[PATCHv6 35/37] ext4: reserve larger jounral transaction for huge pages
From: Kirill A. Shutemov <hidden>
Date: 2017-01-26 11:58:17
Also in:
linux-ext4, linux-fsdevel, linux-mm, lkml
Subsystem:
ext4 file system, filesystems (vfs and infrastructure), the rest · Maintainers:
"Theodore Ts'o", Alexander Viro, Christian Brauner, Linus Torvalds
If huge pages enabled, in worst case with 2048 blocks underlying a page, each possibly in a different block group we have much more metadata to commit. Let's update estimates accordingly. I was not able to trigger bad situation without the patch as it's hard to construct very fragmented filesystem, but hopefully this change would be enough to address the concern. Signed-off-by: Kirill A. Shutemov <redacted> --- fs/ext4/ext4_jbd2.h | 16 +++++++++++++--- fs/ext4/inode.c | 34 +++++++++++++++++++++++++++------- 2 files changed, 40 insertions(+), 10 deletions(-)
diff --git a/fs/ext4/ext4_jbd2.h b/fs/ext4/ext4_jbd2.h
index f97611171023..6e4e534d6e98 100644
--- a/fs/ext4/ext4_jbd2.h
+++ b/fs/ext4/ext4_jbd2.h@@ -353,11 +353,21 @@ static inline int ext4_journal_restart(handle_t *handle, int nblocks) return 0; } +static inline int __ext4_journal_blocks_per_page(struct inode *inode, bool thp) +{ + int bpp = 0; + if (EXT4_JOURNAL(inode) != NULL) { + bpp = jbd2_journal_blocks_per_page(inode); + if (thp) + bpp <<= HPAGE_PMD_ORDER; + } + return bpp; +} + static inline int ext4_journal_blocks_per_page(struct inode *inode) { - if (EXT4_JOURNAL(inode) != NULL) - return jbd2_journal_blocks_per_page(inode); - return 0; + return __ext4_journal_blocks_per_page(inode, + (inode->i_flags & S_HUGE_MODE) != S_HUGE_NEVER); } static inline int ext4_journal_force_commit(journal_t *journal)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 5bf68bbe65ec..c30562b6e685 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c@@ -141,6 +141,7 @@ static int __ext4_journalled_writepage(struct page *page, unsigned int len); static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh); static int ext4_meta_trans_blocks(struct inode *inode, int lblocks, int pextents); +static int __ext4_writepage_trans_blocks(struct inode *inode, int bpp); /* * Test whether an inode is a fast symlink.
@@ -4496,6 +4497,21 @@ void ext4_set_inode_flags(struct inode *inode) !ext4_should_journal_data(inode) && !ext4_has_inline_data(inode) && !ext4_encrypted_inode(inode)) new_fl |= S_DAX; + + if ((new_fl & S_HUGE_MODE) != S_HUGE_NEVER && + EXT4_JOURNAL(inode) != NULL) { + int bpp = __ext4_journal_blocks_per_page(inode, true); + int credits = __ext4_writepage_trans_blocks(inode, bpp); + + if (EXT4_JOURNAL(inode)->j_max_transaction_buffers < credits) { + pr_warn_once("EXT4-fs (%s): " + "journal is too small for huge pages. " + "Disable huge pages support.\n", + inode->i_sb->s_id); + new_fl &= ~S_HUGE_MODE; + } + } + inode_set_flags(inode, new_fl, S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC|S_DAX); }
@@ -5471,6 +5487,16 @@ static int ext4_meta_trans_blocks(struct inode *inode, int lblocks, return ret; } +static int __ext4_writepage_trans_blocks(struct inode *inode, int bpp) +{ + int ret = ext4_meta_trans_blocks(inode, bpp, bpp); + + /* Account for data blocks for journalled mode */ + if (ext4_should_journal_data(inode)) + ret += bpp; + return ret; +} + /* * Calculate the total number of credits to reserve to fit * the modification of a single pages into a single transaction,
@@ -5484,14 +5510,8 @@ static int ext4_meta_trans_blocks(struct inode *inode, int lblocks, int ext4_writepage_trans_blocks(struct inode *inode) { int bpp = ext4_journal_blocks_per_page(inode); - int ret; - - ret = ext4_meta_trans_blocks(inode, bpp, bpp); - /* Account for data blocks for journalled mode */ - if (ext4_should_journal_data(inode)) - ret += bpp; - return ret; + return __ext4_writepage_trans_blocks(inode, bpp); } /*
--
2.11.0