From: Juergen Gross <jgross@suse.com>
To: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org
Cc: Juergen Gross <jgross@suse.com>, Jonathan Corbet <corbet@lwn.net>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Stefano Stabellini <sstabellini@kernel.org>,
xen-devel@lists.xenproject.org
Subject: [PATCH 1/3] xen: remove tmem driver
Date: Mon, 27 May 2019 12:32:05 +0200 [thread overview]
Message-ID: <20190527103207.13287-2-jgross@suse.com> (raw)
In-Reply-To: <20190527103207.13287-1-jgross@suse.com>
The Xen tmem (transcendent memory) driver can be removed, as the
related Xen hypervisor feature never made it past the "experimental"
state and will be removed in future Xen versions (>= 4.13).
The xen-selfballoon driver depends on tmem, so it can be removed, too.
Signed-off-by: Juergen Gross <jgross@suse.com>
---
Documentation/admin-guide/kernel-parameters.txt | 21 -
drivers/xen/Kconfig | 23 -
drivers/xen/Makefile | 2 -
drivers/xen/tmem.c | 419 -----------------
drivers/xen/xen-balloon.c | 2 -
drivers/xen/xen-selfballoon.c | 579 ------------------------
include/xen/balloon.h | 8 -
include/xen/tmem.h | 18 -
8 files changed, 1072 deletions(-)
delete mode 100644 drivers/xen/tmem.c
delete mode 100644 drivers/xen/xen-selfballoon.c
delete mode 100644 include/xen/tmem.h
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 138f6664b2e2..2660f1a983a3 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4663,27 +4663,6 @@
Force threading of all interrupt handlers except those
marked explicitly IRQF_NO_THREAD.
- tmem [KNL,XEN]
- Enable the Transcendent memory driver if built-in.
-
- tmem.cleancache=0|1 [KNL, XEN]
- Default is on (1). Disable the usage of the cleancache
- API to send anonymous pages to the hypervisor.
-
- tmem.frontswap=0|1 [KNL, XEN]
- Default is on (1). Disable the usage of the frontswap
- API to send swap pages to the hypervisor. If disabled
- the selfballooning and selfshrinking are force disabled.
-
- tmem.selfballooning=0|1 [KNL, XEN]
- Default is on (1). Disable the driving of swap pages
- to the hypervisor.
-
- tmem.selfshrinking=0|1 [KNL, XEN]
- Default is on (1). Partial swapoff that immediately
- transfers pages from Xen hypervisor back to the
- kernel based on different criteria.
-
topology= [S390]
Format: {off | on}
Specify if the kernel should make use of the cpu
diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index ec6558b79e9d..79cc75096f42 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -10,21 +10,6 @@ config XEN_BALLOON
the system to expand the domain's memory allocation, or alternatively
return unneeded memory to the system.
-config XEN_SELFBALLOONING
- bool "Dynamically self-balloon kernel memory to target"
- depends on XEN && XEN_BALLOON && CLEANCACHE && SWAP && XEN_TMEM
- help
- Self-ballooning dynamically balloons available kernel memory driven
- by the current usage of anonymous memory ("committed AS") and
- controlled by various sysfs-settable parameters. Configuring
- FRONTSWAP is highly recommended; if it is not configured, self-
- ballooning is disabled by default. If FRONTSWAP is configured,
- frontswap-selfshrinking is enabled by default but can be disabled
- with the 'tmem.selfshrink=0' kernel boot parameter; and self-ballooning
- is enabled by default but can be disabled with the 'tmem.selfballooning=0'
- kernel boot parameter. Note that systems without a sufficiently
- large swap device should not enable self-ballooning.
-
config XEN_BALLOON_MEMORY_HOTPLUG
bool "Memory hotplug support for Xen balloon driver"
depends on XEN_BALLOON && MEMORY_HOTPLUG
@@ -191,14 +176,6 @@ config SWIOTLB_XEN
def_bool y
select SWIOTLB
-config XEN_TMEM
- tristate
- depends on !ARM && !ARM64
- default m if (CLEANCACHE || FRONTSWAP)
- help
- Shim to interface in-kernel Transcendent Memory hooks
- (e.g. cleancache and frontswap) to Xen tmem hypercalls.
-
config XEN_PCIDEV_BACKEND
tristate "Xen PCI-device backend driver"
depends on PCI && X86 && XEN
diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
index ad3844d9f876..0c4efa6fe450 100644
--- a/drivers/xen/Makefile
+++ b/drivers/xen/Makefile
@@ -17,14 +17,12 @@ dom0-$(CONFIG_X86) += pcpu.o
obj-$(CONFIG_XEN_DOM0) += $(dom0-y)
obj-$(CONFIG_BLOCK) += biomerge.o
obj-$(CONFIG_XEN_BALLOON) += xen-balloon.o
-obj-$(CONFIG_XEN_SELFBALLOONING) += xen-selfballoon.o
obj-$(CONFIG_XEN_DEV_EVTCHN) += xen-evtchn.o
obj-$(CONFIG_XEN_GNTDEV) += xen-gntdev.o
obj-$(CONFIG_XEN_GRANT_DEV_ALLOC) += xen-gntalloc.o
obj-$(CONFIG_XENFS) += xenfs/
obj-$(CONFIG_XEN_SYS_HYPERVISOR) += sys-hypervisor.o
obj-$(CONFIG_XEN_PVHVM) += platform-pci.o
-obj-$(CONFIG_XEN_TMEM) += tmem.o
obj-$(CONFIG_SWIOTLB_XEN) += swiotlb-xen.o
obj-$(CONFIG_XEN_MCE_LOG) += mcelog.o
obj-$(CONFIG_XEN_PCIDEV_BACKEND) += xen-pciback/
diff --git a/drivers/xen/tmem.c b/drivers/xen/tmem.c
deleted file mode 100644
index 64d7479ad5ad..000000000000
--- a/drivers/xen/tmem.c
+++ /dev/null
@@ -1,419 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * Xen implementation for transcendent memory (tmem)
- *
- * Copyright (C) 2009-2011 Oracle Corp. All rights reserved.
