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Date: Wed, 10 Mar 2021 17:46:56 +0100
From: Michal Hocko <mhocko@...e.com>
To: Minchan Kim <minchan@...nel.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
linux-mm <linux-mm@...ck.org>,
LKML <linux-kernel@...r.kernel.org>,
John Dias <joaodias@...gle.com>,
David Hildenbrand <david@...hat.com>,
Jason Baron <jbaron@...mai.com>
Subject: Re: [PATCH v2] mm: page_alloc: dump migrate-failed pages
On Wed 10-03-21 08:05:36, Minchan Kim wrote:
> On Wed, Mar 10, 2021 at 02:07:05PM +0100, Michal Hocko wrote:
[...]
> > The is a lot of churn indeed. Have you considered adding $FOO_lglvl
> > variants for those so that you can use them for your particular case
> > without affecting most of existing users? Something similar we have
> > discussed in other email thread regarding lru_add_drain_all?
>
> I thought that way but didn't try since it couldn't make them
> atomic(For example, other printk place in other context will
> affect by the $FOO_lglvl).
I do not follow. I meant something like the following (likely incomplete
but you should get an idea).
diff --git a/include/linux/page_owner.h b/include/linux/page_owner.h
index 3468794f83d2..71b402eb8f78 100644
--- a/include/linux/page_owner.h
+++ b/include/linux/page_owner.h
@@ -14,7 +14,7 @@ extern void __set_page_owner(struct page *page,
extern void __split_page_owner(struct page *page, unsigned int nr);
extern void __copy_page_owner(struct page *oldpage, struct page *newpage);
extern void __set_page_owner_migrate_reason(struct page *page, int reason);
-extern void __dump_page_owner(struct page *page);
+extern void __dump_page_owner(struct page *page, const char *loglvl);
extern void pagetypeinfo_showmixedcount_print(struct seq_file *m,
pg_data_t *pgdat, struct zone *zone);
@@ -46,10 +46,10 @@ static inline void set_page_owner_migrate_reason(struct page *page, int reason)
if (static_branch_unlikely(&page_owner_inited))
__set_page_owner_migrate_reason(page, reason);
}
-static inline void dump_page_owner(struct page *page)
+static inline void dump_page_owner(struct page *page, const char *loglvl)
{
if (static_branch_unlikely(&page_owner_inited))
- __dump_page_owner(page);
+ __dump_page_owner(page, loglvl);
}
#else
static inline void reset_page_owner(struct page *page, unsigned int order)
@@ -69,7 +69,7 @@ static inline void copy_page_owner(struct page *oldpage, struct page *newpage)
static inline void set_page_owner_migrate_reason(struct page *page, int reason)
{
}
-static inline void dump_page_owner(struct page *page)
+static inline void dump_page_owner(struct page *page, const char *loglvl)
{
}
#endif /* CONFIG_PAGE_OWNER */
diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c
index 9f8117c7cfdd..1b13135d9916 100644
--- a/kernel/stacktrace.c
+++ b/kernel/stacktrace.c
@@ -14,6 +14,18 @@
#include <linux/kallsyms.h>
#include <linux/stacktrace.h>
+void __stack_trace_print(const unsigned long *entries, unsigned int nr_entries,
+ int spacesconst, char *loglvl)
+{
+ unsigned int i;
+
+ if (WARN_ON(!entries))
+ return;
+
+ for (i = 0; i < nr_entries; i++)
+ printk("%s%*c%pS\n", loglvl, 1 + spaces, ' ', (void *)entries[i]);
+}
+
/**
* stack_trace_print - Print the entries in the stack trace
* @entries: Pointer to storage array
@@ -23,13 +35,7 @@
void stack_trace_print(const unsigned long *entries, unsigned int nr_entries,
int spaces)
{
- unsigned int i;
-
- if (WARN_ON(!entries))
- return;
-
- for (i = 0; i < nr_entries; i++)
- printk("%*c%pS\n", 1 + spaces, ' ', (void *)entries[i]);
+ __stack_trace_print(entries, nr_entries, spaces, KERN_DEFAULT);
}
EXPORT_SYMBOL_GPL(stack_trace_print);
diff --git a/mm/debug.c b/mm/debug.c
index 8a40b3fefbeb..b989ee2ffa89 100644
--- a/mm/debug.c
+++ b/mm/debug.c
@@ -42,7 +42,7 @@ const struct trace_print_flags vmaflag_names[] = {
{0, NULL}
};
-void __dump_page(struct page *page, const char *reason)
+void __dump_page(struct page *page, const char *reason, const char *loglvl)
{
struct page *head = compound_head(page);
struct address_space *mapping;
@@ -64,7 +64,7 @@ void __dump_page(struct page *page, const char *reason)
* dump_page() when detected.
