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[PATCH OLK-5.10 0/4] crypto: hisilicon - fix mailbox operation process
by Weili Qian 07 Jun '23

07 Jun '23

From: JiangShui Yang <yangjiangshui(a)h-partners.com> The mailbox of the Kunpeng accelerator is a special operation. Data(128 bits) needs to be read from hardware or written to hardware at one time. And the operation cannot be canceled by software. Therefore, the software process needs to be modified to avoid mailbox operation errors. Weili Qian (4): crypto: hisilicon/qm - obtain the mailbox configuration at one time vfio/migration: obtain the mailbox configuration at one time crypto: hisilicon/qm - fix the pf2vf timeout when device reset crypto: hisilicon/qm - alloc buffer to set and get xqc drivers/crypto/hisilicon/debugfs.c | 75 +-- .../hisilicon/migration/acc_vf_migration.c | 176 +++--- .../hisilicon/migration/acc_vf_migration.h | 8 +- drivers/crypto/hisilicon/qm.c | 532 +++++++++--------- drivers/crypto/hisilicon/qm_common.h | 5 +- include/linux/hisi_acc_qm.h | 18 +- 6 files changed, 429 insertions(+), 385 deletions(-) -- 2.30.0

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[PATCH OLK-5.10] kobject: Fix slab-out-of-bounds in fill_kobj_path()
by Xia Fukun 07 Jun '23

07 Jun '23

mainline inclusion from mainline-v6.4-rc3 commit 3bb2a01caa813d3a1845d378bbe4169ef280d394 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I697JG CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… ---------------------------------------- In kobject_get_path(), if kobj->name is changed between calls get_kobj_path_length() and fill_kobj_path() and the length becomes longer, then fill_kobj_path() will have an out-of-bounds bug. The actual current problem occurs when the ixgbe probe. In ixgbe_mii_bus_init(), if the length of netdev->dev.kobj.name length becomes longer, out-of-bounds will occur. cpu0 cpu1 ixgbe_probe register_netdev(netdev) netdev_register_kobject device_add kobject_uevent // Sending ADD events systemd-udevd // rename netdev dev_change_name device_rename kobject_rename ixgbe_mii_bus_init | mdiobus_register | __mdiobus_register | device_register | device_add | kobject_uevent | kobject_get_path | len = get_kobj_path_length // old name | path = kzalloc(len, gfp_mask); | kobj->name = name; /* name length becomes * longer */ fill_kobj_path /* kobj path length is * longer than path, * resulting in out of * bounds when filling path */ This is the kasan report: ================================================================== BUG: KASAN: slab-out-of-bounds in fill_kobj_path+0x50/0xc0 Write of size 7 at addr ff1100090573d1fd by task kworker/28:1/673 Workqueue: events work_for_cpu_fn Call Trace: <TASK> dump_stack_lvl+0x34/0x48 print_address_description.constprop.0+0x86/0x1e7 print_report+0x36/0x4f kasan_report+0xad/0x130 kasan_check_range+0x35/0x1c0 memcpy+0x39/0x60 fill_kobj_path+0x50/0xc0 kobject_get_path+0x5a/0xc0 kobject_uevent_env+0x140/0x460 device_add+0x5c7/0x910 __mdiobus_register+0x14e/0x490 ixgbe_probe.cold+0x441/0x574 [ixgbe] local_pci_probe+0x78/0xc0 work_for_cpu_fn+0x26/0x40 process_one_work+0x3b6/0x6a0 worker_thread+0x368/0x520 kthread+0x165/0x1a0 ret_from_fork+0x1f/0x30 This reproducer triggers that bug: while: do rmmod ixgbe sleep 0.5 modprobe ixgbe sleep 0.5 When calling fill_kobj_path() to fill path, if the name length of kobj becomes longer, return failure and retry. This fixes the problem. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Wang Hai <wanghai38(a)huawei.com> Link: https://lore.kernel.org/r/20221220012143.52141-1-wanghai38@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Xia Fukun <xiafukun(a)huawei.com> --- lib/kobject.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/lib/kobject.c b/lib/kobject.c index ea53b30cf483..617a25ec355d 100644 --- a/lib/kobject.c +++ b/lib/kobject.c @@ -144,7 +144,7 @@ static int get_kobj_path_length(struct kobject *kobj) return length; } -static void fill_kobj_path(struct kobject *kobj, char *path, int length) +static int fill_kobj_path(struct kobject *kobj, char *path, int length) { struct kobject *parent; @@ -153,12 +153,16 @@ static void fill_kobj_path(struct kobject *kobj, char *path, int length) int cur = strlen(kobject_name(parent)); /* back up enough to print this name with '/' */ length -= cur; + if (length <= 0) + return -EINVAL; memcpy(path + length, kobject_name(parent), cur); *(path + --length) = '/'; } pr_debug("kobject: '%s' (%p): %s: path = '%s'\n", kobject_name(kobj), kobj, __func__, path); + + return 0; } /** @@ -173,13 +177,17 @@ char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask) char *path; int len; +retry: len = get_kobj_path_length(kobj); if (len == 0) return NULL; path = kzalloc(len, gfp_mask); if (!path) return NULL; - fill_kobj_path(kobj, path, len); + if (fill_kobj_path(kobj, path, len)) { + kfree(path); + goto retry; + } return path; } -- 2.17.1

