diff options
Diffstat (limited to 'mm/page_counter.c')
| -rw-r--r-- | mm/page_counter.c | 63 |
1 files changed, 46 insertions, 17 deletions
diff --git a/mm/page_counter.c b/mm/page_counter.c index a5ff4cbc355a..de31470655f6 100644 --- a/mm/page_counter.c +++ b/mm/page_counter.c @@ -13,26 +13,38 @@ #include <linux/bug.h> #include <asm/page.h> -static void propagate_low_usage(struct page_counter *c, unsigned long usage) +static void propagate_protected_usage(struct page_counter *c, + unsigned long usage) { - unsigned long low_usage, old; + unsigned long protected, old_protected; long delta; if (!c->parent) return; - if (!c->low && !atomic_long_read(&c->low_usage)) - return; + if (c->min || atomic_long_read(&c->min_usage)) { + if (usage <= c->min) + protected = usage; + else + protected = 0; + + old_protected = atomic_long_xchg(&c->min_usage, protected); + delta = protected - old_protected; + if (delta) + atomic_long_add(delta, &c->parent->children_min_usage); + } - if (usage <= c->low) - low_usage = usage; - else - low_usage = 0; + if (c->low || atomic_long_read(&c->low_usage)) { + if (usage <= c->low) + protected = usage; + else + protected = 0; - old = atomic_long_xchg(&c->low_usage, low_usage); - delta = low_usage - old; - if (delta) - atomic_long_add(delta, &c->parent->children_low_usage); + old_protected = atomic_long_xchg(&c->low_usage, protected); + delta = protected - old_protected; + if (delta) + atomic_long_add(delta, &c->parent->children_low_usage); + } } /** @@ -45,7 +57,7 @@ void page_counter_cancel(struct page_counter *counter, unsigned long nr_pages) long new; new = atomic_long_sub_return(nr_pages, &counter->usage); - propagate_low_usage(counter, new); + propagate_protected_usage(counter, new); /* More uncharges than charges? */ WARN_ON_ONCE(new < 0); } @@ -65,7 +77,7 @@ void page_counter_charge(struct page_counter *counter, unsigned long nr_pages) long new; new = atomic_long_add_return(nr_pages, &c->usage); - propagate_low_usage(counter, new); + propagate_protected_usage(counter, new); /* * This is indeed racy, but we can live with some * inaccuracy in the watermark. @@ -109,7 +121,7 @@ bool page_counter_try_charge(struct page_counter *counter, new = atomic_long_add_return(nr_pages, &c->usage); if (new > c->max) { atomic_long_sub(nr_pages, &c->usage); - propagate_low_usage(counter, new); + propagate_protected_usage(counter, new); /* * This is racy, but we can live with some * inaccuracy in the failcnt. @@ -118,7 +130,7 @@ bool page_counter_try_charge(struct page_counter *counter, *fail = c; goto failed; } - propagate_low_usage(counter, new); + propagate_protected_usage(counter, new); /* * Just like with failcnt, we can live with some * inaccuracy in the watermark. @@ -191,6 +203,23 @@ int page_counter_set_max(struct page_counter *counter, unsigned long nr_pages) } /** + * page_counter_set_min - set the amount of protected memory + * @counter: counter + * @nr_pages: value to set + * + * The caller must serialize invocations on the same counter. + */ +void page_counter_set_min(struct page_counter *counter, unsigned long nr_pages) +{ + struct page_counter *c; + + counter->min = nr_pages; + + for (c = counter; c; c = c->parent) + propagate_protected_usage(c, atomic_long_read(&c->usage)); +} + +/** * page_counter_set_low - set the amount of protected memory * @counter: counter * @nr_pages: value to set @@ -204,7 +233,7 @@ void page_counter_set_low(struct page_counter *counter, unsigned long nr_pages) counter->low = nr_pages; for (c = counter; c; c = c->parent) - propagate_low_usage(c, atomic_long_read(&c->usage)); + propagate_protected_usage(c, atomic_long_read(&c->usage)); } /** |