*/
if (page_poisoned) {
- pr_warn("page:%px is uninitialized and poisoned", page);
+ printk("%spage:%px is uninitialized and poisoned", loglvl, page);
goto hex_only;
}
@@ -95,17 +95,17 @@ void __dump_page(struct page *page, const char *reason)
*/
mapcount = PageSlab(head) ? 0 : page_mapcount(page);
- pr_warn("page:%p refcount:%d mapcount:%d mapping:%p index:%#lx pfn:%#lx\n",
+ printk("%spage:%p refcount:%d mapcount:%d mapping:%p index:%#lx pfn:%#lx\n", loglvl,
page, page_ref_count(head), mapcount, mapping,
page_to_pgoff(page), page_to_pfn(page));
if (compound) {
if (hpage_pincount_available(page)) {
- pr_warn("head:%p order:%u compound_mapcount:%d compound_pincount:%d\n",
+ printk("%shead:%p order:%u compound_mapcount:%d compound_pincount:%d\n", loglvl,
head, compound_order(head),
head_compound_mapcount(head),
head_compound_pincount(head));
} else {
- pr_warn("head:%p order:%u compound_mapcount:%d\n",
+ printk("%shead:%p order:%u compound_mapcount:%d\n", loglvl,
head, compound_order(head),
head_compound_mapcount(head));
}
@@ -128,30 +128,31 @@ void __dump_page(struct page *page, const char *reason)
*/
if (get_kernel_nofault(host, &mapping->host) ||
get_kernel_nofault(a_ops, &mapping->a_ops)) {
- pr_warn("failed to read mapping contents, not a valid kernel address?\n");
+ prrintk("%sfailed to read mapping contents, not a valid kernel address?\n",
+ loglvl);
goto out_mapping;
}
if (!host) {
- pr_warn("aops:%ps\n", a_ops);
+ printk("%saops:%ps\n", loglvl, a_ops);
goto out_mapping;
}
if (get_kernel_nofault(dentry_first, &host->i_dentry.first) ||
get_kernel_nofault(ino, &host->i_ino)) {
- pr_warn("aops:%ps with invalid host inode %px\n",
+ printk("%saops:%ps with invalid host inode %px\n", loglvl,
a_ops, host);
goto out_mapping;
}
if (!dentry_first) {
- pr_warn("aops:%ps ino:%lx\n", a_ops, ino);
+ printk("%saops:%ps ino:%lx\n", loglvl, a_ops, ino);
goto out_mapping;
}
dentry_ptr = container_of(dentry_first, struct dentry, d_u.d_alias);
if (get_kernel_nofault(dentry, dentry_ptr)) {
- pr_warn("aops:%ps ino:%lx with invalid dentry %px\n",
+ printk("%saops:%ps ino:%lx with invalid dentry %px\n", loglvl,
a_ops, ino, dentry_ptr);
} else {
/*
@@ -159,38 +160,38 @@ void __dump_page(struct page *page, const char *reason)
* crash, but it's unlikely that we reach here with a
* corrupted struct page
*/
- pr_warn("aops:%ps ino:%lx dentry name:\"%pd\"\n",
+ printk("%saops:%ps ino:%lx dentry name:\"%pd\"\n", loglvl,
a_ops, ino, &dentry);
}
}
out_mapping:
BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
- pr_warn("%sflags: %#lx(%pGp)%s\n", type, head->flags, &head->flags,
+ printk("%s%sflags: %#lx(%pGp)%s\n", loglvl, type, head->flags, &head->flags,
page_cma ? " CMA" : "");
hex_only:
- print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
+ print_hex_dump(loglvl, "%sraw: ", DUMP_PREFIX_NONE, 32,
sizeof(unsigned long), page,
sizeof(struct page), false);
if (head != page)
- print_hex_dump(KERN_WARNING, "head: ", DUMP_PREFIX_NONE, 32,
+ print_hex_dump(loglvl, "head: ", DUMP_PREFIX_NONE, 32,
sizeof(unsigned long), head,
sizeof(struct page), false);
if (reason)
- pr_warn("page dumped because: %s\n", reason);
+ printk("%spage dumped because: %s\n", loglvl, reason);
#ifdef CONFIG_MEMCG
if (!page_poisoned && page->memcg_data)
- pr_warn("pages's memcg:%lx\n", page->memcg_data);
