| Message ID | 20210527045202.1155628-7-david@fromorbit.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | xfs: bunmapi needs updating for deferred freeing | expand |
On Thu, May 27, 2021 at 02:52:02PM +1000, Dave Chinner wrote: > From: Dave Chinner <dchinner@redhat.com> > > Ever since we moved to deferred freeing of extents, we only every > free one extent per transaction. We separated the bulk unmapping of > extents from the submission of EFI/free/EFD transactions, and hence > while we unmap extents in bulk, we only every free one per > transaction. > > Our transaction reservations still live in the era from before > deferred freeing of extents, so still refer to "xfs_bmap_finish" > and it needing to free multiple extents per transaction. These > freeing reservations can now all be reduced to a single extent to > reflect how we currently free extents. > > This significantly reduces the reservation sizes for operations like > truncate and directory operations where they currently reserve space > for freeing up to 4 extents per transaction. > > For a 4kB block size filesytsem with reflink=1,rmapbt=1, the > reservation sizes change like this: > > Reservation Before After > (index) logres logcount logres logcount > 0 write 314104 8 314104 8 > 1 itruncate 579456 8 148608 8 > 2 rename 435840 2 307936 2 > 3 link 191600 2 191600 2 > 4 remove 312960 2 174328 2 > 5 symlink 470656 3 470656 3 > 6 create 469504 2 469504 2 > 7 create_tmpfile 490240 2 490240 2 > 8 mkdir 469504 3 469504 3 > 9 ifree 508664 2 508664 2 > 10 ichange 5752 0 5752 0 > 11 growdata 147840 2 147840 2 > 12 addafork 178936 2 178936 2 > 13 writeid 760 0 760 0 > 14 attrinval 578688 1 147840 1 > 15 attrsetm 26872 3 26872 3 > 16 attrsetrt 16896 0 16896 0 > 17 attrrm 292224 3 148608 3 > 18 clearagi 4224 0 4224 0 > 19 growrtalloc 173944 2 173944 2 > 20 growrtzero 4224 0 4224 0 > 21 growrtfree 10096 0 10096 0 > 22 qm_setqlim 232 1 232 1 > 23 qm_dqalloc 318327 8 318327 8 > 24 qm_quotaoff 4544 1 4544 1 > 25 qm_equotaoff 320 1 320 1 > 26 sb 4224 1 4224 1 > 27 fsyncts 760 0 760 0 > MAX 579456 8 318327 8 > > So we can see that many of the reservations have gone substantially > down in size. itruncate, rename, remove, attrinval and attrrm are > much smaller now. The maximum reservation size has gone from being > attrinval at 579456*8 bytes to dqalloc at 318327*8 bytes. This is a > substantial improvement for common operations. If you're going to play around with log reservations, can you have a quick look at the branch I made to fix all the oversized reservations that we make for rmap and reflink? https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux.git/log/?h=reflink-speedups That's what's next after deferred inode inactivation lands. --D > > Signed-off-by: Dave Chinner <dchinner@redhat.com> > --- > fs/xfs/libxfs/xfs_trans_resv.c | 63 +++++++++++++++++----------------- > 1 file changed, 31 insertions(+), 32 deletions(-) > > diff --git a/fs/xfs/libxfs/xfs_trans_resv.c b/fs/xfs/libxfs/xfs_trans_resv.c > index 02079f55ef20..f5e76eeae281 100644 > --- a/fs/xfs/libxfs/xfs_trans_resv.c > +++ b/fs/xfs/libxfs/xfs_trans_resv.c > @@ -232,8 +232,7 @@ xfs_rtalloc_log_count( > * Various log reservation values. > * > * These are based on the size of the file system block because that is what > - * most transactions manipulate. Each adds in an additional 128 bytes per > - * item logged to try to account for the overhead of the transaction mechanism. > + * most transactions manipulate. > * > * Note: Most of the reservations underestimate the number of allocation > * groups into which they could free extents in the xfs_defer_finish() call. > @@ -262,9 +261,9 @@ xfs_rtalloc_log_count( > * the superblock free block counter: sector size > * the realtime bitmap: ((MAXEXTLEN / rtextsize) / NBBY) bytes > * the realtime summary: 1 block > - * And the bmap_finish transaction can free bmap blocks in a join (t3): > + * And the deferred freeing can free bmap blocks in a join (t3): > * the super block free block counter: sector size > - * two extent allocfree reservations for the AG. > + * one extent allocfree reservation for the AG. > */ > STATIC uint > xfs_calc_write_reservation( > @@ -290,23 +289,25 @@ xfs_calc_write_reservation( > } > > t3 = xfs_calc_buf_res(1, mp->m_sb.sb_sectsize) + > - xfs_allocfree_extent_res(mp) * 