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[PATCH OLK-5.10 0/2] Fix ORC unwinder on paravirt {save,restore}_fl
by Chen Zhongjin 07 Jun '23

07 Jun '23

ISSUE: gitee.com/openeuler/kernel/issues/I6DK3O Chen Zhongjin (2): x86/unwind: Fix orc entry for paravirt {save,restore}_fl x86/unwind: Fix check_paravirt() calls orc_find() before declaration arch/x86/kernel/unwind_orc.c | 45 +++++++++++++++++++++++++++++++++++- 1 file changed, 44 insertions(+), 1 deletion(-) -- 2.17.1

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[PATCH OLK-5.10 0/6] Support dynamic_hugetlb on arm64 and fix some bug
by Liu Shixin 07 Jun '23

07 Jun '23

Support dynamic_hugetlb on arm64 and fix some bug. Liu Shixin (6): mm/dynamic_hugetlb: fix kabi broken when enable CONFIG_DYNAMIC_HUGETLB on arm64 mm/dynamic_hugetlb: support dynamic hugetlb on arm64 mm/dynamic_hugetlb: isolate hugepage without dissolve mm/dynamic_hugetlb: replace spin_lock with mutex_lock and fix kabi broken mm/dynamic_hugetlb: set PagePool to bad page mm/dynamic_hugetlb: fix type error of pfn in __hpool_split_gigantic_page() fs/Kconfig | 2 +- fs/hugetlbfs/inode.c | 2 +- include/linux/dynamic_hugetlb.h | 24 +++++++++++++-- include/linux/memcontrol.h | 6 +++- mm/dynamic_hugetlb.c | 54 +++++++++++++++++++++++++++------ mm/hugetlb.c | 7 +++++ 6 files changed, 80 insertions(+), 15 deletions(-) -- 2.25.1

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[PATCH 0/4] crypto: hisilicon - fix mailbox operation process
by Weili Qian 07 Jun '23

07 Jun '23

The mailbox of the Kunpeng accelerator is a special operation. Data(128 bits) needs to be read from hardware or written to hardware at one time. And the operation cannot be canceled by software. Therefore, the software process needs to be modified to avoid mailbox operation errors. Weili Qian (4): crypto: hisilicon/qm - obtain the mailbox configuration at one time vfio/migration: obtain the mailbox configuration at one time crypto: hisilicon/qm - fix the pf2vf timeout when device reset crypto: hisilicon/qm - alloc buffer to set and get xqc drivers/crypto/hisilicon/debugfs.c | 75 +-- .../hisilicon/migration/acc_vf_migration.c | 176 +++--- .../hisilicon/migration/acc_vf_migration.h | 8 +- drivers/crypto/hisilicon/qm.c | 532 +++++++++--------- drivers/crypto/hisilicon/qm_common.h | 5 +- include/linux/hisi_acc_qm.h | 18 +- 6 files changed, 429 insertions(+), 385 deletions(-) -- 2.30.0

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[PATCH OLK-5.10] kobject: Fix slab-out-of-bounds in fill_kobj_path()
by Xia Fukun 07 Jun '23

