xarray: add the xa_lock to the radix_tree_root
This results in no change in structure size on 64-bit machines as it fits in the padding between the gfp_t and the void *. 32-bit machines will grow the structure from 8 to 12 bytes. Almost all radix trees are protected with (at least) a spinlock, so as they are converted from radix trees to xarrays, the data structures will shrink again. Initialising the spinlock requires a name for the benefit of lockdep, so RADIX_TREE_INIT() now needs to know the name of the radix tree it's initialising, and so do IDR_INIT() and IDA_INIT(). Also add the xa_lock() and xa_unlock() family of wrappers to make it easier to use the lock. If we could rely on -fplan9-extensions in the compiler, we could avoid all of this syntactic sugar, but that wasn't added until gcc 4.6. Link: http://lkml.kernel.org/r/20180313132639.17387-8-willy@infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -1015,7 +1015,7 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
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unsigned int init_segno = segno;
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struct gc_inode_list gc_list = {
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.ilist = LIST_HEAD_INIT(gc_list.ilist),
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.iroot = RADIX_TREE_INIT(GFP_NOFS),
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.iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
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};
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trace_f2fs_gc_begin(sbi->sb, sync, background,
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@ -32,27 +32,28 @@ struct idr {
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#define IDR_RT_MARKER (ROOT_IS_IDR | (__force gfp_t) \
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(1 << (ROOT_TAG_SHIFT + IDR_FREE)))
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#define IDR_INIT_BASE(base) { \
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.idr_rt = RADIX_TREE_INIT(IDR_RT_MARKER), \
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#define IDR_INIT_BASE(name, base) { \
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.idr_rt = RADIX_TREE_INIT(name, IDR_RT_MARKER), \
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.idr_base = (base), \
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.idr_next = 0, \
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}
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/**
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* IDR_INIT() - Initialise an IDR.
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* @name: Name of IDR.
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*
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* A freshly-initialised IDR contains no IDs.
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*/
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#define IDR_INIT IDR_INIT_BASE(0)
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#define IDR_INIT(name) IDR_INIT_BASE(name, 0)
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/**
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* DEFINE_IDR() - Define a statically-allocated IDR
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* @name: Name of IDR
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* DEFINE_IDR() - Define a statically-allocated IDR.
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* @name: Name of IDR.
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*
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* An IDR defined using this macro is ready for use with no additional
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* initialisation required. It contains no IDs.
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*/
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#define DEFINE_IDR(name) struct idr name = IDR_INIT
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#define DEFINE_IDR(name) struct idr name = IDR_INIT(name)
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/**
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* idr_get_cursor - Return the current position of the cyclic allocator
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@ -219,10 +220,10 @@ struct ida {
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struct radix_tree_root ida_rt;
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};
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#define IDA_INIT { \
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.ida_rt = RADIX_TREE_INIT(IDR_RT_MARKER | GFP_NOWAIT), \
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#define IDA_INIT(name) { \
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.ida_rt = RADIX_TREE_INIT(name, IDR_RT_MARKER | GFP_NOWAIT), \
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}
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#define DEFINE_IDA(name) struct ida name = IDA_INIT
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#define DEFINE_IDA(name) struct ida name = IDA_INIT(name)
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int ida_pre_get(struct ida *ida, gfp_t gfp_mask);
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int ida_get_new_above(struct ida *ida, int starting_id, int *p_id);
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@ -110,20 +110,23 @@ struct radix_tree_node {
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#define ROOT_TAG_SHIFT (__GFP_BITS_SHIFT)
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struct radix_tree_root {
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spinlock_t xa_lock;
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gfp_t gfp_mask;
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struct radix_tree_node __rcu *rnode;
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};
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#define RADIX_TREE_INIT(mask) { \
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#define RADIX_TREE_INIT(name, mask) { \
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.xa_lock = __SPIN_LOCK_UNLOCKED(name.xa_lock), \
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.gfp_mask = (mask), \
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.rnode = NULL, \
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}
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#define RADIX_TREE(name, mask) \
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struct radix_tree_root name = RADIX_TREE_INIT(mask)
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struct radix_tree_root name = RADIX_TREE_INIT(name, mask)
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#define INIT_RADIX_TREE(root, mask) \
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do { \
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spin_lock_init(&(root)->xa_lock); \
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(root)->gfp_mask = (mask); \
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(root)->rnode = NULL; \
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} while (0)
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24
include/linux/xarray.h
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24
include/linux/xarray.h
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@ -0,0 +1,24 @@
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/* SPDX-License-Identifier: GPL-2.0+ */
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#ifndef _LINUX_XARRAY_H
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#define _LINUX_XARRAY_H
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/*
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* eXtensible Arrays
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* Copyright (c) 2017 Microsoft Corporation
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* Author: Matthew Wilcox <mawilcox@microsoft.com>
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*/
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#include <linux/spinlock.h>
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#define xa_trylock(xa) spin_trylock(&(xa)->xa_lock)
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#define xa_lock(xa) spin_lock(&(xa)->xa_lock)
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#define xa_unlock(xa) spin_unlock(&(xa)->xa_lock)
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#define xa_lock_bh(xa) spin_lock_bh(&(xa)->xa_lock)
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#define xa_unlock_bh(xa) spin_unlock_bh(&(xa)->xa_lock)
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#define xa_lock_irq(xa) spin_lock_irq(&(xa)->xa_lock)
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#define xa_unlock_irq(xa) spin_unlock_irq(&(xa)->xa_lock)
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#define xa_lock_irqsave(xa, flags) \
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spin_lock_irqsave(&(xa)->xa_lock, flags)
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#define xa_unlock_irqrestore(xa, flags) \
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spin_unlock_irqrestore(&(xa)->xa_lock, flags)
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#endif /* _LINUX_XARRAY_H */
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@ -70,7 +70,7 @@ int pid_max_max = PID_MAX_LIMIT;
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*/
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struct pid_namespace init_pid_ns = {
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.kref = KREF_INIT(2),
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.idr = IDR_INIT,
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.idr = IDR_INIT(init_pid_ns.idr),
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.pid_allocated = PIDNS_ADDING,
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.level = 0,
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.child_reaper = &init_task,
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@ -7,6 +7,7 @@
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#define spinlock_t pthread_mutex_t
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#define DEFINE_SPINLOCK(x) pthread_mutex_t x = PTHREAD_MUTEX_INITIALIZER;
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#define __SPIN_LOCK_UNLOCKED(x) (pthread_mutex_t)PTHREAD_MUTEX_INITIALIZER
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#define spin_lock_irqsave(x, f) (void)f, pthread_mutex_lock(x)
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#define spin_unlock_irqrestore(x, f) (void)f, pthread_mutex_unlock(x)
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