- * Author: Dan Magenheimer
- */
-
-#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
-
-#include <linux/module.h>
-#include <linux/kernel.h>
-#include <linux/types.h>
-#include <linux/init.h>
-#include <linux/pagemap.h>
-#include <linux/cleancache.h>
-#include <linux/frontswap.h>
-
-#include <xen/xen.h>
-#include <xen/interface/xen.h>
-#include <xen/page.h>
-#include <asm/xen/hypercall.h>
-#include <asm/xen/hypervisor.h>
-#include <xen/tmem.h>
-
-#ifndef CONFIG_XEN_TMEM_MODULE
-bool __read_mostly tmem_enabled = false;
-
-static int __init enable_tmem(char *s)
-{
- tmem_enabled = true;
- return 1;
-}
-__setup("tmem", enable_tmem);
-#endif
-
-#ifdef CONFIG_CLEANCACHE
-static bool cleancache __read_mostly = true;
-module_param(cleancache, bool, S_IRUGO);
-static bool selfballooning __read_mostly = true;
-module_param(selfballooning, bool, S_IRUGO);
-#endif /* CONFIG_CLEANCACHE */
-
-#ifdef CONFIG_FRONTSWAP
-static bool frontswap __read_mostly = true;
-module_param(frontswap, bool, S_IRUGO);
-#else /* CONFIG_FRONTSWAP */
-#define frontswap (0)
-#endif /* CONFIG_FRONTSWAP */
-
-#ifdef CONFIG_XEN_SELFBALLOONING
-static bool selfshrinking __read_mostly = true;
-module_param(selfshrinking, bool, S_IRUGO);
-#endif /* CONFIG_XEN_SELFBALLOONING */
-
-#define TMEM_CONTROL 0
-#define TMEM_NEW_POOL 1
-#define TMEM_DESTROY_POOL 2
-#define TMEM_NEW_PAGE 3
-#define TMEM_PUT_PAGE 4
-#define TMEM_GET_PAGE 5
-#define TMEM_FLUSH_PAGE 6
-#define TMEM_FLUSH_OBJECT 7
-#define TMEM_READ 8
-#define TMEM_WRITE 9
-#define TMEM_XCHG 10
-
-/* Bits for HYPERVISOR_tmem_op(TMEM_NEW_POOL) */
-#define TMEM_POOL_PERSIST 1
-#define TMEM_POOL_SHARED 2
-#define TMEM_POOL_PAGESIZE_SHIFT 4
-#define TMEM_VERSION_SHIFT 24
-
-
-struct tmem_pool_uuid {
- u64 uuid_lo;
- u64 uuid_hi;
-};
-
-struct tmem_oid {
- u64 oid[3];
-};
-
-#define TMEM_POOL_PRIVATE_UUID { 0, 0 }
-
-/* flags for tmem_ops.new_pool */
-#define TMEM_POOL_PERSIST 1
-#define TMEM_POOL_SHARED 2
-
-/* xen tmem foundation ops/hypercalls */
-
-static inline int xen_tmem_op(u32 tmem_cmd, u32 tmem_pool, struct tmem_oid oid,
- u32 index, unsigned long gmfn, u32 tmem_offset, u32 pfn_offset, u32 len)
-{
- struct tmem_op op;
- int rc = 0;
-
- op.cmd = tmem_cmd;
- op.pool_id = tmem_pool;
- op.u.gen.oid[0] = oid.oid[0];
- op.u.gen.oid[1] = oid.oid[1];
- op.u.gen.oid[2] = oid.oid[2];
- op.u.gen.index = index;
- op.u.gen.tmem_offset = tmem_offset;
- op.u.gen.pfn_offset = pfn_offset;
- op.u.gen.len = len;
- set_xen_guest_handle(op.u.gen.gmfn, (void *)gmfn);
- rc = HYPERVISOR_tmem_op(&op);
- return rc;
-}
-
-static int xen_tmem_new_pool(struct tmem_pool_uuid uuid,
- u32 flags, unsigned long pagesize)
-{
- struct tmem_op op;
- int rc = 0, pageshift;
-
- for (pageshift = 0; pagesize != 1; pageshift++)
- pagesize >>= 1;
- flags |= (pageshift - 12) << TMEM_POOL_PAGESIZE_SHIFT;
- flags |= TMEM_SPEC_VERSION << TMEM_VERSION_SHIFT;
- op.cmd = TMEM_NEW_POOL;
- op.u.new.uuid[0] = uuid.uuid_lo;
- op.u.new.uuid[1] = uuid.uuid_hi;
- op.u.new.flags = flags;
- rc = HYPERVISOR_tmem_op(&op);
- return rc;
-}
-
-/* xen generic tmem ops */
-
-static int xen_tmem_put_page(u32 pool_id, struct tmem_oid oid,
- u32 index, struct page *page)
-{
- return xen_tmem_op(TMEM_PUT_PAGE, pool_id, oid, index,
- xen_page_to_gfn(page), 0, 0, 0);
-}
-
-static int xen_tmem_get_page(u32 pool_id, struct tmem_oid oid,
- u32 index, struct page *page)
-{
- return xen_tmem_op(TMEM_GET_PAGE, pool_id, oid, index,
- xen_page_to_gfn(page), 0, 0, 0);
-}
-
-static int xen_tmem_flush_page(u32 pool_id, struct tmem_oid oid, u32 index)
-{
- return xen_tmem_op(TMEM_FLUSH_PAGE, pool_id, oid, index,
- 0, 0, 0, 0);
-}
-
-static int xen_tmem_flush_object(u32 pool_id, struct tmem_oid oid)
-{
- return xen_tmem_op(TMEM_FLUSH_OBJECT, pool_id, oid, 0, 0, 0, 0, 0);
-}
-
-
-#ifdef CONFIG_CLEANCACHE
-static int xen_tmem_destroy_pool(u32 pool_id)
