
rcu_segcblist_first_pend_cb(struct rcu_segcblist *rsclp)
{
if (rcu_segcblist_is_enabled(rsclp))
return *rsclp->tails[RCU_DONE_TAIL];
return NULL;
}
/*
* Does the specified rcu_segcblist structure contain callbacks that
* have not yet been processed beyond having been posted, that is,
* does it contain callbacks in its last segment?
*/
static inline bool rcu_segcblist_new_cbs(struct rcu_segcblist *rsclp)
{
return rcu_segcblist_is_enabled(rsclp) &&
!rcu_segcblist_restempty(rsclp, RCU_NEXT_READY_TAIL);
}
/*
* Enqueue the specified callback onto the specified rcu_segcblist
* structure, updating accounting as needed. Note that the ->len
* field may be accessed locklessly, hence the WRITE_ONCE().
* The ->len field is used by rcu_barrier() and friends to determine
* if it must post a callback on this structure, and it is OK
* for rcu_barrier() to sometimes post callbacks needlessly, but
* absolutely not OK for it to ever miss posting a callback.
*/
static inline void rcu_segcblist_enqueue(struct rcu_segcblist *rsclp,
struct rcu_head *rhp, bool lazy)
{
WRITE_ONCE(rsclp->len, rsclp->len + 1); /* ->len sampled locklessly. */
if (lazy)
rsclp->len_lazy++;
smp_mb(); /* Ensure counts are updated before callback is enqueued. */
rhp->next = NULL;
*rsclp->tails[RCU_NEXT_TAIL] = rhp;
rsclp->tails[RCU_NEXT_TAIL] = &rhp->next;
}
/*
* Entrain the specified callback onto the specified rcu_segcblist at
* the end of the last non-empty segment. If the entire rcu_segcblist
* is empty, make no change, but return false.
*
* This is intended for use by rcu_barrier()-like primitives, -not-
* for normal grace-period use. IMPORTANT: The callback you enqueue
* will wait for all prior callbacks, NOT necessarily for a grace
* period. You have been warned.
*/
static inline bool rcu_segcblist_entrain(struct rcu_segcblist *rsclp,
struct rcu_head *rhp, bool lazy)
{
int i;
if (rcu_segcblist_n_cbs(rsclp) == 0)
return false;
WRITE_ONCE(rsclp->len, rsclp->len + 1);
if (lazy)
rsclp->len_lazy++;
smp_mb(); /* Ensure counts are updated before callback is entrained. */
rhp->next = NULL;
for (i = RCU_NEXT_TAIL; i > RCU_DONE_TAIL; i--)
if (rsclp->tails[i] != rsclp->tails[i - 1])
break;
*rsclp->tails[i] = rhp;
for (; i <= RCU_NEXT_TAIL; i++)
rsclp->tails[i] = &rhp->next;
return true;
}
/*
* Extract only the counts from the specified rcu_segcblist structure,
* and place them in the specified rcu_cblist structure. This function
* supports both callback orphaning and invocation, hence the separation
* of counts and callbacks. (Callbacks ready for invocation must be
* orphaned and adopted separately from pending callbacks, but counts
* apply to all callbacks. Locking must be used to make sure that
* both orphaned-callbacks lists are consistent.)
*/
static inline void rcu_segcblist_extract_count(struct rcu_segcblist *rsclp,
struct rcu_cblist *rclp)
{
rclp->len_lazy += rsclp->len_lazy;
rclp->len += rsclp->len;
rsclp->len_lazy = 0;
WRITE_ONCE(rsclp->len, 0); /* ->len sampled locklessly. */
}
/*
* Extract only those callbacks ready to be invoked from the specified
* rcu_segcblist structure and place them in the specified rcu_cblist
* structure.
*/
static inline void rcu_segcblist_extract_done_cbs(struct rcu_segcblist *rsclp,
struct rcu_cblist *rclp)
{
int i;
if (!rcu_segcblist_ready_cbs(rsclp))
return; /* Nothing to do. */
*rclp->tail = rsclp->head;
rsclp->head = *rsclp->tails[RCU_DONE_TAIL];
*rsclp->tails[RCU_DONE_TAIL] = NULL;
rclp->tail = rsclp->tails[RCU_DONE_TAIL];
for (i = RCU_CBLIST_NSEGS - 1; i >= RCU_DONE_TAIL; i--)
if (rsclp->tails[i] == rsclp->tails[RCU_DONE_TAIL])
rsclp->tails[i] = &rsclp->head;
}
/*
* Extract only those callbacks still pending (not yet ready to be
* invoked) from the specified rcu_segcblist structure and place them in
* the specified rcu_cblist structure. Note that this loses information
* about any callbacks that might have been partway done waiting for
* their grace period. Too bad! They will have to start over.
*/
static inline void
rcu_segcblist_extract_pend_cbs(struct rcu_segcblist *rsclp,
struct rcu_cblist *rclp)
{
int i;
if (!rcu_segcblist_pend_cbs(rsclp))
return; /* Nothing to do. */
*rclp->tail = *rsclp->tails[RCU_DONE_TAIL];
rclp->tail = rsclp->tails[RCU_NEXT_TAIL];
*rsclp->tails[RCU_DONE_TAIL] = NULL;
for (i = RCU_DONE_TAIL + 1; i < RCU_CBLIST_NSEGS; i++)
rsclp->tails[i] = rsclp->tails[RCU_DONE_TAIL];
}
/*
* Move the entire contents of the specified rcu_segcblist structure,
* counts, callbacks, and all, to the specified rcu_cblist structure.
* @@@ Why do we need this??? Moving early-boot CBs to NOCB lists?
* @@@ Memory barrier needed? (Not if only used at boot time...)
*/
static inline void rcu_segcblist_extract_all(struct rcu_segcblist *rsclp,
struct rcu_cblist *rclp)
{
rcu_segcblist_extract_done_cbs(rsclp, rclp);
rcu_segcblist_extract_pend_cbs(rsclp, rclp);
rcu_segcblist_extract_count(rsclp, rclp);
}
/*
* Insert counts from the specified rcu_cblist structure in the
* specified rcu_segcblist structure.
