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 5/6] mm,thp: add read-only THP support for (non-shmem) FS
Date: Mon, 24 Jun 2019 15:04:21 +0000 [thread overview]
Message-ID: <5BE23F34-B611-496B-9277-A09C9CC784B1@fb.com> (raw)
In-Reply-To: <20190624145453.u4ej3e4ktyyqjite@box>
> On Jun 24, 2019, at 7:54 AM, Kirill A. Shutemov <kirill@shutemov.name> wrote:
>
> On Mon, Jun 24, 2019 at 02:42:13PM +0000, Song Liu wrote:
>>
>>
>>> On Jun 24, 2019, at 7:27 AM, Kirill A. Shutemov <kirill@shutemov.name> wrote:
>>>
>>> On Mon, Jun 24, 2019 at 02:01:05PM +0000, Song Liu wrote:
>>>>>> @@ -1392,6 +1403,23 @@ static void collapse_file(struct mm_struct *mm,
>>>>>> result = SCAN_FAIL;
>>>>>> goto xa_unlocked;
>>>>>> }
>>>>>> + } else if (!page || xa_is_value(page)) {
>>>>>> + xas_unlock_irq(&xas);
>>>>>> + page_cache_sync_readahead(mapping, &file->f_ra, file,
>>>>>> + index, PAGE_SIZE);
>>>>>> + lru_add_drain();
>>>>>
>>>>> Why?
>>>>
>>>> isolate_lru_page() is likely to fail if we don't drain the pagevecs.
>>>
>>> Please add a comment.
>>
>> Will do.
>>
>>>
>>>>>> + page = find_lock_page(mapping, index);
>>>>>> + if (unlikely(page == NULL)) {
>>>>>> + result = SCAN_FAIL;
>>>>>> + goto xa_unlocked;
>>>>>> + }
>>>>>> + } else if (!PageUptodate(page)) {
>>>>>
>>>>> Maybe we should try wait_on_page_locked() here before give up?
>>>>
>>>> Are you referring to the "if (!PageUptodate(page))" case?
>>>
>>> Yes.
>>
>> I think this case happens when another thread is reading the page in.
>> I could not think of a way to trigger this condition for testing.
>>
>> On the other hand, with current logic, we will retry the page on the
>> next scan, so I guess this is OK.
>
> What I meant that calling wait_on_page_locked() on !PageUptodate() page
> will likely make it up-to-date and we don't need to SCAN_FAIL the attempt.
>
Yeah, I got the point. My only concern is that I don't know how to
reliably trigger this case for testing. I can try to trigger it. But I
don't know whether it will happen easily.
Thanks,
Song
next prev parent reply other threads:[~2019-06-24 15:06 UTC|newest]
Thread overview: 19+ 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 [this message]
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
[not found] <20190624031604.7764-1-hdanton@sina.com>
2019-06-24 4:27 ` [PATCH v7 5/6] mm,thp: add read-only THP support for (non-shmem) FS Song Liu
[not found] <20190624074816.10992-1-hdanton@sina.com>
2019-06-24 21:17 ` [PATCH v7 5/6] mm,thp: add read-only THP support for (non-shmem)FS Song Liu
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=5BE23F34-B611-496B-9277-A09C9CC784B1@fb.com \
--to=songliubraving@fb.com \
--cc=Kernel-team@fb.com \
--cc=akpm@linux-foundation.org \
--cc=hdanton@sina.com \
--cc=kirill.shutemov@linux.intel.com \
--cc=kirill@shutemov.name \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=matthew.wilcox@oracle.com \
--cc=william.kucharski@oracle.com \
/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).