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                 "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 }