07 Jun '23

mainline inclusion from mainline-v6.4-rc3 commit 3bb2a01caa813d3a1845d378bbe4169ef280d394 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I697JG CVE: NA ---------------------------------------- In kobject_get_path(), if kobj->name is changed between calls get_kobj_path_length() and fill_kobj_path() and the length becomes longer, then fill_kobj_path() will have an out-of-bounds bug. The actual current problem occurs when the ixgbe probe. In ixgbe_mii_bus_init(), if the length of netdev->dev.kobj.name length becomes longer, out-of-bounds will occur. cpu0 cpu1 ixgbe_probe register_netdev(netdev) netdev_register_kobject device_add kobject_uevent // Sending ADD events systemd-udevd // rename netdev dev_change_name device_rename kobject_rename ixgbe_mii_bus_init | mdiobus_register | __mdiobus_register | device_register | device_add | kobject_uevent | kobject_get_path | len = get_kobj_path_length // old name | path = kzalloc(len, gfp_mask); | kobj->name = name; /* name length becomes * longer */ fill_kobj_path /* kobj path length is * longer than path, * resulting in out of * bounds when filling path */ This is the kasan report: ================================================================== BUG: KASAN: slab-out-of-bounds in fill_kobj_path+0x50/0xc0 Write of size 7 at addr ff1100090573d1fd by task kworker/28:1/673 Workqueue: events work_for_cpu_fn Call Trace: <TASK> dump_stack_lvl+0x34/0x48 print_address_description.constprop.0+0x86/0x1e7 print_report+0x36/0x4f kasan_report+0xad/0x130 kasan_check_range+0x35/0x1c0 memcpy+0x39/0x60 fill_kobj_path+0x50/0xc0 kobject_get_path+0x5a/0xc0 kobject_uevent_env+0x140/0x460 device_add+0x5c7/0x910 __mdiobus_register+0x14e/0x490 ixgbe_probe.cold+0x441/0x574 [ixgbe] local_pci_probe+0x78/0xc0 work_for_cpu_fn+0x26/0x40 process_one_work+0x3b6/0x6a0 worker_thread+0x368/0x520 kthread+0x165/0x1a0 ret_from_fork+0x1f/0x30 This reproducer triggers that bug: while: do rmmod ixgbe sleep 0.5 modprobe ixgbe sleep 0.5 When calling fill_kobj_path() to fill path, if the name length of kobj becomes longer, return failure and retry. This fixes the problem. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Wang Hai <wanghai38(a)huawei.com> Link: https://lore.kernel.org/r/20221220012143.52141-1-wanghai38@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Xia Fukun <xiafukun(a)huawei.com> --- lib/kobject.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/lib/kobject.c b/lib/kobject.c index ea53b30cf483..617a25ec355d 100644 --- a/lib/kobject.c +++ b/lib/kobject.c @@ -144,7 +144,7 @@ static int get_kobj_path_length(struct kobject *kobj) return length; } -static void fill_kobj_path(struct kobject *kobj, char *path, int length) +static int fill_kobj_path(struct kobject *kobj, char *path, int length) { struct kobject *parent; @@ -153,12 +153,16 @@ static void fill_kobj_path(struct kobject *kobj, char *path, int length) int cur = strlen(kobject_name(parent)); /* back up enough to print this name with '/' */ length -= cur; + if (length <= 0) + return -EINVAL; memcpy(path + length, kobject_name(parent), cur); *(path + --length) = '/'; } pr_debug("kobject: '%s' (%p): %s: path = '%s'\n", kobject_name(kobj), kobj, __func__, path); + + return 0; } /** @@ -173,13 +177,17 @@ char *kobject_get_path(struct kobject *kobj, gfp_t gfp_mask) char *path; int len; +retry: len = get_kobj_path_length(kobj); if (len == 0) return NULL; path = kzalloc(len, gfp_mask); if (!path) return NULL; - fill_kobj_path(kobj, path, len); + if (fill_kobj_path(kobj, path, len)) { + kfree(path); + goto retry; + } return path; } -- 2.17.1

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[PATCH openEuler-1.0-LTS v5 0/2] introduce smart grid scheduler.
by Wang ShaoBo 07 Jun '23

