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writeback: s/bdi/wb/ in mm/page-writeback.c

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Writeback operations will now be per wb (bdi_writeback) instead of
bdi.  Replace the relevant bdi references in symbol names and comments
with wb.  This patch is purely cosmetic and doesn't make any
functional changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Tejun Heo 2015-05-22 17:13:29 -04:00 committed by Jens Axboe
parent a88a341a73
commit de1fff37b2
1 changed files with 134 additions and 136 deletions
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270
mm/page-writeback.c
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@ -595,7 +595,7 @@ static long long pos_ratio_polynom(unsigned long setpoint,
*
* (o) global/bdi setpoints
*
* We want the dirty pages be balanced around the global/bdi setpoints.
* We want the dirty pages be balanced around the global/wb setpoints.
* When the number of dirty pages is higher/lower than the setpoint, the
* dirty position control ratio (and hence task dirty ratelimit) will be
* decreased/increased to bring the dirty pages back to the setpoint.
@ -605,8 +605,8 @@ static long long pos_ratio_polynom(unsigned long setpoint,
* if (dirty < setpoint) scale up pos_ratio
* if (dirty > setpoint) scale down pos_ratio
*
* if (bdi_dirty < bdi_setpoint) scale up pos_ratio
* if (bdi_dirty > bdi_setpoint) scale down pos_ratio
* if (wb_dirty < wb_setpoint) scale up pos_ratio
* if (wb_dirty > wb_setpoint) scale down pos_ratio
*
* task_ratelimit = dirty_ratelimit * pos_ratio >> RATELIMIT_CALC_SHIFT
*
@ -631,7 +631,7 @@ static long long pos_ratio_polynom(unsigned long setpoint,
* 0 +------------.------------------.----------------------*------------->
* freerun^ setpoint^ limit^ dirty pages
*
* (o) bdi control line
* (o) wb control line
*
* ^ pos_ratio
* |
@ -657,27 +657,27 @@ static long long pos_ratio_polynom(unsigned long setpoint,
* | . .
* | . .
* 0 +----------------------.-------------------------------.------------->
* bdi_setpoint^ x_intercept^
* wb_setpoint^ x_intercept^
*
* The bdi control line won't drop below pos_ratio=1/4, so that bdi_dirty can
* The wb control line won't drop below pos_ratio=1/4, so that wb_dirty can
* be smoothly throttled down to normal if it starts high in situations like
* - start writing to a slow SD card and a fast disk at the same time. The SD
* card's bdi_dirty may rush to many times higher than bdi_setpoint.
* - the bdi dirty thresh drops quickly due to change of JBOD workload
* card's wb_dirty may rush to many times higher than wb_setpoint.
* - the wb dirty thresh drops quickly due to change of JBOD workload
*/
static unsigned long wb_position_ratio(struct bdi_writeback *wb,
unsigned long thresh,
unsigned long bg_thresh,
unsigned long dirty,
unsigned long bdi_thresh,
unsigned long bdi_dirty)
unsigned long wb_thresh,
unsigned long wb_dirty)
{
unsigned long write_bw = wb->avg_write_bandwidth;
unsigned long freerun = dirty_freerun_ceiling(thresh, bg_thresh);
unsigned long limit = hard_dirty_limit(thresh);
unsigned long x_intercept;
unsigned long setpoint; /* dirty pages' target balance point */
unsigned long bdi_setpoint;
unsigned long wb_setpoint;
unsigned long span;
long long pos_ratio; /* for scaling up/down the rate limit */
long x;
@ -696,146 +696,145 @@ static unsigned long wb_position_ratio(struct bdi_writeback *wb,
/*
* The strictlimit feature is a tool preventing mistrusted filesystems
* from growing a large number of dirty pages before throttling. For
* such filesystems balance_dirty_pages always checks bdi counters
* against bdi limits. Even if global "nr_dirty" is under "freerun".
