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authorJens Axboe <jens.axboe@oracle.com>2009-05-15 05:32:24 -0400
committerJens Axboe <jens.axboe@oracle.com>2009-05-15 05:32:24 -0400
commitcd17cbfda004fe5f406c01b318c6378d9895896f (patch)
tree821e279bc6d9d52bc13fa6c3905ebbd44a2e4860
parent05dc7b613481c695bb4fc476c6fbb46364b63f62 (diff)
Revert "mm: add /proc controls for pdflush threads"
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 <jens.axboe@oracle.com>
-rw-r--r--Documentation/sysctl/vm.txt28
-rw-r--r--include/linux/writeback.h2
-rw-r--r--kernel/sysctl.c23
-rw-r--r--mm/pdflush.c31
4 files changed, 12 insertions, 72 deletions
diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt
index b716d33912d8..c302ddf629a0 100644
--- a/Documentation/sysctl/vm.txt
+++ b/Documentation/sysctl/vm.txt
@@ -39,8 +39,6 @@ Currently, these files are in /proc/sys/vm:
39- nr_hugepages 39- nr_hugepages
40- nr_overcommit_hugepages 40- nr_overcommit_hugepages
41- nr_pdflush_threads 41- nr_pdflush_threads
42- nr_pdflush_threads_min
43- nr_pdflush_threads_max
44- nr_trim_pages (only if CONFIG_MMU=n) 42- nr_trim_pages (only if CONFIG_MMU=n)
45- numa_zonelist_order 43- numa_zonelist_order
46- oom_dump_tasks 44- oom_dump_tasks
@@ -469,32 +467,6 @@ The default value is 0.
469 467
470============================================================== 468==============================================================
471 469
472nr_pdflush_threads_min
473
474This value controls the minimum number of pdflush threads.
475
476At boot time, the kernel will create and maintain 'nr_pdflush_threads_min'
477threads for the kernel's lifetime.
478
479The default value is 2. The minimum value you can specify is 1, and
480the maximum value is the current setting of 'nr_pdflush_threads_max'.
481
482See 'nr_pdflush_threads_max' below for more information.
483
484==============================================================
485
486nr_pdflush_threads_max
487
488This value controls the maximum number of pdflush threads that can be
489created. The pdflush algorithm will create a new pdflush thread (up to
490this maximum) if no pdflush threads have been available for >= 1 second.
491
492The default value is 8. The minimum value you can specify is the
493current value of 'nr_pdflush_threads_min' and the
494maximum is 1000.
495
496==============================================================
497
498overcommit_memory: 470overcommit_memory:
499 471
500This value contains a flag that enables memory overcommitment. 472This value contains a flag that enables memory overcommitment.
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index 9c1ed1fb6ddb..93445477f86a 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -168,8 +168,6 @@ void writeback_set_ratelimit(void);
168/* pdflush.c */ 168/* pdflush.c */
169extern int nr_pdflush_threads; /* Global so it can be exported to sysctl 169extern int nr_pdflush_threads; /* Global so it can be exported to sysctl
170 read-only. */ 170 read-only. */
171extern int nr_pdflush_threads_max; /* Global so it can be exported to sysctl */
172extern int nr_pdflush_threads_min; /* Global so it can be exported to sysctl */
173 171
174 172
175#endif /* WRITEBACK_H */ 173#endif /* WRITEBACK_H */
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index ea78fa101ad6..b2970d56fb76 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -101,7 +101,6 @@ static int __maybe_unused one = 1;
101static int __maybe_unused two = 2; 101static int __maybe_unused two = 2;
102static unsigned long one_ul = 1; 102static unsigned long one_ul = 1;
103static int one_hundred = 100; 103static int one_hundred = 100;
104static int one_thousand = 1000;
105 104
106/* this is needed for the proc_doulongvec_minmax of vm_dirty_bytes */ 105/* this is needed for the proc_doulongvec_minmax of vm_dirty_bytes */
107static unsigned long dirty_bytes_min = 2 * PAGE_SIZE; 106static unsigned long dirty_bytes_min = 2 * PAGE_SIZE;
@@ -1034,28 +1033,6 @@ static struct ctl_table vm_table[] = {
1034 .proc_handler = &proc_dointvec, 1033 .proc_handler = &proc_dointvec,
1035 }, 1034 },
1036 { 1035 {
1037 .ctl_name = CTL_UNNUMBERED,
