From: Nadav Amit <nadav.amit@gmail.com>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc: Nadav Amit <namit@vmware.com>,
Mel Gorman <mgorman@techsingularity.net>,
Andrea Arcangeli <aarcange@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Andy Lutomirski <luto@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Will Deacon <will@kernel.org>, Yu Zhao <yuzhao@google.com>,
x86@kernel.org
Subject: [RFC 19/20] lib/cpumask: introduce cpumask_atomic_or()
Date: Sat, 30 Jan 2021 16:11:31 -0800 [thread overview]
Message-ID: <20210131001132.3368247-20-namit@vmware.com> (raw)
In-Reply-To: <20210131001132.3368247-1-namit@vmware.com>
From: Nadav Amit <namit@vmware.com>
Introduce cpumask_atomic_or() and bitmask_atomic_or() to allow to
perform atomic or operations atomically on cpumasks. This will be used
by the next patch.
To be more efficient, skip atomic operations when no changes are needed.
Signed-off-by: Nadav Amit <namit@vmware.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Cc: Yu Zhao <yuzhao@google.com>
Cc: x86@kernel.org
---
include/linux/bitmap.h | 5 +++++
include/linux/cpumask.h | 12 ++++++++++++
lib/bitmap.c | 25 +++++++++++++++++++++++++
3 files changed, 42 insertions(+)
diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
index 769b7a98e12f..c9a9b784b244 100644
--- a/include/linux/bitmap.h
+++ b/include/linux/bitmap.h
@@ -76,6 +76,7 @@
* bitmap_to_arr32(buf, src, nbits) Copy nbits from buf to u32[] dst
* bitmap_get_value8(map, start) Get 8bit value from map at start
* bitmap_set_value8(map, value, start) Set 8bit value to map at start
+ * bitmap_atomic_or(dst, src, nbits) *dst |= *src (atomically)
*
* Note, bitmap_zero() and bitmap_fill() operate over the region of
* unsigned longs, that is, bits behind bitmap till the unsigned long
@@ -577,6 +578,10 @@ static inline void bitmap_set_value8(unsigned long *map, unsigned long value,
map[index] |= value << offset;
}
+extern void bitmap_atomic_or(volatile unsigned long *dst,
+ const volatile unsigned long *bitmap, unsigned int bits);
+
+
#endif /* __ASSEMBLY__ */
#endif /* __LINUX_BITMAP_H */
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index 3d7e418aa113..0567d73a0192 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -699,6 +699,18 @@ static inline unsigned int cpumask_size(void)
return BITS_TO_LONGS(nr_cpumask_bits) * sizeof(long);
}
+/**
+ * cpumask_atomic_or - *dstp |= *srcp (*dstp is set atomically)
+ * @dstp: the cpumask result (and source which is or'd)
+ * @srcp: the source input
+ */
+static inline void cpumask_atomic_or(volatile struct cpumask *dstp,
+ const volatile struct cpumask *srcp)
+{
+ bitmap_atomic_or(cpumask_bits(dstp), cpumask_bits(srcp),
+ nr_cpumask_bits);
+}
+
/*
* cpumask_var_t: struct cpumask for stack usage.
*
diff --git a/lib/bitmap.c b/lib/bitmap.c
index 6df7b13727d3..50f1842ff891 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -1310,3 +1310,28 @@ void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap, unsigned int nbits)
EXPORT_SYMBOL(bitmap_to_arr32);
#endif
+
+void bitmap_atomic_or(volatile unsigned long *dst,
+ const volatile unsigned long *bitmap, unsigned int bits)
+{
+ unsigned int k;
+ unsigned int nr = BITS_TO_LONGS(bits);
+
+ for (k = 0; k < nr; k++) {
+ unsigned long src = bitmap[k];
+
+ /*
+ * Skip atomic operations when no bits are changed. Do not use
+ * bitmap[k] directly to avoid redundant loads as bitmap
+ * variable is volatile.
