mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git
synced 2026-04-04 20:57:45 -04:00
8e38607aa4
Patch series "mm: folio_zero_user: clear page ranges", v11.
This series adds clearing of contiguous page ranges for hugepages.
The series improves on the current discontiguous clearing approach in two
ways:
- clear pages in a contiguous fashion.
- use batched clearing via clear_pages() wherever exposed.
The first is useful because it allows us to make much better use of
hardware prefetchers.
The second, enables advertising the real extent to the processor. Where
specific instructions support it (ex. string instructions on x86; "mops"
on arm64 etc), a processor can optimize based on this because, instead of
seeing a sequence of 8-byte stores, or a sequence of 4KB pages, it sees a
larger unit being operated on.
For instance, AMD Zen uarchs (for extents larger than LLC-size) switch to
a mode where they start eliding cacheline allocation. This is helpful not
just because it results in higher bandwidth, but also because now the
cache is not evicting useful cachelines and replacing them with zeroes.
Demand faulting a 64GB region shows performance improvement:
$ perf bench mem mmap -p $pg-sz -f demand -s 64GB -l 5
baseline +series
(GBps +- %stdev) (GBps +- %stdev)
pg-sz=2MB 11.76 +- 1.10% 25.34 +- 1.18% [*] +115.47% preempt=*
pg-sz=1GB 24.85 +- 2.41% 39.22 +- 2.32% + 57.82% preempt=none|voluntary
pg-sz=1GB (similar) 52.73 +- 0.20% [#] +112.19% preempt=full|lazy
[*] This improvement is because switching to sequential clearing
allows the hardware prefetchers to do a much better job.
[#] For pg-sz=1GB a large part of the improvement is because of the
cacheline elision mentioned above. preempt=full|lazy improves upon
that because, not needing explicit invocations of cond_resched() to
ensure reasonable preemption latency, it can clear the full extent
as a single unit. In comparison the maximum extent used for
preempt=none|voluntary is PROCESS_PAGES_NON_PREEMPT_BATCH (32MB).
When provided the full extent the processor forgoes allocating
cachelines on this path almost entirely.
(The hope is that eventually, in the fullness of time, the lazy
preemption model will be able to do the same job that none or
voluntary models are used for, allowing us to do away with
cond_resched().)
Raghavendra also tested previous version of the series on AMD Genoa and
sees similar improvement [1] with preempt=lazy.
$ perf bench mem map -p $page-size -f populate -s 64GB -l 10
base patched change
pg-sz=2MB 12.731939 GB/sec 26.304263 GB/sec 106.6%
pg-sz=1GB 26.232423 GB/sec 61.174836 GB/sec 133.2%
This patch (of 8):
Let's drop all variants that effectively map to clear_page() and provide
it in a generic variant instead.
We'll use the macro clear_user_page to indicate whether an architecture
provides it's own variant.
Also, clear_user_page() is only called from the generic variant of
clear_user_highpage(), so define it only if the architecture does not
provide a clear_user_highpage(). And, for simplicity define it in
linux/highmem.h.
Note that for parisc, clear_page() and clear_user_page() map to
clear_page_asm(), so we can just get rid of the custom clear_user_page()
implementation. There is a clear_user_page_asm() function on parisc, that
seems to be unused. Not sure what's up with that.
Link: https://lkml.kernel.org/r/20260107072009.1615991-1-ankur.a.arora@oracle.com
Link: https://lkml.kernel.org/r/20260107072009.1615991-2-ankur.a.arora@oracle.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Co-developed-by: Ankur Arora <ankur.a.arora@oracle.com>
Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ankur Arora <ankur.a.arora@oracle.com>
Cc: "Borislav Petkov (AMD)" <bp@alien8.de>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Konrad Rzessutek Wilk <konrad.wilk@oracle.com>
Cc: Lance Yang <ioworker0@gmail.com>
Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc: Li Zhe <lizhe.67@bytedance.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Raghavendra K T <raghavendra.kt@amd.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
144 lines
3.3 KiB
C
144 lines
3.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
|
|
/*
|
|
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
|
|
*/
|
|
#ifndef __ASM_ARC_PAGE_H
|
|
#define __ASM_ARC_PAGE_H
|
|
|
|
#include <uapi/asm/page.h>
|
|
|
|
#ifdef CONFIG_ARC_HAS_PAE40
|
|
|
|
#define MAX_POSSIBLE_PHYSMEM_BITS 40
|
|
#define PAGE_MASK_PHYS (0xff00000000ull | PAGE_MASK)
|
|
|
|
#else /* CONFIG_ARC_HAS_PAE40 */
|
|
|
|
#define MAX_POSSIBLE_PHYSMEM_BITS 32
|
|
#define PAGE_MASK_PHYS PAGE_MASK
|
|
|
|
#endif /* CONFIG_ARC_HAS_PAE40 */
|
|
|
|
#ifndef __ASSEMBLER__
|
|
|
|
#define clear_page(paddr) memset((paddr), 0, PAGE_SIZE)
|
|
#define copy_user_page(to, from, vaddr, pg) copy_page(to, from)
|
|
#define copy_page(to, from) memcpy((to), (from), PAGE_SIZE)
|
|
|
|
struct vm_area_struct;
|
|
struct page;
|
|
|
|
#define __HAVE_ARCH_COPY_USER_HIGHPAGE
|
|
|
|
void copy_user_highpage(struct page *to, struct page *from,
|
|
unsigned long u_vaddr, struct vm_area_struct *vma);
|
|
|
|
#define clear_user_page clear_user_page
|
|
void clear_user_page(void *to, unsigned long u_vaddr, struct page *page);
|
|
|
|
typedef struct {
|
|
unsigned long pgd;
|
|
} pgd_t;
|
|
|
|
#define pgd_val(x) ((x).pgd)
|
|
#define __pgd(x) ((pgd_t) { (x) })
|
|
|
|
#if CONFIG_PGTABLE_LEVELS > 3
|
|
|
|
typedef struct {
|
|
unsigned long pud;
|
|
} pud_t;
|
|
|
|
#define pud_val(x) ((x).pud)
|
|
#define __pud(x) ((pud_t) { (x) })
|
|
|
|
#endif
|
|
|
|
#if CONFIG_PGTABLE_LEVELS > 2
|
|
|
|
typedef struct {
|
|
unsigned long pmd;
|
|
} pmd_t;
|
|
|
|
#define pmd_val(x) ((x).pmd)
|
|
#define __pmd(x) ((pmd_t) { (x) })
|
|
|
|
#endif
|
|
|
|
typedef struct {
|
|
#ifdef CONFIG_ARC_HAS_PAE40
|
|
unsigned long long pte;
|
|
#else
|
|
unsigned long pte;
|
|
#endif
|
|
} pte_t;
|
|
|
|
#define pte_val(x) ((x).pte)
|
|
#define __pte(x) ((pte_t) { (x) })
|
|
|
|
typedef struct {
|
|
unsigned long pgprot;
|
|
} pgprot_t;
|
|
|
|
#define pgprot_val(x) ((x).pgprot)
|
|
#define __pgprot(x) ((pgprot_t) { (x) })
|
|
#define pte_pgprot(x) __pgprot(pte_val(x))
|
|
|
|
typedef struct page *pgtable_t;
|
|
|
|
/*
|
|
* When HIGHMEM is enabled we have holes in the memory map so we need
|
|
* pfn_valid() that takes into account the actual extents of the physical
|
|
* memory
|
|
*/
|
|
#ifdef CONFIG_HIGHMEM
|
|
|
|
extern unsigned long arch_pfn_offset;
|
|
#define ARCH_PFN_OFFSET arch_pfn_offset
|
|
|
|
extern int pfn_valid(unsigned long pfn);
|
|
#define pfn_valid pfn_valid
|
|
|
|
#else /* CONFIG_HIGHMEM */
|
|
|
|
#define ARCH_PFN_OFFSET virt_to_pfn((void *)CONFIG_LINUX_RAM_BASE)
|
|
|
|
#endif /* CONFIG_HIGHMEM */
|
|
|
|
/*
|
|
* __pa, __va, virt_to_page (ALERT: deprecated, don't use them)
|
|
*
|
|
* These macros have historically been misnamed
|
|
* virt here means link-address/program-address as embedded in object code.
|
|
* And for ARC, link-addr = physical address
|
|
*/
|
|
#define __pa(vaddr) ((unsigned long)(vaddr))
|
|
#define __va(paddr) ((void *)((unsigned long)(paddr)))
|
|
|
|
/*
|
|
* Use virt_to_pfn with caution:
|
|
* If used in pte or paddr related macros, it could cause truncation
|
|
* in PAE40 builds
|
|
* As a rule of thumb, only use it in helpers starting with virt_
|
|
* You have been warned !
|
|
*/
|
|
static inline unsigned long virt_to_pfn(const void *kaddr)
|
|
{
|
|
return __pa(kaddr) >> PAGE_SHIFT;
|
|
}
|
|
|
|
#define virt_to_page(kaddr) pfn_to_page(virt_to_pfn(kaddr))
|
|
#define virt_addr_valid(kaddr) pfn_valid(virt_to_pfn(kaddr))
|
|
|
|
/* Default Permissions for stack/heaps pages (Non Executable) */
|
|
#define VM_DATA_DEFAULT_FLAGS VM_DATA_FLAGS_NON_EXEC
|
|
|
|
#define WANT_PAGE_VIRTUAL 1
|
|
|
|
#include <asm-generic/memory_model.h> /* page_to_pfn, pfn_to_page */
|
|
#include <asm-generic/getorder.h>
|
|
|
|
#endif /* !__ASSEMBLER__ */
|
|
|
|
#endif
|