From: Song Liu <songliubraving@fb.com>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: "linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"matthew.wilcox@oracle.com" <matthew.wilcox@oracle.com>,
"kirill.shutemov@linux.intel.com"
<kirill.shutemov@linux.intel.com>,
Kernel Team <Kernel-team@fb.com>,
"william.kucharski@oracle.com" <william.kucharski@oracle.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"hdanton@sina.com" <hdanton@sina.com>
Subject: Re: [PATCH v7 6/6] mm,thp: avoid writes to file with THP in pagecache
Date: Mon, 24 Jun 2019 14:01:34 +0000 [thread overview]
Message-ID: <623599AD-71C3-49B9-83A0-F1B8771E0EAE@fb.com> (raw)
In-Reply-To: <20190624124936.2vq55jc3qstxrujj@box>
> On Jun 24, 2019, at 5:49 AM, Kirill A. Shutemov <kirill@shutemov.name> wrote:
>
> On Sat, Jun 22, 2019 at 10:47:49PM -0700, Song Liu wrote:
>> In previous patch, an application could put part of its text section in
>> THP via madvise(). These THPs will be protected from writes when the
>> application is still running (TXTBSY). However, after the application
>> exits, the file is available for writes.
>>
>> This patch avoids writes to file THP by dropping page cache for the file
>> when the file is open for write. A new counter nr_thps is added to struct
>> address_space. In do_last(), if the file is open for write and nr_thps
>> is non-zero, we drop page cache for the whole file.
>>
>> Reported-by: kbuild test robot <lkp@intel.com>
>> Signed-off-by: Song Liu <songliubraving@fb.com>
>> ---
>> fs/inode.c | 3 +++
>> fs/namei.c | 22 +++++++++++++++++++++-
>> include/linux/fs.h | 32 ++++++++++++++++++++++++++++++++
>> mm/filemap.c | 1 +
>> mm/khugepaged.c | 4 +++-
>> 5 files changed, 60 insertions(+), 2 deletions(-)
>>
>> diff --git a/fs/inode.c b/fs/inode.c
>> index df6542ec3b88..518113a4e219 100644
>> --- a/fs/inode.c
>> +++ b/fs/inode.c
>> @@ -181,6 +181,9 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
>> mapping->flags = 0;
>> mapping->wb_err = 0;
>> atomic_set(&mapping->i_mmap_writable, 0);
>> +#ifdef CONFIG_READ_ONLY_THP_FOR_FS
>> + atomic_set(&mapping->nr_thps, 0);
>> +#endif
>> mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE);
>> mapping->private_data = NULL;
>> mapping->writeback_index = 0;
>> diff --git a/fs/namei.c b/fs/namei.c
>> index 20831c2fbb34..de64f24b58e9 100644
>> --- a/fs/namei.c
>> +++ b/fs/namei.c
>> @@ -3249,6 +3249,22 @@ static int lookup_open(struct nameidata *nd, struct path *path,
>> return error;
>> }
>>
>> +/*
>> + * The file is open for write, so it is not mmapped with VM_DENYWRITE. If
>> + * it still has THP in page cache, drop the whole file from pagecache
>> + * before processing writes. This helps us avoid handling write back of
>> + * THP for now.
>> + */
>> +static inline void release_file_thp(struct file *file)
>> +{
>> +#ifdef CONFIG_READ_ONLY_THP_FOR_FS
>
> Please, use IS_ENABLED() where it is possible.
>
I will fix them all.
Thanks,
Song
prev parent reply other threads:[~2019-06-24 14:04 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-23 5:47 [PATCH v7 0/6] Enable THP for text section of non-shmem files Song Liu
2019-06-23 5:47 ` [PATCH v7 1/6] filemap: check compound_head(page)->mapping in filemap_fault() Song Liu
2019-06-23 5:47 ` [PATCH v7 2/6] filemap: update offset check " Song Liu
2019-06-23 5:47 ` [PATCH v7 3/6] mm,thp: stats for file backed THP Song Liu
2019-06-23 5:47 ` [PATCH v7 4/6] khugepaged: rename collapse_shmem() and khugepaged_scan_shmem() Song Liu
2019-06-23 5:47 ` [PATCH v7 5/6] mm,thp: add read-only THP support for (non-shmem) FS Song Liu
2019-06-24 12:47 ` Kirill A. Shutemov
2019-06-24 14:01 ` Song Liu
2019-06-24 14:27 ` Kirill A. Shutemov
2019-06-24 14:42 ` Song Liu
2019-06-24 14:54 ` Kirill A. Shutemov
2019-06-24 15:04 ` Song Liu
2019-06-24 15:15 ` Kirill A. Shutemov
2019-06-24 16:33 ` Song Liu
2019-06-23 5:47 ` [PATCH v7 6/6] mm,thp: avoid writes to file with THP in pagecache Song Liu
2019-06-24 12:49 ` Kirill A. Shutemov
2019-06-24 14:01 ` Song Liu [this message]
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