*/
static inline void rcu_segcblist_insert_count(struct rcu_segcblist *rsclp,
struct rcu_cblist *rclp)
{
rsclp->len_lazy += rclp->len_lazy;
/* ->len sampled locklessly. */
WRITE_ONCE(rsclp->len, rsclp->len + rclp->len);
rclp->len_lazy = 0;
rclp->len = 0;
}
/*
* Move callbacks from the specified rcu_cblist to the beginning of the
* done-callbacks segment of the specified rcu_segcblist.
*/
static inline void rcu_segcblist_insert_done_cbs(struct rcu_segcblist *rsclp,
struct rcu_cblist *rclp)
{
int i;
if (!rclp->head)
return; /* No callbacks to move. */
*rclp->tail = rsclp->head;
rsclp->head = rclp->head;
for (i = RCU_DONE_TAIL; i < RCU_CBLIST_NSEGS; i++)
if (&rsclp->head == rsclp->tails[i])
rsclp->tails[i] = rclp->tail;
else
break;
rclp->head = NULL;
rclp->tail = &rclp->head;
}
/*
* Move callbacks from the specified rcu_cblist to the end of the
* new-callbacks segment of the specified rcu_segcblist.
*/
static inline void rcu_segcblist_insert_pend_cbs(struct rcu_segcblist *rsclp,
struct rcu_cblist *rclp)
{
if (!rclp->head)
return; /* Nothing to do. */
*rsclp->tails[RCU_NEXT_TAIL] = rclp->head;
rsclp->tails[RCU_NEXT_TAIL] = rclp->tail;
rclp->head = NULL;
rclp->tail = &rclp->head;
}
/*
* Advance the callbacks in the specified rcu_segcblist structure based
* on the current value passed in for the grace-period counter.
*/
static inline void rcu_segcblist_advance(struct rcu_segcblist *rsclp,
unsigned long seq)
{
int i, j;
WARN_ON_ONCE(!rcu_segcblist_is_enabled(rsclp));
if (rcu_segcblist_restempty(rsclp, RCU_DONE_TAIL))
return;
/*
* Find all callbacks whose ->gp_seq numbers indicate that they
* are ready to invoke, and put them into the RCU_DONE_TAIL segment.
*/
for (i = RCU_WAIT_TAIL; i < RCU_NEXT_TAIL; i++) {
if (ULONG_CMP_LT(seq, rsclp->gp_seq[i]))
break;
rsclp->tails[RCU_DONE_TAIL] = rsclp->tails[i];
}
/* If no callbacks moved, nothing more need be done. */
if (i == RCU_WAIT_TAIL)
return;
/* Clean up tail pointers that might have been misordered above. */
for (j = RCU_WAIT_TAIL; j < i; j++)
rsclp->tails[j] = rsclp->tails[RCU_DONE_TAIL];
/*
* Callbacks moved, so clean up the misordered ->tails[] pointers
* that now point into the middle of the list of ready-to-invoke
* callbacks. The overall effect is to copy down the later pointers
* into the gap that was created by the now-ready segments.
*/
for (j = RCU_WAIT_TAIL; i < RCU_NEXT_TAIL; i++, j++) {
if (rsclp->tails[j] == rsclp->tails[RCU_NEXT_TAIL])
break; /* No more callbacks. */
rsclp->tails[j] = rsclp->tails[i];
rsclp->gp_seq[j] = rsclp->gp_seq[i];
}
}
/*
* "Accelerate" callbacks based on more-accurate grace-period information.
* The reason for this is that RCU does not synchronize the beginnings and
* ends of grace periods, and that callbacks are posted locally. This in
* turn means that the callbacks must be labelled conservatively early
* on, as getting exact information would degrade both performance and
* scalability. When more accurate grace-period information becomes
* available, previously posted callbacks can be "accelerated", marking
* them to complete at the end of the earlier grace period.
*
* This function operates on an rcu_segcblist structure, and also the
* grace-period sequence number seq at which new callbacks would become
* ready to invoke. Returns true if there are callbacks that won't be
* ready to invoke until seq, false otherwise.
*/
static inline bool rcu_segcblist_accelerate(struct rcu_segcblist *rsclp,
unsigned long seq)
{
int i;
WARN_ON_ONCE(!rcu_segcblist_is_enabled(rsclp));
if (rcu_segcblist_restempty(rsclp, RCU_DONE_TAIL))
return false;
/*
* Find the segment preceding the oldest segment of callbacks
* whose ->gp_seq[] completion is at or after that passed in via
* "seq", skipping any empty segments. This oldest segment, along
* with any later segments, can be merged in with any newly arrived
* callbacks in the RCU_NEXT_TAIL segment, and assigned "seq"
* as their ->gp_seq[] grace-period completion sequence number.
*/
for (i = RCU_NEXT_READY_TAIL; i > RCU_DONE_TAIL; i--)
if (rsclp->tails[i] != rsclp->tails[i - 1] &&
ULONG_CMP_LT(rsclp->gp_seq[i], seq))
break;
/*
* If all the segments contain callbacks that correspond to
* earlier grace-period sequence numbers than "seq", leave.
* Assuming that the rcu_segcblist structure has enough
* segments in its arrays, this can only happen if some of
* the non-done segments contain callbacks that really are
* ready to invoke. This situation will get straightened
* out by the next call to rcu_segcblist_advance().
*
* Also advance to the oldest segment of callbacks whose
* ->gp_seq[] completion is at or after that passed in via "seq",
* skipping any empty segments.
*/
if (++i >= RCU_NEXT_TAIL)
return false;
/*
* Merge all later callbacks, including newly arrived callbacks,
* into the segment located by the for-loop above. Assign "seq"
* as the ->gp_seq[] value in order to correctly handle the case
* where there were no pending callbacks in the rcu_segcblist
* structure other than in the RCU_NEXT_TAIL segment.
