linux_dsm_epyc7002/fs/xfs
Dave Chinner ddbca70cc4 xfs: allocate xattr buffer on demand
When doing file lookups and checking for permissions, we end up in
xfs_get_acl() to see if there are any ACLs on the inode. This
requires and xattr lookup, and to do that we have to supply a buffer
large enough to hold an maximum sized xattr.

On workloads were we are accessing a wide range of cache cold files
under memory pressure (e.g. NFS fileservers) we end up spending a
lot of time allocating the buffer. The buffer is 64k in length, so
is a contiguous multi-page allocation, and if that then fails we
fall back to vmalloc(). Hence the allocation here is /expensive/
when we are looking up hundreds of thousands of files a second.

Initial numbers from a bpf trace show average time in xfs_get_acl()
is ~32us, with ~19us of that in the memory allocation. Note these
are average times, so there are going to be affected by the worst
case allocations more than the common fast case...

To avoid this, we could just do a "null"  lookup to see if the ACL
xattr exists and then only do the allocation if it exists. This,
however, optimises the path for the "no ACL present" case at the
expense of the "acl present" case. i.e. we can halve the time in
xfs_get_acl() for the no acl case (i.e down to ~10-15us), but that
then increases the ACL case by 30% (i.e. up to 40-45us).

To solve this and speed up both cases, drive the xattr buffer
allocation into the attribute code once we know what the actual
xattr length is. For the no-xattr case, we avoid the allocation
completely, speeding up that case. For the common ACL case, we'll
end up with a fast heap allocation (because it'll be smaller than a
page), and only for the rarer "we have a remote xattr" will we have
a multi-page allocation occur. Hence the common ACL case will be
much faster, too.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-08-30 22:43:57 -07:00
..
libxfs xfs: allocate xattr buffer on demand 2019-08-30 22:43:57 -07:00
scrub xfs: make attr lookup returns consistent 2019-08-30 22:43:57 -07:00
Kconfig treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
kmem.c xfs: add kmem_alloc_io() 2019-08-26 17:43:15 -07:00
kmem.h xfs: add kmem_alloc_io() 2019-08-26 17:43:15 -07:00
Makefile xfs: move xfs_trans_inode.c to libxfs/ 2019-07-15 08:10:18 -07:00
mrlock.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_acl.c xfs: allocate xattr buffer on demand 2019-08-30 22:43:57 -07:00
xfs_acl.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_aops.c for-linus-20190715 2019-07-15 21:20:52 -07:00
xfs_aops.h xfs: remove the unused xfs_count_page_state declaration 2019-06-30 09:05:17 -07:00
xfs_attr_inactive.c fs: xfs: Remove KM_NOSLEEP and KM_SLEEP. 2019-08-26 12:06:22 -07:00
xfs_attr_list.c fs: xfs: Remove KM_NOSLEEP and KM_SLEEP. 2019-08-26 12:06:22 -07:00
xfs_bio_io.c xfs: chain bios the right way around in xfs_rw_bdev 2019-07-10 10:04:16 -07:00
xfs_bmap_item.c xfs: remove unnecessary int returns from deferred bmap functions 2019-08-28 08:31:02 -07:00
xfs_bmap_item.h xfs: merge xfs_bud_init into xfs_trans_get_bud 2019-06-28 19:27:36 -07:00
xfs_bmap_util.c xfs: remove unnecessary int returns from deferred bmap functions 2019-08-28 08:31:02 -07:00
xfs_bmap_util.h xfs: flush removing page cache in xfs_reflink_remap_prep 2018-11-21 10:10:53 -08:00
xfs_buf_item.c fs: xfs: Remove KM_NOSLEEP and KM_SLEEP. 2019-08-26 12:06:22 -07:00
xfs_buf_item.h xfs: remove the xfs_log_item_t typedef 2019-06-28 19:27:33 -07:00
xfs_buf.c xfs: add kmem_alloc_io() 2019-08-26 17:43:15 -07:00
xfs_buf.h xfs: get allocation alignment from the buftarg 2019-08-26 17:43:14 -07:00
xfs_dir2_readdir.c xfs: remove unused header files 2019-06-28 19:30:43 -07:00
xfs_discard.c xfs: remove unused header files 2019-06-28 19:30:43 -07:00
