freebsd-dev/module/spl/spl-vmem.c
Richard Yao c2fa09454e Add hooks for disabling direct reclaim
The port of XFS to Linux introduced a thread-specific PF_FSTRANS bit
that is used to mark contexts which are processing transactions.  When
set, allocations in this context can dip into kernel memory reserves
to avoid deadlocks during writeback.  Linux 3.9 provided the additional
PF_MEMALLOC_NOIO for disabling __GFP_IO in page allocations, which XFS
began using in 3.15.

This patch implements hooks for marking transactions via PF_FSTRANS.
When an allocation is performed in the context of PF_FSTRANS, any
KM_SLEEP allocation is transparently converted to a GFP_NOIO allocation.

Additionally, when using a Linux 3.9 or newer kernel, it will set
PF_MEMALLOC_NOIO to prevent direct reclaim from entering pageout() on
on any KM_PUSHPAGE or KM_NOSLEEP allocation.  This effectively allows
the spl_vmalloc() helper function to be used safely in a thread which
is responsible for IO.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2015-01-16 13:55:09 -08:00

135 lines
3.3 KiB
C

/*
* Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
* Copyright (C) 2007 The Regents of the University of California.
* Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
* Written by Brian Behlendorf <behlendorf1@llnl.gov>.
* UCRL-CODE-235197
*
* This file is part of the SPL, Solaris Porting Layer.
* For details, see <http://zfsonlinux.org/>.
*
* The SPL is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*
* The SPL is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with the SPL. If not, see <http://www.gnu.org/licenses/>.
*/
#include <sys/debug.h>
#include <sys/vmem.h>
#include <linux/mm_compat.h>
#include <linux/module.h>
vmem_t *heap_arena = NULL;
EXPORT_SYMBOL(heap_arena);
vmem_t *zio_alloc_arena = NULL;
EXPORT_SYMBOL(zio_alloc_arena);
vmem_t *zio_arena = NULL;
EXPORT_SYMBOL(zio_arena);
size_t
vmem_size(vmem_t *vmp, int typemask)
{
ASSERT3P(vmp, ==, NULL);
ASSERT3S(typemask & VMEM_ALLOC, ==, VMEM_ALLOC);
ASSERT3S(typemask & VMEM_FREE, ==, VMEM_FREE);
return (VMALLOC_TOTAL);
}
EXPORT_SYMBOL(vmem_size);
/*
* Public vmem_alloc(), vmem_zalloc() and vmem_free() interfaces.
*/
void *
spl_vmem_alloc(size_t size, int flags, const char *func, int line)
{
ASSERT0(flags & ~KM_PUBLIC_MASK);
flags |= KM_VMEM;
#if !defined(DEBUG_KMEM)
return (spl_kmem_alloc_impl(size, flags, NUMA_NO_NODE));
#elif !defined(DEBUG_KMEM_TRACKING)
return (spl_kmem_alloc_debug(size, flags, NUMA_NO_NODE));
#else
return (spl_kmem_alloc_track(size, flags, func, line, NUMA_NO_NODE));
#endif
}
EXPORT_SYMBOL(spl_vmem_alloc);
void *
spl_vmem_zalloc(size_t size, int flags, const char *func, int line)
{
ASSERT0(flags & ~KM_PUBLIC_MASK);
flags |= (KM_VMEM | KM_ZERO);
#if !defined(DEBUG_KMEM)
return (spl_kmem_alloc_impl(size, flags, NUMA_NO_NODE));
#elif !defined(DEBUG_KMEM_TRACKING)
return (spl_kmem_alloc_debug(size, flags, NUMA_NO_NODE));
#else
return (spl_kmem_alloc_track(size, flags, func, line, NUMA_NO_NODE));
#endif
}
EXPORT_SYMBOL(spl_vmem_zalloc);
void
spl_vmem_free(const void *buf, size_t size)
{
#if !defined(DEBUG_KMEM)
return (spl_kmem_free_impl(buf, size));
#elif !defined(DEBUG_KMEM_TRACKING)
return (spl_kmem_free_debug(buf, size));
#else
return (spl_kmem_free_track(buf, size));
#endif
}
EXPORT_SYMBOL(spl_vmem_free);
/*
* Public vmalloc() interface designed to be safe to be called during I/O.
*/
void *
spl_vmalloc(unsigned long size, gfp_t lflags, pgprot_t prot)
{
#if defined(PF_MEMALLOC_NOIO)
void *ptr;
unsigned noio_flag = 0;
if (spl_fstrans_check())
noio_flag = memalloc_noio_save();
ptr = __vmalloc(size, lflags, prot);
if (spl_fstrans_check())
memalloc_noio_restore(noio_flag);
return (ptr);
#else
return (__vmalloc(size, lflags, prot));
#endif
}
EXPORT_SYMBOL(spl_vmalloc);
int
spl_vmem_init(void)
{
return (0);
}
void
spl_vmem_fini(void)
{
}