* [to-be-updated] hugetlb-add-per-hstate-mutex-to-synchronize-user-adjustments.patch removed from -mm tree
@ 2021-04-09 5:06 akpm
0 siblings, 0 replies; only message in thread
From: akpm @ 2021-04-09 5:06 UTC (permalink / raw)
To: almasrymina, aneesh.kumar, david, guro, hdanton, iamjoonsoo.kim,
linmiaohe, longman, mhocko, mike.kravetz, minchan, mm-commits,
naoya.horiguchi, osalvador, peterx, peterz, rientjes, shakeelb,
song.bao.hua, songmuchun, will, willy
The patch titled
Subject: hugetlb: add per-hstate mutex to synchronize user adjustments
has been removed from the -mm tree. Its filename was
hugetlb-add-per-hstate-mutex-to-synchronize-user-adjustments.patch
This patch was dropped because an updated version will be merged
------------------------------------------------------
From: Mike Kravetz <mike.kravetz@oracle.com>
Subject: hugetlb: add per-hstate mutex to synchronize user adjustments
The helper routine hstate_next_node_to_alloc accesses and modifies the
hstate variable next_nid_to_alloc. The helper is used by the routines
alloc_pool_huge_page and adjust_pool_surplus. adjust_pool_surplus is
called with hugetlb_lock held. However, alloc_pool_huge_page can not be
called with the hugetlb lock held as it will call the page allocator. Two
instances of alloc_pool_huge_page could be run in parallel or
alloc_pool_huge_page could run in parallel with adjust_pool_surplus which
may result in the variable next_nid_to_alloc becoming invalid for the
caller and pages being allocated on the wrong node.
Both alloc_pool_huge_page and adjust_pool_surplus are only called from the
routine set_max_huge_pages after boot. set_max_huge_pages is only called
as the reusult of a user writing to the proc/sysfs nr_hugepages, or
nr_hugepages_mempolicy file to adjust the number of hugetlb pages.
It makes little sense to allow multiple adjustment to the number of
hugetlb pages in parallel. Add a mutex to the hstate and use it to only
allow one hugetlb page adjustment at a time. This will synchronize
modifications to the next_nid_to_alloc variable.
Link: https://lkml.kernel.org/r/20210331034148.112624-4-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: Barry Song <song.bao.hua@hisilicon.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: HORIGUCHI NAOYA <naoya.horiguchi@nec.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Waiman Long <longman@redhat.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
include/linux/hugetlb.h | 1 +
mm/hugetlb.c | 8 ++++++++
2 files changed, 9 insertions(+)
--- a/include/linux/hugetlb.h~hugetlb-add-per-hstate-mutex-to-synchronize-user-adjustments
+++ a/include/linux/hugetlb.h
@@ -559,6 +559,7 @@ HPAGEFLAG(Freed, freed)
#define HSTATE_NAME_LEN 32
/* Defines one hugetlb page size */
struct hstate {
+ struct mutex resize_lock;
int next_nid_to_alloc;
int next_nid_to_free;
unsigned int order;
--- a/mm/hugetlb.c~hugetlb-add-per-hstate-mutex-to-synchronize-user-adjustments
+++ a/mm/hugetlb.c
@@ -2731,6 +2731,11 @@ static int set_max_huge_pages(struct hst
else
return -ENOMEM;
+ /*
+ * resize_lock mutex prevents concurrent adjustments to number of
+ * pages in hstate via the proc/sysfs interfaces.
+ */
+ mutex_lock(&h->resize_lock);
spin_lock(&hugetlb_lock);
/*
@@ -2763,6 +2768,7 @@ static int set_max_huge_pages(struct hst
if (hstate_is_gigantic(h) && !IS_ENABLED(CONFIG_CONTIG_ALLOC)) {
if (count > persistent_huge_pages(h)) {
spin_unlock(&hugetlb_lock);
+ mutex_unlock(&h->resize_lock);
NODEMASK_FREE(node_alloc_noretry);
return -EINVAL;
}
@@ -2837,6 +2843,7 @@ static int set_max_huge_pages(struct hst
out:
h->max_huge_pages = persistent_huge_pages(h);
spin_unlock(&hugetlb_lock);
+ mutex_unlock(&h->resize_lock);
NODEMASK_FREE(node_alloc_noretry);
@@ -3324,6 +3331,7 @@ void __init hugetlb_add_hstate(unsigned
BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
BUG_ON(order == 0);
h = &hstates[hugetlb_max_hstate++];
+ mutex_init(&h->resize_lock);
h->order = order;
h->mask = ~(huge_page_size(h) - 1);
for (i = 0; i < MAX_NUMNODES; ++i)
_
Patches currently in -mm which might be from mike.kravetz@oracle.com are
hugetlb-create-remove_hugetlb_page-to-separate-functionality.patch
hugetlb-call-update_and_free_page-without-hugetlb_lock.patch
hugetlb-change-free_pool_huge_page-to-remove_pool_huge_page.patch
hugetlb-make-free_huge_page-irq-safe.patch
hugetlb-make-free_huge_page-irq-safe-fix.patch
hugetlb-add-lockdep_assert_held-calls-for-hugetlb_lock.patch
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2021-04-09 5:06 [to-be-updated] hugetlb-add-per-hstate-mutex-to-synchronize-user-adjustments.patch removed from -mm tree akpm
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