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author | Rafael J. Wysocki <rjw@sisk.pl> | 2012-05-11 21:15:09 +0200 |
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committer | Rafael J. Wysocki <rjw@sisk.pl> | 2012-05-11 21:15:09 +0200 |
commit | 351520a9ebfdf2f36cd97c1192f280e0ac7fdcfc (patch) | |
tree | 8f177d2c59be90ebcedc98ed508832a7ebbd7e0a /fs | |
parent | Merge branch 'pm-domains' (diff) | |
parent | PM / Sleep: User space wakeup sources garbage collector Kconfig option (diff) | |
download | linux-351520a9ebfdf2f36cd97c1192f280e0ac7fdcfc.tar.xz linux-351520a9ebfdf2f36cd97c1192f280e0ac7fdcfc.zip |
Merge branch 'pm-sleep'
* pm-sleep:
PM / Sleep: User space wakeup sources garbage collector Kconfig option
PM / Sleep: Make the limit of user space wakeup sources configurable
PM / Documentation: suspend-and-cpuhotplug.txt: Fix typo
PM / Sleep: Fix a mistake in a conditional in autosleep_store()
epoll: Add a flag, EPOLLWAKEUP, to prevent suspend while epoll events are ready
PM / Sleep: Add user space interface for manipulating wakeup sources, v3
PM / Sleep: Add "prevent autosleep time" statistics to wakeup sources
PM / Sleep: Implement opportunistic sleep, v2
PM / Sleep: Add wakeup_source_activate and wakeup_source_deactivate tracepoints
PM / Sleep: Change wakeup source statistics to follow Android
PM / Sleep: Use wait queue to signal "no wakeup events in progress"
PM / Sleep: Look for wakeup events in later stages of device suspend
PM / Hibernate: Hibernate/thaw fixes/improvements
Diffstat (limited to 'fs')
-rw-r--r-- | fs/eventpoll.c | 90 |
1 files changed, 87 insertions, 3 deletions
diff --git a/fs/eventpoll.c b/fs/eventpoll.c index c0b3c70ee87a..2cf0f2153be5 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -33,6 +33,7 @@ #include <linux/bitops.h> #include <linux/mutex.h> #include <linux/anon_inodes.h> +#include <linux/device.h> #include <asm/uaccess.h> #include <asm/io.h> #include <asm/mman.h> @@ -87,7 +88,7 @@ */ /* Epoll private bits inside the event mask */ -#define EP_PRIVATE_BITS (EPOLLONESHOT | EPOLLET) +#define EP_PRIVATE_BITS (EPOLLWAKEUP | EPOLLONESHOT | EPOLLET) /* Maximum number of nesting allowed inside epoll sets */ #define EP_MAX_NESTS 4 @@ -154,6 +155,9 @@ struct epitem { /* List header used to link this item to the "struct file" items list */ struct list_head fllink; + /* wakeup_source used when EPOLLWAKEUP is set */ + struct wakeup_source *ws; + /* The structure that describe the interested events and the source fd */ struct epoll_event event; }; @@ -194,6 +198,9 @@ struct eventpoll { */ struct epitem *ovflist; + /* wakeup_source used when ep_scan_ready_list is running */ + struct wakeup_source *ws; + /* The user that created the eventpoll descriptor */ struct user_struct *user; @@ -588,8 +595,10 @@ static int ep_scan_ready_list(struct eventpoll *ep, * queued into ->ovflist but the "txlist" might already * contain them, and the list_splice() below takes care of them. */ - if (!ep_is_linked(&epi->rdllink)) + if (!ep_is_linked(&epi->rdllink)) { list_add_tail(&epi->rdllink, &ep->rdllist); + __pm_stay_awake(epi->ws); + } } /* * We need to set back ep->ovflist to EP_UNACTIVE_PTR, so that after @@ -602,6 +611,7 @@ static int ep_scan_ready_list(struct eventpoll *ep, * Quickly re-inject items left on "txlist". */ list_splice(&txlist, &ep->rdllist); + __pm_relax(ep->ws); if (!list_empty(&ep->rdllist)) { /* @@ -656,6 +666,8 @@ static int ep_remove(struct eventpoll *ep, struct epitem *epi) list_del_init(&epi->rdllink); spin_unlock_irqrestore(&ep->lock, flags); + wakeup_source_unregister(epi->ws); + /* At this point it is safe to free the eventpoll item */ kmem_cache_free(epi_cache, epi); @@ -706,6 +718,7 @@ static void ep_free(struct eventpoll *ep) mutex_unlock(&epmutex); mutex_destroy(&ep->mtx); free_uid(ep->user); + wakeup_source_unregister(ep->ws); kfree(ep); } @@ -737,6 +750,7 @@ static int ep_read_events_proc(struct eventpoll *ep, struct list_head *head, * callback, but it's not actually ready, as far as * caller requested events goes. We can remove it here. */ + __pm_relax(epi->ws); list_del_init(&epi->rdllink); } } @@ -927,13 +941,23 @@ static int ep_poll_callback(wait_queue_t *wait, unsigned mode, int sync, void *k if (epi->next == EP_UNACTIVE_PTR) { epi->next = ep->ovflist; ep->ovflist = epi; + if (epi->ws) { + /* + * Activate