diff options
| author | Song Liu | 2019-11-30 17:57:19 -0800 |
|---|---|---|
| committer | Linus Torvalds | 2019-12-01 12:59:09 -0800 |
| commit | 75f360696ce9d8ec8b253452b23b3e24c0689b4b (patch) | |
| tree | 9e2c219ca30d2b4ef0c6f426e653518bb77422f1 /mm | |
| parent | f1fe80d4ae3396cf3665bd6dc77f4004c1c2e9f8 (diff) | |
mm/thp: flush file for !is_shmem PageDirty() case in collapse_file()
For non-shmem file THPs, khugepaged only collapses read only .text
mapping (VM_DENYWRITE). These pages should not be dirty except the case
where the file hasn't been flushed since first write.
Call filemap_flush() in collapse_file() to accelerate the write back in
such cases.
Link: http://lkml.kernel.org/r/20191106060930.2571389-3-songliubraving@fb.com
Signed-off-by: Song Liu <songliubraving@fb.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/khugepaged.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/mm/khugepaged.c b/mm/khugepaged.c index a8a57bebb5fa..b679908743cb 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1602,6 +1602,24 @@ static void collapse_file(struct mm_struct *mm, result = SCAN_FAIL; goto xa_unlocked; } + } else if (PageDirty(page)) { + /* + * khugepaged only works on read-only fd, + * so this page is dirty because it hasn't + * been flushed since first write. There + * won't be new dirty pages. + * + * Trigger async flush here and hope the + * writeback is done when khugepaged + * revisits this page. + * + * This is a one-off situation. We are not + * forcing writeback in loop. + */ + xas_unlock_irq(&xas); + filemap_flush(mapping); + result = SCAN_FAIL; + goto xa_unlocked; } else if (trylock_page(page)) { get_page(page); xas_unlock_irq(&xas); |