+ */
+ if (!(src & ~dst[k]))
+ continue;
+
+ if (BITS_PER_LONG == 64)
+ atomic64_or(src, (atomic64_t*)&dst[k]);
+ else
+ atomic_or(src, (atomic_t*)&dst[k]);
+ }
+}
+EXPORT_SYMBOL(bitmap_atomic_or);
--
2.25.1
next prev parent reply other threads:[~2021-01-31 0:21 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-31 0:11 [RFC 00/20] TLB batching consolidation and enhancements Nadav Amit
2021-01-31 0:11 ` [RFC 01/20] mm/tlb: fix fullmm semantics Nadav Amit
2021-01-31 1:02 ` Andy Lutomirski
2021-01-31 1:19 ` Nadav Amit
2021-01-31 2:57 ` Andy Lutomirski
2021-02-01 7:30 ` Nadav Amit
2021-02-01 11:36 ` Peter Zijlstra
2021-02-02 9:32 ` Nadav Amit
2021-02-02 11:00 ` Peter Zijlstra
2021-02-02 21:35 ` Nadav Amit
2021-02-03 9:44 ` Will Deacon
2021-02-04 3:20 ` Nadav Amit
2021-01-31 0:11 ` [RFC 02/20] mm/mprotect: use mmu_gather Nadav Amit
2021-01-31 0:11 ` [RFC 03/20] mm/mprotect: do not flush on permission promotion Nadav Amit
2021-01-31 1:07 ` Andy Lutomirski
2021-01-31 1:17 ` Nadav Amit
2021-01-31 2:59 ` Andy Lutomirski
[not found] ` <7a6de15a-a570-31f2-14d6-a8010296e694@citrix.com>
2021-02-01 5:58 ` Nadav Amit
2021-02-01 15:38 ` Andrew Cooper
2021-01-31 0:11 ` [RFC 04/20] mm/mapping_dirty_helpers: use mmu_gather Nadav Amit
2021-01-31 0:11 ` [RFC 05/20] mm/tlb: move BATCHED_UNMAP_TLB_FLUSH to tlb.h Nadav Amit
2021-01-31 0:11 ` [RFC 06/20] fs/task_mmu: use mmu_gather interface of clear-soft-dirty Nadav Amit
2021-01-31 0:11 ` [RFC 07/20] mm: move x86 tlb_gen to generic code Nadav Amit
2021-01-31 18:26 ` Andy Lutomirski
2021-01-31 0:11 ` [RFC 08/20] mm: store completed TLB generation Nadav Amit
2021-01-31 20:32 ` Andy Lutomirski
2021-02-01 7:28 ` Nadav Amit
2021-02-01 16:53 ` Andy Lutomirski
2021-02-01 11:52 ` Peter Zijlstra
2021-01-31 0:11 ` [RFC 09/20] mm: create pte/pmd_tlb_flush_pending() Nadav Amit
2021-01-31 0:11 ` [RFC 10/20] mm: add pte_to_page() Nadav Amit
2021-01-31 0:11 ` [RFC 11/20] mm/tlb: remove arch-specific tlb_start/end_vma() Nadav Amit
2021-02-01 12:09 ` Peter Zijlstra
2021-02-02 6:41 ` Nicholas Piggin
2021-02-02 7:20 ` Nadav Amit
2021-02-02 9:31 ` Peter Zijlstra
2021-02-02 9:54 ` Nadav Amit
2021-02-02 11:04 ` Peter Zijlstra
2021-01-31 0:11 ` [RFC 12/20] mm/tlb: save the VMA that is flushed during tlb_start_vma() Nadav Amit
2021-02-01 12:28 ` Peter Zijlstra
2021-01-31 0:11 ` [RFC 13/20] mm/tlb: introduce tlb_start_ptes() and tlb_end_ptes() Nadav Amit
[not found] ` <YBaBcc2jEGaxuxH0@fedora.tometzki.de>
2021-02-01 7:29 ` Nadav Amit
2021-02-01 13:19 ` Peter Zijlstra
2021-02-01 23:00 ` Nadav Amit
2021-01-31 0:11 ` [RFC 14/20] mm: move inc/dec_tlb_flush_pending() to mmu_gather.c Nadav Amit
2021-01-31 0:11 ` [RFC 15/20] mm: detect deferred TLB flushes in vma granularity Nadav Amit
2021-02-01 22:04 ` Nadav Amit
2021-02-02 0:14 ` Andy Lutomirski
2021-02-02 20:51 ` Nadav Amit
2021-02-04 4:35 ` Andy Lutomirski
2021-01-31 0:11 ` [RFC 16/20] mm/tlb: per-page table generation tracking Nadav Amit
2021-01-31 0:11 ` [RFC 17/20] mm/tlb: updated completed deferred TLB flush conditionally Nadav Amit
2021-01-31 0:11 ` [RFC 18/20] mm: make mm_cpumask() volatile Nadav Amit
2021-01-31 0:11 ` Nadav Amit [this message]
2021-01-31 0:11 ` [RFC 20/20] mm/rmap: avoid potential races Nadav Amit
2021-08-23 8:05 ` Huang, Ying
2021-08-23 15:50 ` Nadav Amit
2021-08-24 0:36 ` Huang, Ying
2021-01-31 0:39 ` [RFC 00/20] TLB batching consolidation and enhancements Andy Lutomirski
2021-01-31 1:08 ` Nadav Amit
2021-01-31 3:30 ` Nicholas Piggin
2021-01-31 7:57 ` Nadav Amit
2021-01-31 8:14 ` Nadav Amit
2021-02-01 12:44 ` Peter Zijlstra
2021-02-02 7:14 ` Nicholas Piggin
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=20210131001132.3368247-20-namit@vmware.com \
--to=nadav.amit@gmail.com \
--cc=aarcange@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=dave.hansen@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=luto@kernel.org \
--cc=mgorman@techsingularity.net \
--cc=namit@vmware.com \
--cc=peterz@infradead.org \
--cc=tglx@linutronix.de \
--cc=will@kernel.org \
--cc=x86@kernel.org \
--cc=yuzhao@google.com \
/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).