xfs_discard.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
xfs_dquot_item.c fs: xfs: Remove KM_NOSLEEP and KM_SLEEP. 2019-08-26 12:06:22 -07:00
xfs_dquot_item.h xfs: remove the xfs_log_item_t typedef 2019-06-28 19:27:33 -07:00
xfs_dquot.c xfs: remove all *_ITER_ABORT values 2019-08-29 21:22:41 -07:00
xfs_dquot.h xfs: remove the debug-only q_transp field from struct xfs_dquot 2019-06-12 08:59:59 -07:00
xfs_error.c fs: xfs: Remove KM_NOSLEEP and KM_SLEEP. 2019-08-26 12:06:22 -07:00
xfs_error.h xfs: Introduce XFS_PTAG_VERIFIER_ERROR panic mask 2019-02-11 16:07:00 -08:00
xfs_export.c xfs: remove unused header files 2019-06-28 19:30:43 -07:00
xfs_export.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_extent_busy.c fs: xfs: Remove KM_NOSLEEP and KM_SLEEP. 2019-08-26 12:06:22 -07:00
xfs_extent_busy.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_extfree_item.c fs: xfs: Remove KM_NOSLEEP and KM_SLEEP. 2019-08-26 12:06:22 -07:00
xfs_extfree_item.h xfs: merge xfs_efd_init into xfs_trans_get_efd 2019-06-28 19:27:35 -07:00
xfs_file.c - virtio_pmem: The new virtio_pmem facility introduces a paravirtualized 2019-07-18 10:52:08 -07:00
xfs_filestream.c xfs: remove unused header files 2019-06-28 19:30:43 -07:00
xfs_filestream.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_fsmap.c xfs: remove all *_ITER_CONTINUE values 2019-08-30 22:43:56 -07:00
xfs_fsmap.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_fsops.c xfs: remove unused header files 2019-06-28 19:30:43 -07:00
xfs_fsops.h xfs: change some error-less functions to void types 2019-05-01 20:26:30 -07:00
xfs_globals.c xfs: multithreaded iwalk implementation 2019-07-03 07:33:26 -07:00
xfs_health.c xfs: introduce new v5 bulkstat structure 2019-07-03 20:36:26 -07:00
xfs_icache.c fs: xfs: Remove KM_NOSLEEP and KM_SLEEP. 2019-08-26 12:06:22 -07:00
xfs_icache.h xfs: rename the speculative block allocation reclaim toggle functions 2019-04-26 12:28:55 -07:00
xfs_icreate_item.c fs: xfs: Remove KM_NOSLEEP and KM_SLEEP. 2019-08-26 12:06:22 -07:00
xfs_icreate_item.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_inode_item.c fs: xfs: Remove KM_NOSLEEP and KM_SLEEP. 2019-08-26 12:06:22 -07:00
xfs_inode_item.h xfs: remove the xfs_log_item_t typedef 2019-06-28 19:27:33 -07:00
xfs_inode.c fs: xfs: Remove KM_NOSLEEP and KM_SLEEP. 2019-08-26 12:06:22 -07:00
xfs_inode.h xfs: widen inode delalloc block counter to 64-bits 2019-04-23 08:36:23 -07:00
xfs_ioctl32.c fs: xfs: Remove KM_NOSLEEP and KM_SLEEP. 2019-08-26 12:06:22 -07:00
xfs_ioctl32.h xfs: remove various bulk request typedef usage 2019-07-03 20:36:25 -07:00
xfs_ioctl.c xfs: allocate xattr buffer on demand 2019-08-30 22:43:57 -07:00
xfs_ioctl.h xfs: introduce v5 inode group structure 2019-07-03 20:36:27 -07:00
xfs_iomap.c xfs: remove XFS_TRANS_NOFS 2019-06-30 09:05:17 -07:00
xfs_iomap.h xfs: fix SEEK_DATA for speculative COW fork preallocation 2019-02-21 07:55:07 -08:00
xfs_iops.c xfs: fix missing ILOCK unlock when xfs_setattr_nonsize fails due to EDQUOT 2019-08-22 20:55:54 -07:00
xfs_iops.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_itable.c xfs: remove all *_ITER_ABORT values 2019-08-29 21:22:41 -07:00
xfs_itable.h xfs: remove all *_ITER_ABORT values 2019-08-29 21:22:41 -07:00
xfs_iwalk.c xfs: remove all *_ITER_ABORT values 2019-08-29 21:22:41 -07:00
xfs_iwalk.h xfs: remove all *_ITER_CONTINUE values 2019-08-30 22:43:56 -07:00
xfs_linux.h xfs: use bios directly to read and write the log recovery buffers 2019-06-28 19:27:26 -07:00
xfs_log_cil.c fs: xfs: Remove KM_NOSLEEP and KM_SLEEP. 2019-08-26 12:06:22 -07:00
xfs_log_priv.h fs: xfs: xfs_log: Change return type from int to void 2019-07-03 08:21:58 -07:00
xfs_log_recover.c xfs: add kmem_alloc_io() 2019-08-26 17:43:15 -07:00
