From: Alexandre Ghiti <alex@ghiti.fr>
To: Matthew Wilcox <willy@infradead.org>, linux-arch@vger.kernel.org
Cc: Yin Fengwei <fengwei.yin@intel.com>,
linux-mm@kvack.org, linux-alpha@vger.kernel.org,
linux-csky@vger.kernel.org, linux-m68k@lists.linux-m68k.org,
linux-mips@vger.kernel.org, Dinh Nguyen <dinguyen@kernel.org>,
linux-parisc@vger.kernel.org, linux-sh@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev,
openrisc@lists.librecores.org, linuxppc-dev@lists.ozlabs.org,
linux-riscv@lists.infradead.org, sparclinux@vger.kernel.org,
linux-xtensa@linux-xtensa.org
Subject: Re: API for setting multiple PTEs at once
Date: Tue, 14 Feb 2023 10:55:43 +0100 [thread overview]
Message-ID: <0bf59207-838b-2a0b-a95e-925a6bbf1913@ghiti.fr> (raw)
In-Reply-To: <Y+K0O35jNNzxiXE6@casper.infradead.org>
Hi Matthew,
On 2/7/23 21:27, Matthew Wilcox wrote:
> On Thu, Feb 02, 2023 at 09:14:23PM +0000, Matthew Wilcox wrote:
>> For those of you not subscribed, linux-mm is currently discussing
>> how best to handle page faults on large folios. I simply made it work
>> when adding large folio support. Now Yin Fengwei is working on
>> making it fast.
> OK, here's an actual implementation:
>
> https://lore.kernel.org/linux-mm/20230207194937.122543-3-willy@infradead.org/
>
> It survives a run of xfstests. If your architecture doesn't store its
> PFNs at PAGE_SHIFT, you're going to want to implement your own set_ptes(),
> or you'll see entirely the wrong pages mapped into userspace. You may
> also wish to implement set_ptes() if it can be done more efficiently
> than __pte(pteval(pte) + PAGE_SIZE).
>
> Architectures that implement things like flush_icache_page() and
> update_mmu_cache() may want to propose batched versions of those.
> That's alpha, csky, m68k, mips, nios2, parisc, sh,
> arm, loongarch, openrisc, powerpc, riscv, sparc and xtensa.
> Maintainers BCC'd, mailing lists CC'd.
>
> I'm happy to collect implementations and submit them as part of a v6.
Please find below the riscv implementation for set_ptes:
diff --git a/arch/riscv/include/asm/pgtable.h
b/arch/riscv/include/asm/pgtable.h
index ebee56d47003..10bf812776a4 100644
--- a/arch/riscv/include/asm/pgtable.h
+++ b/arch/riscv/include/asm/pgtable.h
@@ -463,6 +463,20 @@ static inline void set_pte_at(struct mm_struct *mm,
__set_pte_at(mm, addr, ptep, pteval);
}
+#define set_ptes set_ptes
+static inline void set_ptes(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, pte_t pte, unsigned int nr)
+{
+ for (;;) {
+ set_pte_at(mm, addr, ptep, pte);
+ if (--nr == 0)
+ break;
+ ptep++;
+ addr += PAGE_SIZE;
+ pte = __pte(pte_val(pte) + (1 << _PAGE_PFN_SHIFT));
+ }
+}
+
static inline void pte_clear(struct mm_struct *mm,
unsigned long addr, pte_t *ptep)
{
Thanks,
Alex
next prev parent reply other threads:[~2023-02-14 9:56 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <Y9wnr8SGfGGbi/bk@casper.infradead.org>
2023-02-07 20:27 ` API for setting multiple PTEs at once Matthew Wilcox
2023-02-08 11:23 ` Alexandre Ghiti
2023-02-08 12:09 ` Yin, Fengwei
2023-02-08 13:35 ` Matthew Wilcox
2023-02-14 9:55 ` Alexandre Ghiti [this message]
2023-02-20 8:29 ` Rolf Eike Beer
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