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authorLinus Torvalds <torvalds@linux-foundation.org>2015-10-24 07:20:57 +0900
committerLinus Torvalds <torvalds@linux-foundation.org>2015-10-24 07:20:57 +0900
commitea1ee5ff1b500ccdc64782ecef13d276afb08f14 (patch)
tree085cb2fc7a5b4b4395f1f13cb05d989aa18bce8e /mm
parentef594c421a0f96197f28d205e2ee58a83c1e0e37 (diff)
parente27c5b9d23168cc2cb8fec147ae7ed1f7a2005c3 (diff)
downloadlinux-ea1ee5ff1b500ccdc64782ecef13d276afb08f14.tar.bz2
Merge branch 'for-linus' of git://git.kernel.dk/linux-block
Pull block layer fixes from Jens Axboe: "A final set of fixes for 4.3. It is (again) bigger than I would have liked, but it's all been through the testing mill and has been carefully reviewed by multiple parties. Each fix is either a regression fix for this cycle, or is marked stable. You can scold me at KS. The pull request contains: - Three simple fixes for NVMe, fixing regressions since 4.3. From Arnd, Christoph, and Keith. - A single xen-blkfront fix from Cathy, fixing a NULL dereference if an error is returned through the staste change callback. - Fixup for some bad/sloppy code in nbd that got introduced earlier in this cycle. From Markus Pargmann. - A blk-mq tagset use-after-free fix from Junichi. - A backing device lifetime fix from Tejun, fixing a crash. - And finally, a set of regression/stable fixes for cgroup writeback from Tejun" * 'for-linus' of git://git.kernel.dk/linux-block: writeback: remove broken rbtree_postorder_for_each_entry_safe() usage in cgwb_bdi_destroy() NVMe: Fix memory leak on retried commands block: don't release bdi while request_queue has live references nvme: use an integer value to Linux errno values blk-mq: fix use-after-free in blk_mq_free_tag_set() nvme: fix 32-bit build warning writeback: fix incorrect calculation of available memory for memcg domains writeback: memcg dirty_throttle_control should be initialized with wb->memcg_completions writeback: bdi_writeback iteration must not skip dying ones writeback: fix bdi_writeback iteration in wakeup_dirtytime_writeback() writeback: laptop_mode_timer_fn() needs rcu_read_lock() around bdi_writeback iteration nbd: Add locking for tasks xen-blkfront: check for null drvdata in blkback_changed (XenbusStateClosing)
Diffstat (limited to 'mm')
-rw-r--r--mm/backing-dev.c36
-rw-r--r--mm/memcontrol.c35
-rw-r--r--mm/page-writeback.c54
3 files changed, 79 insertions, 46 deletions
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 2df8ddcb0ca0..619984fc07ec 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -480,6 +480,10 @@ static void cgwb_release_workfn(struct work_struct *work)
release_work);
struct backing_dev_info *bdi = wb->bdi;
+ spin_lock_irq(&cgwb_lock);
+ list_del_rcu(&wb->bdi_node);
+ spin_unlock_irq(&cgwb_lock);
+
wb_shutdown(wb);
css_put(wb->memcg_css);
@@ -575,6 +579,7 @@ static int cgwb_create(struct backing_dev_info *bdi,
ret = radix_tree_insert(&bdi->cgwb_tree, memcg_css->id, wb);
if (!ret) {
atomic_inc(&bdi->usage_cnt);
+ list_add_tail_rcu(&wb->bdi_node, &bdi->wb_list);
list_add(&wb->memcg_node, memcg_cgwb_list);
list_add(&wb->blkcg_node, blkcg_cgwb_list);
css_get(memcg_css);
@@ -676,7 +681,7 @@ static int cgwb_bdi_init(struct backing_dev_info *bdi)
static void cgwb_bdi_destroy(struct backing_dev_info *bdi)
{
struct radix_tree_iter iter;
- struct bdi_writeback_congested *congested, *congested_n;
+ struct rb_node *rbn;
void **slot;
WARN_ON(test_bit(WB_registered, &bdi->wb.state));
@@ -686,9 +691,11 @@ static void cgwb_bdi_destroy(struct backing_dev_info *bdi)
radix_tree_for_each_slot(slot, &bdi->cgwb_tree, &iter, 0)
cgwb_kill(*slot);
- rbtree_postorder_for_each_entry_safe(congested, congested_n,
- &bdi->cgwb_congested_tree, rb_node) {
- rb_erase(&congested->rb_node, &bdi->cgwb_congested_tree);
+ while ((rbn = rb_first(&bdi->cgwb_congested_tree))) {
+ struct bdi_writeback_congested *congested =
+ rb_entry(rbn, struct bdi_writeback_congested, rb_node);
+
+ rb_erase(rbn, &bdi->cgwb_congested_tree);
congested->bdi = NULL; /* mark @congested unlinked */
