Suparna Bhattacharya wrote:
>
> > +#define PG_slab 8 /* kill me if needed: slab debug */
>
> A little plea for mercy for this tiny bit :)
Sure, I'll update the comment.
Things are getting a *little* squeezy in the page->flags
department. The zone takes eight, and of the remaining
24, I'm showing 18 used up. A couple of these can be
recycled easily. I added two to support delayed allocate:
PG_disk_reserved: page has a disk-reservation
PG_space_reclaim: icky hack to avoid deadlocking when
writeback is forced to collapse outstanding
reservations.
A number of the reasons for delalloc are going away now;
we'll be able to do multipage bio-based writeback and
readahead for the map-at-prepare_write buffer-based
filesystems. We'll see.
Updated patchset is at
http://www.zip.com.au/~akpm/linux/patches/2.5/2.5.8-pre3/
It hasn't quite recovered from the changed buffer/page
relationship yet - a heavy dbench run on 1k blocksize ext2
dies after half an hour over a page which didn't come unlocked.
- Went back to open-coded per-CPU page accumulators. I
stared at the assembly for some time and it looked OK,
so I'm not sure what went wrong with the `percpu' version.
I'll have another shot later.
- Split fs/fs-writeback.c out from fs/inode.c. These are
all the functions related to sending bulk file data to
storage. fs/inode.c contains the inode writeback code,
the hashing, all the other stuff involved with manipulating
the state of in-core inodes.
I think this is a reasonable splitup - it makes the diff
more readable too...
- include/linux/writeback.h is for communication between
fs/fs-writeback.c, mm/page-writeback.c and fs/inode.c
- Lots more changes to fs/buffer.c; many of them pointless
cleanups and shuffling functions around and documenting
stuff.
- Documenting the VM/fs locking ordering rules, slowly.
- The locking between __set_page_dirty_buffers(),
try_to_free_buffers() and the functions which attach
buffers to pages is coming together. This exclusion
is needed to preserve the buffer-page relationship
which has been proposed.
It would be a ton easier and cleaner if set_page_dirty
was called under the page lock, but that's rather hard
to arrange. Maybe that would be a better approach.
- We need to talk wli into doing a hashed wakeup for the
buffer layer. Then buffer_head will be:
struct buffer_head {
sector_t b_blocknr; /* block number */
unsigned short b_size; /* block size */
kdev_t b_dev; /* device (B_FREE = free) */
struct block_device *b_bdev;
atomic_t b_count; /* users using this block */
unsigned long b_state; /* buffer state bitmap (see above) */
struct buffer_head *b_this_page;/* circular list of buffers in one page */
char * b_data; /* pointer to data block */
struct page *b_page; /* the page this bh is mapped to */
void (*b_end_io)(struct buffer_head *bh, int uptodate); /* I/O completion */
void *b_private; /* reserved for b_end_io */
struct list_head b_inode_buffers; /* doubly linked list of inode dirty buffers */
};
I suspect we can also remove b_dev, maybe b_size, conceivably
b_data.
-
-
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This archive was generated by hypermail 2b29 : Mon Apr 15 2002 - 22:00:19 EST