xref: /openbmc/linux/fs/xfs/kmem.c (revision d0b5e15f)
1  /*
2   * Copyright (c) 2000-2005 Silicon Graphics, Inc.
3   * All Rights Reserved.
4   *
5   * This program is free software; you can redistribute it and/or
6   * modify it under the terms of the GNU General Public License as
7   * published by the Free Software Foundation.
8   *
9   * This program is distributed in the hope that it would be useful,
10   * but WITHOUT ANY WARRANTY; without even the implied warranty of
11   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12   * GNU General Public License for more details.
13   *
14   * You should have received a copy of the GNU General Public License
15   * along with this program; if not, write the Free Software Foundation,
16   * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
17   */
18  #include <linux/mm.h>
19  #include <linux/highmem.h>
20  #include <linux/slab.h>
21  #include <linux/swap.h>
22  #include <linux/blkdev.h>
23  #include <linux/backing-dev.h>
24  #include "kmem.h"
25  #include "xfs_message.h"
26  
27  /*
28   * Greedy allocation.  May fail and may return vmalloced memory.
29   */
30  void *
31  kmem_zalloc_greedy(size_t *size, size_t minsize, size_t maxsize)
32  {
33  	void		*ptr;
34  	size_t		kmsize = maxsize;
35  
36  	while (!(ptr = vzalloc(kmsize))) {
37  		if ((kmsize >>= 1) <= minsize)
38  			kmsize = minsize;
39  	}
40  	if (ptr)
41  		*size = kmsize;
42  	return ptr;
43  }
44  
45  void *
46  kmem_alloc(size_t size, xfs_km_flags_t flags)
47  {
48  	int	retries = 0;
49  	gfp_t	lflags = kmem_flags_convert(flags);
50  	void	*ptr;
51  
52  	do {
53  		ptr = kmalloc(size, lflags);
54  		if (ptr || (flags & (KM_MAYFAIL|KM_NOSLEEP)))
55  			return ptr;
56  		if (!(++retries % 100))
57  			xfs_err(NULL,
58  		"possible memory allocation deadlock in %s (mode:0x%x)",
59  					__func__, lflags);
60  		congestion_wait(BLK_RW_ASYNC, HZ/50);
61  	} while (1);
62  }
63  
64  void *
65  kmem_zalloc_large(size_t size, xfs_km_flags_t flags)
66  {
67  	unsigned noio_flag = 0;
68  	void	*ptr;
69  	gfp_t	lflags;
70  
71  	ptr = kmem_zalloc(size, flags | KM_MAYFAIL);
72  	if (ptr)
73  		return ptr;
74  
75  	/*
76  	 * __vmalloc() will allocate data pages and auxillary structures (e.g.
77  	 * pagetables) with GFP_KERNEL, yet we may be under GFP_NOFS context
78  	 * here. Hence we need to tell memory reclaim that we are in such a
79  	 * context via PF_MEMALLOC_NOIO to prevent memory reclaim re-entering
80  	 * the filesystem here and potentially deadlocking.
81  	 */
82  	if ((current->flags & PF_FSTRANS) || (flags & KM_NOFS))
83  		noio_flag = memalloc_noio_save();
84  
85  	lflags = kmem_flags_convert(flags);
86  	ptr = __vmalloc(size, lflags | __GFP_HIGHMEM | __GFP_ZERO, PAGE_KERNEL);
87  
88  	if ((current->flags & PF_FSTRANS) || (flags & KM_NOFS))
89  		memalloc_noio_restore(noio_flag);
90  
91  	return ptr;
92  }
93  
94  void *
95  kmem_realloc(const void *ptr, size_t newsize, size_t oldsize,
96  	     xfs_km_flags_t flags)
97  {
98  	void	*new;
99  
100  	new = kmem_alloc(newsize, flags);
101  	if (ptr) {
102  		if (new)
103  			memcpy(new, ptr,
104  				((oldsize < newsize) ? oldsize : newsize));
105  		kmem_free(ptr);
106  	}
107  	return new;
108  }
109  
110  void *
111  kmem_zone_alloc(kmem_zone_t *zone, xfs_km_flags_t flags)
112  {
113  	int	retries = 0;
114  	gfp_t	lflags = kmem_flags_convert(flags);
115  	void	*ptr;
116  
117  	do {
118  		ptr = kmem_cache_alloc(zone, lflags);
119  		if (ptr || (flags & (KM_MAYFAIL|KM_NOSLEEP)))
120  			return ptr;
121  		if (!(++retries % 100))
122  			xfs_err(NULL,
123  		"possible memory allocation deadlock in %s (mode:0x%x)",
124  					__func__, lflags);
125  		congestion_wait(BLK_RW_ASYNC, HZ/50);
126  	} while (1);
127  }
128