2; > + xfs_allocfree_extent_res(mp); > > return XFS_DQUOT_LOGRES(mp) + max3(t1, t2, t3); > } > > /* > - * In truncating a file we free up to two extents at once. We can modify (t1): > + * In truncating a file we defer freeing so we only free one extent per > + * transaction for normal files. For rt files we limit to 2 extents per > + * transaction. > + * We can modify (t1): > * the inode being truncated: inode size > * the inode's bmap btree: (max depth + 1) * block size > - * And the bmap_finish transaction can free the blocks and bmap blocks (t2): > - * the super block to reflect the freed blocks: sector size > - * four extent allocfree reservations for the AG. > - * Or, if it's a realtime file (t3): > + * Or, if it's a realtime file (t2): > * the super block to reflect the freed blocks: sector size > * the realtime bitmap: 2 exts * ((MAXEXTLEN / rtextsize) / NBBY) bytes > * the realtime summary: 2 exts * 1 block > - * two extent allocfree reservations for the AG. > + * And the deferred freeing can free the blocks and bmap blocks (t3): > + * the super block to reflect the freed blocks: sector size > + * one extent allocfree reservation for the AG. > */ > STATIC uint > xfs_calc_itruncate_reservation( > @@ -318,17 +319,16 @@ xfs_calc_itruncate_reservation( > t1 = xfs_calc_inode_res(mp, 1) + > xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK) + 1, blksz); > > - t2 = xfs_calc_buf_res(1, mp->m_sb.sb_sectsize) + > - xfs_allocfree_extent_res(mp) * 4; > - > if (xfs_sb_version_hasrealtime(&mp->m_sb)) { > - t3 = xfs_calc_buf_res(1, mp->m_sb.sb_sectsize) + > - xfs_calc_buf_res(xfs_rtalloc_log_count(mp, 2), blksz) + > - xfs_allocfree_extent_res(mp) * 2; > + t2 = xfs_calc_buf_res(1, mp->m_sb.sb_sectsize) + > + xfs_calc_buf_res(xfs_rtalloc_log_count(mp, 2), blksz); > } else { > - t3 = 0; > + t2 = 0; > } > > + t3 = xfs_calc_buf_res(1, mp->m_sb.sb_sectsize) + > + xfs_allocfree_extent_res(mp); > + > return XFS_DQUOT_LOGRES(mp) + max3(t1, t2, t3); > } > > @@ -337,10 +337,9 @@ xfs_calc_itruncate_reservation( > * the four inodes involved: 4 * inode size > * the two directory btrees: 2 * (max depth + v2) * dir block size > * the two directory bmap btrees: 2 * max depth * block size > - * And the bmap_finish transaction can free dir and bmap blocks (two sets > - * of bmap blocks) giving: > + * And the deferred freeing can free dir and bmap blocks giving: > * the superblock for the free block count: sector size > - * three extent allocfree reservations for the AG. > + * one extent allocfree reservations for the AG. > */ > STATIC uint > xfs_calc_rename_reservation( > @@ -351,7 +350,7 @@ xfs_calc_rename_reservation( > xfs_calc_buf_res(2 * XFS_DIROP_LOG_COUNT(mp), > XFS_FSB_TO_B(mp, 1))), > (xfs_calc_buf_res(1, mp->m_sb.sb_sectsize) + > - xfs_allocfree_extent_res(mp) * 3)); > + xfs_allocfree_extent_res(mp))); > } > > /* > @@ -375,7 +374,7 @@ xfs_calc_iunlink_remove_reservation( > * the linked inode: inode size > * the directory btree could split: (max depth + v2) * dir block size > * the directory bmap btree could join or split: (max depth + v2) * blocksize > - * And the bmap_finish transaction can free some bmap blocks giving: > + * And the deferred freeing can free bmap blocks giving: > * the superblock for the free block count: sector size > * one extent allocfree reservation for the AG. > */ > @@ -411,9 +410,9 @@ xfs_calc_iunlink_add_reservation(xfs_mount_t *mp) > * the removed inode: inode size > * the directory btree could join: (max depth + v2) * dir block size > * the directory bmap btree could join or split: (max depth + v2) * blocksize > - * And the bmap_finish transaction can free the dir and bmap blocks giving: > + * And the deferred freeing can free the dir and bmap blocks giving: > * the superblock for the free block count: sector size > - * two extent allocfree reservations for the AG. > + * one extent allocfree reservation for the AG. > */ > STATIC uint > xfs_calc_remove_reservation( > @@ -425,7 +424,7 @@ xfs_calc_remove_reservation( > xfs_calc_buf_res(XFS_DIROP_LOG_COUNT(mp), > XFS_FSB_TO_B(mp, 1))), > (xfs_calc_buf_res(1, mp->m_sb.sb_sectsize) + > - xfs_allocfree_extent_res(mp) * 2)); > + xfs_allocfree_extent_res(mp))); > } > > /* > @@ -670,9 +669,9 @@ xfs_calc_addafork_reservation( > * Removing the attribute fork of a file > * the inode being