linux/block/cfq-iosched.c, branch v2.6.20-rc4

[PATCH] cfq-iosched: merging problem

2007-01-02T17:46:16Z

Two issues: - The final return 1 should be a return 0, otherwise comparing cfqq is a noop. - bio_sync() only checks the sync flag, while rq_is_sync() checks both for READ and sync. The latter is what we want. Expand the bio check to include reads, and relax the restriction to allow merging of async io into sync requests. In the future we want to clean up the SYNC logic, right now it means both sync request (such as READ and O_DIRECT WRITE) and unplug-on-issue. Leave that for later. Signed-off-by: Jens Axboe Signed-off-by: Linus Torvalds

[PATCH] cfq-iosched: tighten allow merge criteria

2006-12-22T22:13:08Z

The logic in cfq_allow_merge() wasn't clear enough - basically allow merging for the same queues only. Do a fast check for 'rq and bio both sync/async' before doing the cfqq hash lookup. This is verified to work with the fixed elv_try_merge() from commit bb4067e34159648d394943d5e2a011f838bff22f. Signed-off-by: Jens Axboe Signed-off-by: Linus Torvalds

[PATCH] cfq-iosched: don't allow sync merges across queues

2006-12-20T10:04:12Z

Currently we allow any merge, even if the io originates from different processes. This can cause really bad starvation and unfairness, if those ios happen to be synchronous (reads or direct writes). So add a allow_merge hook to the io scheduler ops, so an io scheduler can help decide whether a bio/process combination may be merged with an existing request. Signed-off-by: Jens Axboe

[PATCH] Propagate down request sync flag

2006-12-13T12:02:26Z

We need to do this, otherwise the io schedulers don't get access to the sync flag. Then they cannot tell the difference between a regular write and an O_DIRECT write, which can cause a performance loss. Signed-off-by: Jens Axboe

[PATCH] slab: remove kmem_cache_t

2006-12-07T16:39:25Z

Replace all uses of kmem_cache_t with struct kmem_cache. The patch was generated using the following script: #!/bin/sh # # Replace one string by another in all the kernel sources. # set -e for file in `find * -name "*.c" -o -name "*.h"|xargs grep -l $1`; do quilt add $file sed -e "1,\$s/$1/$2/g" $file >/tmp/$$ mv /tmp/$$ $file quilt refresh done The script was run like this sh replace kmem_cache_t "struct kmem_cache" Signed-off-by: Christoph Lameter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

2006-12-05T14:37:56Z

Conflicts: drivers/infiniband/core/iwcm.c drivers/net/chelsio/cxgb2.c drivers/net/wireless/bcm43xx/bcm43xx_main.c drivers/net/wireless/prism54/islpci_eth.c drivers/usb/core/hub.h drivers/usb/input/hid-core.c net/core/netpoll.c Fix up merge failures with Linus's head and fix new compilation failures. Signed-Off-By: David Howells

[BLOCK] Cleanup unused variable passing

2006-12-01T09:42:33Z

- ->init_queue() does not need the elevator passed in - ->put_request() is a hot path and need not have the queue passed in - cfq_update_io_seektime() does not need cfqd passed in Signed-off-by: Jens Axboe

WorkStruct: Pass the work_struct pointer instead of context data

2006-11-22T14:55:48Z

Pass the work_struct pointer to the work function rather than context data. The work function can use container_of() to work out the data. For the cases where the container of the work_struct may go away the moment the pending bit is cleared, it is made possible to defer the release of the structure by deferring the clearing of the pending bit. To make this work, an extra flag is introduced into the management side of the work_struct. This governs auto-release of the structure upon execution. Ordinarily, the work queue executor would release the work_struct for further scheduling or deallocation by clearing the pending bit prior to jumping to the work function. This means that, unless the driver makes some guarantee itself that the work_struct won't go away, the work function may not access anything else in the work_struct or its container lest they be deallocated.. This is a problem if the auxiliary data is taken away (as done by the last patch). However, if the pending bit is *not* cleared before jumping to the work function, then the work function *may* access the work_struct and its container with no problems. But then the work function must itself release the work_struct by calling work_release(). In most cases, automatic release is fine, so this is the default. Special initiators exist for the non-auto-release case (ending in _NAR). Signed-Off-By: David Howells

[PATCH] CFQ: request <-> request merging rr_list fixup

2006-10-31T16:12:45Z

In very rare circumstances would we be pruning a merged request and at the same time delete the implicated cfqq from the rr_list, and not readd it when the merged request got added. This could cause io stalls until that process issued io again. Fix it up by putting the rr_list add handling into cfq_add_rq_rb(), identical to how pruning is handled in cfq_del_rq_rb(). This fixes a hang reproducible with fsx-linux. Signed-off-by: Jens Axboe Signed-off-by: Linus Torvalds

[PATCH] CFQ: bad locking in changed_ioprio()

2006-10-30T19:01:50Z

When the ioprio code recently got juggled a bit, a bug was introduced. changed_ioprio() is no longer called with interrupts disabled, so using plain spin_lock() on the queue_lock is a bug. Signed-off-by: Jens Axboe Signed-off-by: Linus Torvalds