-{
- struct tmem_oid oid = { { 0 } };
-
- return xen_tmem_op(TMEM_DESTROY_POOL, pool_id, oid, 0, 0, 0, 0, 0);
-}
-
-/* cleancache ops */
-
-static void tmem_cleancache_put_page(int pool, struct cleancache_filekey key,
- pgoff_t index, struct page *page)
-{
- u32 ind = (u32) index;
- struct tmem_oid oid = *(struct tmem_oid *)&key;
-
- if (pool < 0)
- return;
- if (ind != index)
- return;
- mb(); /* ensure page is quiescent; tmem may address it with an alias */
- (void)xen_tmem_put_page((u32)pool, oid, ind, page);
-}
-
-static int tmem_cleancache_get_page(int pool, struct cleancache_filekey key,
- pgoff_t index, struct page *page)
-{
- u32 ind = (u32) index;
- struct tmem_oid oid = *(struct tmem_oid *)&key;
- int ret;
-
- /* translate return values to linux semantics */
- if (pool < 0)
- return -1;
- if (ind != index)
- return -1;
- ret = xen_tmem_get_page((u32)pool, oid, ind, page);
- if (ret == 1)
- return 0;
- else
- return -1;
-}
-
-static void tmem_cleancache_flush_page(int pool, struct cleancache_filekey key,
- pgoff_t index)
-{
- u32 ind = (u32) index;
- struct tmem_oid oid = *(struct tmem_oid *)&key;
-
- if (pool < 0)
- return;
- if (ind != index)
- return;
- (void)xen_tmem_flush_page((u32)pool, oid, ind);
-}
-
-static void tmem_cleancache_flush_inode(int pool, struct cleancache_filekey key)
-{
- struct tmem_oid oid = *(struct tmem_oid *)&key;
-
- if (pool < 0)
- return;
- (void)xen_tmem_flush_object((u32)pool, oid);
-}
-
-static void tmem_cleancache_flush_fs(int pool)
-{
- if (pool < 0)
- return;
- (void)xen_tmem_destroy_pool((u32)pool);
-}
-
-static int tmem_cleancache_init_fs(size_t pagesize)
-{
- struct tmem_pool_uuid uuid_private = TMEM_POOL_PRIVATE_UUID;
-
- return xen_tmem_new_pool(uuid_private, 0, pagesize);
-}
-
-static int tmem_cleancache_init_shared_fs(uuid_t *uuid, size_t pagesize)
-{
- struct tmem_pool_uuid shared_uuid;
-
- shared_uuid.uuid_lo = *(u64 *)&uuid->b[0];
- shared_uuid.uuid_hi = *(u64 *)&uuid->b[8];
- return xen_tmem_new_pool(shared_uuid, TMEM_POOL_SHARED, pagesize);
-}
-
-static const struct cleancache_ops tmem_cleancache_ops = {
- .put_page = tmem_cleancache_put_page,
- .get_page = tmem_cleancache_get_page,
- .invalidate_page = tmem_cleancache_flush_page,
- .invalidate_inode = tmem_cleancache_flush_inode,
- .invalidate_fs = tmem_cleancache_flush_fs,
- .init_shared_fs = tmem_cleancache_init_shared_fs,
- .init_fs = tmem_cleancache_init_fs
-};
-#endif
-
-#ifdef CONFIG_FRONTSWAP
-/* frontswap tmem operations */
-
-/* a single tmem poolid is used for all frontswap "types" (swapfiles) */
-static int tmem_frontswap_poolid;
-
-/*
- * Swizzling increases objects per swaptype, increasing tmem concurrency
- * for heavy swaploads. Later, larger nr_cpus -> larger SWIZ_BITS
- */
-#define SWIZ_BITS 4
-#define SWIZ_MASK ((1 << SWIZ_BITS) - 1)
-#define _oswiz(_type, _ind) ((_type << SWIZ_BITS) | (_ind & SWIZ_MASK))
-#define iswiz(_ind) (_ind >> SWIZ_BITS)
-
-static inline struct tmem_oid oswiz(unsigned type, u32 ind)
-{
- struct tmem_oid oid = { .oid = { 0 } };
- oid.oid[0] = _oswiz(type, ind);
- return oid;
-}
-
-/* returns 0 if the page was successfully put into frontswap, -1 if not */
-static int tmem_frontswap_store(unsigned type, pgoff_t offset,
- struct page *page)
-{
- u64 ind64 = (u64)offset;
- u32 ind = (u32)offset;
- int pool = tmem_frontswap_poolid;
- int ret;
-
- /* THP isn't supported */
- if (PageTransHuge(page))
- return -1;
-
- if (pool < 0)
- return -1;
- if (ind64 != ind)
- return -1;
- mb(); /* ensure page is quiescent; tmem may address it with an alias */
- ret = xen_tmem_put_page(pool, oswiz(type, ind), iswiz(ind), page);
- /* translate Xen tmem return values to linux semantics */
- if (ret == 1)
- return 0;
- else
- return -1;
-}
-
-/*
- * returns 0 if the page was successfully gotten from frontswap, -1 if
- * was not present (should never happen!)
