Merge tag 'mm-stable-2022-05-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull more MM updates from Andrew Morton:

 - Two follow-on fixes for the post-5.19 series "Use pageblock_order for
   cma and alloc_contig_range alignment", from Zi Yan.

 - A series of z3fold cleanups and fixes from Miaohe Lin.

 - Some memcg selftests work from Michal Koutný <mkoutny@suse.com>

 - Some swap fixes and cleanups from Miaohe Lin

 - Several individual minor fixups

* tag 'mm-stable-2022-05-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (25 commits)
  mm/shmem.c: suppress shift warning
  mm: Kconfig: reorganize misplaced mm options
  mm: kasan: fix input of vmalloc_to_page()
  mm: fix is_pinnable_page against a cma page
  mm: filter out swapin error entry in shmem mapping
  mm/shmem: fix infinite loop when swap in shmem error at swapoff time
  mm/madvise: free hwpoison and swapin error entry in madvise_free_pte_range
  mm/swapfile: fix lost swap bits in unuse_pte()
  mm/swapfile: unuse_pte can map random data if swap read fails
  selftests: memcg: factor out common parts of memory.{low,min} tests
  selftests: memcg: remove protection from top level memcg
  selftests: memcg: adjust expected reclaim values of protected cgroups
  selftests: memcg: expect no low events in unprotected sibling
  selftests: memcg: fix compilation
  mm/z3fold: fix z3fold_page_migrate races with z3fold_map
  mm/z3fold: fix z3fold_reclaim_page races with z3fold_free
  mm/z3fold: always clear PAGE_CLAIMED under z3fold page lock
  mm/z3fold: put z3fold page back into unbuddied list when reclaim or migration fails
  revert "mm/z3fold.c: allow __GFP_HIGHMEM in z3fold_alloc"
  mm/z3fold: throw warning on failure of trylock_page in z3fold_alloc
  ...

2 files changed, 151 insertions, 185 deletions

diff --git a/tools/testing/selftests/cgroup/memcg_protection.m b/tools/testing/selftests/cgroup/memcg_protection.m
new file mode 100644
index 000000000000..051daa3477b6
--- /dev/null
+++ b/tools/testing/selftests/cgroup/memcg_protection.m
@@ -0,0 +1,89 @@
+% SPDX-License-Identifier: GPL-2.0
+%
+% run as: octave-cli memcg_protection.m
+%
+% This script simulates reclaim protection behavior on a single level of memcg
+% hierarchy to illustrate how overcommitted protection spreads among siblings
+% (as it depends also on their current consumption).
+%
+% Simulation assumes siblings consumed the initial amount of memory (w/out
+% reclaim) and then the reclaim starts, all memory is reclaimable, i.e. treated
+% same. It simulates only non-low reclaim and assumes all memory.min = 0.
+%
+% Input configurations
+% --------------------
+% E number	parent effective protection
+% n vector	nominal protection of siblings set at the given level (memory.low)
+% c vector	current consumption -,,- (memory.current)
+
+% example from testcase (values in GB)
+E = 50 / 1024;
+n = [75 25 0 500 ] / 1024;
+c = [50 50 50 0] / 1024;
+
+% Reclaim parameters
+% ------------------
+
+% Minimal reclaim amount (GB)
+cluster = 32*4 / 2**20;
+
+% Reclaim coefficient (think as 0.5^sc->priority)
+alpha = .1
+
+% Simulation parameters
+% ---------------------
+epsilon = 1e-7;
+timeout = 1000;
+
+% Simulation loop
+% ---------------
+
+ch = [];
+eh = [];
+rh = [];
+
+for t = 1:timeout
+        % low_usage
+        u = min(c, n);
+        siblings = sum(u);
+
+        % effective_protection()
+        protected = min(n, c);                % start with nominal
+        e = protected * min(1, E / siblings); % normalize overcommit
+
+        % recursive protection
+        unclaimed = max(0, E - siblings);
+        parent_overuse = sum(c) - siblings;
+        if (unclaimed > 0 && parent_overuse > 0)
+                overuse = max(0, c - protected);
+                e += unclaimed * (overuse / parent_overuse);
+        endif
+
+        % get_scan_count()
+        r = alpha * c;             % assume all memory is in a single LRU list
+
+        % commit 1bc63fb1272b ("mm, memcg: make scan aggression always exclude protection")
+        sz = max(e, c);
+        r .*= (1 - (e+epsilon) ./ (sz+epsilon));
+
+        % uncomment to debug prints
+        % e, c, r
+
+        % nothing to reclaim, reached equilibrium
+        if max(r) < epsilon
+                break;
+        endif
+
+        % SWAP_CLUSTER_MAX roundup
+        r = max(r, (r > epsilon) .* cluster);
+        % XXX here I do parallel reclaim of all siblings
+        % in reality reclaim is serialized and each sibling recalculates own residual
+        c = max(c - r, 0);
+
+        ch = [ch ; c];
+        eh = [eh ; e];
+        rh = [rh ; r];
+endfor
+
+t
+c, e
diff --git a/tools/testing/selftests/cgroup/test_memcontrol.c b/tools/testing/selftests/cgroup/test_memcontrol.c
index 44a974ec472c..8833359556f3 100644
--- a/tools/testing/selftests/cgroup/test_memcontrol.c
+++ b/tools/testing/selftests/cgroup/test_memcontrol.c
@@ -190,13 +190,6 @@ cleanup:
 	return ret;
 }
 