* such filesystems balance_dirty_pages always checks wb counters
* against wb limits. Even if global "nr_dirty" is under "freerun".
* This is especially important for fuse which sets bdi->max_ratio to
* 1% by default. Without strictlimit feature, fuse writeback may
* consume arbitrary amount of RAM because it is accounted in
* NR_WRITEBACK_TEMP which is not involved in calculating "nr_dirty".
*
* Here, in wb_position_ratio(), we calculate pos_ratio based on
* two values: bdi_dirty and bdi_thresh. Let's consider an example:
* two values: wb_dirty and wb_thresh. Let's consider an example:
* total amount of RAM is 16GB, bdi->max_ratio is equal to 1%, global
* limits are set by default to 10% and 20% (background and throttle).
* Then bdi_thresh is 1% of 20% of 16GB. This amounts to ~8K pages.
* wb_dirty_limit(wb, bg_thresh) is about ~4K pages. bdi_setpoint is
* about ~6K pages (as the average of background and throttle bdi
* Then wb_thresh is 1% of 20% of 16GB. This amounts to ~8K pages.
* wb_dirty_limit(wb, bg_thresh) is about ~4K pages. wb_setpoint is
* about ~6K pages (as the average of background and throttle wb
* limits). The 3rd order polynomial will provide positive feedback if
* bdi_dirty is under bdi_setpoint and vice versa.
* wb_dirty is under wb_setpoint and vice versa.
*
* Note, that we cannot use global counters in these calculations
* because we want to throttle process writing to a strictlimit BDI
* because we want to throttle process writing to a strictlimit wb
* much earlier than global "freerun" is reached (~23MB vs. ~2.3GB
* in the example above).
*/
if (unlikely(wb->bdi->capabilities & BDI_CAP_STRICTLIMIT)) {
long long bdi_pos_ratio;
unsigned long bdi_bg_thresh;
long long wb_pos_ratio;
unsigned long wb_bg_thresh;
if (bdi_dirty < 8)
if (wb_dirty < 8)
return min_t(long long, pos_ratio * 2,
2 << RATELIMIT_CALC_SHIFT);
if (bdi_dirty >= bdi_thresh)
if (wb_dirty >= wb_thresh)
return 0;
bdi_bg_thresh = div_u64((u64)bdi_thresh * bg_thresh, thresh);
bdi_setpoint = dirty_freerun_ceiling(bdi_thresh,
bdi_bg_thresh);
wb_bg_thresh = div_u64((u64)wb_thresh * bg_thresh, thresh);
wb_setpoint = dirty_freerun_ceiling(wb_thresh, wb_bg_thresh);
if (bdi_setpoint == 0 || bdi_setpoint == bdi_thresh)
if (wb_setpoint == 0 || wb_setpoint == wb_thresh)
return 0;
bdi_pos_ratio = pos_ratio_polynom(bdi_setpoint, bdi_dirty,
bdi_thresh);
wb_pos_ratio = pos_ratio_polynom(wb_setpoint, wb_dirty,
wb_thresh);
/*
* Typically, for strictlimit case, bdi_setpoint << setpoint
* and pos_ratio >> bdi_pos_ratio. In the other words global
* Typically, for strictlimit case, wb_setpoint << setpoint
* and pos_ratio >> wb_pos_ratio. In the other words global
* state ("dirty") is not limiting factor and we have to
* make decision based on bdi counters. But there is an
* make decision based on wb counters. But there is an
* important case when global pos_ratio should get precedence:
* global limits are exceeded (e.g. due to activities on other
* BDIs) while given strictlimit BDI is below limit.
* wb's) while given strictlimit wb is below limit.
*
* "pos_ratio * bdi_pos_ratio" would work for the case above,
* "pos_ratio * wb_pos_ratio" would work for the case above,
* but it would look too non-natural for the case of all
* activity in the system coming from a single strictlimit BDI
* activity in the system coming from a single strictlimit wb
* with bdi->max_ratio == 100%.