truncated: inode size > * the inode's bmap btree: max depth * block size > - * And the bmap_finish transaction can free the blocks and bmap blocks: > + * And the deferred freeing can free the blocks and bmap blocks: > * the super block to reflect the freed blocks: sector size > - * four extent allocfree reservations for the AG. > + * one extent allocfree reservation for the AG. > */ > STATIC uint > xfs_calc_attrinval_reservation( > @@ -682,7 +681,7 @@ xfs_calc_attrinval_reservation( > xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_ATTR_FORK), > XFS_FSB_TO_B(mp, 1))), > (xfs_calc_buf_res(1, mp->m_sb.sb_sectsize) + > - xfs_allocfree_extent_res(mp) * 4)); > + xfs_allocfree_extent_res(mp))); > } > > /* > @@ -730,9 +729,9 @@ xfs_calc_attrsetrt_reservation( > * the inode: inode size > * the attribute btree could join: max depth * block size > * the inode bmap btree could join or split: max depth * block size > - * And the bmap_finish transaction can free the attr blocks freed giving: > + * And the deferred freeing can free the attr blocks freed giving: > * the superblock for the free block count: sector size > - * two extent allocfree reservations for the AG. > + * one extent allocfree reservations for the AG. > */ > STATIC uint > xfs_calc_attrrm_reservation( > @@ -746,7 +745,7 @@ xfs_calc_attrrm_reservation( > XFS_BM_MAXLEVELS(mp, XFS_ATTR_FORK)) + > xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK), 0)), > (xfs_calc_buf_res(1, mp->m_sb.sb_sectsize) + > - xfs_allocfree_extent_res(mp) * 2)); > + xfs_allocfree_extent_res(mp))); > } > > /* > -- > 2.31.1 >
On Wed, May 26, 2021 at 11:19:47PM -0700, Darrick J. Wong wrote: > On Thu, May 27, 2021 at 02:52:02PM +1000, Dave Chinner wrote: > > From: Dave Chinner <dchinner@redhat.com> > > > > Ever since we moved to deferred freeing of extents, we only every > > free one extent per transaction. We separated the bulk unmapping of > > extents from the submission of EFI/free/EFD transactions, and hence > > while we unmap extents in bulk, we only every free one per > > transaction. > > > > Our transaction reservations still live in the era from before > > deferred freeing of extents, so still refer to "xfs_bmap_finish" > > and it needing to free multiple extents per transaction. These > > freeing reservations can now all be reduced to a single extent to > > reflect how we currently free extents. > > > > This significantly reduces the reservation sizes for operations like > > truncate and directory operations where they currently reserve space > > for freeing up to 4 extents per transaction. > > > > For a 4kB block size filesytsem with reflink=1,rmapbt=1, the > > reservation sizes change like this: > > > > Reservation Before After > > (index) logres logcount logres logcount > > 0 write 314104 8 314104 8 > > 1 itruncate 579456 8 148608 8 > > 2 rename 435840 2 307936 2 > > 3 link 191600 2 191600 2 > > 4 remove 312960 2 174328 2 > > 5 symlink 470656 3 470656 3 > > 6 create 469504 2 469504 2 > > 7 create_tmpfile 490240 2 490240 2 > > 8 mkdir 469504 3 469504 3 > > 9 ifree 508664 2 508664 2 > > 10 ichange 5752 0 5752 0 > > 11 growdata 147840 2 147840 2 > > 12 addafork 178936 2 178936 2 > > 13 writeid 760 0 760 0 > > 14 attrinval 578688 1 147840 1 > > 15 attrsetm 26872 3 26872 3 > > 16 attrsetrt 16896 0 16896 0 > > 17 attrrm 292224 3 148608 3 > > 18 clearagi 4224 0 4224 0 > > 19 growrtalloc 173944 2 173944 2 > > 20 growrtzero 4224 0 4224 0 > > 21 growrtfree 10096 0 10096 0 > > 22 qm_setqlim 232 1 232 1 > > 23 qm_dqalloc 318327 8 318327 8 > > 24 qm_quotaoff 4544 1 4544 1 > > 25 qm_equotaoff 320 1 320 1 > > 26 sb 4224 1 4224 1 > > 27 fsyncts 760 0 760 0 > > MAX 579456 8 318327 8 > > > > So we can see that many of the reservations have gone substantially > > down in size. itruncate, rename, remove, attrinval and attrrm are > > much smaller now. The maximum reservation size has gone from being > > attrinval at 579456*8 bytes to dqalloc at 318327*8 bytes. This is a > > substantial improvement for common operations. > > If you're going to play around with log reservations, can you have a > quick look at the branch I made to fix all the oversized reservations > that we make for rmap and reflink? > > https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux.git/log/?h=reflink-speedups > > That's what's next after deferred inode inactivation lands. They all look reasonable at a first pass. I'd need to do more than read the patches to say they are definitely correct, but they certainly don't seem unreasonable to me. I'd also have to run numbers like the table above so I can quantify the reductions, but nothing shouted "don't do this!" to me.... Cheers, Dave.