- */
-static int tmem_frontswap_load(unsigned type, pgoff_t offset,
- struct page *page)
-{
- u64 ind64 = (u64)offset;
- u32 ind = (u32)offset;
- int pool = tmem_frontswap_poolid;
- int ret;
-
- if (pool < 0)
- return -1;
- if (ind64 != ind)
- return -1;
- ret = xen_tmem_get_page(pool, oswiz(type, ind), iswiz(ind), page);
- /* translate Xen tmem return values to linux semantics */
- if (ret == 1)
- return 0;
- else
- return -1;
-}
-
-/* flush a single page from frontswap */
-static void tmem_frontswap_flush_page(unsigned type, pgoff_t offset)
-{
- u64 ind64 = (u64)offset;
- u32 ind = (u32)offset;
- int pool = tmem_frontswap_poolid;
-
- if (pool < 0)
- return;
- if (ind64 != ind)
- return;
- (void) xen_tmem_flush_page(pool, oswiz(type, ind), iswiz(ind));
-}
-
-/* flush all pages from the passed swaptype */
-static void tmem_frontswap_flush_area(unsigned type)
-{
- int pool = tmem_frontswap_poolid;
- int ind;
-
- if (pool < 0)
- return;
- for (ind = SWIZ_MASK; ind >= 0; ind--)
- (void)xen_tmem_flush_object(pool, oswiz(type, ind));
-}
-
-static void tmem_frontswap_init(unsigned ignored)
-{
- struct tmem_pool_uuid private = TMEM_POOL_PRIVATE_UUID;
-
- /* a single tmem poolid is used for all frontswap "types" (swapfiles) */
- if (tmem_frontswap_poolid < 0)
- tmem_frontswap_poolid =
- xen_tmem_new_pool(private, TMEM_POOL_PERSIST, PAGE_SIZE);
-}
-
-static struct frontswap_ops tmem_frontswap_ops = {
- .store = tmem_frontswap_store,
- .load = tmem_frontswap_load,
- .invalidate_page = tmem_frontswap_flush_page,
- .invalidate_area = tmem_frontswap_flush_area,
- .init = tmem_frontswap_init
-};
-#endif
-
-static int __init xen_tmem_init(void)
-{
- if (!xen_domain())
- return 0;
-#ifdef CONFIG_FRONTSWAP
- if (tmem_enabled && frontswap) {
- char *s = "";
-
- tmem_frontswap_poolid = -1;
- frontswap_register_ops(&tmem_frontswap_ops);
- pr_info("frontswap enabled, RAM provided by Xen Transcendent Memory%s\n",
- s);
- }
-#endif
-#ifdef CONFIG_CLEANCACHE
- BUILD_BUG_ON(sizeof(struct cleancache_filekey) != sizeof(struct tmem_oid));
- if (tmem_enabled && cleancache) {
- int err;
-
- err = cleancache_register_ops(&tmem_cleancache_ops);
- if (err)
- pr_warn("xen-tmem: failed to enable cleancache: %d\n",
- err);
- else
- pr_info("cleancache enabled, RAM provided by "
- "Xen Transcendent Memory\n");
- }
-#endif
-#ifdef CONFIG_XEN_SELFBALLOONING
- /*
- * There is no point of driving pages to the swap system if they
- * aren't going anywhere in tmem universe.
- */
- if (!frontswap) {
- selfshrinking = false;
- selfballooning = false;
- }
- xen_selfballoon_init(selfballooning, selfshrinking);
-#endif
- return 0;
-}
-
-module_init(xen_tmem_init)
-MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Dan Magenheimer <dan.magenheimer@oracle.com>");
-MODULE_DESCRIPTION("Shim to Xen transcendent memory");
diff --git a/drivers/xen/xen-balloon.c b/drivers/xen/xen-balloon.c
index a67236b02452..6d12fc368210 100644
--- a/drivers/xen/xen-balloon.c
+++ b/drivers/xen/xen-balloon.c
@@ -129,8 +129,6 @@ void xen_balloon_init(void)
{
register_balloon(&balloon_dev);
- register_xen_selfballooning(&balloon_dev);
-
register_xenstore_notifier(&xenstore_notifier);
}
EXPORT_SYMBOL_GPL(xen_balloon_init);
diff --git a/drivers/xen/xen-selfballoon.c b/drivers/xen/xen-selfballoon.c
deleted file mode 100644
index 246f6122c9ee..000000000000
--- a/drivers/xen/xen-selfballoon.c
+++ /dev/null
@@ -1,579 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/******************************************************************************
- * Xen selfballoon driver (and optional frontswap self-shrinking driver)
- *
- * Copyright (c) 2009-2011, Dan Magenheimer, Oracle Corp.
- *
- * This code complements the cleancache and frontswap patchsets to optimize
- * support for Xen Transcendent Memory ("tmem"). The policy it implements
- * is rudimentary and will likely improve over time, but it does work well
- * enough today.
- *
- * Two functionalities are implemented here which both use "control theory"
- * (feedback) to optimize memory utilization. In a virtualized environment
- * such as Xen, RAM is often a scarce resource and we would like to ensure
- * that each of a possibly large number of virtual machines is using RAM
- * efficiently, i.e. using as little as possible when under light load
- * and obtaining as much as possible when memory demands are high.
