diff options
author | Tamir Duberstein <tamird@google.com> | 2020-06-25 14:17:00 -0700 |
---|---|---|
committer | gVisor bot <gvisor-bot@google.com> | 2020-06-25 14:18:33 -0700 |
commit | 4069461877d843654d18db74a5962b332f1226aa (patch) | |
tree | 48affc2bd8c7de9ae5f2cd19307c7ccbb63553b9 /pkg/sentry | |
parent | 00ee5abaa70965b1baad996f53d3dc2a17805fcf (diff) |
Avoid an allocation in epoll
PiperOrigin-RevId: 318346153
Diffstat (limited to 'pkg/sentry')
-rw-r--r-- | pkg/sentry/kernel/epoll/epoll.go | 32 | ||||
-rw-r--r-- | pkg/sentry/kernel/epoll/epoll_state.go | 2 |
2 files changed, 15 insertions, 19 deletions
diff --git a/pkg/sentry/kernel/epoll/epoll.go b/pkg/sentry/kernel/epoll/epoll.go index 679ab495d..4c0f1e41f 100644 --- a/pkg/sentry/kernel/epoll/epoll.go +++ b/pkg/sentry/kernel/epoll/epoll.go @@ -107,7 +107,7 @@ type EventPoll struct { // different lock to avoid circular lock acquisition order involving // the wait queue mutexes and mu. The full order is mu, observed file // wait queue mutex, then listsMu; this allows listsMu to be acquired - // when readyCallback is called. + // when (*pollEntry).Callback is called. // // An entry is always in one of the following lists: // readyList -- when there's a chance that it's ready to have @@ -116,7 +116,7 @@ type EventPoll struct { // readEvents() functions always call the entry's file // Readiness() function to confirm it's ready. // waitingList -- when there's no chance that the entry is ready, - // so it's waiting for the readyCallback to be called + // so it's waiting for the (*pollEntry).Callback to be called // on it before it gets moved to the readyList. // disabledList -- when the entry is disabled. This happens when // a one-shot entry gets delivered via readEvents(). @@ -269,23 +269,19 @@ func (e *EventPoll) ReadEvents(max int) []linux.EpollEvent { return ret } -// readyCallback is called when one of the files we're polling becomes ready. It -// moves said file to the readyList if it's currently in the waiting list. -type readyCallback struct { - context *pollEntry -} - // Callback implements waiter.EntryCallback.Callback. -func (r *readyCallback) Callback(*waiter.Entry) { - entry := r.context - e := entry.epoll +// +// Callback is called when one of the files we're polling becomes ready. It +// moves said file to the readyList if it's currently in the waiting list. +func (p *pollEntry) Callback(*waiter.Entry) { + e := p.epoll e.listsMu.Lock() - if entry.curList == &e.waitingList { - e.waitingList.Remove(entry) - e.readyList.PushBack(entry) - entry.curList = &e.readyList + if p.curList == &e.waitingList { + e.waitingList.Remove(p) + e.readyList.PushBack(p) + p.curList = &e.readyList e.listsMu.Unlock() e.Notify(waiter.EventIn) @@ -312,7 +308,7 @@ func (e *EventPoll) initEntryReadiness(entry *pollEntry) { // Check if the file happens to already be in a ready state. ready := f.Readiness(entry.mask) & entry.mask if ready != 0 { - (&readyCallback{context: entry}).Callback(&entry.waiter) + entry.Callback(&entry.waiter) } } @@ -384,7 +380,7 @@ func (e *EventPoll) AddEntry(id FileIdentifier, flags EntryFlags, mask waiter.Ev flags: flags, mask: mask, } - entry.waiter.Callback = &readyCallback{context: entry} + entry.waiter.Callback = entry e.files[id] = entry entry.file = refs.NewWeakRef(id.File, entry) @@ -407,7 +403,7 @@ func (e *EventPoll) UpdateEntry(id FileIdentifier, flags EntryFlags, mask waiter } // Unregister the old mask and remove entry from the list it's in, so - // readyCallback is guaranteed to not be called on this entry anymore. + // (*pollEntry).Callback is guaranteed to not be called on this entry anymore. entry.id.File.EventUnregister(&entry.waiter) // Remove entry from whatever list it's in. This ensure that no other diff --git a/pkg/sentry/kernel/epoll/epoll_state.go b/pkg/sentry/kernel/epoll/epoll_state.go index 02f9aabfa..7c61e0258 100644 --- a/pkg/sentry/kernel/epoll/epoll_state.go +++ b/pkg/sentry/kernel/epoll/epoll_state.go @@ -21,7 +21,7 @@ import ( // afterLoad is invoked by stateify. func (p *pollEntry) afterLoad() { - p.waiter.Callback = &readyCallback{context: p} + p.waiter.Callback = p p.file = refs.NewWeakRef(p.id.File, p) p.id.File.EventRegister(&p.waiter, p.mask) } |