On Thu, May 27, 2021 at 06:52:15PM +1000, Dave Chinner wrote: > On Wed, May 26, 2021 at 11:19:47PM -0700, Darrick J. Wong wrote: > > On Thu, May 27, 2021 at 02:52:02PM +1000, Dave Chinner wrote: > > > From: Dave Chinner <dchinner@redhat.com> > > > > > > Ever since we moved to deferred freeing of extents, we only every > > > free one extent per transaction. We separated the bulk unmapping of > > > extents from the submission of EFI/free/EFD transactions, and hence > > > while we unmap extents in bulk, we only every free one per > > > transaction. > > > > > > Our transaction reservations still live in the era from before > > > deferred freeing of extents, so still refer to "xfs_bmap_finish" > > > and it needing to free multiple extents per transaction. These > > > freeing reservations can now all be reduced to a single extent to > > > reflect how we currently free extents. > > > > > > This significantly reduces the reservation sizes for operations like > > > truncate and directory operations where they currently reserve space > > > for freeing up to 4 extents per transaction. > > > > > > For a 4kB block size filesytsem with reflink=1,rmapbt=1, the > > > reservation sizes change like this: > > > > > > Reservation Before After > > > (index) logres logcount logres logcount > > > 0 write 314104 8 314104 8 > > > 1 itruncate 579456 8 148608 8 > > > 2 rename 435840 2 307936 2 > > > 3 link 191600 2 191600 2 > > > 4 remove 312960 2 174328 2 > > > 5 symlink 470656 3 470656 3 > > > 6 create 469504 2 469504 2 > > > 7 create_tmpfile 490240 2 490240 2 > > > 8 mkdir 469504 3 469504 3 > > > 9 ifree 508664 2 508664 2 > > > 10 ichange 5752 0 5752 0 > > > 11 growdata 147840 2 147840 2 > > > 12 addafork 178936 2 178936 2 > > > 13 writeid 760 0 760 0 > > > 14 attrinval 578688 1 147840 1 > > > 15 attrsetm 26872 3 26872 3 > > > 16 attrsetrt 16896 0 16896 0 > > > 17 attrrm 292224 3 148608 3 > > > 18 clearagi 4224 0 4224 0 > > > 19 growrtalloc 173944 2 173944 2 > > > 20 growrtzero 4224 0 4224 0 > > > 21 growrtfree 10096 0 10096 0 > > > 22 qm_setqlim 232 1 232 1 > > > 23 qm_dqalloc 318327 8 318327 8 > > > 24 qm_quotaoff 4544 1 4544 1 > > > 25 qm_equotaoff 320 1 320 1 > > > 26 sb 4224 1 4224 1 > > > 27 fsyncts 760 0 760 0 > > > MAX 579456 8 318327 8 > > > > > > So we can see that many of the reservations have gone substantially > > > down in size. itruncate, rename, remove, attrinval and attrrm are > > > much smaller now. The maximum reservation size has gone from being > > > attrinval at 579456*8 bytes to dqalloc at 318327*8 bytes. This is a > > > substantial improvement for common operations. > > > > If you're going to play around with log reservations, can you have a > > quick look at the branch I made to fix all the oversized reservations > > that we make for rmap and reflink? > > > > https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux.git/log/?h=reflink-speedups > > > > That's what's next after deferred inode inactivation lands. > > They all look reasonable at a first pass. I'd need to do more than > read the patches to say they are definitely correct, but they > certainly don't seem unreasonable to me. I'd also have to run > numbers like the table above so I can quantify the reductions, > but nothing shouted "don't do this!" to me.... Reservations before and after for a sample 100G filesystem: # mkfs.xfs /tmp/a.img meta-data=/tmp/a.img isize=512 agcount=4, agsize=6553600 blks = sectsz=512 attr=2, projid32bit=1 = crc=1 finobt=1, sparse=1, rmapbt=1 = reflink=1 bigtime=1 inobtcount=1 data = bsize=4096 blocks=26214400, imaxpct=25 = sunit=0 swidth=0 blks naming =version 2 bsize=4096 ascii-ci=0, ftype=1 log =internal log bsize=4096 blocks=12800, version=2 = sectsz=512 sunit=0 blks, lazy-count=1 realtime =none extsz=4096 blocks=0, rtextents=0 Look like: <before> <after> type 0 res 294904 count 8 | type 0 res 185080 count 5 type 1 res 547200 count 8 | type 1 res 327552 count 5 type 2 res 410752 count 2 | type 2 res 307936 count 2 