path: root/mm/pdflush.c
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2009-09-11writeback: get rid of pdflush completelyJens Axboe-269/+0
It is now unused, so kill it off. Signed-off-by: Jens Axboe <>
2009-05-15Revert "mm: add /proc controls for pdflush threads"Jens Axboe-19/+12
This reverts commit fafd688e4c0c34da0f3de909881117d374e4c7af. Work is progressing to switch away from pdflush as the process backing for flushing out dirty data. So it seems pointless to add more knobs to control pdflush threads. The original author of the patch did not have any specific use cases for adding the knobs, so we can easily revert this before 2.6.30 to avoid having to maintain this API forever. Signed-off-by: Jens Axboe <>
2009-04-07mm: add /proc controls for pdflush threadsPeter W Morreale-12/+19
Add /proc entries to give the admin the ability to control the minimum and maximum number of pdflush threads. This allows finer control of pdflush on both large and small machines. The rationale is simply one size does not fit all. Admins on large and/or small systems may want to tune the min/max pdflush thread count to best suit their needs. Right now the min/max is hardcoded to 2/8. While probably a fair estimate for smaller machines, large machines with large numbers of CPUs and large numbers of filesystems/block devices may benefit from larger numbers of threads working on different block devices. Even if the background flushing algorithm is radically changed, it is still likely that multiple threads will be involved and admins would still desire finer control on the min/max other than to have to recompile the kernel. The patch adds '/proc/sys/vm/nr_pdflush_threads_min' and '/proc/sys/vm/nr_pdflush_threads_max' with r/w permissions. The minimum value for nr_pdflush_threads_min is 1 and the maximum value is the current value of nr_pdflush_threads_max. This minimum is required since additional thread creation is performed in a pdflush thread itself. The minimum value for nr_pdflush_threads_max is the current value of nr_pdflush_threads_min and the maximum value can be 1000. Documentation/sysctl/vm.txt is also updated. [ fix comment, fix whitespace, use __read_mostly] Signed-off-by: Peter W Morreale <> Reviewed-by: Rik van Riel <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-04-07mm: fix pdflush thread creation upper boundPeter W Morreale-6/+24
Fix a race on creating pdflush threads. Without the patch, it is possible to create more than MAX_PDFLUSH_THREADS threads, and this has been observed in practice on IO loaded SMP machines. The fix involves moving the lock around to protect the check against the thread count and correctly dealing with thread creation failure. This fix also _mostly_ repairs a race condition on how quickly the threads are created. The original intent was to create a pdflush thread (up to the max allowed) every second. Without this patch is is possible to create NCPUS pdflush threads concurrently. The 'mostly' caveat is because an assumption is made that thread creation will be successful. If we fail to create the thread, the miss is not considered fatal. (we will try again in 1 second) Signed-off-by: Peter W Morreale <> Reviewed-by: Rik van Riel <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-03-30cpumask: remove dangerous CPU_MASK_ALL_PTR, &CPU_MASK_ALLRusty Russell-1/+1
Impact: cleanup (Thanks to Al Viro for reminding me of this, via Ingo) CPU_MASK_ALL is the (deprecated) "all bits set" cpumask, defined as so: #define CPU_MASK_ALL (cpumask_t) { { ... } } Taking the address of such a temporary is questionable at best, unfortunately 321a8e9d (cpumask: add CPU_MASK_ALL_PTR macro) added CPU_MASK_ALL_PTR: #define CPU_MASK_ALL_PTR (&CPU_MASK_ALL) Which formalizes this practice. One day gcc could bite us over this usage (though we seem to have gotten away with it so far). So replace everywhere which used &CPU_MASK_ALL or CPU_MASK_ALL_PTR with the modern "cpu_all_mask" (a real const struct cpumask *). Signed-off-by: Rusty Russell <> Acked-by: Ingo Molnar <> Reported-by: Al Viro <> Cc: Mike Travis <>
2009-01-01cpumask: convert mm/Rusty Russell-3/+13
Impact: Use new API Convert kernel mm functions to use struct cpumask. We skip include/linux/percpu.h and mm/allocpercpu.c, which are in flux. Signed-off-by: Rusty Russell <> Signed-off-by: Mike Travis <> Reviewed-by: Christoph Lameter <>
2008-10-16Remove Andrew Morton's old email accountsFrancois Cami-1/+1
People can use the real name an an index into MAINTAINERS to find the current email address. Signed-off-by: Francois Cami <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-07-25pdflush: use time_after() instead of open-coding itOGAWA Hirofumi-2/+2
Signed-off-by: OGAWA Hirofumi <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-05-13mm/pdflush.c: merge the same code in two pathDenis Cheng-2/+2
Signed-off-by: Denis Cheng <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-04-21Merge branch 'for-linus' of ↵Linus Torvalds-2/+2
git:// * 'for-linus' of git:// (24 commits) DOC: A couple corrections and clarifications in USB doc. Generate a slightly more informative error msg for bad HZ fix typo "is" -> "if" in Makefile ext*: spelling fix prefered -> preferred DOCUMENTATION: Use newer DEFINE_SPINLOCK macro in docs. KEYS: Fix the comment to match the file name in rxrpc-type.h. RAID: remove trailing space from printk line DMA engine: typo fixes Remove unused MAX_NODES_SHIFT MAINTAINERS: Clarify access to OCFS2 development mailing list. V4L: Storage class should be before const qualifier (sn9c102) V4L: Storage class should be before const qualifier sonypi: Storage class should be before const qualifier intel_menlow: Storage class should be before const qualifier DVB: Storage class should be before const qualifier arm: Storage class should be before const qualifier ALSA: Storage class should be before const qualifier acpi: Storage class should be before const qualifier firmware_sample_driver.c: fix coding style MAINTAINERS: Add ati_remote2 driver ... Fixed up trivial conflicts in firmware_sample_driver.c