-static int alloc_pagecache_50M(const char *cgroup, void *arg)
-{
-	int fd = (long)arg;
-
-	return alloc_pagecache(fd, MB(50));
-}
-
 static int alloc_pagecache_50M_noexit(const char *cgroup, void *arg)
 {
 	int fd = (long)arg;
@@ -247,33 +240,39 @@ static int cg_test_proc_killed(const char *cgroup)
 
 /*
  * First, this test creates the following hierarchy:
- * A       memory.min = 50M,  memory.max = 200M
- * A/B     memory.min = 50M,  memory.current = 50M
+ * A       memory.min = 0,    memory.max = 200M
+ * A/B     memory.min = 50M
  * A/B/C   memory.min = 75M,  memory.current = 50M
  * A/B/D   memory.min = 25M,  memory.current = 50M
  * A/B/E   memory.min = 0,    memory.current = 50M
  * A/B/F   memory.min = 500M, memory.current = 0
  *
- * Usages are pagecache, but the test keeps a running
+ * (or memory.low if we test soft protection)
+ *
+ * Usages are pagecache and the test keeps a running
  * process in every leaf cgroup.
  * Then it creates A/G and creates a significant
- * memory pressure in it.
+ * memory pressure in A.
  *
+ * Then it checks actual memory usages and expects that:
  * A/B    memory.current ~= 50M
- * A/B/C  memory.current ~= 33M
- * A/B/D  memory.current ~= 17M
- * A/B/F  memory.current ~= 0
+ * A/B/C  memory.current ~= 29M
+ * A/B/D  memory.current ~= 21M
+ * A/B/E  memory.current ~= 0
+ * A/B/F  memory.current  = 0
+ * (for origin of the numbers, see model in memcg_protection.m.)
  *
  * After that it tries to allocate more than there is
- * unprotected memory in A available, and checks
- * checks that memory.min protects pagecache even
- * in this case.
+ * unprotected memory in A available, and checks that:
+ * a) memory.min protects pagecache even in this case,
+ * b) memory.low allows reclaiming page cache with low events.
  */
-static int test_memcg_min(const char *root)
+static int test_memcg_protection(const char *root, bool min)
 {
-	int ret = KSFT_FAIL;
+	int ret = KSFT_FAIL, rc;
 	char *parent[3] = {NULL};
 	char *children[4] = {NULL};
+	const char *attribute = min ? "memory.min" : "memory.low";
 	long c[4];
 	int i, attempts;
 	int fd;
@@ -297,8 +296,10 @@ static int test_memcg_min(const char *root)
 	if (cg_create(parent[0]))
 		goto cleanup;
 
-	if (cg_read_long(parent[0], "memory.min")) {
-		ret = KSFT_SKIP;
+	if (cg_read_long(parent[0], attribute)) {
+		/* No memory.min on older kernels is fine */
+		if (min)
+			ret = KSFT_SKIP;
 		goto cleanup;
 	}
 
@@ -335,17 +336,15 @@ static int test_memcg_min(const char *root)
 			      (void *)(long)fd);
 	}
 