type 3 res 187760 count 2 type 3 res 187760 count 2 type 4 res 290688 count 2 | type 4 res 180864 count 2 type 5 res 434560 count 3 | type 5 res 269824 count 3 type 6 res 433408 count 2 | type 6 res 268672 count 2 type 7 res 450432 count 2 | type 7 res 285696 count 2 type 8 res 433408 count 3 | type 8 res 268672 count 3 type 9 res 468728 count 2 | type 9 res 303992 count 2 type 10 res 2168 count 0 type 10 res 2168 count 0 type 11 res 137088 count 2 | type 11 res 82176 count 2 type 12 res 163320 count 2 | type 12 res 108408 count 2 type 13 res 760 count 0 type 13 res 760 count 0 type 14 res 546432 count 1 | type 14 res 326784 count 1 type 15 res 23288 count 3 type 15 res 23288 count 3 type 16 res 13312 count 0 type 16 res 13312 count 0 type 17 res 274304 count 3 | type 17 res 164480 count 3 type 18 res 640 count 0 type 18 res 640 count 0 type 19 res 158328 count 2 | type 19 res 103416 count 2 type 20 res 4224 count 0 type 20 res 4224 count 0 type 21 res 6512 count 0 type 21 res 6512 count 0 type 22 res 232 count 1 type 22 res 232 count 1 type 23 res 299127 count 8 | type 23 res 189303 count 5 type 24 res 848 count 1 type 24 res 848 count 1 type 25 res 208 count 1 type 25 res 208 count 1 type 26 res 640 count 1 type 26 res 640 count 1 type 27 res 760 count 0 type 27 res 760 count 0 type -1 res 547200 count 8 type -1 res 327552 count 5 IOWs, a 63% reduction in the size of an itruncate reservations. Note that the patchset also includes the necessary pieces to continue formatting filesystems with the same minimum log size rules as before so that you can format with a new xfsprogs and still be able to mount on an older kernel. --D > > Cheers, > > Dave. > -- > Dave Chinner > david@fromorbit.com
On Thu, May 27, 2021 at 05:01:53PM -0700, Darrick J. Wong wrote: > On Thu, May 27, 2021 at 06:52:15PM +1000, Dave Chinner wrote: > > On Wed, May 26, 2021 at 11:19:47PM -0700, Darrick J. Wong wrote: > > > On Thu, May 27, 2021 at 02:52:02PM +1000, Dave Chinner wrote: > > > > From: Dave Chinner <dchinner@redhat.com> > > > > > > > > Ever since we moved to deferred freeing of extents, we only every > > > > free one extent per transaction. We separated the bulk unmapping of > > > > extents from the submission of EFI/free/EFD transactions, and hence > > > > while we unmap extents in bulk, we only every free one per > > > > transaction. > > > > > > > > Our transaction reservations still live in the era from before > > > > deferred freeing of extents, so still refer to "xfs_bmap_finish" > > > > and it needing to free multiple extents per transaction. These > > > > freeing reservations can now all be reduced to a single extent to > > > > reflect how we currently free extents. > > > > > > > > This significantly reduces the reservation sizes for operations like > > > > truncate and directory operations where they currently reserve space > > > > for freeing up to 4 extents per transaction. > > > > > > > > For a 4kB block size filesytsem with reflink=1,rmapbt=1, the > > > > reservation sizes change like this: > > > > > > > > Reservation Before After > > > > (index) logres logcount logres logcount > > > > 0 write 314104 8 314104 8 > > > > 1 itruncate 579456 8 148608 8 > > > > 2 rename 435840 2 307936 2 > > > > 3 link 191600 2 191600 2 > > > > 4 remove 312960 2 174328 2 > > > > 5 symlink 470656 3 470656 3 > > > > 6 create 469504 2 469504 2 > > > > 7 create_tmpfile 490240 2 490240 2 > > > > 8 mkdir 469504 3 469504 3 > > > > 9 ifree 508664 2 508664 2 > > > > 10 ichange 5752 0 5752 0 > > > > 11 growdata 147840 2 147840 2 > > > > 12 addafork 178936 2 178936 2 > > > > 13 writeid 760 0 760 0 > > > > 14 attrinval 578688 1 147840 1 > > > > 15 attrsetm 26872 3 26872 3 > > > > 16 attrsetrt 16896 0 16896 0 > > > > 17 attrrm 292224 3 148608 3 > > > > 18 clearagi 4224 0 4224 0 > > > > 19 growrtalloc 173944 2 173944 2 > > > > 20 growrtzero 4224 0 4224 0 > > > > 21 growrtfree 10096 0 10096 0 > > > > 22 qm_setqlim 232 1 232 1 > > > > 23 qm_dqalloc 318327 8 318327 8 > > > > 24 qm_quotaoff 4544 1 4544 1 > > > > 25 qm_equotaoff 320 1 320 1 > > > > 26 sb 4224 1 4224 1 > > > > 27 fsyncts 760 0 760 0 > > > > MAX 579456 8 318327 8 > > > > > > > > So we can see that many of the reservations have gone substantially > > > > down in size. itruncate, rename, remove, attrinval and attrrm are > > > > much smaller