*/
for (; i < RCU_NEXT_TAIL; i++) {
rsclp->tails[i] = rsclp->tails[RCU_NEXT_TAIL];
rsclp->gp_seq[i] = seq;
}
return true;
}
/*
* Scan the specified rcu_segcblist structure for callbacks that need
* a grace period later than the one specified by "seq". We don't look
* at the RCU_DONE_TAIL or RCU_NEXT_TAIL segments because they don't
* have a grace-period sequence number.
*/
static inline bool rcu_segcblist_future_gp_needed(struct rcu_segcblist *rsclp,
unsigned long seq)
{
int i;
for (i = RCU_WAIT_TAIL; i < RCU_NEXT_TAIL; i++)
if (rsclp->tails[i - 1] != rsclp->tails[i] &&
ULONG_CMP_LT(seq, rsclp->gp_seq[i]))
return true;
return false;
}
/*
* Interim function to return rcu_segcblist head pointer. Longer term, the
* rcu_segcblist will be used more pervasively, removing the need for this
* function.
*/
static inline struct rcu_head *rcu_segcblist_head(struct rcu_segcblist *rsclp)
{
return rsclp->head;
}
/*
* Interim function to return rcu_segcblist head pointer. Longer term, the
* rcu_segcblist will be used more pervasively, removing the need for this
* function.
*/
static inline struct rcu_head **rcu_segcblist_tail(struct rcu_segcblist *rsclp)
{
WARN_ON_ONCE(rcu_segcblist_empty(rsclp));
return rsclp->tails[RCU_NEXT_TAIL];
}
#endif /* __KERNEL_RCU_SEGCBLIST_H */
init/Kconfig
View file @ 20652ed6
...@@ -573,6 +573,9 @@ config RCU_STALL_COMMON ...@@ -573,6 +573,9 @@ config RCU_STALL_COMMON
the tiny variants to disable RCU CPU stall warnings, while the tiny variants to disable RCU CPU stall warnings, while
making these warnings mandatory for the tree variants. making these warnings mandatory for the tree variants.
config RCU_NEED_SEGCBLIST
def_bool ( TREE_RCU || PREEMPT_RCU || TINY_SRCU || TREE_SRCU )
config CONTEXT_TRACKING config CONTEXT_TRACKING
bool bool
......
kernel/rcu/Makefile
View file @ 20652ed6
...@@ -12,3 +12,4 @@ obj-$(CONFIG_TREE_RCU) += tree.o ...@@ -12,3 +12,4 @@ obj-$(CONFIG_TREE_RCU) += tree.o
obj-$(CONFIG_PREEMPT_RCU) += tree.o obj-$(CONFIG_PREEMPT_RCU) += tree.o
obj-$(CONFIG_TREE_RCU_TRACE) += tree_trace.o obj-$(CONFIG_TREE_RCU_TRACE) += tree_trace.o
obj-$(CONFIG_TINY_RCU) += tiny.o obj-$(CONFIG_TINY_RCU) += tiny.o
obj-$(CONFIG_RCU_NEED_SEGCBLIST) += rcu_segcblist.o
kernel/rcu/rcu_segcblist.c 0 → 100644
View file @ 20652ed6
/*
* RCU segmented callback lists, function definitions
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, you can access it online at
* http://www.gnu.org/licenses/gpl-2.0.html.
*
* Copyright IBM Corporation, 2017
*
* Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include "rcu_segcblist.h"
/* Initialize simple callback list. */
void rcu_cblist_init(struct rcu_cblist *rclp)
{
rclp->head = NULL;
rclp->tail = &rclp->head;
rclp->len = 0;
rclp->len_lazy = 0;
}
/*
* Debug function to actually count the number of callbacks.
* If the number exceeds the limit specified, return -1.
*/
long rcu_cblist_count_cbs(struct rcu_cblist *rclp, long lim)
{
int cnt = 0;
struct rcu_head **rhpp = &rclp->head;
for (;;) {
if (!*rhpp)
return cnt;
if (++cnt > lim)
return -1;
rhpp = &(*rhpp)->next;
}
}
/*
* Dequeue the oldest rcu_head structure from the specified callback
* list. This function assumes that the callback is non-lazy, but
* the caller can later invoke rcu_cblist_dequeued_lazy() if it
* finds otherwise (and if it cares about laziness). This allows
* different users to have different ways of determining laziness.
*/
struct rcu_head *rcu_cblist_dequeue(struct rcu_cblist *rclp)
{
struct rcu_head *rhp;
rhp = rclp->head;
if (!rhp)
return NULL;
rclp->len--;
rclp->head = rhp->next;
if (!rclp->head)
rclp->tail = &rclp->head;
return rhp;
}
/*
* Initialize an rcu_segcblist structure.
*/
void rcu_segcblist_init(struct rcu_segcblist *rsclp)
{
int i;
BUILD_BUG_ON(RCU_NEXT_TAIL + 1 != ARRAY_SIZE(rsclp->gp_seq));
BUILD_BUG_ON(ARRAY_SIZE(rsclp->tails) != ARRAY_SIZE(rsclp->gp_seq));
rsclp->head = NULL;
for (i = 0; i < RCU_CBLIST_NSEGS; i++)
rsclp->tails[i] = &rsclp->head;
rsclp->len = 0;
rsclp->len_lazy = 0;
}
/*
* Disable the specified rcu_segcblist structure, so that callbacks can
* no longer be posted to it. This structure must be empty.
*/
void rcu_segcblist_disable(struct rcu_segcblist *rsclp)
{
WARN_ON_ONCE(!rcu_segcblist_empty(rsclp));
WARN_ON_ONCE(rcu_segcblist_n_cbs(rsclp));
WARN_ON_ONCE(rcu_segcblist_n_lazy_cbs(rsclp));
rsclp->tails[RCU_NEXT_TAIL] = NULL;
}
/*
* Is the specified segment of the specified rcu_segcblist structure
* empty of callbacks?
