diff options
Diffstat (limited to 'src/runtime/mpagealloc.go')
| -rw-r--r-- | src/runtime/mpagealloc.go | 43 |
1 files changed, 32 insertions, 11 deletions
diff --git a/src/runtime/mpagealloc.go b/src/runtime/mpagealloc.go index 60f7f9ff58..8b3c62c375 100644 --- a/src/runtime/mpagealloc.go +++ b/src/runtime/mpagealloc.go @@ -233,16 +233,12 @@ type pageAlloc struct { // The address to start an allocation search with. It must never // point to any memory that is not contained in inUse, i.e. - // inUse.contains(searchAddr) must always be true. + // inUse.contains(searchAddr.addr()) must always be true. The one + // exception to this rule is that it may take on the value of + // maxOffAddr to indicate that the heap is exhausted. // - // When added with arenaBaseOffset, we guarantee that - // all valid heap addresses (when also added with - // arenaBaseOffset) below this value are allocated and - // not worth searching. - // - // Note that adding in arenaBaseOffset transforms addresses - // to a new address space with a linear view of the full address - // space on architectures with segmented address spaces. + // We guarantee that all valid heap addresses below this value + // are allocated and not worth searching. searchAddr offAddr // start and end represent the chunk indices @@ -518,6 +514,30 @@ func (s *pageAlloc) allocRange(base, npages uintptr) uintptr { return uintptr(scav) * pageSize } +// findMappedAddr returns the smallest mapped offAddr that is +// >= addr. That is, if addr refers to mapped memory, then it is +// returned. If addr is higher than any mapped region, then +// it returns maxOffAddr. +// +// s.mheapLock must be held. +func (s *pageAlloc) findMappedAddr(addr offAddr) offAddr { + // If we're not in a test, validate first by checking mheap_.arenas. + // This is a fast path which is only safe to use outside of testing. + ai := arenaIndex(addr.addr()) + if s.test || mheap_.arenas[ai.l1()] == nil || mheap_.arenas[ai.l1()][ai.l2()] == nil { + vAddr, ok := s.inUse.findAddrGreaterEqual(addr.addr()) + if ok { + return offAddr{vAddr} + } else { + // The candidate search address is greater than any + // known address, which means we definitely have no + // free memory left. + return maxOffAddr + } + } + return addr +} + // find searches for the first (address-ordered) contiguous free region of // npages in size and returns a base address for that region. // @@ -526,6 +546,7 @@ func (s *pageAlloc) allocRange(base, npages uintptr) uintptr { // // find also computes and returns a candidate s.searchAddr, which may or // may not prune more of the address space than s.searchAddr already does. +// This candidate is always a valid s.searchAddr. // // find represents the slow path and the full radix tree search. // @@ -695,7 +716,7 @@ nextLevel: // We found a sufficiently large run of free pages straddling // some boundary, so compute the address and return it. addr := levelIndexToOffAddr(l, i).add(uintptr(base) * pageSize).addr() - return addr, firstFree.base + return addr, s.findMappedAddr(firstFree.base) } if l == 0 { // We're at level zero, so that means we've exhausted our search. @@ -741,7 +762,7 @@ nextLevel: // found an even narrower free window. searchAddr := chunkBase(ci) + uintptr(searchIdx)*pageSize foundFree(offAddr{searchAddr}, chunkBase(ci+1)-searchAddr) - return addr, firstFree.base + return addr, s.findMappedAddr(firstFree.base) } // alloc allocates npages worth of memory from the page heap, returning the base |