-	if (cg_write(parent[0], "memory.min", "50M"))
+	if (cg_write(parent[1],   attribute, "50M"))
 		goto cleanup;
-	if (cg_write(parent[1], "memory.min", "50M"))
+	if (cg_write(children[0], attribute, "75M"))
 		goto cleanup;
-	if (cg_write(children[0], "memory.min", "75M"))
+	if (cg_write(children[1], attribute, "25M"))
 		goto cleanup;
-	if (cg_write(children[1], "memory.min", "25M"))
+	if (cg_write(children[2], attribute, "0"))
 		goto cleanup;
-	if (cg_write(children[2], "memory.min", "0"))
-		goto cleanup;
-	if (cg_write(children[3], "memory.min", "500M"))
+	if (cg_write(children[3], attribute, "500M"))
 		goto cleanup;
 
 	attempts = 0;
@@ -365,170 +364,35 @@ static int test_memcg_min(const char *root)
 	for (i = 0; i < ARRAY_SIZE(children); i++)
 		c[i] = cg_read_long(children[i], "memory.current");
 
-	if (!values_close(c[0], MB(33), 10))
+	if (!values_close(c[0], MB(29), 10))
 		goto cleanup;
 
-	if (!values_close(c[1], MB(17), 10))
+	if (!values_close(c[1], MB(21), 10))
 		goto cleanup;
 
 	if (c[3] != 0)
 		goto cleanup;
 
-	if (!cg_run(parent[2], alloc_anon, (void *)MB(170)))
-		goto cleanup;
-
-	if (!values_close(cg_read_long(parent[1], "memory.current"), MB(50), 3))
-		goto cleanup;
-
-	ret = KSFT_PASS;
-
-cleanup:
-	for (i = ARRAY_SIZE(children) - 1; i >= 0; i--) {
-		if (!children[i])
-			continue;
-
-		cg_destroy(children[i]);
-		free(children[i]);
-	}
-
-	for (i = ARRAY_SIZE(parent) - 1; i >= 0; i--) {
-		if (!parent[i])
-			continue;
-
-		cg_destroy(parent[i]);
-		free(parent[i]);
-	}
-	close(fd);
-	return ret;
-}
-
-/*
- * First, this test creates the following hierarchy:
- * A       memory.low = 50M,  memory.max = 200M
- * A/B     memory.low = 50M,  memory.current = 50M
- * A/B/C   memory.low = 75M,  memory.current = 50M
- * A/B/D   memory.low = 25M,  memory.current = 50M
- * A/B/E   memory.low = 0,    memory.current = 50M
- * A/B/F   memory.low = 500M, memory.current = 0
- *
- * Usages are pagecache.
- * Then it creates A/G an creates a significant
- * memory pressure in it.
- *
- * Then it checks actual memory usages and expects that:
- * A/B    memory.current ~= 50M
- * A/B/   memory.current ~= 33M
- * A/B/D  memory.current ~= 17M
- * A/B/F  memory.current ~= 0
- *
- * After that it tries to allocate more than there is
- * unprotected memory in A available,
- * and checks low and oom events in memory.events.
- */
-static int test_memcg_low(const char *root)
-{
-	int ret = KSFT_FAIL;
-	char *parent[3] = {NULL};
-	char *children[4] = {NULL};
-	long low, oom;
-	long c[4];
-	int i;
-	int fd;
-
-	fd = get_temp_fd();
-	if (fd < 0)
-		goto cleanup;
-
-	parent[0] = cg_name(root, "memcg_test_0");
-	if (!parent[0])
-		goto cleanup;
-
-	parent[1] = cg_name(parent[0], "memcg_test_1");
-	if (!parent[1])
-		goto cleanup;
-
-	parent[2] = cg_name(parent[0], "memcg_test_2");
-	if (!parent[2])
-		goto cleanup;
-
-	if (cg_create(parent[0]))
-		goto cleanup;
-
-	if (cg_read_long(parent[0], "memory.low"))
-		goto cleanup;
-
-	if (cg_write(parent[0], "cgroup.subtree_control", "+memory"))
-		goto cleanup;
-
-	if (cg_write(parent[0], "memory.max", "200M"))
-		goto cleanup;
-
-	if (cg_write(parent[0], "memory.swap.max", "0"))
-		goto cleanup;
-
-	if (cg_create(parent[1]))
-		goto cleanup;
-
-	if (cg_write(parent[1], "cgroup.subtree_control", "+memory"))
+	rc = cg_run(parent[2], alloc_anon, (void *)MB(170));
+	if (min && !rc)
 		goto cleanup;
-
-	if (cg_create(parent[2]))
+	else if (!min && rc) {
+		fprintf(stderr,
+			"memory.low prevents from allocating anon memory\n");
 		goto cleanup;
-
-	for (i = 0; i < ARRAY_SIZE(children); i++) {
-		children[i] = cg_name_indexed(parent[1], "child_memcg", i);
-		if (!children[i])
-			goto cleanup;
-
-		if (cg_create(children[i]))
-			goto cleanup;
-
-		if (i > 2)
-			continue;
-
-		if (cg_run(children[i], alloc_pagecache_50M, (void *)(long)fd))
-			goto cleanup;
 	}
 