ep->ws since epi->ws may get + * deactivated at any time. + */ + __pm_stay_awake(ep->ws); + } + } goto out_unlock; } /* If this file is already in the ready list we exit soon */ - if (!ep_is_linked(&epi->rdllink)) + if (!ep_is_linked(&epi->rdllink)) { list_add_tail(&epi->rdllink, &ep->rdllist); + __pm_stay_awake(epi->ws); + } /* * Wake up ( if active ) both the eventpoll wait list and the ->poll() @@ -1091,6 +1115,30 @@ static int reverse_path_check(void) return error; } +static int ep_create_wakeup_source(struct epitem *epi) +{ + const char *name; + + if (!epi->ep->ws) { + epi->ep->ws = wakeup_source_register("eventpoll"); + if (!epi->ep->ws) + return -ENOMEM; + } + + name = epi->ffd.file->f_path.dentry->d_name.name; + epi->ws = wakeup_source_register(name); + if (!epi->ws) + return -ENOMEM; + + return 0; +} + +static void ep_destroy_wakeup_source(struct epitem *epi) +{ + wakeup_source_unregister(epi->ws); + epi->ws = NULL; +} + /* * Must be called with "mtx" held. */ @@ -1118,6 +1166,13 @@ static int ep_insert(struct eventpoll *ep, struct epoll_event *event, epi->event = *event; epi->nwait = 0; epi->next = EP_UNACTIVE_PTR; + if (epi->event.events & EPOLLWAKEUP) { + error = ep_create_wakeup_source(epi); + if (error) + goto error_create_wakeup_source; + } else { + epi->ws = NULL; + } /* Initialize the poll table using the queue callback */ epq.epi = epi; @@ -1164,6 +1219,7 @@ static int ep_insert(struct eventpoll *ep, struct epoll_event *event, /* If the file is already "ready" we drop it inside the ready list */ if ((revents & event->events) && !ep_is_linked(&epi->rdllink)) { list_add_tail(&epi->rdllink, &ep->rdllist); + __pm_stay_awake(epi->ws); /* Notify waiting tasks that events are available */ if (waitqueue_active(&ep->wq)) @@ -1204,6 +1260,9 @@ error_unregister: list_del_init(&epi->rdllink); spin_unlock_irqrestore(&ep->lock, flags); + wakeup_source_unregister(epi->ws); + +error_create_wakeup_source: kmem_cache_free(epi_cache, epi); return error; @@ -1229,6 +1288,12 @@ static int ep_modify(struct eventpoll *ep, struct epitem *epi, struct epoll_even epi->event.events = event->events; pt._key = event->events; epi->event.data = event->data; /* protected by mtx */ + if (epi->event.events & EPOLLWAKEUP) { + if (!epi->ws) + ep_create_wakeup_source(epi); + } else if (epi->ws) { + ep_destroy_wakeup_source(epi); + } /* * Get current event bits. We can safely use the file* here because @@ -1244,6 +1309,7 @@ static int ep_modify(struct eventpoll *ep, struct epitem *epi, struct epoll_even spin_lock_irq(&ep->lock); if (!ep_is_linked(&epi->rdllink)) { list_add_tail(&epi->rdllink, &ep->rdllist); + __pm_stay_awake(epi->ws); /* Notify waiting tasks that events are available */ if (waitqueue_active(&ep->wq)) @@ -1282,6 +1348,18 @@ static int ep_send_events_proc(struct eventpoll *ep, struct list_head *head, !list_empty(head) && eventcnt < esed->maxevents;) { epi = list_first_entry(head, struct epitem, rdllink); + /* + * Activate ep->ws before deactivating epi->ws to prevent + * triggering auto-suspend here (in case we reactive epi->ws + * below). + * + * This could be rearranged to delay the deactivation of epi->ws + * instead, but then epi->ws would temporarily be out of sync + * with ep_is_linked(). + */ + if (epi->ws && epi->ws->active) + __pm_stay_awake(ep->ws); + __pm_relax(epi->ws); list_del_init(&epi->rdllink); pt._key = epi->event.events; @@ -1298,6 +1376,7 @@ static int ep_send_events_proc(struct eventpoll *ep, struct list_head *head, if (__put_user(revents, &uevent->events) || __put_user(epi->event.data, &uevent->data)) { list_add(&epi->rdllink, head); + __pm_stay_awake(epi->ws); return eventcnt ? eventcnt : -EFAULT; } eventcnt++; @@ -1317,6 +1396,7 @@ static int ep_send_events_proc(struct eventpoll *ep, struct list_head *head, * poll callback will queue them in ep->ovflist. */ list_add_tail(&epi->rdllink, &ep->rdllist); + __pm_stay_awake(epi->ws); } } } @@ -1629,6 +1709,10 @@ SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd, if (!tfile->f_op || !tfile->f_op->poll) goto error_tgt_fput; + /* Check if EPOLLWAKEUP is allowed */ + if ((epds.events & EPOLLWAKEUP) && !capable(CAP_EPOLLWAKEUP)) + goto error_tgt_fput; + /* * We have to check that the file structure underneath the file descriptor * the user passed to us _is_ an eventpoll file. And also we do not permit |