*
* Note that min() below somewhat changes the dynamics of the
* control system. Normally, pos_ratio value can be well over 3
* (when globally we are at freerun and bdi is well below bdi
* (when globally we are at freerun and wb is well below wb
* setpoint). Now the maximum pos_ratio in the same situation
* is 2. We might want to tweak this if we observe the control
* system is too slow to adapt.
*/
return min(pos_ratio, bdi_pos_ratio);
return min(pos_ratio, wb_pos_ratio);
}
/*
* We have computed basic pos_ratio above based on global situation. If
* the bdi is over/under its share of dirty pages, we want to scale
* the wb is over/under its share of dirty pages, we want to scale
* pos_ratio further down/up. That is done by the following mechanism.
*/
/*
* bdi setpoint
* wb setpoint
*
* f(bdi_dirty) := 1.0 + k * (bdi_dirty - bdi_setpoint)
* f(wb_dirty) := 1.0 + k * (wb_dirty - wb_setpoint)
*
* x_intercept - bdi_dirty
* x_intercept - wb_dirty
* := --------------------------
* x_intercept - bdi_setpoint
* x_intercept - wb_setpoint
*
* The main bdi control line is a linear function that subjects to
* The main wb control line is a linear function that subjects to
*
* (1) f(bdi_setpoint) = 1.0
* (2) k = - 1 / (8 * write_bw) (in single bdi case)
* or equally: x_intercept = bdi_setpoint + 8 * write_bw
* (1) f(wb_setpoint) = 1.0
* (2) k = - 1 / (8 * write_bw) (in single wb case)
* or equally: x_intercept = wb_setpoint + 8 * write_bw
*
* For single bdi case, the dirty pages are observed to fluctuate
* For single wb case, the dirty pages are observed to fluctuate
* regularly within range
* [bdi_setpoint - write_bw/2, bdi_setpoint + write_bw/2]
* [wb_setpoint - write_bw/2, wb_setpoint + write_bw/2]
* for various filesystems, where (2) can yield in a reasonable 12.5%
* fluctuation range for pos_ratio.
*
* For JBOD case, bdi_thresh (not bdi_dirty!) could fluctuate up to its
* For JBOD case, wb_thresh (not wb_dirty!) could fluctuate up to its
* own size, so move the slope over accordingly and choose a slope that
* yields 100% pos_ratio fluctuation on suddenly doubled bdi_thresh.
* yields 100% pos_ratio fluctuation on suddenly doubled wb_thresh.
*/
if (unlikely(bdi_thresh > thresh))
bdi_thresh = thresh;
if (unlikely(wb_thresh > thresh))
wb_thresh = thresh;
/*
* It's very possible that bdi_thresh is close to 0 not because the
* It's very possible that wb_thresh is close to 0 not because the
* device is slow, but that it has remained inactive for long time.
* Honour such devices a reasonable good (hopefully IO efficient)
* threshold, so that the occasional writes won't be blocked and active
* writes can rampup the threshold quickly.
*/
bdi_thresh = max(bdi_thresh, (limit - dirty) / 8);
wb_thresh = max(wb_thresh, (limit - dirty) / 8);
/*
* scale global setpoint to bdi's:
* bdi_setpoint = setpoint * bdi_thresh / thresh
* scale global setpoint to wb's:
* wb_setpoint = setpoint * wb_thresh / thresh
*/
x = div_u64((u64)bdi_thresh << 16, thresh + 1);
bdi_setpoint = setpoint * (u64)x >> 16;
x = div_u64((u64)wb_thresh << 16, thresh + 1);
wb_setpoint = setpoint * (u64)x >> 16;
/*
* Use span=(8*write_bw) in single bdi case as indicated by
* (thresh - bdi_thresh ~= 0) and transit to bdi_thresh in JBOD case.
