Under heavy load, hot metadata pages are often locked by non-committed
transactions, making them difficult to flush to disk. This prevents
the sync point from advancing past a transaction that had modified the
page.
There is a point during the sync barrier processing where all
outstanding transactions have been committed to disk, but no new
transaction have been allowed to proceed. This is the best time
to write the metadata.
Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>
If a metadata page is kept active, it is possible that the sync barrier logic
continues to trigger, even if all active transactions have been phyically
written to the journal. This can cause a hang, since the completion of the
journal I/O is what unsets the sync barrier flag to allow new transactions
to be created.
Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>
1. Establish a simple API for process freezing defined in linux/include/sched.h:
frozen(process) Check for frozen process
freezing(process) Check if a process is being frozen
freeze(process) Tell a process to freeze (go to refrigerator)
thaw_process(process) Restart process
frozen_process(process) Process is frozen now
2. Remove all references to PF_FREEZE and PF_FROZEN from all
kernel sources except sched.h
3. Fix numerous locations where try_to_freeze is manually done by a driver
4. Remove the argument that is no longer necessary from two function calls.
5. Some whitespace cleanup
6. Clear potential race in refrigerator (provides an open window of PF_FREEZE
cleared before setting PF_FROZEN, recalc_sigpending does not check
PF_FROZEN).
This patch does not address the problem of freeze_processes() violating the rule
that a task may only modify its own flags by setting PF_FREEZE. This is not clean
in an SMP environment. freeze(process) is therefore not SMP safe!
Signed-off-by: Christoph Lameter <christoph@lameter.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
fs/jfs/jfs_logmgr.c: In function `jfs_flush_journal':
fs/jfs/jfs_logmgr.c:1632: warning: unused variable `mp'
Some debug code in jfs_flush_journal does nothing when CONFIG_JFS_DEBUG
is not defined. Place the whole code segment within an ifdef to avoid
unnecessary code to be compiled and the warning to be issued.
Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>
This patch adds jfs_syncpt, which calls lmLogSync to write sync points
to the journal both in jfs_sync_fs and when sync barrier processing
completes.
lmLogSync accomplishes two things: 1) it pushes logged-but-dirty
metadata pages to disk, and 2) it writes a sync record to the journal
so that jfs_fsck doesn't need to replay more transactions than is
necessary.
Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
jfs has never worked on architecutures where the page size was not 4K.
Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
JFS code has always assumed a page size of 4K. This patch fixes the
non-pagecache uses of pages to deal with larger pages.
Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Dave Kleikamp