xfs_log.c xfs: add kmem_alloc_io() 2019-08-26 17:43:15 -07:00
xfs_log.h fs: xfs: xfs_log: Change return type from int to void 2019-07-03 08:21:58 -07:00
xfs_message.c xfs: remove unused header files 2019-06-28 19:30:43 -07:00
xfs_message.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
xfs_mount.c fs: xfs: Remove KM_NOSLEEP and KM_SLEEP. 2019-08-26 12:06:22 -07:00
xfs_mount.h xfs: add kmem allocation trace points 2019-08-26 17:43:14 -07:00
xfs_mru_cache.c fs: xfs: Remove KM_NOSLEEP and KM_SLEEP. 2019-08-26 12:06:22 -07:00
xfs_mru_cache.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_ondisk.h xfs: wire up the v5 inumbers ioctl 2019-07-03 20:36:28 -07:00
xfs_pnfs.c fs/xfs: Fix return code of xfs_break_leased_layouts() 2019-08-19 18:15:28 -07:00
xfs_pnfs.h xfs: prepare xfs_break_layouts() for another layout type 2018-05-22 07:19:08 -07:00
xfs_pwork.c xfs: poll waiting for quotacheck 2019-07-03 08:21:58 -07:00
xfs_pwork.h xfs: poll waiting for quotacheck 2019-07-03 08:21:58 -07:00
xfs_qm_bhv.c xfs: remove unused header files 2019-06-28 19:30:43 -07:00
xfs_qm_syscalls.c xfs: remove unused header files 2019-06-28 19:30:43 -07:00
xfs_qm.c fs: xfs: Remove KM_NOSLEEP and KM_SLEEP. 2019-08-26 12:06:22 -07:00
xfs_qm.h xfs: widen quota block counters to 64-bit integers 2019-04-23 08:36:23 -07:00
xfs_quota.h xfs: kill the xfs_dqtrx_t typedef 2019-04-23 08:36:23 -07:00
xfs_quotaops.c xfs: remove unused header files 2019-06-28 19:30:43 -07:00
xfs_refcount_item.c xfs: remove unnecessary int returns from deferred refcount functions 2019-08-28 08:31:02 -07:00
xfs_refcount_item.h xfs: merge xfs_cud_init into xfs_trans_get_cud 2019-06-28 19:27:35 -07:00
xfs_reflink.c xfs: remove unnecessary int returns from deferred bmap functions 2019-08-28 08:31:02 -07:00
xfs_reflink.h xfs: don't pass iomap flags to xfs_reflink_allocate_cow 2019-02-25 09:04:31 -08:00
xfs_rmap_item.c fs: xfs: Remove KM_NOSLEEP and KM_SLEEP. 2019-08-26 12:06:22 -07:00
xfs_rmap_item.h xfs: merge xfs_rud_init into xfs_trans_get_rud 2019-06-28 19:27:36 -07:00
xfs_rtalloc.c fs: xfs: Remove KM_NOSLEEP and KM_SLEEP. 2019-08-26 12:06:22 -07:00
xfs_rtalloc.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_stats.c xfs: remove unused header files 2019-06-28 19:30:43 -07:00
xfs_stats.h xfs: use offsetof() in place of offset macros for __xfsstats 2018-10-18 17:21:39 +11:00
xfs_super.c xfs: remove unused header files 2019-06-28 19:30:43 -07:00
xfs_super.h xfs: include WARN, REPAIR build options in XFS_BUILD_OPTIONS 2019-06-12 08:37:40 -07:00
xfs_symlink.c xfs: remove unused header files 2019-06-28 19:30:43 -07:00
xfs_symlink.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_sysctl.c xfs: remove unused header files 2019-06-28 19:30:43 -07:00
xfs_sysctl.h xfs: multithreaded iwalk implementation 2019-07-03 07:33:26 -07:00
xfs_sysfs.c xfs: multithreaded iwalk implementation 2019-07-03 07:33:26 -07:00
xfs_sysfs.h xfs: convert to SPDX license tags 2018-06-06 14:17:53 -07:00
xfs_trace.c xfs: remove unused header files 2019-06-28 19:30:43 -07:00
xfs_trace.h xfs: add kmem_alloc_io() 2019-08-26 17:43:15 -07:00
xfs_trans_ail.c xfs: remove the xfs_log_item_t typedef 2019-06-28 19:27:33 -07:00
xfs_trans_buf.c xfs: remove unused header files 2019-06-28 19:30:43 -07:00
xfs_trans_dquot.c fs: xfs: Remove KM_NOSLEEP and KM_SLEEP. 2019-08-26 12:06:22 -07:00
xfs_trans_priv.h xfs: don't use xfs_trans_free_items in the commit path 2019-06-28 19:27:31 -07:00
xfs_trans.c fs: xfs: Remove KM_NOSLEEP and KM_SLEEP. 2019-08-26 12:06:22 -07:00
xfs_trans.h xfs: merge xfs_trans_bmap.c into xfs_bmap_item.c 2019-06-28 19:29:42 -07:00
xfs_xattr.c xfs: allocate xattr buffer on demand 2019-08-30 22:43:57 -07:00
xfs.h xfs: remove b_last_holder & associated macros 2018-08-12 08:37:31 -07:00