linux-toradex.git/lib/flex_proportions.c, branch v4.9.90

lib+mm: fix few spelling mistakes

2016-02-15T10:18:23+00:00

All are in comments.

Signed-off-by: Bogdan Sikora 
Cc: 
Cc: Rafael Aquini 
Cc: Kent Overstreet 
Cc: Jan Kara 
[jkosina@suse.cz: more fixup]
Acked-by: Rafael Aquini 
Signed-off-by: Jiri Slaby 
Signed-off-by: Jiri Kosina

proportions: add @gfp to init functions

2014-09-08T00:51:30+00:00

Percpu allocator now supports allocation mask.  Add @gfp to
[flex_]proportions init functions so that !GFP_KERNEL allocation masks
can be used with them too.

This patch doesn't make any functional difference.

Signed-off-by: Tejun Heo 
Reviewed-by: Jan Kara 
Cc: Peter Zijlstra

percpu_counter: add @gfp to percpu_counter_init()

2014-09-08T00:51:29+00:00

Percpu allocator now supports allocation mask.  Add @gfp to
percpu_counter_init() so that !GFP_KERNEL allocation masks can be used
with percpu_counters too.

We could have left percpu_counter_init() alone and added
percpu_counter_init_gfp(); however, the number of users isn't that
high and introducing _gfp variants to all percpu data structures would
be quite ugly, so let's just do the conversion.  This is the one with
the most users.  Other percpu data structures are a lot easier to
convert.

This patch doesn't make any functional difference.

Signed-off-by: Tejun Heo 
Acked-by: Jan Kara 
Acked-by: "David S. Miller" 
Cc: x86@kernel.org
Cc: Jens Axboe 
Cc: "Theodore Ts'o" 
Cc: Alexander Viro 
Cc: Andrew Morton

lib/flex_proportions.c: fix corruption of denominator in flexible proportions

2012-09-25T15:59:21+00:00

When racing with CPU hotplug, percpu_counter_sum() can return negative
values for the number of observed events.

This confuses fprop_new_period(), which uses unsigned type and as a
result number of events is set to big *positive* number.  From that
moment on, things go pear shaped and can result e.g.  in division by
zero as denominator is later truncated to 32-bits.

This bug causes a divide-by-zero oops in bdi_dirty_limit() in Borislav's
3.6.0-rc6 based kernel.

Fix the issue by using a signed type in fprop_new_period().  That makes
us bail out from the function without doing anything (mistakenly)
thinking there are no events to age.  That makes aging somewhat
inaccurate but getting accurate data would be rather hard.

Signed-off-by: Jan Kara 
Reported-by: Borislav Petkov 
Reported-by: Srivatsa S. Bhat 
Cc: Wu Fengguang 
Cc: Peter Zijlstra 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

lib: Fix possible deadlock in flexible proportion code

2012-06-08T23:37:55+00:00

When percpu counter function in fprop_new_period() is interrupted by an
interrupt while holding counter lock, it can cause deadlock when the
interrupt wants to take the lock as well. Fix the problem by disabling
interrupts when calling percpu counter functions.

Signed-off-by: Jan Kara 
Signed-off-by: Fengguang Wu

lib: Proportions with flexible period

2012-06-08T23:37:55+00:00

Implement code computing proportions of events of different type (like code in
lib/proportions.c) but allowing periods to have different lengths. This allows
us to have aging periods of fixed wallclock time which gives better proportion
estimates given the hugely varying throughput of different devices - previous
measuring of aging period by number of events has the problem that a reasonable
period length for a system with low-end USB stick is not a reasonable period
length for a system with high-end storage array resulting either in too slow
proportion updates or too fluctuating proportion updates.

Acked-by: Peter Zijlstra 
Signed-off-by: Jan Kara 
Signed-off-by: Fengguang Wu