* Use span=(8*write_bw) in single wb case as indicated by
* (thresh - wb_thresh ~= 0) and transit to wb_thresh in JBOD case.
*
* bdi_thresh thresh - bdi_thresh
* span = ---------- * (8 * write_bw) + ------------------- * bdi_thresh
* thresh thresh
* wb_thresh thresh - wb_thresh
* span = --------- * (8 * write_bw) + ------------------ * wb_thresh
* thresh thresh
*/
span = (thresh - bdi_thresh + 8 * write_bw) * (u64)x >> 16;
x_intercept = bdi_setpoint + span;
span = (thresh - wb_thresh + 8 * write_bw) * (u64)x >> 16;
x_intercept = wb_setpoint + span;
if (bdi_dirty < x_intercept - span / 4) {
pos_ratio = div64_u64(pos_ratio * (x_intercept - bdi_dirty),
x_intercept - bdi_setpoint + 1);
if (wb_dirty < x_intercept - span / 4) {
pos_ratio = div64_u64(pos_ratio * (x_intercept - wb_dirty),
x_intercept - wb_setpoint + 1);
} else
pos_ratio /= 4;
/*
* bdi reserve area, safeguard against dirty pool underrun and disk idle
* wb reserve area, safeguard against dirty pool underrun and disk idle
* It may push the desired control point of global dirty pages higher
* than setpoint.
*/
x_intercept = bdi_thresh / 2;
if (bdi_dirty < x_intercept) {
if (bdi_dirty > x_intercept / 8)
pos_ratio = div_u64(pos_ratio * x_intercept, bdi_dirty);
x_intercept = wb_thresh / 2;
if (wb_dirty < x_intercept) {
if (wb_dirty > x_intercept / 8)
pos_ratio = div_u64(pos_ratio * x_intercept, wb_dirty);
else
pos_ratio *= 8;
}
@ -943,17 +942,17 @@ static void global_update_bandwidth(unsigned long thresh,
}
/*
* Maintain bdi->dirty_ratelimit, the base dirty throttle rate.
* Maintain wb->dirty_ratelimit, the base dirty throttle rate.
*
* Normal bdi tasks will be curbed at or below it in long term.
* Normal wb tasks will be curbed at or below it in long term.
* Obviously it should be around (write_bw / N) when there are N dd tasks.
*/
static void wb_update_dirty_ratelimit(struct bdi_writeback *wb,
unsigned long thresh,
unsigned long bg_thresh,
unsigned long dirty,
unsigned long bdi_thresh,
unsigned long bdi_dirty,
unsigned long wb_thresh,
unsigned long wb_dirty,
unsigned long dirtied,
unsigned long elapsed)
{
@ -976,7 +975,7 @@ static void wb_update_dirty_ratelimit(struct bdi_writeback *wb,
dirty_rate = (dirtied - wb->dirtied_stamp) * HZ / elapsed;
pos_ratio = wb_position_ratio(wb, thresh, bg_thresh, dirty,
bdi_thresh, bdi_dirty);
wb_thresh, wb_dirty);
/*
* task_ratelimit reflects each dd's dirty rate for the past 200ms.
*/
@ -986,7 +985,7 @@ static void wb_update_dirty_ratelimit(struct bdi_writeback *wb,
/*
* A linear estimation of the "balanced" throttle rate. The theory is,
* if there are N dd tasks, each throttled at task_ratelimit, the bdi's
* if there are N dd tasks, each throttled at task_ratelimit, the wb's
* dirty_rate will be measured to be (N * task_ratelimit). So the below
* formula will yield the balanced rate limit (write_bw / N).