- * Since RAM needs vary highly dynamically and sometimes dramatically,
- * "hysteresis" is used, that is, memory target is determined not just
- * on current data but also on past data stored in the system.
- *
- * "Selfballooning" creates memory pressure by managing the Xen balloon
- * driver to decrease and increase available kernel memory, driven
- * largely by the target value of "Committed_AS" (see /proc/meminfo).
- * Since Committed_AS does not account for clean mapped pages (i.e. pages
- * in RAM that are identical to pages on disk), selfballooning has the
- * affect of pushing less frequently used clean pagecache pages out of
- * kernel RAM and, presumably using cleancache, into Xen tmem where
- * Xen can more efficiently optimize RAM utilization for such pages.
- *
- * When kernel memory demand unexpectedly increases faster than Xen, via
- * the selfballoon driver, is able to (or chooses to) provide usable RAM,
- * the kernel may invoke swapping. In most cases, frontswap is able
- * to absorb this swapping into Xen tmem. However, due to the fact
- * that the kernel swap subsystem assumes swapping occurs to a disk,
- * swapped pages may sit on the disk for a very long time; even if
- * the kernel knows the page will never be used again. This is because
- * the disk space costs very little and can be overwritten when
- * necessary. When such stale pages are in frontswap, however, they
- * are taking up valuable real estate. "Frontswap selfshrinking" works
- * to resolve this: When frontswap activity is otherwise stable
- * and the guest kernel is not under memory pressure, the "frontswap
- * selfshrinking" accounts for this by providing pressure to remove some
- * pages from frontswap and return them to kernel memory.
- *
- * For both "selfballooning" and "frontswap-selfshrinking", a worker
- * thread is used and sysfs tunables are provided to adjust the frequency
- * and rate of adjustments to achieve the goal, as well as to disable one
- * or both functions independently.
- *
- * While some argue that this functionality can and should be implemented
- * in userspace, it has been observed that bad things happen (e.g. OOMs).
- *
- * System configuration note: Selfballooning should not be enabled on
- * systems without a sufficiently large swap device configured; for best
- * results, it is recommended that total swap be increased by the size
- * of the guest memory. Note, that selfballooning should be disabled by default
- * if frontswap is not configured. Similarly selfballooning should be enabled
- * by default if frontswap is configured and can be disabled with the
- * "tmem.selfballooning=0" kernel boot option. Finally, when frontswap is
- * configured, frontswap-selfshrinking can be disabled with the
- * "tmem.selfshrink=0" kernel boot option.
- *
- * Selfballooning is disallowed in domain0 and force-disabled.
- *
- */
-
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-
-#include <linux/kernel.h>
-#include <linux/memblock.h>
-#include <linux/swap.h>
-#include <linux/mm.h>
-#include <linux/mman.h>
-#include <linux/workqueue.h>
-#include <linux/device.h>
-#include <xen/balloon.h>
-#include <xen/tmem.h>
-#include <xen/xen.h>
-
-/* Enable/disable with sysfs. */
-static int xen_selfballooning_enabled __read_mostly;
-
-/*
- * Controls rate at which memory target (this iteration) approaches
- * ultimate goal when memory need is increasing (up-hysteresis) or
- * decreasing (down-hysteresis). Higher values of hysteresis cause
- * slower increases/decreases. The default values for the various
- * parameters were deemed reasonable by experimentation, may be
- * workload-dependent, and can all be adjusted via sysfs.
- */
-static unsigned int selfballoon_downhysteresis __read_mostly = 8;
-static unsigned int selfballoon_uphysteresis __read_mostly = 1;
-
-/* In HZ, controls frequency of worker invocation. */
-static unsigned int selfballoon_interval __read_mostly = 5;
-
-/*
- * Minimum usable RAM in MB for selfballooning target for balloon.
- * If non-zero, it is added to totalreserve_pages and self-ballooning
- * will not balloon below the sum. If zero, a piecewise linear function
- * is calculated as a minimum and added to totalreserve_pages. Note that
- * setting this value indiscriminately may cause OOMs and crashes.
- */
-static unsigned int selfballoon_min_usable_mb;
-
-/*
- * Amount of RAM in MB to add to the target number of pages.
- * Can be used to reserve some more room for caches and the like.
- */
-static unsigned int selfballoon_reserved_mb;
-
-static void selfballoon_process(struct work_struct *work);
-static DECLARE_DELAYED_WORK(selfballoon_worker, selfballoon_process);
-
-#ifdef CONFIG_FRONTSWAP
-#include <linux/frontswap.h>
-
-/* Enable/disable with sysfs. */
-static bool frontswap_selfshrinking __read_mostly;
-
-/*
- * The default values for the following parameters were deemed reasonable
- * by experimentation, may be workload-dependent, and can all be
- * adjusted via sysfs.
- */
-
-/* Control rate for frontswap shrinking. Higher hysteresis is slower. */
-static unsigned int frontswap_hysteresis __read_mostly = 20;
-
-/*
- * Number of selfballoon worker invocations to wait before observing that
- * frontswap selfshrinking should commence. Note that selfshrinking does
- * not use a separate worker thread.
- */
-static unsigned int frontswap_inertia __read_mostly = 3;
-
-/* Countdown to next invocation of frontswap_shrink() */
-static unsigned long frontswap_inertia_counter;
-
-/*
- * Invoked by the selfballoon worker thread, uses current number of pages
- * in frontswap (frontswap_curr_pages()), previous status, and control
- * values (hysteresis and inertia) to determine if frontswap should be
- * shrunk and what the new frontswap size should be. Note that
- * frontswap_shrink is essentially a partial swapoff that immediately
- * transfers pages from the "swap device" (frontswap) back into kernel
- * RAM; despite the name, frontswap "shrinking" is very different from
- * the "shrinker" interface used by the kernel MM subsystem to reclaim
- * memory.