07 Jun '23

introduce smart grid scheduler. v5: 调度部分已完成评审完成代码修改，逃逸部分仍然使用pelt. 内存策略调整模块已经按照review已将进行修改. v4: fix KABI add 'cpu.affinity_domain_mask' add some statistics v3: 修改了patchwork错误，但是KABI还有个问题待解决。 v2: formal version 1. Hui Tang (1): sched: Introduce smart grid scheduling strategy for cfs Wang ShaoBo (1): sched: smart grid: init sched_grid_qos structure on QOS purpose fs/proc/array.c | 13 + include/linux/sched.h | 18 ++ include/linux/sched/grid_qos.h | 84 +++++++ include/linux/sched/sysctl.h | 4 + init/Kconfig | 13 + kernel/fork.c | 9 + kernel/sched/Makefile | 1 + kernel/sched/core.c | 147 ++++++++++++ kernel/sched/fair.c | 425 ++++++++++++++++++++++++++++++++- kernel/sched/grid/Makefile | 2 + kernel/sched/grid/internal.h | 6 + kernel/sched/grid/power.c | 10 + kernel/sched/grid/qos.c | 125 ++++++++++ kernel/sched/grid/stat.c | 15 ++ kernel/sched/sched.h | 50 ++++ kernel/sysctl.c | 9 + mm/mempolicy.c | 12 +- 17 files changed, 940 insertions(+), 3 deletions(-) create mode 100644 include/linux/sched/grid_qos.h create mode 100644 kernel/sched/grid/Makefile create mode 100644 kernel/sched/grid/internal.h create mode 100644 kernel/sched/grid/power.c create mode 100644 kernel/sched/grid/qos.c create mode 100644 kernel/sched/grid/stat.c -- 2.25.1

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[PATCH OLK-5.10 0/2] block: iocost bugfix
by Li Nan 07 Jun '23

07 Jun '23

This patch series fix iocost life cycle bug. Li Nan (2): block: fix null-pointer dereference in ioc_pd_init block: fix order error in blk_release_queue block/blk-core.c | 2 -- block/blk-sysfs.c | 2 ++ 2 files changed, 2 insertions(+), 2 deletions(-) -- 2.39.2

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[PATCH OLK-5.10 00/35] xfs: fixes patchs and backport patchs
by Long Li 07 Jun '23

