From: Jens Axboe <axboe@kernel.dk> mainline inclusion from mainline-v6.10-rc2 commit fb7d3bc4149395c1ae99029c852eab6c28fc3c88 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/ICPOEB CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- If the folio is marked as streaming, drop pages when writeback completes. Intended to be used with RWF_DONTCACHE, to avoid needing sync writes for uncached IO. Link: https://lkml.kernel.org/r/20241220154831.1086649-10-axboe@kernel.dk Signed-off-by: Jens Axboe <axboe@kernel.dk> Cc: Brian Foster <bfoster@redhat.com> Cc: Chris Mason <clm@meta.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Conflicts: mm/filemap.c [Context conflicts] Signed-off-by: Long Li <leo.lilong@huawei.com> --- mm/filemap.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/mm/filemap.c b/mm/filemap.c index b729176c7abe..8ab7ff56cd7d 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1593,12 +1593,35 @@ int folio_wait_private_2_killable(struct folio *folio) } EXPORT_SYMBOL(folio_wait_private_2_killable); +/* + * If folio was marked as dropbehind, then pages should be dropped when writeback + * completes. Do that now. If we fail, it's likely because of a big folio - + * just reset dropbehind for that case and latter completions should invalidate. + */ +static void folio_end_dropbehind_write(struct folio *folio) +{ + /* + * Hitting !in_task() should not happen off RWF_DONTCACHE writeback, + * but can happen if normal writeback just happens to find dirty folios + * that were created as part of uncached writeback, and that writeback + * would otherwise not need non-IRQ handling. Just skip the + * invalidation in that case. + */ + if (in_task() && folio_trylock(folio)) { + if (folio->mapping) + folio_unmap_invalidate(folio->mapping, folio, 0); + folio_unlock(folio); + } +} + /** * folio_end_writeback - End writeback against a folio. * @folio: The folio. */ void folio_end_writeback(struct folio *folio) { + bool folio_dropbehind = false; + /* * folio_test_clear_reclaim() could be used here but it is an * atomic operation and overkill in this particular case. Failing @@ -1618,12 +1641,17 @@ void folio_end_writeback(struct folio *folio) * reused before the folio_wake(). */ folio_get(folio); + if (!folio_test_dirty(folio)) + folio_dropbehind = folio_test_clear_dropbehind(folio); if (!__folio_end_writeback(folio)) BUG(); smp_mb__after_atomic(); folio_wake(folio, PG_writeback); acct_reclaim_writeback(folio); + + if (folio_dropbehind) + folio_end_dropbehind_write(folio); folio_put(folio); } EXPORT_SYMBOL(folio_end_writeback); -- 2.39.2