now. The maximum reservation size has gone from being > > > > attrinval at 579456*8 bytes to dqalloc at 318327*8 bytes. This is a > > > > substantial improvement for common operations. > > > > > > If you're going to play around with log reservations, can you have a > > > quick look at the branch I made to fix all the oversized reservations > > > that we make for rmap and reflink? > > > > > > https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux.git/log/?h=reflink-speedups > > > > > > That's what's next after deferred inode inactivation lands. > > > > They all look reasonable at a first pass. I'd need to do more than > > read the patches to say they are definitely correct, but they > > certainly don't seem unreasonable to me. I'd also have to run > > numbers like the table above so I can quantify the reductions, > > but nothing shouted "don't do this!" to me.... > > Reservations before and after for a sample 100G filesystem: .... > type -1 res 547200 count 8 type -1 res 327552 count 5 > > IOWs, a 63% reduction in the size of an itruncate reservations. Nice! Do you want to add the three reservation patches from this patchset to your branch? Because... > Note that the patchset also includes the necessary pieces to continue > formatting filesystems with the same minimum log size rules as before so > that you can format with a new xfsprogs and still be able to mount on an > older kernel. ... this will be needed for either of these reduction patchsets. Cheers, Dave.
On Fri, May 28, 2021 at 12:30:00PM +1000, Dave Chinner wrote: > On Thu, May 27, 2021 at 05:01:53PM -0700, Darrick J. Wong wrote: > > On Thu, May 27, 2021 at 06:52:15PM +1000, Dave Chinner wrote: > > > On Wed, May 26, 2021 at 11:19:47PM -0700, Darrick J. Wong wrote: > > > > On Thu, May 27, 2021 at 02:52:02PM +1000, Dave Chinner wrote: > > > > > From: Dave Chinner <dchinner@redhat.com> > > > > > > > > > > Ever since we moved to deferred freeing of extents, we only every > > > > > free one extent per transaction. We separated the bulk unmapping of > > > > > extents from the submission of EFI/free/EFD transactions, and hence > > > > > while we unmap extents in bulk, we only every free one per > > > > > transaction. > > > > > > > > > > Our transaction reservations still live in the era from before > > > > > deferred freeing of extents, so still refer to "xfs_bmap_finish" > > > > > and it needing to free multiple extents per transaction. These > > > > > freeing reservations can now all be reduced to a single extent to > > > > > reflect how we currently free extents. > > > > > > > > > > This significantly reduces the reservation sizes for operations like > > > > > truncate and directory operations where they currently reserve space > > > > > for freeing up to 4 extents per transaction. > > > > > > > > > > For a 4kB block size filesytsem with reflink=1,rmapbt=1, the > > > > > reservation sizes change like this: > > > > > > > > > > Reservation Before After > > > > > (index) logres logcount logres logcount > > > > > 0 write 314104 8 314104 8 > > > > > 1 itruncate 579456 8 148608 8 > > > > > 2 rename 435840 2 307936 2 > > > > > 3 link 191600 2 191600 2 > > > > > 4 remove 312960 2 174328 2 > > > > > 5 symlink 470656 3 470656 3 > > > > > 6 create 469504 2 469504 2 > > > > > 7 create_tmpfile 490240 2 490240 2 > > > > > 8 mkdir 469504 3 469504 3 > > > > > 9 ifree 508664 2 508664 2 > > > > > 10 ichange 5752 0 5752 0 > > > > > 11 growdata 147840 2 147840 2 > > > > > 12 addafork 178936 2 178936 2 > > > > > 13 writeid 760 0 760 0 > > > > > 14 attrinval 578688 1 147840 1 > > > > > 15 attrsetm 26872 3 26872 3 > > > > > 16 attrsetrt 16896 0 16896 0 > > > > > 17 attrrm 292224 3 148608 3 > > > > > 18 clearagi 4224 0 4224 0 > > > > > 19 growrtalloc 173944 2 173944 2 > > > > > 20 growrtzero 4224 0 4224 0 > > > > > 21 growrtfree 10096 0 10096 0 > > > > > 22 qm_setqlim 232 1 232 1 > > > > > 23 qm_dqalloc 318327 8 318327 8 > > > > > 24 qm_quotaoff 4544 1 4544 1 > > > > > 25 qm_equotaoff 320 1 320 1 > > > > > 26 sb 4224 1 4224 1 > > > > > 27 fsyncts 760 0 760 0 > > > > > MAX 579456 8 318327 8 > > > > > > > > > > So we can see that many of the reservations have gone substantially > > > > > down in size. itruncate, rename, remove, attrinval and attrrm are > > > > > much smaller now. The maximum reservation size has