-	if (cg_write(parent[0], "memory.low", "50M"))
-		goto cleanup;
-	if (cg_write(parent[1], "memory.low", "50M"))
-		goto cleanup;
-	if (cg_write(children[0], "memory.low", "75M"))
-		goto cleanup;
-	if (cg_write(children[1], "memory.low", "25M"))
-		goto cleanup;
-	if (cg_write(children[2], "memory.low", "0"))
-		goto cleanup;
-	if (cg_write(children[3], "memory.low", "500M"))
-		goto cleanup;
-
-	if (cg_run(parent[2], alloc_anon, (void *)MB(148)))
-		goto cleanup;
-
 	if (!values_close(cg_read_long(parent[1], "memory.current"), MB(50), 3))
 		goto cleanup;
 
-	for (i = 0; i < ARRAY_SIZE(children); i++)
-		c[i] = cg_read_long(children[i], "memory.current");
-
-	if (!values_close(c[0], MB(33), 10))
-		goto cleanup;
-
-	if (!values_close(c[1], MB(17), 10))
-		goto cleanup;
-
-	if (c[3] != 0)
-		goto cleanup;
-
-	if (cg_run(parent[2], alloc_anon, (void *)MB(166))) {
-		fprintf(stderr,
-			"memory.low prevents from allocating anon memory\n");
+	if (min) {
+		ret = KSFT_PASS;
 		goto cleanup;
 	}
 
 	for (i = 0; i < ARRAY_SIZE(children); i++) {
-		int no_low_events_index = has_recursiveprot ? 2 : 1;
+		int no_low_events_index = 1;
+		long low, oom;
 
 		oom = cg_read_key_long(children[i], "memory.events", "oom ");
 		low = cg_read_key_long(children[i], "memory.events", "low ");
@@ -564,6 +428,16 @@ cleanup:
 	return ret;
 }
 
+static int test_memcg_min(const char *root)
+{
+	return test_memcg_protection(root, true);
+}
+
+static int test_memcg_low(const char *root)
+{
+	return test_memcg_protection(root, false);
+}
+
 static int alloc_pagecache_max_30M(const char *cgroup, void *arg)
 {
 	size_t size = MB(50);
@@ -1241,7 +1115,16 @@ static int test_memcg_oom_group_leaf_events(const char *root)
 	if (cg_read_key_long(child, "memory.events", "oom_kill ") <= 0)
 		goto cleanup;
 
-	if (cg_read_key_long(parent, "memory.events", "oom_kill ") <= 0)
+	parent_oom_events = cg_read_key_long(
+			parent, "memory.events", "oom_kill ");
+	/*
+	 * If memory_localevents is not enabled (the default), the parent should
+	 * count OOM events in its children groups. Otherwise, it should not
+	 * have observed any events.
+	 */
+	if (has_localevents && parent_oom_events != 0)
+		goto cleanup;
+	else if (!has_localevents && parent_oom_events <= 0)
 		goto cleanup;
 
 	ret = KSFT_PASS;
@@ -1349,20 +1232,14 @@ static int test_memcg_oom_group_score_events(const char *root)
 	if (!cg_run(memcg, alloc_anon, (void *)MB(100)))
 		goto cleanup;
 
-	parent_oom_events = cg_read_key_long(
-			parent, "memory.events", "oom_kill ");
-	/*
-	 * If memory_localevents is not enabled (the default), the parent should
-	 * count OOM events in its children groups. Otherwise, it should not
-	 * have observed any events.
-	 */
-	if ((has_localevents && parent_oom_events == 0) ||
-	     parent_oom_events > 0)
-		ret = KSFT_PASS;
+	if (cg_read_key_long(memcg, "memory.events", "oom_kill ") != 3)
+		goto cleanup;
 
 	if (kill(safe_pid, SIGKILL))
 		goto cleanup;
 
+	ret = KSFT_PASS;
+
 cleanup:
 	if (memcg)
 		cg_destroy(memcg);