From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, linux-mm@kvack.org,
liuzixian4@huawei.com, mike.kravetz@oracle.com,
mm-commits@vger.kernel.org, naoya.horiguchi@nec.com,
stable@vger.kernel.org, torvalds@linux-foundation.org
Subject: [patch 2/8] mm/hugetlb: initialize hugetlb_usage in mm_init
Date: Wed, 08 Sep 2021 18:10:05 -0700 [thread overview]
Message-ID: <20210909011005.6UTH8UzKk%akpm@linux-foundation.org> (raw)
In-Reply-To: <20210908180859.d523d4bb4ad8eec11c61500d@linux-foundation.org>
From: Liu Zixian <liuzixian4@huawei.com>
Subject: mm/hugetlb: initialize hugetlb_usage in mm_init
After fork, the child process will get incorrect (2x) hugetlb_usage.
If a process uses 5 2MB hugetlb pages in an anonymous mapping,
HugetlbPages: 10240 kB
and then forks, the child will show,
HugetlbPages: 20480 kB
The reason for double the amount is because hugetlb_usage will be copied
from the parent and then increased when we copy page tables from parent to
child. Child will have 2x actual usage.
Fix this by adding hugetlb_count_init in mm_init.
Link: https://lkml.kernel.org/r/20210826071742.877-1-liuzixian4@huawei.com
Fixes: 5d317b2b6536 ("mm: hugetlb: proc: add HugetlbPages field to /proc/PID/status")
Signed-off-by: Liu Zixian <liuzixian4@huawei.com>
Reviewed-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
include/linux/hugetlb.h | 9 +++++++++
kernel/fork.c | 1 +
2 files changed, 10 insertions(+)
--- a/include/linux/hugetlb.h~mm-hugetlb-initialize-hugetlb_usage-in-mm_init
+++ a/include/linux/hugetlb.h
@@ -858,6 +858,11 @@ static inline spinlock_t *huge_pte_lockp
void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm);
+static inline void hugetlb_count_init(struct mm_struct *mm)
+{
+ atomic_long_set(&mm->hugetlb_usage, 0);
+}
+
static inline void hugetlb_count_add(long l, struct mm_struct *mm)
{
atomic_long_add(l, &mm->hugetlb_usage);
@@ -1042,6 +1047,10 @@ static inline spinlock_t *huge_pte_lockp
return &mm->page_table_lock;
}
+static inline void hugetlb_count_init(struct mm_struct *mm)
+{
+}
+
static inline void hugetlb_report_usage(struct seq_file *f, struct mm_struct *m)
{
}
--- a/kernel/fork.c~mm-hugetlb-initialize-hugetlb_usage-in-mm_init
+++ a/kernel/fork.c
@@ -1063,6 +1063,7 @@ static struct mm_struct *mm_init(struct
mm->pmd_huge_pte = NULL;
#endif
mm_init_uprobes_state(mm);
+ hugetlb_count_init(mm);
if (current->mm) {
mm->flags = current->mm->flags & MMF_INIT_MASK;
_
next prev parent reply other threads:[~2021-09-09 1:10 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-09 1:08 incoming Andrew Morton
2021-09-09 1:10 ` [patch 1/8] mm/hmm: bypass devmap pte when all pfn requested flags are fulfilled Andrew Morton
2021-09-09 1:10 ` Andrew Morton [this message]
2021-09-09 1:10 ` [patch 3/8] mm,vmscan: fix divide by zero in get_scan_count Andrew Morton
2021-09-09 1:10 ` [patch 4/8] mm/page_alloc.c: avoid accessing uninitialized pcp page migratetype Andrew Morton
2021-09-09 1:10 ` [patch 5/8] mmap_lock: change trace and locking order Andrew Morton
2021-09-09 12:56 ` Liam Howlett
2021-09-09 1:10 ` [patch 6/8] mm/kmemleak: allow __GFP_NOLOCKDEP passed to kmemleak's gfp Andrew Morton
2021-09-09 1:10 ` [patch 7/8] mm/mempolicy: fix a race between offset_il_node and mpol_rebind_task Andrew Morton
2021-09-09 1:10 ` [patch 8/8] nds32/setup: remove unused memblock_region variable in setup_memory() Andrew Morton
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210909011005.6UTH8UzKk%akpm@linux-foundation.org \
--to=akpm@linux-foundation.org \
--cc=linux-mm@kvack.org \
--cc=liuzixian4@huawei.com \
--cc=mike.kravetz@oracle.com \
--cc=mm-commits@vger.kernel.org \
--cc=naoya.horiguchi@nec.com \
--cc=stable@vger.kernel.org \
--cc=torvalds@linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).