+ printk("%spages's memcg:%lx\n", loglvl, page->memcg_data);
#endif
}
void dump_page(struct page *page, const char *reason)
{
- __dump_page(page, reason);
- dump_page_owner(page);
+ __dump_page(page, reason, KERN_WARNING);
+ dump_page_owner(page, KERN_ALERT);
}
EXPORT_SYMBOL(dump_page);
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 519a60d5b6f7..20b500f76667 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -637,7 +637,7 @@ static void bad_page(struct page *page, const char *reason)
pr_alert("BUG: Bad page state in process %s pfn:%05lx\n",
current->comm, page_to_pfn(page));
__dump_page(page, reason);
- dump_page_owner(page);
+ dump_page_owner(page, KERN_ALERT);
print_modules();
dump_stack();
diff --git a/mm/page_owner.c b/mm/page_owner.c
index af464bb7fbe7..ff5908605925 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -406,7 +406,7 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn,
return -ENOMEM;
}
-void __dump_page_owner(struct page *page)
+void __dump_page_owner(struct page *page, const char *loglvl)
{
struct page_ext *page_ext = lookup_page_ext(page);
struct page_owner *page_owner;
@@ -417,7 +417,7 @@ void __dump_page_owner(struct page *page)
int mt;
if (unlikely(!page_ext)) {
- pr_alert("There is not page extension available.\n");
+ printk("There is not page extension available.\n", loglvl);
return;
}
@@ -426,38 +426,38 @@ void __dump_page_owner(struct page *page)
mt = gfp_migratetype(gfp_mask);
if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) {
- pr_alert("page_owner info is not present (never set?)\n");
+ printk("%spage_owner info is not present (never set?)\n", loglvl);
return;
}
if (test_bit(PAGE_EXT_OWNER_ALLOCATED, &page_ext->flags))
- pr_alert("page_owner tracks the page as allocated\n");
+ printk("%spage_owner tracks the page as allocated\n", loglvl);
else
- pr_alert("page_owner tracks the page as freed\n");
+ printk("page_owner tracks the page as freed\n", loglvl);
- pr_alert("page last allocated via order %u, migratetype %s, gfp_mask %#x(%pGg), pid %d, ts %llu\n",
+ printk("%spage last allocated via order %u, migratetype %s, gfp_mask %#x(%pGg), pid %d, ts %llu\n", loglvl,
page_owner->order, migratetype_names[mt], gfp_mask, &gfp_mask,
page_owner->pid, page_owner->ts_nsec);
handle = READ_ONCE(page_owner->handle);
if (!handle) {
- pr_alert("page_owner allocation stack trace missing\n");
+ printk("%spage_owner allocation stack trace missing\n", loglvl);
} else {
nr_entries = stack_depot_fetch(handle, &entries);
- stack_trace_print(entries, nr_entries, 0);
+ __stack_trace_print(entries, nr_entries, 0, loglvl);
}
handle = READ_ONCE(page_owner->free_handle);
if (!handle) {
- pr_alert("page_owner free stack trace missing\n");
+ printk("%spage_owner free stack trace missing\n", loglvl);
} else {
nr_entries = stack_depot_fetch(handle, &entries);
- pr_alert("page last free stack trace:\n");
- stack_trace_print(entries, nr_entries, 0);
+ printk("page last free stack trace:\n", loglvl);
+ __stack_trace_print(entries, nr_entries, 0, loglvl);
}
if (page_owner->last_migrate_reason != -1)
- pr_alert("page has been migrated, last migrate reason: %s\n",
+ printk("%spage has been migrated, last migrate reason: %s\n", loglvl,
migrate_reason_names[page_owner->last_migrate_reason]);
}
--
Michal Hocko
SUSE Labs
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