*/
bool rcu_segcblist_segempty(struct rcu_segcblist *rsclp, int seg)
{
if (seg == RCU_DONE_TAIL)
return &rsclp->head == rsclp->tails[RCU_DONE_TAIL];
return rsclp->tails[seg - 1] == rsclp->tails[seg];
}
/*
* Does the specified rcu_segcblist structure contain callbacks that
* are ready to be invoked?
*/
bool rcu_segcblist_ready_cbs(struct rcu_segcblist *rsclp)
{
return rcu_segcblist_is_enabled(rsclp) &&
&rsclp->head != rsclp->tails[RCU_DONE_TAIL];
}
/*
* Does the specified rcu_segcblist structure contain callbacks that
* are still pending, that is, not yet ready to be invoked?
*/
bool rcu_segcblist_pend_cbs(struct rcu_segcblist *rsclp)
{
return rcu_segcblist_is_enabled(rsclp) &&
!rcu_segcblist_restempty(rsclp, RCU_DONE_TAIL);
}
/*
* Dequeue and return the first ready-to-invoke callback. If there
* are no ready-to-invoke callbacks, return NULL. Disables interrupts
* to avoid interference. Does not protect from interference from other
* CPUs or tasks.
*/
struct rcu_head *rcu_segcblist_dequeue(struct rcu_segcblist *rsclp)
{
unsigned long flags;
int i;
struct rcu_head *rhp;
local_irq_save(flags);
if (!rcu_segcblist_ready_cbs(rsclp)) {
local_irq_restore(flags);
return NULL;
}
rhp = rsclp->head;
BUG_ON(!rhp);
rsclp->head = rhp->next;
for (i = RCU_DONE_TAIL; i < RCU_CBLIST_NSEGS; i++) {
if (rsclp->tails[i] != &rhp->next)
break;
rsclp->tails[i] = &rsclp->head;
}
smp_mb(); /* Dequeue before decrement for rcu_barrier(). */
WRITE_ONCE(rsclp->len, rsclp->len - 1);
local_irq_restore(flags);
return rhp;
}
/*
* Account for the fact that a previously dequeued callback turned out
* to be marked as lazy.
*/
void rcu_segcblist_dequeued_lazy(struct rcu_segcblist *rsclp)
{
unsigned long flags;
local_irq_save(flags);
rsclp->len_lazy--;
local_irq_restore(flags);
}
/*
* Return a pointer to the first callback in the specified rcu_segcblist
* structure. This is useful for diagnostics.
*/
struct rcu_head *rcu_segcblist_first_cb(struct rcu_segcblist *rsclp)
{
if (rcu_segcblist_is_enabled(rsclp))
return rsclp->head;
return NULL;
}
/*
* Return a pointer to the first pending callback in the specified
* rcu_segcblist structure. This is useful just after posting a given
* callback -- if that callback is the first pending callback, then
* you cannot rely on someone else having already started up the required
* grace period.
*/
struct rcu_head *rcu_segcblist_first_pend_cb(struct rcu_segcblist *rsclp)
{
if (rcu_segcblist_is_enabled(rsclp))
return *rsclp->tails[RCU_DONE_TAIL];
return NULL;
}
/*
* Does the specified rcu_segcblist structure contain callbacks that
* have not yet been processed beyond having been posted, that is,
* does it contain callbacks in its last segment?
*/
bool rcu_segcblist_new_cbs(struct rcu_segcblist *rsclp)
{
return rcu_segcblist_is_enabled(rsclp) &&
!rcu_segcblist_restempty(rsclp, RCU_NEXT_READY_TAIL);
}
/*
* Enqueue the specified callback onto the specified rcu_segcblist
* structure, updating accounting as needed. Note that the ->len
* field may be accessed locklessly, hence the WRITE_ONCE().
* The ->len field is used by rcu_barrier() and friends to determine
* if it must post a callback on this structure, and it is OK
* for rcu_barrier() to sometimes post callbacks needlessly, but
* absolutely not OK for it to ever miss posting a callback.
*/
void rcu_segcblist_enqueue(struct rcu_segcblist *rsclp,
struct rcu_head *rhp, bool lazy)
{
WRITE_ONCE(rsclp->len, rsclp->len + 1); /* ->len sampled locklessly. */
if (lazy)
rsclp->len_lazy++;
smp_mb(); /* Ensure counts are updated before callback is enqueued. */
rhp->next = NULL;
*rsclp->tails[RCU_NEXT_TAIL] = rhp;
rsclp->tails[RCU_NEXT_TAIL] = &rhp->next;
}
/*
* Entrain the specified callback onto the specified rcu_segcblist at
* the end of the last non-empty segment. If the entire rcu_segcblist
* is empty, make no change, but return false.
*
* This is intended for use by rcu_barrier()-like primitives, -not-
* for normal grace-period use. IMPORTANT: The callback you enqueue
* will wait for all prior callbacks, NOT necessarily for a grace
* period. You have been warned.
*/
bool rcu_segcblist_entrain(struct rcu_segcblist *rsclp,
struct rcu_head *rhp, bool lazy)
{
int i;
if (rcu_segcblist_n_cbs(rsclp) == 0)
return false;
WRITE_ONCE(rsclp->len, rsclp->len + 1);
if (lazy)
rsclp->len_lazy++;
smp_mb(); /* Ensure counts are updated before callback is entrained. */
rhp->next = NULL;
for (i = RCU_NEXT_TAIL; i > RCU_DONE_TAIL; i--)
if (rsclp->tails[i] != rsclp->tails[i - 1])
break;
*rsclp->tails[i] = rhp;
for (; i <= RCU_NEXT_TAIL; i++)
rsclp->tails[i] = &rhp->next;
return true;
}
/*
* Extract only the counts from the specified rcu_segcblist structure,
* and place them in the specified rcu_cblist structure. This function
* supports both callback orphaning and invocation, hence the separation
* of counts and callbacks. (Callbacks ready for invocation must be
* orphaned and adopted separately from pending callbacks, but counts
* apply to all callbacks. Locking must be used to make sure that
* both orphaned-callbacks lists are consistent.)
