[PATCH AUTOSEL 4.4 1/3] workqueue: Kick a worker based on the actual activation of delayed works

[PATCH AUTOSEL 4.4 1/3] workqueue: Kick a worker based on the actual activation of delayed works

[Sasha Levin]

From: Yunfeng Ye <yeyunfeng@huawei.com>

[ Upstream commit 01341fbd0d8d4e717fc1231cdffe00343088ce0b ]

In realtime scenario, We do not want to have interference on the
isolated cpu cores. but when invoking alloc_workqueue() for percpu wq
on the housekeeping cpu, it kick a kworker on the isolated cpu.

  alloc_workqueue
    pwq_adjust_max_active
      wake_up_worker

The comment in pwq_adjust_max_active() said:
  "Need to kick a worker after thawed or an unbound wq's
   max_active is bumped"

So it is unnecessary to kick a kworker for percpu's wq when invoking
alloc_workqueue(). this patch only kick a worker based on the actual
activation of delayed works.

Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 kernel/workqueue.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 3fb2d45c0b42f..6b293804cd734 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -3361,17 +3361,24 @@ static void pwq_adjust_max_active(struct pool_workqueue *pwq)
 	 * is updated and visible.
 	 */
 	if (!freezable || !workqueue_freezing) {
+		bool kick = false;
+
 		pwq->max_active = wq->saved_max_active;
 
 		while (!list_empty(&pwq->delayed_works) &&
-		       pwq->nr_active < pwq->max_active)
+		       pwq->nr_active < pwq->max_active) {
 			pwq_activate_first_delayed(pwq);
+			kick = true;
+		}
 
 		/*
 		 * Need to kick a worker after thawed or an unbound wq's
-		 * max_active is bumped.  It's a slow path.  Do it always.
+		 * max_active is bumped. In realtime scenarios, always kicking a
+		 * worker will cause interference on the isolated cpu cores, so
+		 * let's kick iff work items were activated.
 		 */
-		wake_up_worker(pwq->pool);
+		if (kick)
+			wake_up_worker(pwq->pool);
 	} else {
 		pwq->max_active = 0;
 	}
-- 
2.27.0

[PATCH AUTOSEL 4.4 2/3] lib/genalloc: fix the overflow when size is too big

[Sasha Levin]

From: Huang Shijie <sjhuang@iluvatar.ai>

[ Upstream commit 36845663843fc59c5d794e3dc0641472e3e572da ]

Some graphic card has very big memory on chip, such as 32G bytes.

In the following case, it will cause overflow:

    pool = gen_pool_create(PAGE_SHIFT, NUMA_NO_NODE);
    ret = gen_pool_add(pool, 0x1000000, SZ_32G, NUMA_NO_NODE);

    va = gen_pool_alloc(pool, SZ_4G);

The overflow occurs in gen_pool_alloc_algo_owner():

		....
		size = nbits << order;
		....

The @nbits is "int" type, so it will overflow.
Then the gen_pool_avail() will return the wrong value.

This patch converts some "int" to "unsigned long", and
changes the compare code in while.

Link: https://lkml.kernel.org/r/20201229060657.3389-1-sjhuang@iluvatar.ai
Signed-off-by: Huang Shijie <sjhuang@iluvatar.ai>
Reported-by: Shi Jiasheng <jiasheng.shi@iluvatar.ai>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 lib/genalloc.c | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/lib/genalloc.c b/lib/genalloc.c
index e3a475b14e260..b8ac0450a2a68 100644
--- a/lib/genalloc.c
+++ b/lib/genalloc.c
@@ -83,14 +83,14 @@ static int clear_bits_ll(unsigned long *addr, unsigned long mask_to_clear)
  * users set the same bit, one user will return remain bits, otherwise
  * return 0.
  */
-static int bitmap_set_ll(unsigned long *map, int start, int nr)
+static int bitmap_set_ll(unsigned long *map, unsigned long start, unsigned long nr)
 {
 	unsigned long *p = map + BIT_WORD(start);
-	const int size = start + nr;
+	const unsigned long size = start + nr;
 	int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
 	unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
 
