218b4e0a76
For kernels which do not implement a per-suberblock shrinker, those older than Linux 3.1, the shrink_dcache_parent() function was used to attempt to reclaim dentries. This was found not be entirely reliable and could lead to performance issues on older kernels running meta-data heavy workloads. To address this issue a zfs_sb_prune_aliases() function has been added to implement this functionality. It relies on traversing the list of znodes for a filesystem and adding them to a private list with a reference held. The private list can then be safely walked outside the z_znodes_lock to prune dentires and drop the last reference so the inode can be freed. This provides the same synchronous behavior as the per-filesystem shrinker and has the advantage of depending on only long standing interfaces. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Tim Chase <tim@chase2k.com> Closes #3501
20 lines
482 B
Plaintext
20 lines
482 B
Plaintext
dnl #
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dnl # 2.6.12 API change
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dnl # d_prune_aliases() helper function available.
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dnl #
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AC_DEFUN([ZFS_AC_KERNEL_D_PRUNE_ALIASES],
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[AC_MSG_CHECKING([whether d_prune_aliases() is available])
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ZFS_LINUX_TRY_COMPILE_SYMBOL([
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#include <linux/dcache.h>
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], [
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struct inode *ip = NULL;
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d_prune_aliases(ip);
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], [d_prune_aliases], [fs/dcache.c], [
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AC_MSG_RESULT(yes)
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AC_DEFINE(HAVE_D_PRUNE_ALIASES, 1,
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[d_prune_aliases() is available])
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], [
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AC_MSG_RESULT(no)
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])
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])
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