- */
-static void frontswap_selfshrink(void)
-{
- static unsigned long cur_frontswap_pages;
- unsigned long last_frontswap_pages;
- unsigned long tgt_frontswap_pages;
-
- last_frontswap_pages = cur_frontswap_pages;
- cur_frontswap_pages = frontswap_curr_pages();
- if (!cur_frontswap_pages ||
- (cur_frontswap_pages > last_frontswap_pages)) {
- frontswap_inertia_counter = frontswap_inertia;
- return;
- }
- if (frontswap_inertia_counter && --frontswap_inertia_counter)
- return;
- if (cur_frontswap_pages <= frontswap_hysteresis)
- tgt_frontswap_pages = 0;
- else
- tgt_frontswap_pages = cur_frontswap_pages -
- (cur_frontswap_pages / frontswap_hysteresis);
- frontswap_shrink(tgt_frontswap_pages);
- frontswap_inertia_counter = frontswap_inertia;
-}
-
-#endif /* CONFIG_FRONTSWAP */
-
-#define MB2PAGES(mb) ((mb) << (20 - PAGE_SHIFT))
-#define PAGES2MB(pages) ((pages) >> (20 - PAGE_SHIFT))
-
-/*
- * Use current balloon size, the goal (vm_committed_as), and hysteresis
- * parameters to set a new target balloon size
- */
-static void selfballoon_process(struct work_struct *work)
-{
- unsigned long cur_pages, goal_pages, tgt_pages, floor_pages;
- unsigned long useful_pages;
- bool reset_timer = false;
-
- if (xen_selfballooning_enabled) {
- cur_pages = totalram_pages();
- tgt_pages = cur_pages; /* default is no change */
- goal_pages = vm_memory_committed() +
- totalreserve_pages +
- MB2PAGES(selfballoon_reserved_mb);
-#ifdef CONFIG_FRONTSWAP
- /* allow space for frontswap pages to be repatriated */
- if (frontswap_selfshrinking)
- goal_pages += frontswap_curr_pages();
-#endif
- if (cur_pages > goal_pages)
- tgt_pages = cur_pages -
- ((cur_pages - goal_pages) /
- selfballoon_downhysteresis);
- else if (cur_pages < goal_pages)
- tgt_pages = cur_pages +
- ((goal_pages - cur_pages) /
- selfballoon_uphysteresis);
- /* else if cur_pages == goal_pages, no change */
- useful_pages = max_pfn - totalreserve_pages;
- if (selfballoon_min_usable_mb != 0)
- floor_pages = totalreserve_pages +
- MB2PAGES(selfballoon_min_usable_mb);
- /* piecewise linear function ending in ~3% slope */
- else if (useful_pages < MB2PAGES(16))
- floor_pages = max_pfn; /* not worth ballooning */
- else if (useful_pages < MB2PAGES(64))
- floor_pages = totalreserve_pages + MB2PAGES(16) +
- ((useful_pages - MB2PAGES(16)) >> 1);
- else if (useful_pages < MB2PAGES(512))
- floor_pages = totalreserve_pages + MB2PAGES(40) +
- ((useful_pages - MB2PAGES(40)) >> 3);
- else /* useful_pages >= MB2PAGES(512) */
- floor_pages = totalreserve_pages + MB2PAGES(99) +
- ((useful_pages - MB2PAGES(99)) >> 5);
- if (tgt_pages < floor_pages)
- tgt_pages = floor_pages;
- balloon_set_new_target(tgt_pages +
- balloon_stats.current_pages - totalram_pages());
- reset_timer = true;
- }
-#ifdef CONFIG_FRONTSWAP
- if (frontswap_selfshrinking) {
- frontswap_selfshrink();
- reset_timer = true;
- }
-#endif
- if (reset_timer)
- schedule_delayed_work(&selfballoon_worker,
- selfballoon_interval * HZ);
-}
-
-#ifdef CONFIG_SYSFS
-
-#include <linux/capability.h>
-
-#define SELFBALLOON_SHOW(name, format, args...) \
- static ssize_t show_##name(struct device *dev, \
- struct device_attribute *attr, \
- char *buf) \
- { \
- return sprintf(buf, format, ##args); \
- }
-
-SELFBALLOON_SHOW(selfballooning, "%d\n", xen_selfballooning_enabled);
-
-static ssize_t store_selfballooning(struct device *dev,
- struct device_attribute *attr,
- const char *buf,
- size_t count)
-{
- bool was_enabled = xen_selfballooning_enabled;
- unsigned long tmp;
- int err;
-
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
-
- err = kstrtoul(buf, 10, &tmp);
- if (err)
- return err;
- if ((tmp != 0) && (tmp != 1))
- return -EINVAL;
-
- xen_selfballooning_enabled = !!tmp;
- if (!was_enabled && xen_selfballooning_enabled)
- schedule_delayed_work(&selfballoon_worker,
- selfballoon_interval * HZ);
-
- return count;
-}
-
-static DEVICE_ATTR(selfballooning, S_IRUGO | S_IWUSR,
- show_selfballooning, store_selfballooning);
-
-SELFBALLOON_SHOW(selfballoon_interval, "%d\n", selfballoon_interval);
-
-static ssize_t store_selfballoon_interval(struct device *dev,
- struct device_attribute *attr,
- const char *buf,
- size_t count)
-{
- unsigned long val;
- int err;
-
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
- err = kstrtoul(buf, 10, &val);
- if (err)
- return err;
- if (val == 0)
- return -EINVAL;
- selfballoon_interval = val;
- return count;
-}
-
