mirror of
https://github.com/brain-hackers/linux-brain.git
synced 2024-06-09 07:16:21 +09:00
a9659476d4
When failslab was originally written, the intention of the
"ignore-gfp-wait" flag default value ("N") was to fail GFP_ATOMIC
allocations. Those were defined as (__GFP_HIGH), and the code would test
for __GFP_WAIT (0x10u).
However, since then, __GFP_WAIT was replaced by __GFP_RECLAIM
(___GFP_DIRECT_RECLAIM|___GFP_KSWAPD_RECLAIM), and GFP_ATOMIC is now
defined as (__GFP_HIGH|__GFP_ATOMIC|__GFP_KSWAPD_RECLAIM).
This means that when the flag is false, almost no allocation ever fails
(as even GFP_ATOMIC allocations contain ___GFP_KSWAPD_RECLAIM).
Restore the original intent of the code, by ignoring calls that directly
reclaim only (__GFP_DIRECT_RECLAIM), and thus, failing GFP_ATOMIC calls
again by default.
Link: http://lkml.kernel.org/r/20190520214514.81360-1-drinkcat@chromium.org
Fixes: 71baba4b92 ("mm, page_alloc: rename __GFP_WAIT to __GFP_RECLAIM")
Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
Reviewed-by: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
63 lines
1.4 KiB
C
63 lines
1.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
#include <linux/fault-inject.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/mm.h>
|
|
#include "slab.h"
|
|
|
|
static struct {
|
|
struct fault_attr attr;
|
|
bool ignore_gfp_reclaim;
|
|
bool cache_filter;
|
|
} failslab = {
|
|
.attr = FAULT_ATTR_INITIALIZER,
|
|
.ignore_gfp_reclaim = true,
|
|
.cache_filter = false,
|
|
};
|
|
|
|
bool __should_failslab(struct kmem_cache *s, gfp_t gfpflags)
|
|
{
|
|
/* No fault-injection for bootstrap cache */
|
|
if (unlikely(s == kmem_cache))
|
|
return false;
|
|
|
|
if (gfpflags & __GFP_NOFAIL)
|
|
return false;
|
|
|
|
if (failslab.ignore_gfp_reclaim &&
|
|
(gfpflags & __GFP_DIRECT_RECLAIM))
|
|
return false;
|
|
|
|
if (failslab.cache_filter && !(s->flags & SLAB_FAILSLAB))
|
|
return false;
|
|
|
|
return should_fail(&failslab.attr, s->object_size);
|
|
}
|
|
|
|
static int __init setup_failslab(char *str)
|
|
{
|
|
return setup_fault_attr(&failslab.attr, str);
|
|
}
|
|
__setup("failslab=", setup_failslab);
|
|
|
|
#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
|
|
static int __init failslab_debugfs_init(void)
|
|
{
|
|
struct dentry *dir;
|
|
umode_t mode = S_IFREG | 0600;
|
|
|
|
dir = fault_create_debugfs_attr("failslab", NULL, &failslab.attr);
|
|
if (IS_ERR(dir))
|
|
return PTR_ERR(dir);
|
|
|
|
debugfs_create_bool("ignore-gfp-wait", mode, dir,
|
|
&failslab.ignore_gfp_reclaim);
|
|
debugfs_create_bool("cache-filter", mode, dir,
|
|
&failslab.cache_filter);
|
|
|
|
return 0;
|
|
}
|
|
|
|
late_initcall(failslab_debugfs_init);
|
|
|
|
#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
|