2008-04-21trivial: small cleanupsPavel Machek-2/+2
These are small cleanups all over the tree. Trivial style and comment changes to fs/select.c, kernel/signal.c, kernel/stop_machine.c & mm/pdflush.c Signed-off-by: Pavel Machek <> Signed-off-by: Jesper Juhl <>
2008-04-19cpuset: modify cpuset_set_cpus_allowed to use cpumask pointerMike Travis-2/+2
* Modify cpuset_cpus_allowed to return the currently allowed cpuset via a pointer argument instead of as the function return value. * Use new set_cpus_allowed_ptr function. * Cleanup CPU_MASK_ALL and NODE_MASK_ALL uses. Depends on: [sched-devel]: sched: add new set_cpus_allowed_ptr function Signed-off-by: Mike Travis <> Signed-off-by: Ingo Molnar <>
2007-07-17Freezer: make kernel threads nonfreezable by defaultRafael J. Wysocki-0/+1
Currently, the freezer treats all tasks as freezable, except for the kernel threads that explicitly set the PF_NOFREEZE flag for themselves. This approach is problematic, since it requires every kernel thread to either set PF_NOFREEZE explicitly, or call try_to_freeze(), even if it doesn't care for the freezing of tasks at all. It seems better to only require the kernel threads that want to or need to be frozen to use some freezer-related code and to remove any freezer-related code from the other (nonfreezable) kernel threads, which is done in this patch. The patch causes all kernel threads to be nonfreezable by default (ie. to have PF_NOFREEZE set by default) and introduces the set_freezable() function that should be called by the freezable kernel threads in order to unset PF_NOFREEZE. It also makes all of the currently freezable kernel threads call set_freezable(), so it shouldn't cause any (intentional) change of behaviour to appear. Additionally, it updates documentation to describe the freezing of tasks more accurately. [ build fixes] Signed-off-by: Rafael J. Wysocki <> Acked-by: Nigel Cunningham <> Cc: Pavel Machek <> Cc: Oleg Nesterov <> Cc: Gautham R Shenoy <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2006-12-07[PATCH] Add include/linux/freezer.h and move definitions from sched.hNigel Cunningham-0/+1
Move process freezing functions from include/linux/sched.h to freezer.h, so that modifications to the freezer or the kernel configuration don't require recompiling just about everything. [ fix ueagle driver] Signed-off-by: Nigel Cunningham <> Cc: "Rafael J. Wysocki" <> Cc: Pavel Machek <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2006-06-25[PATCH] pdflush: handle resume wakeupsAndrew Morton-8/+7
pdflush is carefully designed to ensure that all wakeups have some corresponding work to do - if a woken-up pdflush thread discovers that it hasn't been given any work to do then this is considered an error. That all broke when swsusp came along - because a timer-delivered wakeup to a frozen pdflush thread will just get lost. This causes the pdflush thread to get lost as well: the writeback timer is supposed to be re-armed by pdflush in process context, but pdflush doesn't execute the callout which does this. Fix that up by ignoring the return value from try_to_freeze(): jsut proceed, see if we have any work pending and only go back to sleep if that is not the case. Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2006-06-23[PATCH] More BUG_ON conversionEric Sesterhenn-2/+1
Signed-off-by: Eric Sesterhenn <> Signed-off-by: Alexey Dobriyan <> Cc: Bartlomiej Zolnierkiewicz <> Cc: Alan Cox <> Cc: James Bottomley <> Acked-by: "Salyzyn, Mark" <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2006-01-08[PATCH] Swap Migration V5: PF_SWAPWRITE to allow writing to swapChristoph Lameter-1/+1
Add PF_SWAPWRITE to control a processes permission to write to swap. - Use PF_SWAPWRITE in may_write_to_queue() instead of checking for kswapd and pdflush - Set PF_SWAPWRITE flag for kswapd and pdflush Signed-off-by: Christoph Lameter <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2005-10-30[PATCH] cpusets: confine pdflush to its cpusetPaul Jackson-0/+13
This patch keeps pdflush daemons on the same cpuset as their parent, the kthread daemon. Some large NUMA configurations put as much as they can of kernel threads and other classic Unix load in what's called a bootcpuset, keeping the rest of the system free for dedicated jobs. This effort is thwarted by pdflush, which dynamically destroys and recreates pdflush daemons depending on load. It's easy enough to force the originally created pdflush deamons into the bootcpuset, at system boottime. But the pdflush threads created later were allowed to run freely across the system, due to the necessary line in their startup kthread(): set_cpus_allowed(current, CPU_MASK_ALL); By simply coding pdflush to start its threads with the cpus_allowed restrictions of its cpuset (inherited from kthread, its parent) we can ensure that dynamically created pdflush threads are also kept in the bootcpuset. On systems w/o cpusets, or w/o a bootcpuset implementation, the following will have no affect, leaving pdflush to run on any CPU, as before. Signed-off-by: Paul Jackson <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2005-06-25[PATCH] Cleanup patch for process freezingChristoph Lameter-1/+1
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 <> Signed-off-by: Linus Torvalds <>
2005-04-16Linux-2.6.12-rc2v2.6.12-rc2Linus Torvalds-0/+228
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!