You will probably be encountering just a few files for the first time:
@table @file
-@item devices/disk.h
-@itemx devices/disk.c
-Provides access to the physical disk, abstracting away the rather awful
-IDE interface. You will use this interface to access the swap disk.
+@item devices/block.h
+@itemx devices/block.c
+Provides sector-based read and write access to block device. You will
+use this interface to access the swap partition as a block device.
@end table
@node Memory Terminology
@node Swap Slots
@subsubsection Swap Slots
-A @dfn{swap slot} is a continuous, page-size region of disk space on the
-swap disk. Although hardware limitations dictating the placement of
+A @dfn{swap slot} is a continuous, page-size region of disk space in the
+swap partition. Although hardware limitations dictating the placement of
slots are looser than for pages and frames, swap slots should be
page-aligned because there is no downside in doing so.
The swap table tracks in-use and free swap slots. It should allow
picking an unused swap slot for evicting a page from its frame to the
-swap disk. It should allow freeing a swap slot when its page is read
+swap partition. It should allow freeing a swap slot when its page is read
back or the process whose page was swapped is terminated.
-You may use the disk on interface @code{hd1:1} as the swap disk, using
-the disk interface prototyped in @code{devices/disk.h}. From the
+You may use the @code{BLOCK_SWAP} block device for swapping, obtaining
+the @struct{block} that represents it by calling @func{block_get_role}.
+From the
@file{vm/build} directory, use the command @code{pintos-mkdisk swap.dsk
-@var{n}} to create an @var{n} MB swap disk named @file{swap.dsk}.
-Afterward, @file{swap.dsk} will automatically be attached as
-@code{hd1:1} when you run @command{pintos}. Alternatively, you can tell
+--swap-size=@var{n}} to create an disk named @file{swap.dsk} that
+contains a @var{n}-MB swap partition.
+Afterward, @file{swap.dsk} will automatically be attached as an extra disk
+when you run @command{pintos}. Alternatively, you can tell
@command{pintos} to use a temporary @var{n}-MB swap disk for a single
-run with @option{--swap-disk=@var{n}}.
+run with @option{--swap-size=@var{n}}.
Swap slots should be allocated lazily, that is, only when they are
actually required by eviction. Reading data pages from the executable
what functionality we require your OS to support. We will expect
you to come up with a design that makes sense. You will have the
freedom to choose how to handle page faults, how to organize the swap
-disk, how to implement paging, etc.
+partition, how to implement paging, etc.
@menu
* Project 3 Design Document::
@itemize @bullet
@item
If @code{page_read_bytes} equals @code{PGSIZE}, the page should be demand
-paged from disk on its first access.
+paged from the underlying file on its first access.
@item
If @code{page_zero_bytes} equals @code{PGSIZE}, the page does not need to
@item
Otherwise, neither @code{page_read_bytes} nor @code{page_zero_bytes}
equals @code{PGSIZE}. In this case, an initial part of the page is to
-be read from disk and the remainder zeroed.
+be read from the underlying file and the remainder zeroed.
@end itemize
@node Stack Growth
If the file's length is not a multiple of @code{PGSIZE}, then some
bytes in the final mapped page ``stick out'' beyond the end of the
-file. Set these bytes to zero when the page is faulted in from disk,
+file. Set these bytes to zero when the page is faulted in from the
+file system,
and discard them when the page is written back to disk.
If successful, this function returns a ``mapping ID'' that
You can layer some other allocator on top of @func{palloc_get_page} if
you like, but it should be the underlying mechanism.
-Also, you can use the @option{-ul} option to @command{pintos} to limit
+Also, you can use the @option{-ul} kernel command-line option to limit
the size of the user pool, which makes it easy to test your VM
implementation with various user memory sizes.
@end table
projects / pintos-anon / blobdiff