07 Jun '23

Allison Henderson (1): xfs: increase rename inode reservation ChenXiaoSong (1): xfs: fix NULL pointer dereference in xfs_getbmap() Darrick J. Wong (6): xfs: check return codes when flushing block devices xfs: fix maxlevels comparisons in the btree staging code xfs: shut down filesystem if we xfs_trans_cancel with deferred work items xfs: don't expose internal symlink metadata buffers to the vfs xfs: fix negative array access in xfs_getbmap iomap: iomap: fix memory corruption when recording errors during writeback Dave Chinner (13): xfs: remove xfs_blkdev_issue_flush xfs: AIL should be log centric xfs: shutdown in intent recovery has non-intent items in the AIL xfs: log shutdown triggers should only shut down the log xfs: xfs_do_force_shutdown needs to block racing shutdowns xfs: xfs_trans_commit() path must check for log shutdown xfs: shutdown during log recovery needs to mark the log shutdown xfs: remove XFS_PREALLOC_SYNC xfs: fallocate() should call file_modified() xfs: sb verifier doesn't handle uncached sb buffer xfs: write page faults in iomap are not buffered writes iomap: write iomap validity checks xfs: use iomap_valid method to detect stale cached iomaps Gao Xiang (1): xfs: account extra freespace btree splits for multiple allocations Guo Xuenan (3): Revert "[Huawei] xfs: fix uaf when leaf dir bestcount not match with dir data blocks" xfs: fix exception caused by unexpected illegal bestcount in leaf dir xfs: force shutdown xfs when xfs_attr_inactive fails Long Li (4): xfs: fix ag count overflow during growfs xfs: fix hung when transaction commit fail in xfs_inactive_ifree xfs: fix a UAF when inode item push xfs: fix a UAF in xfs_iflush_abort_clean Shida Zhang (1): xfs: trim the mapp array accordingly in xfs_da_grow_inode_int Wu Guanghao (1): xfs: fix the problem of mount failure caused by not refreshing mp->m_sb Ye Bin (2): xfs: fix BUG_ON in xfs_getbmap() xfs: fix dead loop when do mount with IO fault injection Zhang Yi (2): xfs: factor out __xfs_da3_node_read() xfs: atomic drop extent entries when inactiving attr fs/iomap/apply.c | 14 +++- fs/iomap/buffered-io.c | 29 ++++++++- fs/xfs/libxfs/xfs_alloc.c | 9 ++- fs/xfs/libxfs/xfs_alloc.h | 1 + fs/xfs/libxfs/xfs_bmap.c | 7 +- fs/xfs/libxfs/xfs_btree_staging.c | 4 +- fs/xfs/libxfs/xfs_da_btree.c | 7 +- fs/xfs/libxfs/xfs_da_btree.h | 15 ++++- fs/xfs/libxfs/xfs_dir2_leaf.c | 21 ++---- fs/xfs/libxfs/xfs_ialloc.c | 1 + fs/xfs/libxfs/xfs_sb.c | 2 +- fs/xfs/libxfs/xfs_trans_resv.c | 4 +- fs/xfs/xfs_aops.c | 2 +- fs/xfs/xfs_attr_inactive.c | 66 ++++++++++++++----- fs/xfs/xfs_bmap_util.c | 34 +++++----- fs/xfs/xfs_buf.c | 7 +- fs/xfs/xfs_buf.h | 7 +- fs/xfs/xfs_buf_item.c | 20 ++++++ fs/xfs/xfs_buf_item_recover.c | 24 +++++++ fs/xfs/xfs_file.c | 49 ++++++++------ fs/xfs/xfs_fsops.c | 9 ++- fs/xfs/xfs_inode.c | 5 +- fs/xfs/xfs_inode_item.c | 11 +++- fs/xfs/xfs_iomap.c | 105 ++++++++++++++++++++++++------ fs/xfs/xfs_iomap.h | 7 +- fs/xfs/xfs_iops.c | 34 +--------- fs/xfs/xfs_log.c | 68 +++++++++++++------ fs/xfs/xfs_log_cil.c | 4 +- fs/xfs/xfs_log_priv.h | 11 ++++ fs/xfs/xfs_log_recover.c | 56 ++++++---------- fs/xfs/xfs_mount.c | 1 + fs/xfs/xfs_pnfs.c | 12 ++-- fs/xfs/xfs_super.c | 7 -- fs/xfs/xfs_super.h | 1 - fs/xfs/xfs_symlink.c | 27 +++++--- fs/xfs/xfs_trans.c | 61 ++++++++++++----- fs/xfs/xfs_trans_ail.c | 30 ++++----- fs/xfs/xfs_trans_priv.h | 3 +- include/linux/iomap.h | 39 +++++++++-- 39 files changed, 549 insertions(+), 265 deletions(-) -- 2.31.1

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[PATCH OLK-5.10] mm: page_counter: remove unneeded atomic ops for low/min
by Peng Zhang 07 Jun '23

