forked from Minki/linux
4034247a0d
Various places in the kernel - largely in filesystems - respond to a memory allocation failure by looping around and re-trying. Some of these cannot conveniently use __GFP_NOFAIL, for reasons such as: - a GFP_ATOMIC allocation, which __GFP_NOFAIL doesn't work on - a need to check for the process being signalled between failures - the possibility that other recovery actions could be performed - the allocation is quite deep in support code, and passing down an extra flag to say if __GFP_NOFAIL is wanted would be clumsy. Many of these currently use congestion_wait() which (in almost all cases) simply waits the given timeout - congestion isn't tracked for most devices. It isn't clear what the best delay is for loops, but it is clear that the various filesystems shouldn't be responsible for choosing a timeout. This patch introduces memalloc_retry_wait() with takes on that responsibility. Code that wants to retry a memory allocation can call this function passing the GFP flags that were used. It will wait however is appropriate. For now, it only considers __GFP_NORETRY and whatever gfpflags_allow_blocking() tests. If blocking is allowed without __GFP_NORETRY, then alloc_page either made some reclaim progress, or waited for a while, before failing. So there is no need for much further waiting. memalloc_retry_wait() will wait until the current jiffie ends. If this condition is not met, then alloc_page() won't have waited much if at all. In that case memalloc_retry_wait() waits about 200ms. This is the delay that most current loops uses. linux/sched/mm.h needs to be included in some files now, but linux/backing-dev.h does not. Link: https://lkml.kernel.org/r/163754371968.13692.1277530886009912421@noble.neil.brown.name Signed-off-by: NeilBrown <neilb@suse.de> Cc: Dave Chinner <david@fromorbit.com> Cc: Michal Hocko <mhocko@suse.com> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Jaegeuk Kim <jaegeuk@kernel.org> Cc: Chao Yu <chao@kernel.org> Cc: Darrick J. Wong <djwong@kernel.org> Cc: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
31 lines
681 B
C
31 lines
681 B
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* Copyright (c) 2000-2005 Silicon Graphics, Inc.
|
|
* All Rights Reserved.
|
|
*/
|
|
#include "xfs.h"
|
|
#include "xfs_message.h"
|
|
#include "xfs_trace.h"
|
|
|
|
void *
|
|
kmem_alloc(size_t size, xfs_km_flags_t flags)
|
|
{
|
|
int retries = 0;
|
|
gfp_t lflags = kmem_flags_convert(flags);
|
|
void *ptr;
|
|
|
|
trace_kmem_alloc(size, flags, _RET_IP_);
|
|
|
|
do {
|
|
ptr = kmalloc(size, lflags);
|
|
if (ptr || (flags & KM_MAYFAIL))
|
|
return ptr;
|
|
if (!(++retries % 100))
|
|
xfs_err(NULL,
|
|
"%s(%u) possible memory allocation deadlock size %u in %s (mode:0x%x)",
|
|
current->comm, current->pid,
|
|
(unsigned int)size, __func__, lflags);
|
|
memalloc_retry_wait(lflags);
|
|
} while (1);
|
|
}
|