From: Will Deacon <will@kernel.org>
To: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org,
Will Deacon <will@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Jan Kara <jack@suse.cz>, Minchan Kim <minchan@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Vinayak Menon <vinmenon@codeaurora.org>,
Hugh Dickins <hughd@google.com>,
kernel-team@android.com
Subject: [PATCH v3 3/8] arm64: mm: Implement arch_wants_old_prefaulted_pte()
Date: Thu, 14 Jan 2021 17:59:29 +0000 [thread overview]
Message-ID: <20210114175934.13070-4-will@kernel.org> (raw)
In-Reply-To: <20210114175934.13070-1-will@kernel.org>
On CPUs with hardware AF/DBM, initialising prefaulted PTEs as 'old'
improves vmscan behaviour and does not appear to introduce any overhead
elsewhere.
Implement arch_wants_old_prefaulted_pte() to return 'true' if we detect
hardware access flag support at runtime. This can be extended in future
based on MIDR matching if necessary.
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
---
arch/arm64/include/asm/pgtable.h | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 501562793ce2..e17b96d0e4b5 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -980,7 +980,17 @@ static inline bool arch_faults_on_old_pte(void)
return !cpu_has_hw_af();
}
-#define arch_faults_on_old_pte arch_faults_on_old_pte
+#define arch_faults_on_old_pte arch_faults_on_old_pte
+
+/*
+ * Experimentally, it's cheap to set the access flag in hardware and we
+ * benefit from prefaulting mappings as 'old' to start with.
+ */
+static inline bool arch_wants_old_prefaulted_pte(void)
+{
+ return !arch_faults_on_old_pte();
+}
+#define arch_wants_old_prefaulted_pte arch_wants_old_prefaulted_pte
#endif /* !__ASSEMBLY__ */
--
2.30.0.284.gd98b1dd5eaa7-goog
next prev parent reply other threads:[~2021-01-14 18:00 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-14 17:59 [PATCH v3 0/8] Create 'old' ptes for faultaround mappings on arm64 with hardware access flag Will Deacon
2021-01-14 17:59 ` [PATCH v3 1/8] mm: Cleanup faultaround and finish_fault() codepaths Will Deacon
2021-02-09 20:24 ` Guenter Roeck
2021-02-10 11:44 ` Will Deacon
2021-02-10 14:57 ` Guenter Roeck
2021-01-14 17:59 ` [PATCH v3 2/8] mm: Allow architectures to request 'old' entries when prefaulting Will Deacon
2021-01-14 17:59 ` Will Deacon [this message]
2021-01-14 17:59 ` [RFC PATCH 4/8] mm: Separate fault info out of 'struct vm_fault' Will Deacon
2021-01-14 18:16 ` Linus Torvalds
2021-01-14 19:00 ` Will Deacon
2021-01-14 19:09 ` Linus Torvalds
2021-01-14 19:41 ` Will Deacon
2021-01-14 20:09 ` Nick Desaulniers
2021-01-14 21:11 ` Linus Torvalds
2021-01-15 9:23 ` Will Deacon
2021-01-15 21:32 ` Linus Torvalds
2021-01-20 0:00 ` Nick Desaulniers
2021-01-14 17:59 ` [RFC PATCH 5/8] mm: Pass 'address' to map to do_set_pte() and drop FAULT_FLAG_PREFAULT Will Deacon
2021-01-14 18:17 ` Linus Torvalds
2021-01-15 10:24 ` Will Deacon
2021-01-14 17:59 ` [RFC PATCH 6/8] mm: Avoid modifying vmf.info.address in __collapse_huge_page_swapin() Will Deacon
2021-01-14 17:59 ` [RFC PATCH 7/8] mm: Use static initialisers for 'info' field of 'struct vm_fault' Will Deacon
2021-01-14 17:59 ` [RFC PATCH 8/8] mm: Mark 'info' field of 'struct vm_fault' as 'const' Will Deacon
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210114175934.13070-4-will@kernel.org \
--to=will@kernel.org \
--cc=akpm@linux-foundation.org \
--cc=catalin.marinas@arm.com \
--cc=hughd@google.com \
--cc=jack@suse.cz \
--cc=kernel-team@android.com \
--cc=kirill.shutemov@linux.intel.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=minchan@kernel.org \
--cc=torvalds@linux-foundation.org \
--cc=vinmenon@codeaurora.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).