07 Jun '23

From: Shakeel Butt <shakeelb(a)google.com> mainline inclusion from mainline-v6.1-rc1 commit cfdab60bfa66b2dc0391c9e405b8af6039924cd4 category: perf bugzilla: https://gitee.com/openeuler/kernel/issues/I7BHGR CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… -------------------------------- Patch series "memcg: optimize charge codepath", v2. Recently Linux networking stack has moved from a very old per socket pre-charge caching to per-cpu caching to avoid pre-charge fragmentation and unwarranted OOMs. One impact of this change is that for network traffic workloads, memcg charging codepath can become a bottleneck. The kernel test robot has also reported this regression[1]. This patch series tries to improve the memcg charging for such workloads. This patch series implement three optimizations: (A) Reduce atomic ops in page counter update path. (B) Change layout of struct page_counter to eliminate false sharing between usage and high. (C) Increase the memcg charge batch to 64. To evaluate the impact of these optimizations, on a 72 CPUs machine, we ran the following workload in root memcg and then compared with scenario where the workload is run in a three level of cgroup hierarchy with top level having min and low setup appropriately. $ netserver -6 # 36 instances of netperf with following params $ netperf -6 -H ::1 -l 60 -t TCP_SENDFILE -- -m 10K Results (average throughput of netperf): 1. root memcg 21694.8 Mbps 2. 6.0-rc1 10482.7 Mbps (-51.6%) 3. 6.0-rc1 + (A) 14542.5 Mbps (-32.9%) 4. 6.0-rc1 + (B) 12413.7 Mbps (-42.7%) 5. 6.0-rc1 + (C) 17063.7 Mbps (-21.3%) 6. 6.0-rc1 + (A+B+C) 20120.3 Mbps (-7.2%) With all three optimizations, the memcg overhead of this workload has been reduced from 51.6% to just 7.2%. [1] https://lore.kernel.org/linux-mm/20220619150456.GB34471@xsang-OptiPlex-9020/ This patch (of 3): For cgroups using low or min protections, the function propagate_protected_usage() was doing an atomic xchg() operation irrespectively. We can optimize out this atomic operation for one specific scenario where the workload is using the protection (i.e. min > 0) and the usage is above the protection (i.e. usage > min). This scenario is actually very common where the users want a part of their workload to be protected against the external reclaim. Though this optimization does introduce a race when the usage is around the protection and concurrent charges and uncharged trip it over or under the protection. In such cases, we might see lower effective protection but the subsequent charge/uncharge will correct it. To evaluate the impact of this optimization, on a 72 CPUs machine, we ran the following workload in a three level of cgroup hierarchy with top level having min and low setup appropriately to see if this optimization is effective for the mentioned case. $ netserver -6 # 36 instances of netperf with following params $ netperf -6 -H ::1 -l 60 -t TCP_SENDFILE -- -m 10K Results (average throughput of netperf): Without (6.0-rc1) 10482.7 Mbps With patch 14542.5 Mbps (38.7% improvement) With the patch, the throughput improved by 38.7% Link: https://lkml.kernel.org/r/20220825000506.239406-1-shakeelb@google.com Link: https://lkml.kernel.org/r/20220825000506.239406-2-shakeelb@google.com Signed-off-by: Shakeel Butt <shakeelb(a)google.com> Reported-by: kernel test robot <oliver.sang(a)intel.com> Acked-by: Soheil Hassas Yeganeh <soheil(a)google.com> Reviewed-by: Feng Tang <feng.tang(a)intel.com> Acked-by: Roman Gushchin <roman.gushchin(a)linux.dev> Acked-by: Michal Hocko <mhocko(a)suse.com> Cc: Eric Dumazet <edumazet(a)google.com> Cc: Johannes Weiner <hannes(a)cmpxchg.org> Cc: "Michal Koutný" <mkoutny(a)suse.com> Cc: Muchun Song <songmuchun(a)bytedance.com> Cc: Oliver Sang <oliver.sang(a)intel.com> Cc: Soheil Hassas Yeganeh <soheil(a)google.com> Signed-off-by: Andrew Morton <akpm(a)linux-foundation.org> Signed-off-by: ZhangPeng <zhangpeng362(a)huawei.com> --- mm/page_counter.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/mm/page_counter.c b/mm/page_counter.c index 6d8715e3255d..e67e54e836b1 100644 --- a/mm/page_counter.c +++ b/mm/page_counter.c @@ -17,24 +17,23 @@ static void propagate_protected_usage(struct page_counter *c, unsigned long usage) { unsigned long protected, old_protected; - unsigned long low, min; long delta; if (!c->parent) return; - min = READ_ONCE(c->min); - if (min || atomic_long_read(&c->min_usage)) { - protected = min(usage, min); + protected = min(usage, READ_ONCE(c->min)); + old_protected = atomic_long_read(&c->min_usage); + if (protected != old_protected) { old_protected = atomic_long_xchg(&c->min_usage, protected); delta = protected - old_protected; if (delta) atomic_long_add(delta, &c->parent->children_min_usage); } - low = READ_ONCE(c->low); - if (low || atomic_long_read(&c->low_usage)) { - protected = min(usage, low); + protected = min(usage, READ_ONCE(c->low)); + old_protected = atomic_long_read(&c->low_usage); + if (protected != old_protected) { old_protected = atomic_long_xchg(&c->low_usage, protected); delta = protected - old_protected; if (delta) -- 2.25.1

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