1038 .procname = "nr_pdflush_threads_min",
1039 .data = &nr_pdflush_threads_min,
1040 .maxlen = sizeof nr_pdflush_threads_min,
1041 .mode = 0644 /* read-write */,
1042 .proc_handler = &proc_dointvec_minmax,
1043 .strategy = &sysctl_intvec,
1044 .extra1 = &one,
1045 .extra2 = &nr_pdflush_threads_max,
1046 },
1047 {
1048 .ctl_name = CTL_UNNUMBERED,
1049 .procname = "nr_pdflush_threads_max",
1050 .data = &nr_pdflush_threads_max,
1051 .maxlen = sizeof nr_pdflush_threads_max,
1052 .mode = 0644 /* read-write */,
1053 .proc_handler = &proc_dointvec_minmax,
1054 .strategy = &sysctl_intvec,
1055 .extra1 = &nr_pdflush_threads_min,
1056 .extra2 = &one_thousand,
1057 },
1058 {
1059 .ctl_name = VM_SWAPPINESS, 1036 .ctl_name = VM_SWAPPINESS,
1060 .procname = "swappiness", 1037 .procname = "swappiness",
1061 .data = &vm_swappiness, 1038 .data = &vm_swappiness,
diff --git a/mm/pdflush.c b/mm/pdflush.c
index f2caf96993f8..235ac440c44e 100644
--- a/mm/pdflush.c
+++ b/mm/pdflush.c
@@ -58,14 +58,6 @@ static DEFINE_SPINLOCK(pdflush_lock);
58int nr_pdflush_threads = 0; 58int nr_pdflush_threads = 0;
59 59
60/* 60/*
61 * The max/min number of pdflush threads. R/W by sysctl at
62 * /proc/sys/vm/nr_pdflush_threads_max/min
63 */
64int nr_pdflush_threads_max __read_mostly = MAX_PDFLUSH_THREADS;
65int nr_pdflush_threads_min __read_mostly = MIN_PDFLUSH_THREADS;
66
67
68/*
69 * The time at which the pdflush thread pool last went empty 61 * The time at which the pdflush thread pool last went empty
70 */ 62 */
71static unsigned long last_empty_jifs; 63static unsigned long last_empty_jifs;
@@ -76,7 +68,7 @@ static unsigned long last_empty_jifs;
76 * Thread pool management algorithm: 68 * Thread pool management algorithm:
77 * 69 *
78 * - The minimum and maximum number of pdflush instances are bound 70 * - The minimum and maximum number of pdflush instances are bound
79 * by nr_pdflush_threads_min and nr_pdflush_threads_max. 71 * by MIN_PDFLUSH_THREADS and MAX_PDFLUSH_THREADS.
80 * 72 *
81 * - If there have been no idle pdflush instances for 1 second, create 73 * - If there have been no idle pdflush instances for 1 second, create
82 * a new one. 74 * a new one.
@@ -142,13 +134,14 @@ static int __pdflush(struct pdflush_work *my_work)
142 * To throttle creation, we reset last_empty_jifs. 134 * To throttle creation, we reset last_empty_jifs.
143 */ 135 */
144 if (time_after(jiffies, last_empty_jifs + 1 * HZ)) { 136 if (time_after(jiffies, last_empty_jifs + 1 * HZ)) {
145 if (list_empty(&pdflush_list) && 137 if (list_empty(&pdflush_list)) {
146 nr_pdflush_threads < nr_pdflush_threads_max) { 138 if (nr_pdflush_threads < MAX_PDFLUSH_THREADS) {
147 last_empty_jifs = jiffies; 139 last_empty_jifs = jiffies;
148 nr_pdflush_threads++; 140 nr_pdflush_threads++;
149 spin_unlock_irq(&pdflush_lock); 141 spin_unlock_irq(&pdflush_lock);
150 start_one_pdflush_thread(); 142 start_one_pdflush_thread();
151 spin_lock_irq(&pdflush_lock); 143 spin_lock_irq(&pdflush_lock);
144 }
152 } 145 }
153 } 146 }
154 147
@@ -160,7 +153,7 @@ static int __pdflush(struct pdflush_work *my_work)
160 */ 153 */
161 if (list_empty(&pdflush_list)) 154 if (list_empty(&pdflush_list))
162 continue; 155 continue;
163 if (nr_pdflush_threads <= nr_pdflush_threads_min) 156 if (nr_pdflush_threads <= MIN_PDFLUSH_THREADS)
164 continue; 157 continue;
165 pdf = list_entry(pdflush_list.prev, struct pdflush_work, list); 158 pdf = list_entry(pdflush_list.prev, struct pdflush_work, list);
166 if (time_after(jiffies, pdf->when_i_went_to_sleep + 1 * HZ)) { 159 if (time_after(jiffies, pdf->when_i_went_to_sleep + 1 * HZ)) {
@@ -266,9 +259,9 @@ static int __init pdflush_init(void)
266 * Pre-set nr_pdflush_threads... If we fail to create, 259 * Pre-set nr_pdflush_threads... If we fail to create,
267 * the count will be decremented. 260 * the count will be decremented.
268 */ 261 */
269 nr_pdflush_threads = nr_pdflush_threads_min; 262 nr_pdflush_threads = MIN_PDFLUSH_THREADS;
270 263
271 for (i = 0; i < nr_pdflush_threads_min; i++) 264 for (i = 0; i < MIN_PDFLUSH_THREADS; i++)
272 start_one_pdflush_thread(); 265 start_one_pdflush_thread();
273 return 0; 266 return 0;
274} 267}