-static DEVICE_ATTR(selfballoon_interval, S_IRUGO | S_IWUSR,
- show_selfballoon_interval, store_selfballoon_interval);
-
-SELFBALLOON_SHOW(selfballoon_downhys, "%d\n", selfballoon_downhysteresis);
-
-static ssize_t store_selfballoon_downhys(struct device *dev,
- struct device_attribute *attr,
- const char *buf,
- size_t count)
-{
- unsigned long val;
- int err;
-
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
- err = kstrtoul(buf, 10, &val);
- if (err)
- return err;
- if (val == 0)
- return -EINVAL;
- selfballoon_downhysteresis = val;
- return count;
-}
-
-static DEVICE_ATTR(selfballoon_downhysteresis, S_IRUGO | S_IWUSR,
- show_selfballoon_downhys, store_selfballoon_downhys);
-
-
-SELFBALLOON_SHOW(selfballoon_uphys, "%d\n", selfballoon_uphysteresis);
-
-static ssize_t store_selfballoon_uphys(struct device *dev,
- struct device_attribute *attr,
- const char *buf,
- size_t count)
-{
- unsigned long val;
- int err;
-
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
- err = kstrtoul(buf, 10, &val);
- if (err)
- return err;
- if (val == 0)
- return -EINVAL;
- selfballoon_uphysteresis = val;
- return count;
-}
-
-static DEVICE_ATTR(selfballoon_uphysteresis, S_IRUGO | S_IWUSR,
- show_selfballoon_uphys, store_selfballoon_uphys);
-
-SELFBALLOON_SHOW(selfballoon_min_usable_mb, "%d\n",
- selfballoon_min_usable_mb);
-
-static ssize_t store_selfballoon_min_usable_mb(struct device *dev,
- struct device_attribute *attr,
- const char *buf,
- size_t count)
-{
- unsigned long val;
- int err;
-
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
- err = kstrtoul(buf, 10, &val);
- if (err)
- return err;
- if (val == 0)
- return -EINVAL;
- selfballoon_min_usable_mb = val;
- return count;
-}
-
-static DEVICE_ATTR(selfballoon_min_usable_mb, S_IRUGO | S_IWUSR,
- show_selfballoon_min_usable_mb,
- store_selfballoon_min_usable_mb);
-
-SELFBALLOON_SHOW(selfballoon_reserved_mb, "%d\n",
- selfballoon_reserved_mb);
-
-static ssize_t store_selfballoon_reserved_mb(struct device *dev,
- struct device_attribute *attr,
- const char *buf,
- size_t count)
-{
- unsigned long val;
- int err;
-
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
- err = kstrtoul(buf, 10, &val);
- if (err)
- return err;
- if (val == 0)
- return -EINVAL;
- selfballoon_reserved_mb = val;
- return count;
-}
-
-static DEVICE_ATTR(selfballoon_reserved_mb, S_IRUGO | S_IWUSR,
- show_selfballoon_reserved_mb,
- store_selfballoon_reserved_mb);
-
-
-#ifdef CONFIG_FRONTSWAP
-SELFBALLOON_SHOW(frontswap_selfshrinking, "%d\n", frontswap_selfshrinking);
-
-static ssize_t store_frontswap_selfshrinking(struct device *dev,
- struct device_attribute *attr,
- const char *buf,
- size_t count)
-{
- bool was_enabled = frontswap_selfshrinking;
- unsigned long tmp;
- int err;
-
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
- err = kstrtoul(buf, 10, &tmp);
- if (err)
- return err;
- if ((tmp != 0) && (tmp != 1))
- return -EINVAL;
- frontswap_selfshrinking = !!tmp;
- if (!was_enabled && !xen_selfballooning_enabled &&
- frontswap_selfshrinking)
- schedule_delayed_work(&selfballoon_worker,
- selfballoon_interval * HZ);
-
- return count;
-}
-
-static DEVICE_ATTR(frontswap_selfshrinking, S_IRUGO | S_IWUSR,
- show_frontswap_selfshrinking, store_frontswap_selfshrinking);
-
-SELFBALLOON_SHOW(frontswap_inertia, "%d\n", frontswap_inertia);
-
-static ssize_t store_frontswap_inertia(struct device *dev,
- struct device_attribute *attr,
- const char *buf,
- size_t count)
-{
- unsigned long val;
- int err;
-
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
- err = kstrtoul(buf, 10, &val);
- if (err)
- return err;
- if (val == 0)
- return -EINVAL;
- frontswap_inertia = val;
- frontswap_inertia_counter = val;
- return count;
-}
-
-static DEVICE_ATTR(frontswap_inertia, S_IRUGO | S_IWUSR,
- show_frontswap_inertia, store_frontswap_inertia);
-
-SELFBALLOON_SHOW(frontswap_hysteresis, "%d\n", frontswap_hysteresis);
-
-static ssize_t store_frontswap_hysteresis(struct device *dev,
- struct device_attribute *attr,
- const char *buf,
- size_t count)
-{
- unsigned long val;
- int err;
-
- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
- err = kstrtoul(buf, 10, &val);
- if (err)
- return err;
- if (val == 0)
- return -EINVAL;
- frontswap_hysteresis = val;
- return count;
-}
-
-static DEVICE_ATTR(frontswap_hysteresis, S_IRUGO | S_IWUSR,
- show_frontswap_hysteresis, store_frontswap_hysteresis);
-
-#endif /* CONFIG_FRONTSWAP */
-
-static struct attribute *selfballoon_attrs[] = {