*
@ -1025,7 +1024,7 @@ static void wb_update_dirty_ratelimit(struct bdi_writeback *wb,
/*
* We could safely do this and return immediately:
*
* bdi->dirty_ratelimit = balanced_dirty_ratelimit;
* wb->dirty_ratelimit = balanced_dirty_ratelimit;
*
* However to get a more stable dirty_ratelimit, the below elaborated
* code makes use of task_ratelimit to filter out singular points and
@ -1059,22 +1058,22 @@ static void wb_update_dirty_ratelimit(struct bdi_writeback *wb,
step = 0;
/*
* For strictlimit case, calculations above were based on bdi counters
* For strictlimit case, calculations above were based on wb counters
* and limits (starting from pos_ratio = wb_position_ratio() and up to
* balanced_dirty_ratelimit = task_ratelimit * write_bw / dirty_rate).
* Hence, to calculate "step" properly, we have to use bdi_dirty as
* "dirty" and bdi_setpoint as "setpoint".
* Hence, to calculate "step" properly, we have to use wb_dirty as
* "dirty" and wb_setpoint as "setpoint".
*
* We rampup dirty_ratelimit forcibly if bdi_dirty is low because
* it's possible that bdi_thresh is close to zero due to inactivity
* We rampup dirty_ratelimit forcibly if wb_dirty is low because
* it's possible that wb_thresh is close to zero due to inactivity
* of backing device (see the implementation of wb_dirty_limit()).
*/
if (unlikely(wb->bdi->capabilities & BDI_CAP_STRICTLIMIT)) {
dirty = bdi_dirty;
if (bdi_dirty < 8)
setpoint = bdi_dirty + 1;
dirty = wb_dirty;
if (wb_dirty < 8)
setpoint = wb_dirty + 1;
else
setpoint = (bdi_thresh +
setpoint = (wb_thresh +
wb_dirty_limit(wb, bg_thresh)) / 2;
}
@ -1116,8 +1115,8 @@ void __wb_update_bandwidth(struct bdi_writeback *wb,
unsigned long thresh,
unsigned long bg_thresh,
unsigned long dirty,
unsigned long bdi_thresh,
unsigned long bdi_dirty,
unsigned long wb_thresh,
unsigned long wb_dirty,
unsigned long start_time)
{
unsigned long now = jiffies;
@ -1144,7 +1143,7 @@ void __wb_update_bandwidth(struct bdi_writeback *wb,
if (thresh) {
global_update_bandwidth(thresh, dirty, now);
wb_update_dirty_ratelimit(wb, thresh, bg_thresh, dirty,
bdi_thresh, bdi_dirty,
wb_thresh, wb_dirty,
dirtied, elapsed);
}
wb_update_write_bandwidth(wb, elapsed, written);
@ -1159,15 +1158,15 @@ static void wb_update_bandwidth(struct bdi_writeback *wb,
unsigned long thresh,
unsigned long bg_thresh,
unsigned long dirty,
unsigned long bdi_thresh,
unsigned long bdi_dirty,
unsigned long wb_thresh,
unsigned long wb_dirty,
unsigned long start_time)
{
if (time_is_after_eq_jiffies(wb->bw_time_stamp + BANDWIDTH_INTERVAL))
return;
spin_lock(&wb->list_lock);
__wb_update_bandwidth(wb, thresh, bg_thresh, dirty,
bdi_thresh, bdi_dirty, start_time);
wb_thresh, wb_dirty, start_time);
spin_unlock(&wb->list_lock);
}
@ -1189,7 +1188,7 @@ static unsigned long dirty_poll_interval(unsigned long dirty,
}
static unsigned long wb_max_pause(struct bdi_writeback *wb,
unsigned long bdi_dirty)
unsigned long wb_dirty)
{
unsigned long bw = wb->avg_write_bandwidth;
unsigned long t;
@ -1201,7 +1200,7 @@ static unsigned long wb_max_pause(struct bdi_writeback *wb,
*
* 8 serves as the safety ratio.