*/
void rcu_segcblist_extract_count(struct rcu_segcblist *rsclp,
struct rcu_cblist *rclp)
{
rclp->len_lazy += rsclp->len_lazy;
rclp->len += rsclp->len;
rsclp->len_lazy = 0;
WRITE_ONCE(rsclp->len, 0); /* ->len sampled locklessly. */
}
/*
* Extract only those callbacks ready to be invoked from the specified
* rcu_segcblist structure and place them in the specified rcu_cblist
* structure.
*/
void rcu_segcblist_extract_done_cbs(struct rcu_segcblist *rsclp,
struct rcu_cblist *rclp)
{
int i;
if (!rcu_segcblist_ready_cbs(rsclp))
return; /* Nothing to do. */
*rclp->tail = rsclp->head;
rsclp->head = *rsclp->tails[RCU_DONE_TAIL];
*rsclp->tails[RCU_DONE_TAIL] = NULL;
rclp->tail = rsclp->tails[RCU_DONE_TAIL];
for (i = RCU_CBLIST_NSEGS - 1; i >= RCU_DONE_TAIL; i--)
if (rsclp->tails[i] == rsclp->tails[RCU_DONE_TAIL])
rsclp->tails[i] = &rsclp->head;
}
/*
* Extract only those callbacks still pending (not yet ready to be
* invoked) from the specified rcu_segcblist structure and place them in
* the specified rcu_cblist structure. Note that this loses information
* about any callbacks that might have been partway done waiting for
* their grace period. Too bad! They will have to start over.
*/
void rcu_segcblist_extract_pend_cbs(struct rcu_segcblist *rsclp,
struct rcu_cblist *rclp)
{
int i;
if (!rcu_segcblist_pend_cbs(rsclp))
return; /* Nothing to do. */
*rclp->tail = *rsclp->tails[RCU_DONE_TAIL];
rclp->tail = rsclp->tails[RCU_NEXT_TAIL];
*rsclp->tails[RCU_DONE_TAIL] = NULL;
for (i = RCU_DONE_TAIL + 1; i < RCU_CBLIST_NSEGS; i++)
rsclp->tails[i] = rsclp->tails[RCU_DONE_TAIL];
}
/*
* Insert counts from the specified rcu_cblist structure in the
* specified rcu_segcblist structure.
*/
void rcu_segcblist_insert_count(struct rcu_segcblist *rsclp,
struct rcu_cblist *rclp)
{
rsclp->len_lazy += rclp->len_lazy;
/* ->len sampled locklessly. */
WRITE_ONCE(rsclp->len, rsclp->len + rclp->len);
rclp->len_lazy = 0;
rclp->len = 0;
}
/*
* Move callbacks from the specified rcu_cblist to the beginning of the
* done-callbacks segment of the specified rcu_segcblist.
*/
void rcu_segcblist_insert_done_cbs(struct rcu_segcblist *rsclp,
struct rcu_cblist *rclp)
{
int i;
if (!rclp->head)
return; /* No callbacks to move. */
*rclp->tail = rsclp->head;
rsclp->head = rclp->head;
for (i = RCU_DONE_TAIL; i < RCU_CBLIST_NSEGS; i++)
if (&rsclp->head == rsclp->tails[i])
rsclp->tails[i] = rclp->tail;
else
break;
rclp->head = NULL;
rclp->tail = &rclp->head;
}
/*
* Move callbacks from the specified rcu_cblist to the end of the
* new-callbacks segment of the specified rcu_segcblist.
*/
void rcu_segcblist_insert_pend_cbs(struct rcu_segcblist *rsclp,
struct rcu_cblist *rclp)
{
if (!rclp->head)
return; /* Nothing to do. */
*rsclp->tails[RCU_NEXT_TAIL] = rclp->head;
rsclp->tails[RCU_NEXT_TAIL] = rclp->tail;
rclp->head = NULL;
rclp->tail = &rclp->head;
}
/*
* Advance the callbacks in the specified rcu_segcblist structure based
* on the current value passed in for the grace-period counter.
*/
void rcu_segcblist_advance(struct rcu_segcblist *rsclp, unsigned long seq)
{
int i, j;
WARN_ON_ONCE(!rcu_segcblist_is_enabled(rsclp));
if (rcu_segcblist_restempty(rsclp, RCU_DONE_TAIL))
return;
/*
* Find all callbacks whose ->gp_seq numbers indicate that they
* are ready to invoke, and put them into the RCU_DONE_TAIL segment.
*/
for (i = RCU_WAIT_TAIL; i < RCU_NEXT_TAIL; i++) {
if (ULONG_CMP_LT(seq, rsclp->gp_seq[i]))
break;
rsclp->tails[RCU_DONE_TAIL] = rsclp->tails[i];
}
/* If no callbacks moved, nothing more need be done. */
if (i == RCU_WAIT_TAIL)
return;
/* Clean up tail pointers that might have been misordered above. */
for (j = RCU_WAIT_TAIL; j < i; j++)
rsclp->tails[j] = rsclp->tails[RCU_DONE_TAIL];
/*
* Callbacks moved, so clean up the misordered ->tails[] pointers
* that now point into the middle of the list of ready-to-invoke
* callbacks. The overall effect is to copy down the later pointers
* into the gap that was created by the now-ready segments.
*/
for (j = RCU_WAIT_TAIL; i < RCU_NEXT_TAIL; i++, j++) {
if (rsclp->tails[j] == rsclp->tails[RCU_NEXT_TAIL])
break; /* No more callbacks. */
rsclp->tails[j] = rsclp->tails[i];
rsclp->gp_seq[j] = rsclp->gp_seq[i];
}
}
/*
* "Accelerate" callbacks based on more-accurate grace-period information.
