From: Guo Mengqi guomengqi3@huawei.com
hulk inclusion category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I5XQS4 CVE: NA
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If current->flag is set as PF_MEMALLOC, memcgroup will not check current's allocation against memory use limit, which cause system run out of memory.
According to https://lkml.indiana.edu/hypermail/linux/kernel/0911.2/00576.html, PF_MEMALLOC shall only be used when more memory are sure to be freed as a result of this allocation.
Do not use PF_MEMALLOC, rather, remove __GFP_RECLAIM from gfp_mask to ensure no reclaim.
Signed-off-by: Guo Mengqi guomengqi3@huawei.com --- include/linux/hugetlb.h | 6 ++++-- mm/hugetlb.c | 3 +++ mm/share_pool.c | 27 +++------------------------ 3 files changed, 10 insertions(+), 26 deletions(-)
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 0dfe08439095..ea2c249281fc 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -621,9 +621,11 @@ int huge_add_to_page_cache(struct page *page, struct address_space *mapping, #define HUGETLB_ALLOC_NONE 0x00 #define HUGETLB_ALLOC_NORMAL 0x01 /* normal hugepage */ #define HUGETLB_ALLOC_BUDDY 0x02 /* buddy hugepage */ -#define HUGETLB_ALLOC_MASK (HUGETLB_ALLOC_NONE | \ +#define HUGETLB_ALLOC_NORECLAIM 0x04 /* no reclaim */ +#define HUGETLB_ALLOC_MASK (HUGETLB_ALLOC_NONE | \ HUGETLB_ALLOC_NORMAL | \ - HUGETLB_ALLOC_BUDDY) + HUGETLB_ALLOC_BUDDY | \ + HUGETLB_ALLOC_NORECLAIM)
const struct hstate *hugetlb_get_hstate(void); struct page *hugetlb_alloc_hugepage(int nid, int flag); diff --git a/mm/hugetlb.c b/mm/hugetlb.c index c3b73c0b7e7e..3d59f4298cbe 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -6256,6 +6256,9 @@ struct page *hugetlb_alloc_hugepage(int nid, int flag) if (enable_charge_mighp) gfp_mask |= __GFP_ACCOUNT;
+ if (flag & HUGETLB_ALLOC_NORECLAIM) + gfp_mask &= ~__GFP_RECLAIM; + if (flag & HUGETLB_ALLOC_NORMAL) page = hugetlb_alloc_hugepage_normal(h, gfp_mask, nid); else if (flag & HUGETLB_ALLOC_BUDDY) diff --git a/mm/share_pool.c b/mm/share_pool.c index a119d8bf542d..4f76ecf742c4 100644 --- a/mm/share_pool.c +++ b/mm/share_pool.c @@ -2449,35 +2449,13 @@ static void sp_alloc_fallback(struct sp_area *spa, struct sp_alloc_context *ac) static int sp_alloc_populate(struct mm_struct *mm, struct sp_area *spa, struct sp_alloc_context *ac) { - int ret = 0; - unsigned long sp_addr = spa->va_start; - unsigned int noreclaim_flag = 0; - - /* - * The direct reclaim and compact may take a long - * time. As a result, sp mutex will be hold for too - * long time to casue the hung task problem. In this - * case, set the PF_MEMALLOC flag to prevent the - * direct reclaim and compact from being executed. - * Since direct reclaim and compact are not performed - * when the fragmentation is severe or the memory is - * insufficient, 2MB continuous physical pages fail - * to be allocated. This situation is allowed. - */ - if (spa->is_hugepage) - noreclaim_flag = memalloc_noreclaim_save(); - /* * We are not ignoring errors, so if we fail to allocate * physical memory we just return failure, so we won't encounter * page fault later on, and more importantly sp_make_share_u2k() * depends on this feature (and MAP_LOCKED) to work correctly. */ - ret = do_mm_populate(mm, sp_addr, ac->populate, 0); - if (spa->is_hugepage) - memalloc_noreclaim_restore(noreclaim_flag); - - return ret; + return do_mm_populate(mm, spa->va_start, ac->populate, 0); }
static long sp_mbind(struct mm_struct *mm, unsigned long start, unsigned long len, @@ -4233,7 +4211,8 @@ vm_fault_t sharepool_no_page(struct mm_struct *mm,
page = alloc_huge_page(vma, haddr, 0); if (IS_ERR(page)) { - page = hugetlb_alloc_hugepage(node_id, HUGETLB_ALLOC_BUDDY); + page = hugetlb_alloc_hugepage(node_id, + HUGETLB_ALLOC_BUDDY | HUGETLB_ALLOC_NORECLAIM); if (!page) page = ERR_PTR(-ENOMEM); }