*/
t = bdi_dirty / (1 + bw / roundup_pow_of_two(1 + HZ / 8));
t = wb_dirty / (1 + bw / roundup_pow_of_two(1 + HZ / 8));
t++;
return min_t(unsigned long, t, MAX_PAUSE);
@ -1285,31 +1284,31 @@ static long wb_min_pause(struct bdi_writeback *wb,
static inline void wb_dirty_limits(struct bdi_writeback *wb,
unsigned long dirty_thresh,
unsigned long background_thresh,
unsigned long *bdi_dirty,
unsigned long *bdi_thresh,
unsigned long *bdi_bg_thresh)
unsigned long *wb_dirty,
unsigned long *wb_thresh,
unsigned long *wb_bg_thresh)
{
unsigned long wb_reclaimable;
/*
* bdi_thresh is not treated as some limiting factor as
* wb_thresh is not treated as some limiting factor as
* dirty_thresh, due to reasons
* - in JBOD setup, bdi_thresh can fluctuate a lot
* - in JBOD setup, wb_thresh can fluctuate a lot
* - in a system with HDD and USB key, the USB key may somehow
* go into state (bdi_dirty >> bdi_thresh) either because
* bdi_dirty starts high, or because bdi_thresh drops low.
* go into state (wb_dirty >> wb_thresh) either because
* wb_dirty starts high, or because wb_thresh drops low.
* In this case we don't want to hard throttle the USB key
* dirtiers for 100 seconds until bdi_dirty drops under
* bdi_thresh. Instead the auxiliary bdi control line in
* dirtiers for 100 seconds until wb_dirty drops under
* wb_thresh. Instead the auxiliary wb control line in
* wb_position_ratio() will let the dirtier task progress
* at some rate <= (write_bw / 2) for bringing down bdi_dirty.
* at some rate <= (write_bw / 2) for bringing down wb_dirty.
*/
*bdi_thresh = wb_dirty_limit(wb, dirty_thresh);
*wb_thresh = wb_dirty_limit(wb, dirty_thresh);
if (bdi_bg_thresh)
*bdi_bg_thresh = dirty_thresh ? div_u64((u64)*bdi_thresh *
background_thresh,
dirty_thresh) : 0;
if (wb_bg_thresh)
*wb_bg_thresh = dirty_thresh ? div_u64((u64)*wb_thresh *
background_thresh,
dirty_thresh) : 0;
/*
* In order to avoid the stacked BDI deadlock we need
@ -1321,12 +1320,12 @@ static inline void wb_dirty_limits(struct bdi_writeback *wb,
* actually dirty; with m+n sitting in the percpu
* deltas.
*/
if (*bdi_thresh < 2 * wb_stat_error(wb)) {
if (*wb_thresh < 2 * wb_stat_error(wb)) {
wb_reclaimable = wb_stat_sum(wb, WB_RECLAIMABLE);
*bdi_dirty = wb_reclaimable + wb_stat_sum(wb, WB_WRITEBACK);
*wb_dirty = wb_reclaimable + wb_stat_sum(wb, WB_WRITEBACK);
} else {
wb_reclaimable = wb_stat(wb, WB_RECLAIMABLE);
*bdi_dirty = wb_reclaimable + wb_stat(wb, WB_WRITEBACK);
*wb_dirty = wb_reclaimable + wb_stat(wb, WB_WRITEBACK);
}
}
@ -1360,9 +1359,9 @@ static void balance_dirty_pages(struct address_space *mapping,
for (;;) {
unsigned long now = jiffies;
unsigned long uninitialized_var(bdi_thresh);
unsigned long uninitialized_var(wb_thresh);
unsigned long thresh;
unsigned long uninitialized_var(bdi_dirty);
unsigned long uninitialized_var(wb_dirty);
unsigned long dirty;
unsigned long bg_thresh;
@ -1380,10 +1379,10 @@ static void balance_dirty_pages(struct address_space *mapping,
if (unlikely(strictlimit)) {
wb_dirty_limits(wb, dirty_thresh, background_thresh,
&bdi_dirty, &bdi_thresh, &bg_thresh);
&wb_dirty, &wb_thresh, &bg_thresh);
dirty = bdi_dirty;
thresh = bdi_thresh;
dirty = wb_dirty;
thresh = wb_thresh;
} else {
dirty = nr_dirty;
thresh = dirty_thresh;
@ -1393,10 +1392,10 @@ static void balance_dirty_pages(struct address_space *mapping,
/*
* Throttle it only when the background writeback cannot
* catch-up. This avoids (excessively) small writeouts
* when the bdi limits are ramping up in case of !strictlimit.
