From e26148d934762b61133a64b6862f870624ff617d Mon Sep 17 00:00:00 2001 From: Tim Schmielau Date: Fri, 14 Oct 2005 15:59:05 -0700 Subject: [PATCH] Fix copy-and-paste error in BSD accounting Fix copy and paste error in jiffies_to_AHZ conversion which leads to wrong BSD accounting information on alpha and ia64 when CONFIG_BSD_PROCESS_ACCT_V3 is turned on. Also update comment to match reorganised header files. Signed-off-by: Tim Schmielau Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/acct.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/acct.h b/include/linux/acct.h index 1993a3691768..19f70462b3be 100644 --- a/include/linux/acct.h +++ b/include/linux/acct.h @@ -162,13 +162,13 @@ typedef struct acct acct_t; #ifdef __KERNEL__ /* * Yet another set of HZ to *HZ helper functions. - * See for the original. + * See for the original. */ static inline u32 jiffies_to_AHZ(unsigned long x) { #if (TICK_NSEC % (NSEC_PER_SEC / AHZ)) == 0 - return x / (HZ / USER_HZ); + return x / (HZ / AHZ); #else u64 tmp = (u64)x * TICK_NSEC; do_div(tmp, (NSEC_PER_SEC / AHZ)); -- cgit v1.2.3-71-gd317 From 688ce17b8599abc548b406c00e4d18ae0dec954f Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sun, 16 Oct 2005 00:17:33 -0700 Subject: [PATCH]: highest_possible_processor_id() has to be a macro ... otherwise, things like alpha and sparc64 break and break badly. They define cpu_possible_map to something else in smp.h *AFTER* having included cpumask.h. If that puppy is a macro, expansion will happen at the actual caller, when we'd already seen #define cpu_possible_map ... and we will get the right thing used. As an inline helper it will be tokenized before we get to that define and that's it; no matter what we define later, it won't affect anything. We get modules with dependency on cpu_possible_map instead of the right symbol (phys_cpu_present_map in case of sparc64), or outright link errors if they are built-in. Signed-off-by: Al Viro Signed-off-by: David S. Miller --- include/linux/cpumask.h | 16 +++++++--------- 1 file changed, 7 insertions(+), 9 deletions(-) (limited to 'include/linux') diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index fe9778301d07..9bdba8169b41 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -393,15 +393,13 @@ extern cpumask_t cpu_present_map; #define for_each_present_cpu(cpu) for_each_cpu_mask((cpu), cpu_present_map) /* Find the highest possible smp_processor_id() */ -static inline unsigned int highest_possible_processor_id(void) -{ - unsigned int cpu, highest = 0; - - for_each_cpu_mask(cpu, cpu_possible_map) - highest = cpu; - - return highest; -} +#define highest_possible_processor_id() \ +({ \ + unsigned int cpu, highest = 0; \ + for_each_cpu_mask(cpu, cpu_possible_map) \ + highest = cpu; \ + highest; \ +}) #endif /* __LINUX_CPUMASK_H */ -- cgit v1.2.3-71-gd317 From b24d18aa743dad0c42918157c5d717686269d3a8 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Sun, 16 Oct 2005 20:29:20 -0700 Subject: [PATCH] list: add missing rcu_dereference on first element It seems that all the list_*_rcu primitives are missing a memory barrier on the very first dereference. For example, #define list_for_each_rcu(pos, head) \ for (pos = (head)->next; prefetch(pos->next), pos != (head); \ pos = rcu_dereference(pos->next)) It will go something like: pos = (head)->next prefetch(pos->next) pos != (head) do stuff We're missing a barrier here. pos = rcu_dereference(pos->next) fetch pos->next barrier given by rcu_dereference(pos->next) store pos Without the missing barrier, the pos->next value may turn out to be stale. In fact, if "do stuff" were also dereferencing pos and relying on list_for_each_rcu to provide the barrier then it may also break. So here is a patch to make sure that we have a barrier for the first element in the list. Signed-off-by: Herbert Xu Acked-by: "Paul E. McKenney" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/list.h | 39 ++++++++++++++++++++++----------------- 1 file changed, 22 insertions(+), 17 deletions(-) (limited to 'include/linux') diff --git a/include/linux/list.h b/include/linux/list.h index e6ec59682274..084971f333fe 100644 --- a/include/linux/list.h +++ b/include/linux/list.h @@ -442,12 +442,14 @@ static inline void list_splice_init(struct list_head *list, * as long as the traversal is guarded by rcu_read_lock(). */ #define list_for_each_rcu(pos, head) \ - for (pos = (head)->next; prefetch(pos->next), pos != (head); \ - pos = rcu_dereference(pos->next)) + for (pos = (head)->next; \ + prefetch(rcu_dereference(pos)->next), pos != (head); \ + pos = pos->next) #define __list_for_each_rcu(pos, head) \ - for (pos = (head)->next; pos != (head); \ - pos = rcu_dereference(pos->next)) + for (pos = (head)->next; \ + rcu_dereference(pos) != (head); \ + pos = pos->next) /** * list_for_each_safe_rcu - iterate over an rcu-protected list safe @@ -461,8 +463,9 @@ static inline void list_splice_init(struct list_head *list, * as long as the traversal is guarded by rcu_read_lock(). */ #define list_for_each_safe_rcu(pos, n, head) \ - for (pos = (head)->next, n = pos->next; pos != (head); \ - pos = rcu_dereference(n), n = pos->next) + for (pos = (head)->next; \ + n = rcu_dereference(pos)->next, pos != (head); \ + pos = n) /** * list_for_each_entry_rcu - iterate over rcu list of given type @@ -474,11 +477,11 @@ static inline void list_splice_init(struct list_head *list, * the _rcu list-mutation primitives such as list_add_rcu() * as long as the traversal is guarded by rcu_read_lock(). */ -#define list_for_each_entry_rcu(pos, head, member) \ - for (pos = list_entry((head)->next, typeof(*pos), member); \ - prefetch(pos->member.next), &pos->member != (head); \ - pos = rcu_dereference(list_entry(pos->member.next, \ - typeof(*pos), member))) +#define list_for_each_entry_rcu(pos, head, member) \ + for (pos = list_entry((head)->next, typeof(*pos), member); \ + prefetch(rcu_dereference(pos)->member.next), \ + &pos->member != (head); \ + pos = list_entry(pos->member.next, typeof(*pos), member)) /** @@ -492,8 +495,9 @@ static inline void list_splice_init(struct list_head *list, * as long as the traversal is guarded by rcu_read_lock(). */ #define list_for_each_continue_rcu(pos, head) \ - for ((pos) = (pos)->next; prefetch((pos)->next), (pos) != (head); \ - (pos) = rcu_dereference((pos)->next)) + for ((pos) = (pos)->next; \ + prefetch(rcu_dereference((pos))->next), (pos) != (head); \ + (pos) = (pos)->next) /* * Double linked lists with a single pointer list head. @@ -696,8 +700,9 @@ static inline void hlist_add_after_rcu(struct hlist_node *prev, pos = n) #define hlist_for_each_rcu(pos, head) \ - for ((pos) = (head)->first; pos && ({ prefetch((pos)->next); 1; }); \ - (pos) = rcu_dereference((pos)->next)) + for ((pos) = (head)->first; \ + rcu_dereference((pos)) && ({ prefetch((pos)->next); 1; }); \ + (pos) = (pos)->next) /** * hlist_for_each_entry - iterate over list of given type @@ -762,9 +767,9 @@ static inline void hlist_add_after_rcu(struct hlist_node *prev, */ #define hlist_for_each_entry_rcu(tpos, pos, head, member) \ for (pos = (head)->first; \ - pos && ({ prefetch(pos->next); 1;}) && \ + rcu_dereference(pos) && ({ prefetch(pos->next); 1;}) && \ ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ - pos = rcu_dereference(pos->next)) + pos = pos->next) #else #warning "don't include kernel headers in userspace" -- cgit v1.2.3-71-gd317 From 5ee832dbc6770135ec8d63296af0a4374557bb79 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 17 Oct 2005 20:01:21 +0200 Subject: [PATCH] rcu: keep rcu callback event counter This makes call_rcu() keep track of how many events there are on the RCU list, and cause a reschedule event when the list gets too long. This helps keep RCU event lists down. Signed-off-by: Linus Torvalds --- include/linux/rcupdate.h | 1 + kernel/rcupdate.c | 11 +++++++++++ 2 files changed, 12 insertions(+) (limited to 'include/linux') diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 4e65eb44adfd..70191a5a148f 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -94,6 +94,7 @@ struct rcu_data { long batch; /* Batch # for current RCU batch */ struct rcu_head *nxtlist; struct rcu_head **nxttail; + long count; /* # of queued items */ struct rcu_head *curlist; struct rcu_head **curtail; struct rcu_head *donelist; diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c index dd99415b1551..2559d4b8f23f 100644 --- a/kernel/rcupdate.c +++ b/kernel/rcupdate.c @@ -109,6 +109,10 @@ void fastcall call_rcu(struct rcu_head *head, rdp = &__get_cpu_var(rcu_data); *rdp->nxttail = head; rdp->nxttail = &head->next; + + if (unlikely(++rdp->count > 10000)) + set_need_resched(); + local_irq_restore(flags); } @@ -140,6 +144,12 @@ void fastcall call_rcu_bh(struct rcu_head *head, rdp = &__get_cpu_var(rcu_bh_data); *rdp->nxttail = head; rdp->nxttail = &head->next; + rdp->count++; +/* + * Should we directly call rcu_do_batch() here ? + * if (unlikely(rdp->count > 10000)) + * rcu_do_batch(rdp); + */ local_irq_restore(flags); } @@ -157,6 +167,7 @@ static void rcu_do_batch(struct rcu_data *rdp) next = rdp->donelist = list->next; list->func(list); list = next; + rdp->count--; if (++count >= maxbatch) break; } -- cgit v1.2.3-71-gd317 From 4faa5285283fad081443e3612ca426a311bb6c7e Mon Sep 17 00:00:00 2001 From: Zach Brown Date: Mon, 17 Oct 2005 16:43:33 -0700 Subject: [PATCH] aio: revert lock_kiocb() lock_kiocb() was introduced to serialize retrying and cancellation. In the process of doing so it tried to sleep waiting for KIF_LOCKED while holding the ctx_lock spinlock. Recent fixes have ensured that multiple concurrent retries won't be attempted for a given iocb. Cancel has other problems and has no significant in-tree users that have been complaining about it. So for the immediate future we'll revert sleeping with the lock held and will address proper cancellation and retry serialization in the future. Signed-off-by: Zach Brown Acked-by: Benjamin LaHaise Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/aio.c | 26 +------------------------- include/linux/aio.h | 7 ++++++- 2 files changed, 7 insertions(+), 26 deletions(-) (limited to 'include/linux') diff --git a/fs/aio.c b/fs/aio.c index d6b1551342b7..9fe7216457d8 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -398,7 +398,7 @@ static struct kiocb fastcall *__aio_get_req(struct kioctx *ctx) if (unlikely(!req)) return NULL; - req->ki_flags = 1 << KIF_LOCKED; + req->ki_flags = 0; req->ki_users = 2; req->ki_key = 0; req->ki_ctx = ctx; @@ -547,25 +547,6 @@ struct kioctx *lookup_ioctx(unsigned long ctx_id) return ioctx; } -static int lock_kiocb_action(void *param) -{ - schedule(); - return 0; -} - -static inline void lock_kiocb(struct kiocb *iocb) -{ - wait_on_bit_lock(&iocb->ki_flags, KIF_LOCKED, lock_kiocb_action, - TASK_UNINTERRUPTIBLE); -} - -static inline void unlock_kiocb(struct kiocb *iocb) -{ - kiocbClearLocked(iocb); - smp_mb__after_clear_bit(); - wake_up_bit(&iocb->ki_flags, KIF_LOCKED); -} - /* * use_mm * Makes the calling kernel thread take on the specified @@ -796,9 +777,7 @@ static int __aio_run_iocbs(struct kioctx *ctx) * Hold an extra reference while retrying i/o. */ iocb->ki_users++; /* grab extra reference */ - lock_kiocb(iocb); aio_run_iocb(iocb); - unlock_kiocb(iocb); if (__aio_put_req(ctx, iocb)) /* drop extra ref */ put_ioctx(ctx); } @@ -1542,7 +1521,6 @@ int fastcall io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb, spin_lock_irq(&ctx->ctx_lock); aio_run_iocb(req); - unlock_kiocb(req); if (!list_empty(&ctx->run_list)) { /* drain the run list */ while (__aio_run_iocbs(ctx)) @@ -1674,7 +1652,6 @@ asmlinkage long sys_io_cancel(aio_context_t ctx_id, struct iocb __user *iocb, if (NULL != cancel) { struct io_event tmp; pr_debug("calling cancel\n"); - lock_kiocb(kiocb); memset(&tmp, 0, sizeof(tmp)); tmp.obj = (u64)(unsigned long)kiocb->ki_obj.user; tmp.data = kiocb->ki_user_data; @@ -1686,7 +1663,6 @@ asmlinkage long sys_io_cancel(aio_context_t ctx_id, struct iocb __user *iocb, if (copy_to_user(result, &tmp, sizeof(tmp))) ret = -EFAULT; } - unlock_kiocb(kiocb); } else ret = -EINVAL; diff --git a/include/linux/aio.h b/include/linux/aio.h index 60def658b246..0decf66117c1 100644 --- a/include/linux/aio.h +++ b/include/linux/aio.h @@ -24,7 +24,12 @@ struct kioctx; #define KIOCB_SYNC_KEY (~0U) /* ki_flags bits */ -#define KIF_LOCKED 0 +/* + * This may be used for cancel/retry serialization in the future, but + * for now it's unused and we probably don't want modules to even + * think they can use it. + */ +/* #define KIF_LOCKED 0 */ #define KIF_KICKED 1 #define KIF_CANCELLED 2 -- cgit v1.2.3-71-gd317