-	while (nr - bits_to_set >= 0) {
+	while (nr >= bits_to_set) {
 		if (set_bits_ll(p, mask_to_set))
 			return nr;
 		nr -= bits_to_set;
@@ -118,14 +118,15 @@ static int bitmap_set_ll(unsigned long *map, int start, int nr)
  * users clear the same bit, one user will return remain bits,
  * otherwise return 0.
  */
-static int bitmap_clear_ll(unsigned long *map, int start, int nr)
+static unsigned long
+bitmap_clear_ll(unsigned long *map, unsigned long start, unsigned long nr)
 {
 	unsigned long *p = map + BIT_WORD(start);
-	const int size = start + nr;
+	const unsigned long size = start + nr;
 	int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
 	unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
 
-	while (nr - bits_to_clear >= 0) {
+	while (nr >= bits_to_clear) {
 		if (clear_bits_ll(p, mask_to_clear))
 			return nr;
 		nr -= bits_to_clear;
@@ -184,8 +185,8 @@ int gen_pool_add_virt(struct gen_pool *pool, unsigned long virt, phys_addr_t phy
 		 size_t size, int nid)
 {
 	struct gen_pool_chunk *chunk;
-	int nbits = size >> pool->min_alloc_order;
-	int nbytes = sizeof(struct gen_pool_chunk) +
+	unsigned long nbits = size >> pool->min_alloc_order;
+	unsigned long nbytes = sizeof(struct gen_pool_chunk) +
 				BITS_TO_LONGS(nbits) * sizeof(long);
 
 	chunk = vzalloc_node(nbytes, nid);
@@ -242,7 +243,7 @@ void gen_pool_destroy(struct gen_pool *pool)
 	struct list_head *_chunk, *_next_chunk;
 	struct gen_pool_chunk *chunk;
 	int order = pool->min_alloc_order;
-	int bit, end_bit;
+	unsigned long bit, end_bit;
 
 	list_for_each_safe(_chunk, _next_chunk, &pool->chunks) {
 		chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
@@ -274,7 +275,7 @@ unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size)
 	struct gen_pool_chunk *chunk;
 	unsigned long addr = 0;
 	int order = pool->min_alloc_order;
-	int nbits, start_bit, end_bit, remain;
+	unsigned long nbits, start_bit, end_bit, remain;
 
 #ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
 	BUG_ON(in_nmi());
@@ -357,7 +358,7 @@ void gen_pool_free(struct gen_pool *pool, unsigned long addr, size_t size)
 {
 	struct gen_pool_chunk *chunk;
 	int order = pool->min_alloc_order;
-	int start_bit, nbits, remain;
+	unsigned long start_bit, nbits, remain;
 
 #ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
 	BUG_ON(in_nmi());
@@ -553,7 +554,7 @@ unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size,
 	index = bitmap_find_next_zero_area(map, size, start, nr, 0);
 
 	while (index < size) {
-		int next_bit = find_next_bit(map, size, index + nr);
+		unsigned long next_bit = find_next_bit(map, size, index + nr);
 		if ((next_bit - index) < len) {
 			len = next_bit - index;
 			start_bit = index;
-- 
2.27.0

[PATCH AUTOSEL 4.4 3/3] depmod: handle the case of /sbin/depmod without /sbin in PATH

[Sasha Levin]

From: Linus Torvalds <torvalds@linux-foundation.org>

[ Upstream commit cedd1862be7e666be87ec824dabc6a2b05618f36 ]

Commit 436e980e2ed5 ("kbuild: don't hardcode depmod path") stopped
hard-coding the path of depmod, but in the process caused trouble for
distributions that had that /sbin location, but didn't have it in the
PATH (generally because /sbin is limited to the super-user path).

Work around it for now by just adding /sbin to the end of PATH in the
depmod.sh script.

Reported-and-tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 scripts/depmod.sh | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/scripts/depmod.sh b/scripts/depmod.sh
index baedaef53ca05..b0cb89e73bc56 100755
--- a/scripts/depmod.sh
+++ b/scripts/depmod.sh
@@ -14,6 +14,8 @@ if ! test -r System.map ; then
 	exit 0
 fi
 
+# legacy behavior: "depmod" in /sbin, no /sbin in PATH
+PATH="$PATH:/sbin"
 if [ -z $(command -v $DEPMOD) ]; then
 	echo "Warning: 'make modules_install' requires $DEPMOD. Please install it." >&2
 	echo "This is probably in the kmod package." >&2
-- 
2.27.0