* The reason for this is that RCU does not synchronize the beginnings and
* ends of grace periods, and that callbacks are posted locally. This in
* turn means that the callbacks must be labelled conservatively early
* on, as getting exact information would degrade both performance and
* scalability. When more accurate grace-period information becomes
* available, previously posted callbacks can be "accelerated", marking
* them to complete at the end of the earlier grace period.
*
* This function operates on an rcu_segcblist structure, and also the
* grace-period sequence number seq at which new callbacks would become
* ready to invoke. Returns true if there are callbacks that won't be
* ready to invoke until seq, false otherwise.
*/
bool rcu_segcblist_accelerate(struct rcu_segcblist *rsclp, unsigned long seq)
{
int i;
WARN_ON_ONCE(!rcu_segcblist_is_enabled(rsclp));
if (rcu_segcblist_restempty(rsclp, RCU_DONE_TAIL))
return false;
/*
* Find the segment preceding the oldest segment of callbacks
* whose ->gp_seq[] completion is at or after that passed in via
* "seq", skipping any empty segments. This oldest segment, along
* with any later segments, can be merged in with any newly arrived
* callbacks in the RCU_NEXT_TAIL segment, and assigned "seq"
* as their ->gp_seq[] grace-period completion sequence number.
*/
for (i = RCU_NEXT_READY_TAIL; i > RCU_DONE_TAIL; i--)
if (rsclp->tails[i] != rsclp->tails[i - 1] &&
ULONG_CMP_LT(rsclp->gp_seq[i], seq))
break;
/*
* If all the segments contain callbacks that correspond to
* earlier grace-period sequence numbers than "seq", leave.
* Assuming that the rcu_segcblist structure has enough
* segments in its arrays, this can only happen if some of
* the non-done segments contain callbacks that really are
* ready to invoke. This situation will get straightened
* out by the next call to rcu_segcblist_advance().
*
* Also advance to the oldest segment of callbacks whose
* ->gp_seq[] completion is at or after that passed in via "seq",
* skipping any empty segments.
*/
if (++i >= RCU_NEXT_TAIL)
return false;
/*
* Merge all later callbacks, including newly arrived callbacks,
* into the segment located by the for-loop above. Assign "seq"
* as the ->gp_seq[] value in order to correctly handle the case
* where there were no pending callbacks in the rcu_segcblist
* structure other than in the RCU_NEXT_TAIL segment.
*/
for (; i < RCU_NEXT_TAIL; i++) {
rsclp->tails[i] = rsclp->tails[RCU_NEXT_TAIL];
rsclp->gp_seq[i] = seq;
}
return true;
}
/*
* Scan the specified rcu_segcblist structure for callbacks that need
* a grace period later than the one specified by "seq". We don't look
* at the RCU_DONE_TAIL or RCU_NEXT_TAIL segments because they don't
* have a grace-period sequence number.
*/
bool rcu_segcblist_future_gp_needed(struct rcu_segcblist *rsclp,
unsigned long seq)
{
int i;
for (i = RCU_WAIT_TAIL; i < RCU_NEXT_TAIL; i++)
if (rsclp->tails[i - 1] != rsclp->tails[i] &&
ULONG_CMP_LT(seq, rsclp->gp_seq[i]))
return true;
return false;
}
kernel/rcu/rcu_segcblist.h 0 → 100644
View file @ 20652ed6
/*
* RCU segmented callback lists, internal-to-rcu header file
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, you can access it online at
* http://www.gnu.org/licenses/gpl-2.0.html.
*
* Copyright IBM Corporation, 2017
*
* Authors: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
*/
#include <linux/rcu_segcblist.h>
/*
* Account for the fact that a previously dequeued callback turned out
* to be marked as lazy.
*/
static inline void rcu_cblist_dequeued_lazy(struct rcu_cblist *rclp)
{
rclp->len_lazy--;
}
/*
* Interim function to return rcu_cblist head pointer. Longer term, the
* rcu_cblist will be used more pervasively, removing the need for this
* function.
*/
static inline struct rcu_head *rcu_cblist_head(struct rcu_cblist *rclp)
{
return rclp->head;
}
/*
* Interim function to return rcu_cblist head pointer. Longer term, the
* rcu_cblist will be used more pervasively, removing the need for this
* function.
*/
static inline struct rcu_head **rcu_cblist_tail(struct rcu_cblist *rclp)
{
WARN_ON_ONCE(!rclp->head);
return rclp->tail;
}
void rcu_cblist_init(struct rcu_cblist *rclp);
long rcu_cblist_count_cbs(struct rcu_cblist *rclp, long lim);
struct rcu_head *rcu_cblist_dequeue(struct rcu_cblist *rclp);
/*
* Is the specified rcu_segcblist structure empty?
*
* But careful! The fact that the ->head field is NULL does not
* necessarily imply that there are no callbacks associated with
* this structure. When callbacks are being invoked, they are
* removed as a group. If callback invocation must be preempted,
* the remaining callbacks will be added back to the list. Either
* way, the counts are updated later.
*
* So it is often the case that rcu_segcblist_n_cbs() should be used
* instead.
*/
static inline bool rcu_segcblist_empty(struct rcu_segcblist *rsclp)
{
return !rsclp->head;
}
/* Return number of callbacks in segmented callback list. */
static inline long rcu_segcblist_n_cbs(struct rcu_segcblist *rsclp)
{
return READ_ONCE(rsclp->len);
}
/* Return number of lazy callbacks in segmented callback list. */
static inline long rcu_segcblist_n_lazy_cbs(struct rcu_segcblist *rsclp)
{
return rsclp->len_lazy;
}
/* Return number of lazy callbacks in segmented callback list. */
static inline long rcu_segcblist_n_nonlazy_cbs(struct rcu_segcblist *rsclp)
{
return rsclp->len - rsclp->len_lazy;
}
/*
* Is the specified rcu_segcblist enabled, for example, not corresponding
* to an offline or callback-offloaded CPU?
*/
static inline bool rcu_segcblist_is_enabled(struct rcu_segcblist *rsclp)
{
return !!rsclp->tails[RCU_NEXT_TAIL];
}
/*
* Are all segments following the specified segment of the specified
* rcu_segcblist structure empty of callbacks? (The specified
* segment might well contain callbacks.)
