xref: /kernel/linux/linux-5.10/fs/xfs/kmem.c (revision 8c2ecf20) 
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
4 * All Rights Reserved.
5 */
6#include "xfs.h"
7#include <linux/backing-dev.h>
8#include "xfs_message.h"
9#include "xfs_trace.h"
10
11void *
12kmem_alloc(size_t size, xfs_km_flags_t flags)
13{
14	int	retries = 0;
15	gfp_t	lflags = kmem_flags_convert(flags);
16	void	*ptr;
17
18	trace_kmem_alloc(size, flags, _RET_IP_);
19
20	do {
21		ptr = kmalloc(size, lflags);
22		if (ptr || (flags & KM_MAYFAIL))
23			return ptr;
24		if (!(++retries % 100))
25			xfs_err(NULL,
26	"%s(%u) possible memory allocation deadlock size %u in %s (mode:0x%x)",
27				current->comm, current->pid,
28				(unsigned int)size, __func__, lflags);
29		congestion_wait(BLK_RW_ASYNC, HZ/50);
30	} while (1);
31}
32
33
34/*
35 * __vmalloc() will allocate data pages and auxiliary structures (e.g.
36 * pagetables) with GFP_KERNEL, yet we may be under GFP_NOFS context here. Hence
37 * we need to tell memory reclaim that we are in such a context via
38 * PF_MEMALLOC_NOFS to prevent memory reclaim re-entering the filesystem here
39 * and potentially deadlocking.
40 */
41static void *
42__kmem_vmalloc(size_t size, xfs_km_flags_t flags)
43{
44	unsigned nofs_flag = 0;
45	void	*ptr;
46	gfp_t	lflags = kmem_flags_convert(flags);
47
48	if (flags & KM_NOFS)
49		nofs_flag = memalloc_nofs_save();
50
51	ptr = __vmalloc(size, lflags);
52
53	if (flags & KM_NOFS)
54		memalloc_nofs_restore(nofs_flag);
55
56	return ptr;
57}
58
59/*
60 * Same as kmem_alloc_large, except we guarantee the buffer returned is aligned
61 * to the @align_mask. We only guarantee alignment up to page size, we'll clamp
62 * alignment at page size if it is larger. vmalloc always returns a PAGE_SIZE
63 * aligned region.
64 */
65void *
66kmem_alloc_io(size_t size, int align_mask, xfs_km_flags_t flags)
67{
68	void	*ptr;
69
70	trace_kmem_alloc_io(size, flags, _RET_IP_);
71
72	if (WARN_ON_ONCE(align_mask >= PAGE_SIZE))
73		align_mask = PAGE_SIZE - 1;
74
75	ptr = kmem_alloc(size, flags | KM_MAYFAIL);
76	if (ptr) {
77		if (!((uintptr_t)ptr & align_mask))
78			return ptr;
79		kfree(ptr);
80	}
81	return __kmem_vmalloc(size, flags);
82}
83
84void *
85kmem_alloc_large(size_t size, xfs_km_flags_t flags)
86{
87	void	*ptr;
88
89	trace_kmem_alloc_large(size, flags, _RET_IP_);
90
91	ptr = kmem_alloc(size, flags | KM_MAYFAIL);
92	if (ptr)
93		return ptr;
94	return __kmem_vmalloc(size, flags);
95}
96