Re: [PATCH v2 0/8] ext4: enable large folio for regular files

Zhang Yi
2025-05-20T13:09:34Z

On 2025/5/20 4:33, Jan Kara wrote:
> On Mon 12-05-25 14:33:11, Zhang Yi wrote:
>> From: Zhang Yi <yi.zhang@huawei.com>
>>
>> Changes since v1:
>> - Rebase codes on 6.15-rc6.
>> - Drop the modifications in block_read_full_folio() which has supported
>> by commit b72e591f74de ("fs/buffer: remove batching from async
>> read").
>> - Fine-tuning patch 6 without modifying the logic.
>>
>> v1: https://lore.kernel.org/linux-ext4/20241125114419.903270-1-yi.zhang@huaweicloud.com/
>>
>> Original Description:
>>
>> Since almost all of the code paths in ext4 have already been converted
>> to use folios, there isn't much additional work required to support
>> large folios. This series completes the remaining work and enables large
>> folios for regular files on ext4, with the exception of fsverity,
>> fscrypt, and data=journal mode.
>>
>> Unlike my other series[1], which enables large folios by converting the
>> buffered I/O path from the classic buffer_head to iomap, this solution
>> is based on the original buffer_head, it primarily modifies the block
>> offset and length calculations within a single folio in the buffer
>> write, buffer read, zero range, writeback, and move extents paths to
>> support large folios, doesn't do further code refactoring and
>> optimization.
>>
>> This series have passed kvm-xfstests in auto mode several times, every
>> thing looks fine, any comments are welcome.
>>
>> About performance:
>>
>> I used the same test script from my iomap series (need to drop the mount
>> opts parameter MOUNT_OPT) [2], run fio tests on the same machine with
>> Intel Xeon Gold 6240 CPU with 400GB system ram, 200GB ramdisk and 4TB
>> nvme ssd disk. Both compared with the base and the IOMAP + large folio
>> changes.
>>
>> == buffer read ==
>>
>> base iomap+large folio base+large folio
>> type bs IOPS BW(M/s) IOPS BW(M/s) IOPS BW(M/s)
>> ----------------------------------------------------------------
>> hole 4K | 576k 2253 | 762k 2975(+32%) | 747k 2918(+29%)
>> hole 64K | 48.7k 3043 | 77.8k 4860(+60%) | 76.3k 4767(+57%)
>> hole 1M | 2960 2960 | 4942 4942(+67%) | 4737 4738(+60%)
>> ramdisk 4K | 443k 1732 | 530k 2069(+19%) | 494k 1930(+11%)
>> ramdisk 64K | 34.5k 2156 | 45.6k 2850(+32%) | 41.3k 2584(+20%)
>> ramdisk 1M | 2093 2093 | 2841 2841(+36%) | 2585 2586(+24%)
>> nvme 4K | 339k 1323 | 364k 1425(+8%) | 344k 1341(+1%)
>> nvme 64K | 23.6k 1471 | 25.2k 1574(+7%) | 25.4k 1586(+8%)
>> nvme 1M | 2012 2012 | 2153 2153(+7%) | 2122 2122(+5%)
>>
>>
>> == buffer write ==
>>
>> O: Overwrite; S: Sync; W: Writeback
>>
>> base iomap+large folio base+large folio
>> type O S W bs IOPS BW IOPS BW(M/s) IOPS BW(M/s)
>> ----------------------------------------------------------------------
>> cache N N N 4K | 417k 1631 | 440k 1719 (+5%) | 423k 1655 (+2%)
>> cache N N N 64K | 33.4k 2088 | 81.5k 5092 (+144%) | 59.1k 3690 (+77%)
>> cache N N N 1M | 2143 2143 | 5716 5716 (+167%) | 3901 3901 (+82%)
>> cache Y N N 4K | 449k 1755 | 469k 1834 (+5%) | 452k 1767 (+1%)
>> cache Y N N 64K | 36.6k 2290 | 82.3k 5142 (+125%) | 67.2k 4200 (+83%)
>> cache Y N N 1M | 2352 2352 | 5577 5577 (+137% | 4275 4276 (+82%)
>> ramdisk N N Y 4K | 365k 1424 | 354k 1384 (-3%) | 372k 1449 (+2%)
>> ramdisk N N Y 64K | 31.2k 1950 | 74.2k 4640 (+138%) | 56.4k 3528 (+81%)
>> ramdisk N N Y 1M | 1968 1968 | 5201 5201 (+164%) | 3814 3814 (+94%)
>> ramdisk N Y N 4K | 9984 39 | 12.9k 51 (+29%) | 9871 39 (-1%)
>> ramdisk N Y N 64K | 5936 371 | 8960 560 (+51%) | 6320 395 (+6%)
>> ramdisk N Y N 1M | 1050 1050 | 1835 1835 (+75%) | 1656 1657 (+58%)
>> ramdisk Y N Y 4K | 411k 1609 | 443k 1731 (+8%) | 441k 1723 (+7%)
>> ramdisk Y N Y 64K | 34.1k 2134 | 77.5k 4844 (+127%) | 66.4k 4151 (+95%)
>> ramdisk Y N Y 1M | 2248 2248 | 5372 5372 (+139%) | 4209 4210 (+87%)
>> ramdisk Y Y N 4K | 182k 711 | 186k 730 (+3%) | 182k 711 (0%)
>> ramdisk Y Y N 64K | 18.7k 1170 | 34.7k 2171 (+86%) | 31.5k 1969 (+68%)
>> ramdisk Y Y N 1M | 1229 1229 | 2269 2269 (+85%) | 1943 1944 (+58%)
>> nvme N N Y 4K | 373k 1458 | 387k 1512 (+4%) | 399k 1559 (+7%)
>> nvme N N Y 64K | 29.2k 1827 | 70.9k 4431 (+143%) | 54.3k 3390 (+86%)
>> nvme N N Y 1M | 1835 1835 | 4919 4919 (+168%) | 3658 3658 (+99%)
>> nvme N Y N 4K | 11.7k 46 | 11.7k 46 (0%) | 11.5k 45 (-1%)
>> nvme N Y N 64K | 6453 403 | 8661 541 (+34%) | 7520 470 (+17%)
>> nvme N Y N 1M | 649 649 | 1351 1351 (+108%) | 885 886 (+37%)
>> nvme Y N Y 4K | 372k 1456 | 433k 1693 (+16%) | 419k 1637 (+12%)
>> nvme Y N Y 64K | 33.0k 2064 | 74.7k 4669 (+126%) | 64.1k 4010 (+94%)
>> nvme Y N Y 1M | 2131 2131 | 5273 5273 (+147%) | 4259 4260 (+100%)
>> nvme Y Y N 4K | 56.7k 222 | 56.4k 220 (-1%) | 59.4k 232 (+5%)
>> nvme Y Y N 64K | 13.4k 840 | 19.4k 1214 (+45%) | 18.5k 1156 (+38%)
>> nvme Y Y N 1M | 714 714 | 1504 1504 (+111%) | 1319 1320 (+85%)
>>
>> [1] https://lore.kernel.org/linux-ext4/20241022111059.2566137-1-yi.zhang@huaweicloud.com/
>> [2] https://lore.kernel.org/linux-ext4/3c01efe6-007a-4422-ad79-0bad3af281b1@huaweicloud.com/
>>
>> Thanks,
>> Yi.
>
> The patches look good to me besides that one issue with journal credits. I
> can see Ted has already picked up the patches so this is probably moot but
> still:
>
> Reviewed-by: Jan Kara <jack@suse.cz>