*/
static inline bool rcu_segcblist_restempty(struct rcu_segcblist *rsclp, int seg)
{
return !*rsclp->tails[seg];
}
/*
* Interim function to return rcu_segcblist head pointer. Longer term, the
* rcu_segcblist will be used more pervasively, removing the need for this
* function.
*/
static inline struct rcu_head *rcu_segcblist_head(struct rcu_segcblist *rsclp)
{
return rsclp->head;
}
/*
* Interim function to return rcu_segcblist head pointer. Longer term, the
* rcu_segcblist will be used more pervasively, removing the need for this
* function.
*/
static inline struct rcu_head **rcu_segcblist_tail(struct rcu_segcblist *rsclp)
{
WARN_ON_ONCE(rcu_segcblist_empty(rsclp));
return rsclp->tails[RCU_NEXT_TAIL];
}
void rcu_segcblist_init(struct rcu_segcblist *rsclp);
void rcu_segcblist_disable(struct rcu_segcblist *rsclp);
bool rcu_segcblist_segempty(struct rcu_segcblist *rsclp, int seg);
bool rcu_segcblist_ready_cbs(struct rcu_segcblist *rsclp);
bool rcu_segcblist_pend_cbs(struct rcu_segcblist *rsclp);
struct rcu_head *rcu_segcblist_dequeue(struct rcu_segcblist *rsclp);
void rcu_segcblist_dequeued_lazy(struct rcu_segcblist *rsclp);
struct rcu_head *rcu_segcblist_first_cb(struct rcu_segcblist *rsclp);
struct rcu_head *rcu_segcblist_first_pend_cb(struct rcu_segcblist *rsclp);
bool rcu_segcblist_new_cbs(struct rcu_segcblist *rsclp);
void rcu_segcblist_enqueue(struct rcu_segcblist *rsclp,
struct rcu_head *rhp, bool lazy);
bool rcu_segcblist_entrain(struct rcu_segcblist *rsclp,
struct rcu_head *rhp, bool lazy);
void rcu_segcblist_extract_count(struct rcu_segcblist *rsclp,
struct rcu_cblist *rclp);
void rcu_segcblist_extract_done_cbs(struct rcu_segcblist *rsclp,
struct rcu_cblist *rclp);
void rcu_segcblist_extract_pend_cbs(struct rcu_segcblist *rsclp,
struct rcu_cblist *rclp);
void rcu_segcblist_insert_count(struct rcu_segcblist *rsclp,
struct rcu_cblist *rclp);
void rcu_segcblist_insert_done_cbs(struct rcu_segcblist *rsclp,
struct rcu_cblist *rclp);
void rcu_segcblist_insert_pend_cbs(struct rcu_segcblist *rsclp,
struct rcu_cblist *rclp);
void rcu_segcblist_advance(struct rcu_segcblist *rsclp, unsigned long seq);
bool rcu_segcblist_accelerate(struct rcu_segcblist *rsclp, unsigned long seq);
bool rcu_segcblist_future_gp_needed(struct rcu_segcblist *rsclp,
unsigned long seq);
kernel/rcu/srcutiny.c
View file @ 20652ed6
...@@ -30,6 +30,7 @@ ...@@ -30,6 +30,7 @@
#include <linux/srcu.h> #include <linux/srcu.h>
#include <linux/rcu_node_tree.h> #include <linux/rcu_node_tree.h>
#include "rcu_segcblist.h"
#include "rcu.h" #include "rcu.h"
static int init_srcu_struct_fields(struct srcu_struct *sp) static int init_srcu_struct_fields(struct srcu_struct *sp)
......
kernel/rcu/srcutree.c
View file @ 20652ed6
...@@ -38,6 +38,7 @@ ...@@ -38,6 +38,7 @@
#include <linux/srcu.h> #include <linux/srcu.h>
#include "rcu.h" #include "rcu.h"
#include "rcu_segcblist.h"
ulong exp_holdoff = 25 * 1000; /* Holdoff (ns) for auto-expediting. */ ulong exp_holdoff = 25 * 1000; /* Holdoff (ns) for auto-expediting. */
module_param(exp_holdoff, ulong, 0444); module_param(exp_holdoff, ulong, 0444);
......
kernel/rcu/tree.c
View file @ 20652ed6
...@@ -2633,9 +2633,8 @@ static void rcu_adopt_orphan_cbs(struct rcu_state *rsp, unsigned long flags) ...@@ -2633,9 +2633,8 @@ static void rcu_adopt_orphan_cbs(struct rcu_state *rsp, unsigned long flags)
return; return;
/* Do the accounting first. */ /* Do the accounting first. */
rdp->n_cbs_adopted += rcu_cblist_n_cbs(&rsp->orphan_done); rdp->n_cbs_adopted += rsp->orphan_done.len;
if (rcu_cblist_n_lazy_cbs(&rsp->orphan_done) != if (rsp->orphan_done.len_lazy != rsp->orphan_done.len)
rcu_cblist_n_cbs(&rsp->orphan_done))
rcu_idle_count_callbacks_posted(); rcu_idle_count_callbacks_posted();
rcu_segcblist_insert_count(&rdp->cblist, &rsp->orphan_done); rcu_segcblist_insert_count(&rdp->cblist, &rsp->orphan_done);
...@@ -2647,9 +2646,9 @@ static void rcu_adopt_orphan_cbs(struct rcu_state *rsp, unsigned long flags) ...@@ -2647,9 +2646,9 @@ static void rcu_adopt_orphan_cbs(struct rcu_state *rsp, unsigned long flags)
/* First adopt the ready-to-invoke callbacks, then the done ones. */ /* First adopt the ready-to-invoke callbacks, then the done ones. */
rcu_segcblist_insert_done_cbs(&rdp->cblist, &rsp->orphan_done); rcu_segcblist_insert_done_cbs(&rdp->cblist, &rsp->orphan_done);
WARN_ON_ONCE(!rcu_cblist_empty(&rsp->orphan_done)); WARN_ON_ONCE(rsp->orphan_done.head);
rcu_segcblist_insert_pend_cbs(&rdp->cblist, &rsp->orphan_pend); rcu_segcblist_insert_pend_cbs(&rdp->cblist, &rsp->orphan_pend);
WARN_ON_ONCE(!rcu_cblist_empty(&rsp->orphan_pend)); WARN_ON_ONCE(rsp->orphan_pend.head);
WARN_ON_ONCE(rcu_segcblist_empty(&rdp->cblist) != WARN_ON_ONCE(rcu_segcblist_empty(&rdp->cblist) !=
!rcu_segcblist_n_cbs(&rdp->cblist)); !rcu_segcblist_n_cbs(&rdp->cblist));
} }
...@@ -2792,17 +2791,16 @@ static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp) ...@@ -2792,17 +2791,16 @@ static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp)
* Stop only if limit reached and CPU has something to do. * Stop only if limit reached and CPU has something to do.