}
@@ -764,15 +771,22 @@ static void cgwb_bdi_destroy(struct backing_dev_info *bdi) { }
int bdi_init(struct backing_dev_info *bdi)
{
+ int ret;
+
bdi->dev = NULL;
bdi->min_ratio = 0;
bdi->max_ratio = 100;
bdi->max_prop_frac = FPROP_FRAC_BASE;
INIT_LIST_HEAD(&bdi->bdi_list);
+ INIT_LIST_HEAD(&bdi->wb_list);
init_waitqueue_head(&bdi->wb_waitq);
- return cgwb_bdi_init(bdi);
+ ret = cgwb_bdi_init(bdi);
+
+ list_add_tail_rcu(&bdi->wb.bdi_node, &bdi->wb_list);
+
+ return ret;
}
EXPORT_SYMBOL(bdi_init);
@@ -823,7 +837,7 @@ static void bdi_remove_from_list(struct backing_dev_info *bdi)
synchronize_rcu_expedited();
}
-void bdi_destroy(struct backing_dev_info *bdi)
+void bdi_unregister(struct backing_dev_info *bdi)
{
/* make sure nobody finds us on the bdi_list anymore */
bdi_remove_from_list(bdi);
@@ -835,9 +849,19 @@ void bdi_destroy(struct backing_dev_info *bdi)
device_unregister(bdi->dev);
bdi->dev = NULL;
}
+}
+void bdi_exit(struct backing_dev_info *bdi)
+{
+ WARN_ON_ONCE(bdi->dev);
wb_exit(&bdi->wb);
}
+
+void bdi_destroy(struct backing_dev_info *bdi)
+{
+ bdi_unregister(bdi);
+ bdi_exit(bdi);
+}
EXPORT_SYMBOL(bdi_destroy);
/*
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index d9b5c817dce8..c57c4423c688 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3741,44 +3741,43 @@ struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb)
/**
* mem_cgroup_wb_stats - retrieve writeback related stats from its memcg
* @wb: bdi_writeback in question
- * @pavail: out parameter for number of available pages
+ * @pfilepages: out parameter for number of file pages
+ * @pheadroom: out parameter for number of allocatable pages according to memcg
* @pdirty: out parameter for number of dirty pages
* @pwriteback: out parameter for number of pages under writeback
*
- * Determine the numbers of available, dirty, and writeback pages in @wb's
- * memcg. Dirty and writeback are self-explanatory. Available is a bit
- * more involved.
+ * Determine the numbers of file, headroom, dirty, and writeback pages in
+ * @wb's memcg. File, dirty and writeback are self-explanatory. Headroom
+ * is a bit more involved.
*
- * A memcg's headroom is "min(max, high) - used". The available memory is
- * calculated as the lowest headroom of itself and the ancestors plus the
- * number of pages already being used for file pages. Note that this
- * doesn't consider the actual amount of available memory in the system.
- * The caller should further cap *@pavail accordingly.
+ * A memcg's headroom is "min(max, high) - used". In the hierarchy, the
+ * headroom is calculated as the lowest headroom of itself and the
+ * ancestors. Note that this doesn't consider the actual amount of
+ * available memory in the system. The caller should further cap
+ * *@pheadroom accordingly.
*/
-void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pavail,
- unsigned long *pdirty, unsigned long *pwriteback)
+void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages,
+ unsigned long *pheadroom, unsigned long *pdirty,
+ unsigned long *pwriteback)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
struct mem_cgroup *parent;
- unsigned long head_room = PAGE_COUNTER_MAX;
- unsigned long file_pages;
*pdirty = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_DIRTY);
/* this should eventually include NR_UNSTABLE_NFS */
*pwriteback = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_WRITEBACK);
+ *pfilepages = mem_cgroup_nr_lru_pages(memcg, (1 << LRU_INACTIVE_FILE) |
+ (1 << LRU_ACTIVE_FILE));
+ *pheadroom = PAGE_COUNTER_MAX;
- file_pages = mem_cgroup_nr_lru_pages(memcg, (1 << LRU_INACTIVE_FILE) |
- (1 << LRU_ACTIVE_FILE));
while ((parent = parent_mem_cgroup(memcg))) {
unsigned long ceiling = min(memcg->memory.limit, memcg->high);
unsigned long used = page_counter_read(&memcg->memory);
- head_room = min(head_room, ceiling - min(ceiling, used));
+ *pheadroom = min(*pheadroom, ceiling - min(ceiling, used));
memcg = parent;
}
-
- *pavail = file_pages + head_room;
}
#else /* CONFIG_CGROUP_WRITEBACK */
