fs/xfs/kmem.c

   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         "%s(%u) possible memory allocation deadlock size %u in %s (mode:0x%x)",
  59                                 current->comm, current->pid,
  60                                 (unsigned int)size, __func__, lflags);
  61                 congestion_wait(BLK_RW_ASYNC, HZ/50);
  62         } while (1);
  63 }
  64
  65 void *
  66 kmem_zalloc_large(size_t size, xfs_km_flags_t flags)
  67 {
  68         unsigned noio_flag = 0;
  69         void    *ptr;
  70         gfp_t   lflags;
  71
  72         ptr = kmem_zalloc(size, flags | KM_MAYFAIL);
  73         if (ptr)
  74                 return ptr;
  75
  76         /*
  77          * __vmalloc() will allocate data pages and auxillary structures (e.g.
  78          * pagetables) with GFP_KERNEL, yet we may be under GFP_NOFS context
  79          * here. Hence we need to tell memory reclaim that we are in such a
  80          * context via PF_MEMALLOC_NOIO to prevent memory reclaim re-entering
  81          * the filesystem here and potentially deadlocking.
  82          */
  83         if ((current->flags & PF_FSTRANS) || (flags & KM_NOFS))
  84                 noio_flag = memalloc_noio_save();
  85
  86         lflags = kmem_flags_convert(flags);
  87         ptr = __vmalloc(size, lflags | __GFP_HIGHMEM | __GFP_ZERO, PAGE_KERNEL);
  88
  89         if ((current->flags & PF_FSTRANS) || (flags & KM_NOFS))
  90                 memalloc_noio_restore(noio_flag);
  91
  92         return ptr;
  93 }
  94
  95 void *
  96 kmem_realloc(const void *ptr, size_t newsize, size_t oldsize,
  97              xfs_km_flags_t flags)
  98 {
  99         void    *new;
 100
 101         new = kmem_alloc(newsize, flags);
 102         if (ptr) {
 103                 if (new)
 104                         memcpy(new, ptr,
 105                                 ((oldsize < newsize) ? oldsize : newsize));
 106                 kmem_free(ptr);
 107         }
 108         return new;
 109 }
 110
 111 void *
 112 kmem_zone_alloc(kmem_zone_t *zone, xfs_km_flags_t flags)
 113 {
 114         int     retries = 0;
 115         gfp_t   lflags = kmem_flags_convert(flags);
 116         void    *ptr;
 117
 118         do {
 119                 ptr = kmem_cache_alloc(zone, lflags);
 120                 if (ptr || (flags & (KM_MAYFAIL|KM_NOSLEEP)))
 121                         return ptr;
 122                 if (!(++retries % 100))
 123                         xfs_err(NULL,
 124                 "%s(%u) possible memory allocation deadlock in %s (mode:0x%x)",
 125                                 current->comm, current->pid,
 126                                 __func__, lflags);
 127                 congestion_wait(BLK_RW_ASYNC, HZ/50);
 128         } while (1);
 129 }