- &dev_attr_selfballooning.attr,
- &dev_attr_selfballoon_interval.attr,
- &dev_attr_selfballoon_downhysteresis.attr,
- &dev_attr_selfballoon_uphysteresis.attr,
- &dev_attr_selfballoon_min_usable_mb.attr,
- &dev_attr_selfballoon_reserved_mb.attr,
-#ifdef CONFIG_FRONTSWAP
- &dev_attr_frontswap_selfshrinking.attr,
- &dev_attr_frontswap_hysteresis.attr,
- &dev_attr_frontswap_inertia.attr,
-#endif
- NULL
-};
-
-static const struct attribute_group selfballoon_group = {
- .name = "selfballoon",
- .attrs = selfballoon_attrs
-};
-#endif
-
-int register_xen_selfballooning(struct device *dev)
-{
- int error = -1;
-
-#ifdef CONFIG_SYSFS
- error = sysfs_create_group(&dev->kobj, &selfballoon_group);
-#endif
- return error;
-}
-EXPORT_SYMBOL(register_xen_selfballooning);
-
-int xen_selfballoon_init(bool use_selfballooning, bool use_frontswap_selfshrink)
-{
- bool enable = false;
- unsigned long reserve_pages;
-
- if (!xen_domain())
- return -ENODEV;
-
- if (xen_initial_domain()) {
- pr_info("Xen selfballooning driver disabled for domain0\n");
- return -ENODEV;
- }
-
- xen_selfballooning_enabled = tmem_enabled && use_selfballooning;
- if (xen_selfballooning_enabled) {
- pr_info("Initializing Xen selfballooning driver\n");
- enable = true;
- }
-#ifdef CONFIG_FRONTSWAP
- frontswap_selfshrinking = tmem_enabled && use_frontswap_selfshrink;
- if (frontswap_selfshrinking) {
- pr_info("Initializing frontswap selfshrinking driver\n");
- enable = true;
- }
-#endif
- if (!enable)
- return -ENODEV;
-
- /*
- * Give selfballoon_reserved_mb a default value(10% of total ram pages)
- * to make selfballoon not so aggressive.
- *
- * There are mainly two reasons:
- * 1) The original goal_page didn't consider some pages used by kernel
- * space, like slab pages and memory used by device drivers.
- *
- * 2) The balloon driver may not give back memory to guest OS fast
- * enough when the workload suddenly aquries a lot of physical memory.
- *
- * In both cases, the guest OS will suffer from memory pressure and
- * OOM killer may be triggered.
- * By reserving extra 10% of total ram pages, we can keep the system
- * much more reliably and response faster in some cases.
- */
- if (!selfballoon_reserved_mb) {
- reserve_pages = totalram_pages() / 10;
- selfballoon_reserved_mb = PAGES2MB(reserve_pages);
- }
- schedule_delayed_work(&selfballoon_worker, selfballoon_interval * HZ);
-
- return 0;
-}
-EXPORT_SYMBOL(xen_selfballoon_init);
diff --git a/include/xen/balloon.h b/include/xen/balloon.h
index 4914b93a23f2..a72ef3f88b39 100644
--- a/include/xen/balloon.h
+++ b/include/xen/balloon.h
@@ -28,14 +28,6 @@ int alloc_xenballooned_pages(int nr_pages, struct page **pages);
void free_xenballooned_pages(int nr_pages, struct page **pages);
struct device;
-#ifdef CONFIG_XEN_SELFBALLOONING
-extern int register_xen_selfballooning(struct device *dev);
-#else
-static inline int register_xen_selfballooning(struct device *dev)
-{
- return -ENOSYS;
-}
-#endif
#ifdef CONFIG_XEN_BALLOON
void xen_balloon_init(void);
diff --git a/include/xen/tmem.h b/include/xen/tmem.h
deleted file mode 100644
index c80bafe31f14..000000000000
--- a/include/xen/tmem.h
+++ /dev/null
@@ -1,18 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _XEN_TMEM_H
-#define _XEN_TMEM_H
-
-#include <linux/types.h>
-
-#ifdef CONFIG_XEN_TMEM_MODULE
-#define tmem_enabled true
-#else
-/* defined in drivers/xen/tmem.c */
-extern bool tmem_enabled;
-#endif
-
-#ifdef CONFIG_XEN_SELFBALLOONING
-extern int xen_selfballoon_init(bool, bool);
-#endif
-
-#endif /* _XEN_TMEM_H */
--
2.16.4
next prev parent reply other threads:[~2019-05-27 10:32 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-27 10:32 [PATCH 0/3] remove tmem and code depending on it Juergen Gross
2019-05-27 10:32 ` Juergen Gross [this message]
2019-05-28 22:44 ` [PATCH 1/3] xen: remove tmem driver Boris Ostrovsky
2019-05-27 10:32 ` [PATCH 2/3] mm: remove cleancache.c Juergen Gross
2019-05-27 13:10 ` David Sterba
2019-05-28 0:50 ` Joseph Qi
2019-05-28 1:24 ` Chao Yu
2019-05-27 10:32 ` [PATCH 3/3] mm: remove tmem specifics from frontswap Juergen Gross
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190527103207.13287-2-jgross@suse.com \
--to=jgross@suse.com \
--cc=boris.ostrovsky@oracle.com \
--cc=corbet@lwn.net \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=sstabellini@kernel.org \
--cc=xen-devel@lists.xenproject.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).