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 0a931cdd4f6b..2c90357c34ea 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -145,9 +145,6 @@ struct dirty_throttle_control {
unsigned long pos_ratio;
};
-#define DTC_INIT_COMMON(__wb) .wb = (__wb), \
- .wb_completions = &(__wb)->completions
-
/*
* Length of period for aging writeout fractions of bdis. This is an
* arbitrarily chosen number. The longer the period, the slower fractions will
@@ -157,12 +154,16 @@ struct dirty_throttle_control {
#ifdef CONFIG_CGROUP_WRITEBACK
-#define GDTC_INIT(__wb) .dom = &global_wb_domain, \
- DTC_INIT_COMMON(__wb)
+#define GDTC_INIT(__wb) .wb = (__wb), \
+ .dom = &global_wb_domain, \
+ .wb_completions = &(__wb)->completions
+
#define GDTC_INIT_NO_WB .dom = &global_wb_domain
-#define MDTC_INIT(__wb, __gdtc) .dom = mem_cgroup_wb_domain(__wb), \
- .gdtc = __gdtc, \
- DTC_INIT_COMMON(__wb)
+
+#define MDTC_INIT(__wb, __gdtc) .wb = (__wb), \
+ .dom = mem_cgroup_wb_domain(__wb), \
+ .wb_completions = &(__wb)->memcg_completions, \
+ .gdtc = __gdtc
static bool mdtc_valid(struct dirty_throttle_control *dtc)
{
@@ -213,7 +214,8 @@ static void wb_min_max_ratio(struct bdi_writeback *wb,
#else /* CONFIG_CGROUP_WRITEBACK */
-#define GDTC_INIT(__wb) DTC_INIT_COMMON(__wb)
+#define GDTC_INIT(__wb) .wb = (__wb), \
+ .wb_completions = &(__wb)->completions
#define GDTC_INIT_NO_WB
#define MDTC_INIT(__wb, __gdtc)
@@ -682,13 +684,19 @@ static unsigned long hard_dirty_limit(struct wb_domain *dom,
return max(thresh, dom->dirty_limit);
}
-/* memory available to a memcg domain is capped by system-wide clean memory */
-static void mdtc_cap_avail(struct dirty_throttle_control *mdtc)
+/*
+ * Memory which can be further allocated to a memcg domain is capped by
+ * system-wide clean memory excluding the amount being used in the domain.
+ */
+static void mdtc_calc_avail(struct dirty_throttle_control *mdtc,
+ unsigned long filepages, unsigned long headroom)
{
struct dirty_throttle_control *gdtc = mdtc_gdtc(mdtc);
- unsigned long clean = gdtc->avail - min(gdtc->avail, gdtc->dirty);
+ unsigned long clean = filepages - min(filepages, mdtc->dirty);
+ unsigned long global_clean = gdtc->avail - min(gdtc->avail, gdtc->dirty);
+ unsigned long other_clean = global_clean - min(global_clean, clean);
- mdtc->avail = min(mdtc->avail, clean);
+ mdtc->avail = filepages + min(headroom, other_clean);
}
/**
@@ -1562,16 +1570,16 @@ static void balance_dirty_pages(struct address_space *mapping,
}
if (mdtc) {
- unsigned long writeback;
+ unsigned long filepages, headroom, writeback;
/*
* If @wb belongs to !root memcg, repeat the same
* basic calculations for the memcg domain.
*/
- mem_cgroup_wb_stats(wb, &mdtc->avail, &mdtc->dirty,
- &writeback);
- mdtc_cap_avail(mdtc);
+ mem_cgroup_wb_stats(wb, &filepages, &headroom,
+ &mdtc->dirty, &writeback);
mdtc->dirty += writeback;
+ mdtc_calc_avail(mdtc, filepages, headroom);
domain_dirty_limits(mdtc);
@@ -1893,10 +1901,11 @@ bool wb_over_bg_thresh(struct bdi_writeback *wb)
return true;
if (mdtc) {
- unsigned long writeback;
+ unsigned long filepages, headroom, writeback;
- mem_cgroup_wb_stats(wb, &mdtc->avail, &mdtc->dirty, &writeback);
- mdtc_cap_avail(mdtc);
+ mem_cgroup_wb_stats(wb, &filepages, &headroom, &mdtc->dirty,
+ &writeback);
+ mdtc_calc_avail(mdtc, filepages, headroom);
domain_dirty_limits(mdtc); /* ditto, ignore writeback */
if (mdtc->dirty > mdtc->bg_thresh)
@@ -1956,7 +1965,6 @@ void laptop_mode_timer_fn(unsigned long data)
int nr_pages = global_page_state(NR_FILE_DIRTY) +
global_page_state(NR_UNSTABLE_NFS);
struct bdi_writeback *wb;
- struct wb_iter iter;
/*
* We want to write everything out, not just down to the dirty
@@ -1965,10 +1973,12 @@ void laptop_mode_timer_fn(unsigned long data)
if (!bdi_has_dirty_io(&q->backing_dev_info))
return;
- bdi_for_each_wb(wb, &q->backing_dev_info, &iter, 0)
+ rcu_read_lock();
+ list_for_each_entry_rcu(wb, &q->backing_dev_info.wb_list, bdi_node)
if (wb_has_dirty_io(wb))
wb_start_writeback(wb, nr_pages, true,
WB_REASON_LAPTOP_TIMER);
+ rcu_read_unlock();
}
/*