* Note: The rcl structure counts down from zero. * Note: The rcl structure counts down from zero.
*/ */
if (-rcu_cblist_n_cbs(&rcl) >= bl && if (-rcl.len >= bl &&
(need_resched() || (need_resched() ||
(!is_idle_task(current) && !rcu_is_callbacks_kthread()))) (!is_idle_task(current) && !rcu_is_callbacks_kthread())))
break; break;
} }
local_irq_save(flags); local_irq_save(flags);
count = -rcu_cblist_n_cbs(&rcl); count = -rcl.len;
trace_rcu_batch_end(rsp->name, count, !rcu_cblist_empty(&rcl), trace_rcu_batch_end(rsp->name, count, !!rcl.head, need_resched(),
need_resched(), is_idle_task(current), is_idle_task(current), rcu_is_callbacks_kthread());
rcu_is_callbacks_kthread());
/* Update counts and requeue any remaining callbacks. */ /* Update counts and requeue any remaining callbacks. */
rcu_segcblist_insert_done_cbs(&rdp->cblist, &rcl); rcu_segcblist_insert_done_cbs(&rdp->cblist, &rcl);
......
kernel/rcu/tree.h
View file @ 20652ed6
...@@ -30,9 +30,10 @@ ...@@ -30,9 +30,10 @@
#include <linux/seqlock.h> #include <linux/seqlock.h>
#include <linux/swait.h> #include <linux/swait.h>
#include <linux/stop_machine.h> #include <linux/stop_machine.h>
#include <linux/rcu_segcblist.h>
#include <linux/rcu_node_tree.h> #include <linux/rcu_node_tree.h>
#include "rcu_segcblist.h"
/* /*
* Dynticks per-CPU state. * Dynticks per-CPU state.
*/ */
......
kernel/rcu/tree_plugin.h
View file @ 20652ed6
...@@ -1934,20 +1934,20 @@ static bool __maybe_unused rcu_nocb_adopt_orphan_cbs(struct rcu_state *rsp, ...@@ -1934,20 +1934,20 @@ static bool __maybe_unused rcu_nocb_adopt_orphan_cbs(struct rcu_state *rsp,
struct rcu_data *rdp, struct rcu_data *rdp,
unsigned long flags) unsigned long flags)
{ {
long ql = rcu_cblist_n_cbs(&rsp->orphan_done); long ql = rsp->orphan_done.len;
long qll = rcu_cblist_n_lazy_cbs(&rsp->orphan_done); long qll = rsp->orphan_done.len_lazy;
/* If this is not a no-CBs CPU, tell the caller to do it the old way. */ /* If this is not a no-CBs CPU, tell the caller to do it the old way. */
if (!rcu_is_nocb_cpu(smp_processor_id())) if (!rcu_is_nocb_cpu(smp_processor_id()))
return false; return false;
/* First, enqueue the donelist, if any. This preserves CB ordering. */ /* First, enqueue the donelist, if any. This preserves CB ordering. */
if (!rcu_cblist_empty(&rsp->orphan_done)) { if (rsp->orphan_done.head) {
__call_rcu_nocb_enqueue(rdp, rcu_cblist_head(&rsp->orphan_done), __call_rcu_nocb_enqueue(rdp, rcu_cblist_head(&rsp->orphan_done),
rcu_cblist_tail(&rsp->orphan_done), rcu_cblist_tail(&rsp->orphan_done),
ql, qll, flags); ql, qll, flags);
} }
if (!rcu_cblist_empty(&rsp->orphan_pend)) { if (rsp->orphan_pend.head) {
__call_rcu_nocb_enqueue(rdp, rcu_cblist_head(&rsp->orphan_pend), __call_rcu_nocb_enqueue(rdp, rcu_cblist_head(&rsp->orphan_pend),
rcu_cblist_tail(&rsp->orphan_pend), rcu_cblist_tail(&rsp->orphan_pend),
ql, qll, flags); ql, qll, flags);
......
kernel/rcu/tree_trace.c
View file @ 20652ed6
...@@ -277,8 +277,8 @@ static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp) ...@@ -277,8 +277,8 @@ static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
rsp->n_force_qs, rsp->n_force_qs_ngp, rsp->n_force_qs, rsp->n_force_qs_ngp,
rsp->n_force_qs - rsp->n_force_qs_ngp, rsp->n_force_qs - rsp->n_force_qs_ngp,
READ_ONCE(rsp->n_force_qs_lh), READ_ONCE(rsp->n_force_qs_lh),
rcu_cblist_n_lazy_cbs(&rsp->orphan_done), rsp->orphan_done.len_lazy,
rcu_cblist_n_cbs(&rsp->orphan_done)); rsp->orphan_done.len);
for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < rcu_num_nodes; rnp++) { for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < rcu_num_nodes; rnp++) {
if (rnp->level != level) { if (rnp->level != level) {
seq_puts(m, "\n"); seq_puts(m, "\n");
......
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