* when the wb limits are ramping up in case of !strictlimit.
*
* In strictlimit case make decision based on the bdi counters
* and limits. Small writeouts when the bdi limits are ramping
* In strictlimit case make decision based on the wb counters
* and limits. Small writeouts when the wb limits are ramping
* up are the price we consciously pay for strictlimit-ing.
*/
if (dirty <= dirty_freerun_ceiling(thresh, bg_thresh)) {
@ -1412,24 +1411,23 @@ static void balance_dirty_pages(struct address_space *mapping,
if (!strictlimit)
wb_dirty_limits(wb, dirty_thresh, background_thresh,
&bdi_dirty, &bdi_thresh, NULL);
&wb_dirty, &wb_thresh, NULL);
dirty_exceeded = (bdi_dirty > bdi_thresh) &&
dirty_exceeded = (wb_dirty > wb_thresh) &&
((nr_dirty > dirty_thresh) || strictlimit);
if (dirty_exceeded && !wb->dirty_exceeded)
wb->dirty_exceeded = 1;
wb_update_bandwidth(wb, dirty_thresh, background_thresh,
nr_dirty, bdi_thresh, bdi_dirty,
start_time);
nr_dirty, wb_thresh, wb_dirty, start_time);
dirty_ratelimit = wb->dirty_ratelimit;
pos_ratio = wb_position_ratio(wb, dirty_thresh,
background_thresh, nr_dirty,
bdi_thresh, bdi_dirty);
wb_thresh, wb_dirty);
task_ratelimit = ((u64)dirty_ratelimit * pos_ratio) >>
RATELIMIT_CALC_SHIFT;
max_pause = wb_max_pause(wb, bdi_dirty);
max_pause = wb_max_pause(wb, wb_dirty);
min_pause = wb_min_pause(wb, max_pause,
task_ratelimit, dirty_ratelimit,
&nr_dirtied_pause);
@ -1455,8 +1453,8 @@ static void balance_dirty_pages(struct address_space *mapping,
dirty_thresh,
background_thresh,
nr_dirty,
bdi_thresh,
bdi_dirty,
wb_thresh,
wb_dirty,
dirty_ratelimit,
task_ratelimit,
pages_dirtied,
@ -1484,8 +1482,8 @@ static void balance_dirty_pages(struct address_space *mapping,
dirty_thresh,
background_thresh,
nr_dirty,
bdi_thresh,
bdi_dirty,
wb_thresh,
wb_dirty,
dirty_ratelimit,
task_ratelimit,
pages_dirtied,
@ -1508,15 +1506,15 @@ static void balance_dirty_pages(struct address_space *mapping,
/*
* In the case of an unresponding NFS server and the NFS dirty
* pages exceeds dirty_thresh, give the other good bdi's a pipe
* pages exceeds dirty_thresh, give the other good wb's a pipe
* to go through, so that tasks on them still remain responsive.
*
* In theory 1 page is enough to keep the comsumer-producer
* pipe going: the flusher cleans 1 page => the task dirties 1
* more page. However bdi_dirty has accounting errors. So use
* more page. However wb_dirty has accounting errors. So use
* the larger and more IO friendly wb_stat_error.
*/
if (bdi_dirty <= wb_stat_error(wb))
if (wb_dirty <= wb_stat_error(wb))
break;
if (fatal_signal_pending(current))