gone from being > > > > > attrinval at 579456*8 bytes to dqalloc at 318327*8 bytes. This is a > > > > > substantial improvement for common operations. > > > > > > > > If you're going to play around with log reservations, can you have a > > > > quick look at the branch I made to fix all the oversized reservations > > > > that we make for rmap and reflink? > > > > > > > > https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux.git/log/?h=reflink-speedups > > > > > > > > That's what's next after deferred inode inactivation lands. > > > > > > They all look reasonable at a first pass. I'd need to do more than > > > read the patches to say they are definitely correct, but they > > > certainly don't seem unreasonable to me. I'd also have to run > > > numbers like the table above so I can quantify the reductions, > > > but nothing shouted "don't do this!" to me.... > > > > Reservations before and after for a sample 100G filesystem: > .... > > type -1 res 547200 count 8 type -1 res 327552 count 5 > > > > IOWs, a 63% reduction in the size of an itruncate reservations. > > Nice! Do you want to add the three reservation patches from this > patchset to your branch? Because... > > > Note that the patchset also includes the necessary pieces to continue > > formatting filesystems with the same minimum log size rules as before so > > that you can format with a new xfsprogs and still be able to mount on an > > older kernel. > > ... this will be needed for either of these reduction patchsets. I'll add them to the set, but if you want to see that branch submitted any time soon I'll need your help next week to get deferred inode inactivation reviewed. Deal? :) --D > -- > Dave Chinner > david@fromorbit.com
diff --git a/fs/xfs/libxfs/xfs_trans_resv.c b/fs/xfs/libxfs/xfs_trans_resv.c index 02079f55ef20..f5e76eeae281 100644 --- a/fs/xfs/libxfs/xfs_trans_resv.c +++ b/fs/xfs/libxfs/xfs_trans_resv.c @@ -232,8 +232,7 @@ xfs_rtalloc_log_count( * Various log reservation values. * * These are based on the size of the file system block because that is what - * most transactions manipulate. Each adds in an additional 128 bytes per - * item logged to try to account for the overhead of the transaction mechanism. + * most transactions manipulate. * * Note: Most of the reservations underestimate the number of allocation * groups into which they could free extents in the xfs_defer_finish() call. @@ -262,9 +261,9 @@ xfs_rtalloc_log_count( * the superblock free block counter: sector size * the realtime bitmap: ((MAXEXTLEN / rtextsize) / NBBY) bytes * the realtime summary: 1 block - * And the bmap_finish transaction can free bmap blocks in a join (t3): + * And the deferred freeing can free bmap blocks in a join (t3): * the super block free block counter: sector size - * two extent allocfree reservations for the AG. + * one extent allocfree reservation for the AG. */ STATIC uint xfs_calc_write_reservation( @@ -290,23 +289,25 @@ xfs_calc_write_reservation( } t3 = xfs_calc_buf_res(1, mp->m_sb.sb_sectsize) + - xfs_allocfree_extent_res(mp) * 2; + xfs_allocfree_extent_res(mp); return XFS_DQUOT_LOGRES(mp) + max3(t1, t2, t3); } /* - * In truncating a file we free up to two extents at once. We can modify (t1): + * In truncating a file we defer freeing so we only free one extent per + * transaction for normal files. For rt files we limit to 2 extents per + * transaction. + * We can modify (t1): * the inode being truncated: inode size * the inode's bmap btree: (max depth + 1) * block size - * And the bmap_finish transaction can free the blocks and bmap blocks (t2): - * the super block to reflect the freed blocks: sector size - * four extent allocfree reservations for the AG. - * Or, if it's a realtime file (t3): + * Or, if it's a realtime file (t2): * the super block to reflect the freed blocks: sector size * the realtime bitmap: 2 exts * ((MAXEXTLEN / rtextsize) / NBBY) bytes * the realtime summary: 2 exts * 1 block - * two extent allocfree reservations for the AG. + * And the deferred freeing can free the blocks and bmap blocks (t3): + * the super block to reflect the freed blocks: sector size + * one extent allocfree reservation for the AG. */ STATIC uint xfs_calc_itruncate_reservation( @@ -318,17 +319,16 @@ xfs_calc_itruncate_reservation( t1 = xfs_calc_inode_res(mp, 1) + xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK) + 1, blksz); - t2 = xfs_calc_buf_res(1, mp->m_sb.sb_sectsize) + - xfs_allocfree_extent_res(mp) * 4; - if (xfs_sb_version_hasrealtime(&mp->m_sb)) { - t3 = xfs_calc_buf_res(1, mp->m_sb.sb_sectsize) + - xfs_calc_buf_res(xfs_rtalloc_log_count(mp, 2), blksz) + - xfs_allocfree_extent_res(mp) * 2; + t2 = xfs_calc_buf_res(1, mp->m_sb.sb_sectsize) + + xfs_calc_buf_res(xfs_rtalloc_log_count(mp, 2), blksz); } else { - t3 = 0; + t2 = 0; } + t3 = xfs_calc_buf_res(1, mp->m_sb.sb_sectsize) + + xfs_allocfree_extent_res(mp); + return XFS_DQUOT_LOGRES(mp) + max3(t1, t2, t3); } @@ -337,10 +337,9 @@ xfs_calc_itruncate_reservation( * the four inodes involved: 4 * inode size * the two directory btrees: 2 * (max depth + v2) * dir block size * the two directory bmap btrees: 2 * max depth * block size - * And the bmap_finish transaction can free dir and bmap blocks (two sets - * of bmap blocks) giving: + * And the deferred freeing can free dir and bmap blocks giving: * the superblock for the free block count: sector size - * three extent allocfree reservations for the AG. + * one extent allocfree reservations for the AG. */ STATIC uint xfs_calc_rename_reservation( @@ -351,7 +350,7 @@ xfs_calc_rename_reservation( xfs_calc_buf_res(2 * XFS_DIROP_LOG_COUNT(mp), XFS_FSB_TO_B(mp, 1))), (xfs_calc_buf_res(1, mp->m_sb.sb_sectsize) + - xfs_allocfree_extent_res(mp) * 3)); + xfs_allocfree_extent_res(mp))); } /* @@ -375,7 +374,7 @@ xfs_calc_iunlink_remove_reservation( * the linked inode: inode size * the directory btree could split: (max depth + v2) * dir block size * the directory bmap btree could join or split: (max depth + v2) * blocksize - * And the bmap_finish transaction can free some bmap blocks giving: + * And the deferred freeing can free bmap blocks giving: * the superblock for the free block count: sector size * one extent allocfree reservation for the AG. */ @@ -411,9 +410,9 @@ xfs_calc_iunlink_add_reservation(xfs_mount_t *mp) * the removed inode: inode size * the directory btree could join: (max depth + v2) * dir block size * the directory bmap btree could join or split: (max depth + v2) * blocksize - * And the bmap_finish transaction can free the dir and bmap blocks giving: + * And the deferred freeing can free the dir and bmap blocks giving: * the superblock for the free block count: sector size - * two extent allocfree reservations for the AG. + * one extent allocfree reservation for the AG. */ STATIC uint xfs_calc_remove_reservation( @@ -425,7 +424,7 @@ xfs_calc_remove_reservation( xfs_calc_buf_res(XFS_DIROP_LOG_COUNT(mp), XFS_FSB_TO_B(mp, 1))), (xfs_calc_buf_res(1, mp->m_sb.sb_sectsize) + - xfs_allocfree_extent_res(mp) * 2)); + xfs_allocfree_extent_res(mp))); } /* @@ -670,9 +669,9 @@ xfs_calc_addafork_reservation( * Removing the attribute fork of a file * the inode being truncated: inode size * the inode's bmap btree: max depth * block size - * And the bmap_finish transaction can free the blocks and bmap blocks: + * And the deferred freeing can free the blocks and bmap blocks: * the super block to reflect the freed blocks: sector size - * four extent allocfree reservations for the AG. + * one extent allocfree reservation for the AG. */ STATIC uint xfs_calc_attrinval_reservation( @@ -682,7 +681,7 @@ xfs_calc_attrinval_reservation( xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_ATTR_FORK), XFS_FSB_TO_B(mp, 1))), (xfs_calc_buf_res(1, mp->m_sb.sb_sectsize) + - xfs_allocfree_extent_res(mp) * 4)); + xfs_allocfree_extent_res(mp))); } /* @@ -730,9 +729,9 @@ xfs_calc_attrsetrt_reservation( * the inode: inode size * the attribute btree could join: max depth * block size * the inode bmap btree could join or split: max depth * block size - * And the bmap_finish transaction can free the attr blocks freed giving: + * And the deferred freeing can free the attr blocks freed giving: * the superblock for the free block count: sector size - * two extent allocfree reservations for the AG. + * one extent allocfree reservations for the AG. */ STATIC uint xfs_calc_attrrm_reservation( @@ -746,7 +745,7 @@ xfs_calc_attrrm_reservation( XFS_BM_MAXLEVELS(mp, XFS_ATTR_FORK)) + xfs_calc_buf_res(XFS_BM_MAXLEVELS(mp, XFS_DATA_FORK), 0)), (xfs_calc_buf_res(1, mp->m_sb.sb_sectsize) + - xfs_allocfree_extent_res(mp) * 2)); + xfs_allocfree_extent_res(mp))); } /*