From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, catalin.marinas@arm.com,
cohuck@redhat.com, david@redhat.com, hch@infradead.org,
imbrenda@linux.ibm.com, linux-mm@kvack.org, mingo@redhat.com,
mm-commits@vger.kernel.org, npiggin@gmail.com,
rientjes@google.com, tglx@linutronix.de,
torvalds@linux-foundation.org, urezki@gmail.com
Subject: [patch 12/24] mm/vmalloc: add vmalloc_no_huge
Date: Thu, 24 Jun 2021 18:39:36 -0700 [thread overview]
Message-ID: <20210625013936.vemOJ1E0d%akpm@linux-foundation.org> (raw)
In-Reply-To: <20210624183838.ac3161ca4a43989665ac8b2f@linux-foundation.org>
From: Claudio Imbrenda <imbrenda@linux.ibm.com>
Subject: mm/vmalloc: add vmalloc_no_huge
Patch series "mm: add vmalloc_no_huge and use it", v4.
Add vmalloc_no_huge() and export it, so modules can allocate memory with
small pages.
Use the newly added vmalloc_no_huge() in KVM on s390 to get around a
hardware limitation.
This patch (of 2):
Commit 121e6f3258fe3 ("mm/vmalloc: hugepage vmalloc mappings") added
support for hugepage vmalloc mappings, it also added the flag
VM_NO_HUGE_VMAP for __vmalloc_node_range to request the allocation to be
performed with 0-order non-huge pages. This flag is not accessible when
calling vmalloc, the only option is to call directly __vmalloc_node_range,
which is not exported.
This means that a module can't vmalloc memory with small pages.
Case in point: KVM on s390x needs to vmalloc a large area, and it needs to
be mapped with non-huge pages, because of a hardware limitation.
This patch adds the function vmalloc_no_huge, which works like vmalloc,
but it is guaranteed to always back the mapping using small pages. This
new function is exported, therefore it is usable by modules.
[akpm@linux-foundation.org: whitespace fixes, per Christoph]
Link: https://lkml.kernel.org/r/20210614132357.10202-1-imbrenda@linux.ibm.com
Link: https://lkml.kernel.org/r/20210614132357.10202-2-imbrenda@linux.ibm.com
Fixes: 121e6f3258fe3 ("mm/vmalloc: hugepage vmalloc mappings")
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Acked-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
include/linux/vmalloc.h | 1 +
mm/vmalloc.c | 17 +++++++++++++++++
2 files changed, 18 insertions(+)
--- a/include/linux/vmalloc.h~mm-vmalloc-add-vmalloc_no_huge
+++ a/include/linux/vmalloc.h
@@ -135,6 +135,7 @@ extern void *__vmalloc_node_range(unsign
const void *caller);
void *__vmalloc_node(unsigned long size, unsigned long align, gfp_t gfp_mask,
int node, const void *caller);
+void *vmalloc_no_huge(unsigned long size);
extern void vfree(const void *addr);
extern void vfree_atomic(const void *addr);
--- a/mm/vmalloc.c~mm-vmalloc-add-vmalloc_no_huge
+++ a/mm/vmalloc.c
@@ -2999,6 +2999,23 @@ void *vmalloc(unsigned long size)
EXPORT_SYMBOL(vmalloc);
/**
+ * vmalloc_no_huge - allocate virtually contiguous memory using small pages
+ * @size: allocation size
+ *
+ * Allocate enough non-huge pages to cover @size from the page level
+ * allocator and map them into contiguous kernel virtual space.
+ *
+ * Return: pointer to the allocated memory or %NULL on error
+ */
+void *vmalloc_no_huge(unsigned long size)
+{
+ return __vmalloc_node_range(size, 1, VMALLOC_START, VMALLOC_END,
+ GFP_KERNEL, PAGE_KERNEL, VM_NO_HUGE_VMAP,
+ NUMA_NO_NODE, __builtin_return_address(0));
+}
+EXPORT_SYMBOL(vmalloc_no_huge);
+
+/**
* vzalloc - allocate virtually contiguous memory with zero fill
* @size: allocation size
*
_
next prev parent reply other threads:[~2021-06-25 1:39 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-25 1:38 incoming Andrew Morton
2021-06-25 1:39 ` [patch 01/24] mm: page_vma_mapped_walk(): use page for pvmw->page Andrew Morton
2021-06-25 1:39 ` [patch 02/24] mm: page_vma_mapped_walk(): settle PageHuge on entry Andrew Morton
2021-06-25 1:39 ` [patch 03/24] mm: page_vma_mapped_walk(): use pmde for *pvmw->pmd Andrew Morton
2021-06-25 1:39 ` [patch 04/24] mm: page_vma_mapped_walk(): prettify PVMW_MIGRATION block Andrew Morton
2021-06-25 1:39 ` [patch 05/24] mm: page_vma_mapped_walk(): crossing page table boundary Andrew Morton
2021-06-25 1:39 ` [patch 06/24] mm: page_vma_mapped_walk(): add a level of indentation Andrew Morton
2021-06-25 1:39 ` [patch 07/24] mm: page_vma_mapped_walk(): use goto instead of while (1) Andrew Morton
2021-06-25 1:39 ` [patch 08/24] mm: page_vma_mapped_walk(): get vma_address_end() earlier Andrew Morton
2021-06-25 1:39 ` [patch 09/24] mm/thp: fix page_vma_mapped_walk() if THP mapped by ptes Andrew Morton
2021-06-25 1:39 ` [patch 10/24] mm/thp: another PVMW_SYNC fix in page_vma_mapped_walk() Andrew Morton
2021-06-25 1:39 ` [patch 11/24] nilfs2: fix memory leak in nilfs_sysfs_delete_device_group Andrew Morton
2021-06-25 1:39 ` Andrew Morton [this message]
2021-06-25 1:39 ` [patch 13/24] KVM: s390: prepare for hugepage vmalloc Andrew Morton
2021-06-25 1:39 ` [patch 14/24] mm/vmalloc: unbreak kasan vmalloc support Andrew Morton
2021-06-25 1:39 ` [patch 15/24] kthread_worker: split code for canceling the delayed work timer Andrew Morton
2021-06-25 1:39 ` [patch 16/24] kthread: prevent deadlock when kthread_mod_delayed_work() races with kthread_cancel_delayed_work_sync() Andrew Morton
2021-06-25 1:39 ` [patch 17/24] mm, futex: fix shared futex pgoff on shmem huge page Andrew Morton
2021-06-25 1:39 ` [patch 18/24] mm/memory-failure: use a mutex to avoid memory_failure() races Andrew Morton
2021-06-25 1:39 ` [patch 19/24] mm,hwpoison: return -EHWPOISON to denote that the page has already been poisoned Andrew Morton
2021-06-25 1:40 ` [patch 20/24] mm/hwpoison: do not lock page again when me_huge_page() successfully recovers Andrew Morton
2021-06-25 1:40 ` [patch 21/24] mm/page_alloc: __alloc_pages_bulk(): do bounds check before accessing array Andrew Morton
2021-06-25 1:40 ` [patch 22/24] mm/page_alloc: do bulk array bounds check after checking populated elements Andrew Morton
2021-06-25 1:40 ` [patch 23/24] MAINTAINERS: fix Marek's identity again Andrew Morton
2021-06-25 1:40 ` [patch 24/24] mailmap: add Marek's other e-mail address and identity without diacritics Andrew Morton
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