netbird/gvisor
0
0
Fork 0
mirror of https://github.com/netbirdio/gvisor.git synced 2026-05-22 17:12:49 -07:00
Code Issues Packages Projects Releases Wiki Activity

Combine multiple epoll events copies

Browse Source 
Allocate a larger memory buffer and combine multiple copies into one copy,
to reduce the number of copies from kernel memory to user memory.

Signed-off-by: Hang Su <darcy.sh@antfin.com>
This commit is contained in:
Hang Su
2019-07-30 10:53:55 +08:00
parent 4183b9021a
commit 50f3447786
1 changed files with 10 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files
pkg/sentry/syscalls/linux/sys_epoll.go
+10 -9
View File
@@ -107,19 +107,20 @@ func EpollCtl(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sysc
// copyOutEvents copies epoll events from the kernel to user memory.
func copyOutEvents(t *kernel.Task, addr usermem.Addr, e []epoll.Event) error {
const itemLen = 12
if _, ok := addr.AddLength(uint64(len(e)) * itemLen); !ok {
buffLen := len(e) * itemLen
if _, ok := addr.AddLength(uint64(buffLen)); !ok {
return syserror.EFAULT
}
b := t.CopyScratchBuffer(itemLen)
b := t.CopyScratchBuffer(buffLen)
for i := range e {
usermem.ByteOrder.PutUint32(b[0:], e[i].Events)
usermem.ByteOrder.PutUint32(b[4:], uint32(e[i].Data[0]))
usermem.ByteOrder.PutUint32(b[8:], uint32(e[i].Data[1]))
if _, err := t.CopyOutBytes(addr, b); err != nil {
return err
}
addr += itemLen
usermem.ByteOrder.PutUint32(b[i*itemLen:], e[i].Events)
usermem.ByteOrder.PutUint32(b[i*itemLen+4:], uint32(e[i].Data[0]))
usermem.ByteOrder.PutUint32(b[i*itemLen+8:], uint32(e[i].Data[1]))
}
if _, err := t.CopyOutBytes(addr, b); err != nil {
return err
}
return nil