linux/mm/backing-dev.c, branch v2.6.28

mm/backing-dev.c: remove recently-added WARN_ON()

2008-12-10T16:01:52Z

On second thoughts, this is just going to disturb people while telling us things which we already knew. Cc: Peter Korsgaard Cc: Peter Zijlstra Cc: Kay Sievers Cc: David Woodhouse Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

bdi: register sysfs bdi device only once per queue

2008-12-02T23:50:40Z

Devices which share the same queue, like floppies and mtd devices, get registered multiple times in the bdi interface, but bdi accounts only the last registered device of the devices sharing one queue. On remove, all earlier registered devices leak, stay around in sysfs, and cause "duplicate filename" errors if the devices are re-created. This prevents the creation of multiple bdi interfaces per queue, and the bdi device will carry the dev_t name of the block device which is the first one registered, of the pool of devices using the same queue. [akpm@linux-foundation.org: add a WARN_ON so we know which drivers are misbehaving] Tested-by: Peter Korsgaard Acked-by: Peter Zijlstra Signed-off-by: Kay Sievers Cc: David Woodhouse Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: bdi: fix race in bdi_class device creation

2008-05-20T20:31:53Z

There is a race from when a device is created with device_create() and then the drvdata is set with a call to dev_set_drvdata() in which a sysfs file could be open, yet the drvdata will be NULL, causing all sorts of bad things to happen. This patch fixes the problem by using the new function, device_create_vargs(). Many thanks to Arthur Jones for reporting the bug, and testing patches out. Cc: Kay Sievers Cc: Arthur Jones Cc: Peter Zijlstra Cc: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman

mm: bdi: move statistics to debugfs

2008-04-30T15:29:50Z

Move BDI statistics to debugfs: /sys/kernel/debug/bdi//stats Use postcore_initcall() to initialize the sysfs class and debugfs, because debugfs is initialized in core_initcall(). Update descriptions in ABI documentation. Signed-off-by: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: bdi: allow setting a maximum for the bdi dirty limit

2008-04-30T15:29:50Z

Add "max_ratio" to /sys/class/bdi. This indicates the maximum percentage of the global dirty threshold allocated to this bdi. [mszeredi@suse.cz] - fix parsing in max_ratio_store(). - export bdi_set_max_ratio() to modules - limit bdi_dirty with bdi->max_ratio - document new sysfs attribute Signed-off-by: Peter Zijlstra Signed-off-by: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: bdi: allow setting a minimum for the bdi dirty limit

2008-04-30T15:29:50Z

Under normal circumstances each device is given a part of the total write-back cache that relates to its current avg writeout speed in relation to the other devices. min_ratio - allows one to assign a minimum portion of the write-back cache to a particular device. This is useful in situations where you might want to provide a minimum QoS. (One request for this feature came from flash based storage people who wanted to avoid writing out at all costs - they of course needed some pdflush hacks as well) max_ratio - allows one to assign a maximum portion of the dirty limit to a particular device. This is useful in situations where you want to avoid one device taking all or most of the write-back cache. Eg. an NFS mount that is prone to get stuck, or a FUSE mount which you don't trust to play fair. Add "min_ratio" to /sys/class/bdi. This indicates the minimum percentage of the global dirty threshold allocated to this bdi. [mszeredi@suse.cz] - fix parsing in min_ratio_store() - document new sysfs attribute Signed-off-by: Peter Zijlstra Signed-off-by: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: bdi: export BDI attributes in sysfs

2008-04-30T15:29:49Z

Provide a place in sysfs (/sys/class/bdi) for the backing_dev_info object. This allows us to see and set the various BDI specific variables. In particular this properly exposes the read-ahead window for all relevant users and /sys/block//queue/read_ahead_kb should be deprecated. With patient help from Kay Sievers and Greg KH [mszeredi@suse.cz] - split off NFS and FUSE changes into separate patches - document new sysfs attributes under Documentation/ABI - do bdi_class_init as a core_initcall, otherwise the "default" BDI won't be initialized - remove bdi_init_fmt macro, it's not used very much [akpm@linux-foundation.org: fix ia64 warning] Signed-off-by: Peter Zijlstra Cc: Kay Sievers Acked-by: Greg KH Cc: Trond Myklebust Signed-off-by: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/backing-dev.c: fix percpu_counter_destroy call bug in bdi_init

2007-12-05T17:21:18Z

this call should use the array index j, not i. But with this approach, just one int i is enough, int j is not needed. Signed-off-by: Denis Cheng Cc: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: per device dirty threshold

2007-10-17T15:42:45Z

Scale writeback cache per backing device, proportional to its writeout speed. By decoupling the BDI dirty thresholds a number of problems we currently have will go away, namely: - mutual interference starvation (for any number of BDIs); - deadlocks with stacked BDIs (loop, FUSE and local NFS mounts). It might be that all dirty pages are for a single BDI while other BDIs are idling. By giving each BDI a 'fair' share of the dirty limit, each one can have dirty pages outstanding and make progress. A global threshold also creates a deadlock for stacked BDIs; when A writes to B, and A generates enough dirty pages to get throttled, B will never start writeback until the dirty pages go away. Again, by giving each BDI its own 'independent' dirty limit, this problem is avoided. So the problem is to determine how to distribute the total dirty limit across the BDIs fairly and efficiently. A DBI that has a large dirty limit but does not have any dirty pages outstanding is a waste. What is done is to keep a floating proportion between the DBIs based on writeback completions. This way faster/more active devices get a larger share than slower/idle devices. [akpm@linux-foundation.org: fix warnings] [hugh@veritas.com: Fix occasional hang when a task couldn't get out of balance_dirty_pages] Signed-off-by: Peter Zijlstra Signed-off-by: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: scalable bdi statistics counters

2007-10-17T15:42:45Z

Provide scalable per backing_dev_info statistics counters. Signed-off-by: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds