diff options
Diffstat (limited to 'pkg/sentry/fs/fsutil/README.md')
| -rw-r--r-- | pkg/sentry/fs/fsutil/README.md | 17 |
1 files changed, 8 insertions, 9 deletions
diff --git a/pkg/sentry/fs/fsutil/README.md b/pkg/sentry/fs/fsutil/README.md index d3780e9fa..6e677890c 100644 --- a/pkg/sentry/fs/fsutil/README.md +++ b/pkg/sentry/fs/fsutil/README.md @@ -108,9 +108,9 @@ The host then sends a `SIGSEGV` to the sentry because the address range [`A`, `A`+8) is not mapped on the host. The `SIGSEGV` indicates that the memory was accessed writable. The sentry looks up the vma associated with [`A`, `A`+8), finds the file that was mapped and its `CachingInodeOperations`. It then calls -`CachingInodeOperations.MapInto` which allocates memory to back [`A`, `A`+8). It -may choose to allocate more memory (i.e. do "readahead") to minimize subsequent -faults. +`CachingInodeOperations.Translate` which allocates memory to back [`A`, `A`+8). +It may choose to allocate more memory (i.e. do "readahead") to minimize +subsequent faults. Memory that is allocated comes from a host tmpfs file (see `filemem.FileMem`). The host tmpfs file memory is brought up to date with the contents of the mapped @@ -138,12 +138,11 @@ memcpy(A, buffer, 4); ``` Since the first process has already mapped and accessed the same region of the -file writable, `CachingInodeOperations.MapInto` is called but re-maps the memory -that has already been allocated (because the host mapping can be invalidated at -any time) rather than allocating new memory. The address range [`A`, `A`+0x1000) -reflects the same cached view of the file as the first process sees. For -example, reading 8 bytes from the file from either process via read(2) starting -at offset 0 returns a consistent "bbbbaaaa". +file writable, `CachingInodeOperations.Translate` is called but returns the +memory that has already been allocated rather than allocating new memory. The +address range [`A`, `A`+0x1000) reflects the same cached view of the file as the +first process sees. For example, reading 8 bytes from the file from either +process via read(2) starting at offset 0 returns a consistent "bbbbaaaa". When this process no longer needs the shared memory, it may do: |