Thanks for your review and comments. 😉

Yi.

>
> Honza
>>
>> Zhang Yi (8):
>> ext4: make ext4_mpage_readpages() support large folios
>> ext4: make regular file's buffered write path support large folios
>> ext4: make __ext4_block_zero_page_range() support large folio
>> ext4/jbd2: convert jbd2_journal_blocks_per_page() to support large
>> folio
>> ext4: correct the journal credits calculations of allocating blocks
>> ext4: make the writeback path support large folios
>> ext4: make online defragmentation support large folios
>> ext4: enable large folio for regular file
>>
>> fs/ext4/ext4.h | 1 +
>> fs/ext4/ext4_jbd2.c | 3 +-
>> fs/ext4/ext4_jbd2.h | 4 +--
>> fs/ext4/extents.c | 5 +--
>> fs/ext4/ialloc.c | 3 ++
>> fs/ext4/inode.c | 72 ++++++++++++++++++++++++++++++-------------
>> fs/ext4/move_extent.c | 11 +++----
>> fs/ext4/readpage.c | 28 ++++++++++-------
>> fs/jbd2/journal.c | 7 +++--
>> include/linux/jbd2.h | 2 +-
>> 10 files changed, 88 insertions(+), 48 deletions(-)
>>
>> --
>> 2.46.1
>>