diff options
| author | Tim Chase <[email protected]> | 2016-06-16 10:19:32 -0500 |
|---|---|---|
| committer | Brian Behlendorf <[email protected]> | 2016-06-17 13:33:49 -0700 |
| commit | 09fb30e5e91d9f2ed622db6b616084ce1d073384 (patch) | |
| tree | 03232db64f38a3247365d5285283eb23f067f673 | |
| parent | 46ab35954c7a7e4dc6591593c14f672bceee042d (diff) | |
Linux 4.6 compat: Fall back to d_prune_aliases() if necessary
As of 4.6, the icache and dcache LRUs are memcg aware insofar as the
kernel's per-superblock shrinker is concerned. The effect is that dcache
or icache entries added by a task in a non-root memcg won't be scanned
by the shrinker in the context of the root (or NULL) memcg. This defeats
the attempts by zfs_sb_prune() to unpin buffers and can allow metadata to
grow uncontrollably. This patch reverts to the d_prune_aliaes() method
in case the kernel's per-superblock shrinker is not able to free anything.
Signed-off-by: Tim Chase <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>
Signed-off-by: Chunwei Chen <[email protected]>
Closes: #4726
| -rw-r--r-- | module/zfs/zfs_vfsops.c | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/module/zfs/zfs_vfsops.c b/module/zfs/zfs_vfsops.c index 7696071f1..a72841c15 100644 --- a/module/zfs/zfs_vfsops.c +++ b/module/zfs/zfs_vfsops.c @@ -1050,8 +1050,7 @@ zfs_root(zfs_sb_t *zsb, struct inode **ipp) } EXPORT_SYMBOL(zfs_root); -#if !defined(HAVE_SPLIT_SHRINKER_CALLBACK) && !defined(HAVE_SHRINK) && \ - defined(HAVE_D_PRUNE_ALIASES) +#ifdef HAVE_D_PRUNE_ALIASES /* * Linux kernels older than 3.1 do not support a per-filesystem shrinker. * To accommodate this we must improvise and manually walk the list of znodes @@ -1141,15 +1140,29 @@ zfs_sb_prune(struct super_block *sb, unsigned long nr_to_scan, int *objects) } else { *objects = (*shrinker->scan_objects)(shrinker, &sc); } + #elif defined(HAVE_SPLIT_SHRINKER_CALLBACK) *objects = (*shrinker->scan_objects)(shrinker, &sc); #elif defined(HAVE_SHRINK) *objects = (*shrinker->shrink)(shrinker, &sc); #elif defined(HAVE_D_PRUNE_ALIASES) +#define D_PRUNE_ALIASES_IS_DEFAULT *objects = zfs_sb_prune_aliases(zsb, nr_to_scan); #else #error "No available dentry and inode cache pruning mechanism." #endif + +#if defined(HAVE_D_PRUNE_ALIASES) && !defined(D_PRUNE_ALIASES_IS_DEFAULT) +#undef D_PRUNE_ALIASES_IS_DEFAULT + /* + * Fall back to zfs_sb_prune_aliases if the kernel's per-superblock + * shrinker couldn't free anything, possibly due to the inodes being + * allocated in a different memcg. + */ + if (*objects == 0) + *objects = zfs_sb_prune_aliases(zsb, nr_to_scan); +#endif + ZFS_EXIT(zsb); dprintf_ds(zsb->z_os->os_dsl_dataset, |