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Message-ID: <20230802112525.633758009@infradead.org>
Date: Wed, 02 Aug 2023 13:25:00 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: yury.norov@...il.com, andriy.shevchenko@...ux.intel.com,
linux@...musvillemoes.dk
Cc: peterz@...radead.org, Andrew Morton <akpm@...ux-foundation.org>,
linux-kernel@...r.kernel.org, linux-mm@...ck.org,
tglx@...utronix.de, rppt@...nel.org
Subject: [PATCH 2/2] mm,nodemask: Use nr_node_ids
Just like how cpumask uses nr_cpu_ids to limit the bitmap scanning,
make nodemask use nr_node_ids.
Since current users expect MAX_NUMNODES as the end-of-bitmap marker,
retain this behaviour for now.
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
include/linux/nodemask.h | 121 ++++++++++++++++++++++++++++++++++-------------
1 file changed, 89 insertions(+), 32 deletions(-)
--- a/include/linux/nodemask.h
+++ b/include/linux/nodemask.h
@@ -99,6 +99,48 @@
typedef struct { DECLARE_BITMAP(bits, MAX_NUMNODES); } nodemask_t;
extern nodemask_t _unused_nodemask_arg_;
+#if MAX_NUMNODES > 1
+extern unsigned int nr_node_ids;
+#else
+#define nr_node_ids 1U
+#endif
+
+/*
+ * We have several different "preferred sizes" for the nodemask
+ * operations, depending on operation.
+ *
+ * For example, the bitmap scanning and operating operations have
+ * optimized routines that work for the single-word case, but only when
+ * the size is constant. So if NR_CPUS fits in one single word, we are
+ * better off using that small constant, in order to trigger the
+ * optimized bit finding. That is 'small_nodemask_size'.
+ *
+ * The clearing and copying operations will similarly perform better
+ * with a constant size, but we limit that size arbitrarily to four
+ * words. We call this 'large_nodemask_size'.
+ *
+ * Finally, some operations just want the exact limit, either because
+ * they set bits or just don't have any faster fixed-sized versions. We
+ * call this just 'nr_nodemask_bits'.
+ *
+ * Note that these optional constants are always guaranteed to be at
+ * least as big as 'nr_node_ids' itself is, and all our nodemask
+ * allocations are at least that size (see nodemask_size()). The
+ * optimization comes from being able to potentially use a compile-time
+ * constant instead of a run-time generated exact number of CPUs.
+ */
+#if MAX_NUMNODES <= BITS_PER_LONG
+ #define small_nodemask_bits ((unsigned int)MAX_NUMNODES)
+ #define large_nodemask_bits ((unsigned int)MAX_NUMNODES)
+#elif MAX_NUMNODES <= 4*BITS_PER_LONG
+ #define small_nodemask_bits nr_node_ids
+ #define large_nodemask_bits ((unsigned int)MAX_NUMNODES)
+#else
+ #define small_nodemask_bits nr_node_ids
+ #define large_nodemask_bits nr_node_ids
+#endif
+#define nr_nodemask_bits nr_node_ids
+
/**
* nodemask_pr_args - printf args to output a nodemask
* @maskp: nodemask to be printed
@@ -109,7 +151,7 @@ extern nodemask_t _unused_nodemask_arg_;
__nodemask_pr_bits(maskp)
static inline unsigned int __nodemask_pr_numnodes(const nodemask_t *m)
{
- return m ? MAX_NUMNODES : 0;
+ return m ? nr_nodemask_bits : 0;
}
static inline const unsigned long *__nodemask_pr_bits(const nodemask_t *m)
{
@@ -137,13 +179,13 @@ static inline void __node_clear(int node
clear_bit(node, dstp->bits);
}
-#define nodes_setall(dst) __nodes_setall(&(dst), MAX_NUMNODES)
+#define nodes_setall(dst) __nodes_setall(&(dst), large_nodemask_bits)
static inline void __nodes_setall(nodemask_t *dstp, unsigned int nbits)
{
bitmap_fill(dstp->bits, nbits);
}
-#define nodes_clear(dst) __nodes_clear(&(dst), MAX_NUMNODES)
+#define nodes_clear(dst) __nodes_clear(&(dst), large_nodemask_bits)
static inline void __nodes_clear(nodemask_t *dstp, unsigned int nbits)
{
bitmap_zero(dstp->bits, nbits);
@@ -160,7 +202,7 @@ static inline bool __node_test_and_set(i
}
#define nodes_and(dst, src1, src2) \
- __nodes_and(&(dst), &(src1), &(src2), MAX_NUMNODES)
+ __nodes_and(&(dst), &(src1), &(src2), small_nodemask_bits)
static inline void __nodes_and(nodemask_t *dstp, const nodemask_t *src1p,
const nodemask_t *src2p, unsigned int nbits)
{
@@ -168,7 +210,7 @@ static inline void __nodes_and(nodemask_
}
#define nodes_or(dst, src1, src2) \
- __nodes_or(&(dst), &(src1), &(src2), MAX_NUMNODES)
+ __nodes_or(&(dst), &(src1), &(src2), small_nodemask_bits)
static inline void __nodes_or(nodemask_t *dstp, const nodemask_t *src1p,
const nodemask_t *src2p, unsigned int nbits)
{
@@ -176,7 +218,7 @@ static inline void __nodes_or(nodemask_t
}
#define nodes_xor(dst, src1, src2) \
- __nodes_xor(&(dst), &(src1), &(src2), MAX_NUMNODES)
+ __nodes_xor(&(dst), &(src1), &(src2), small_nodemask_bits)
static inline void __nodes_xor(nodemask_t *dstp, const nodemask_t *src1p,
const nodemask_t *src2p, unsigned int nbits)
{
@@ -184,7 +226,7 @@ static inline void __nodes_xor(nodemask_
}
#define nodes_andnot(dst, src1, src2) \
- __nodes_andnot(&(dst), &(src1), &(src2), MAX_NUMNODES)
+ __nodes_andnot(&(dst), &(src1), &(src2), small_nodemask_bits)
static inline void __nodes_andnot(nodemask_t *dstp, const nodemask_t *src1p,
const nodemask_t *src2p, unsigned int nbits)
{
@@ -192,7 +234,7 @@ static inline void __nodes_andnot(nodema
}
#define nodes_complement(dst, src) \
- __nodes_complement(&(dst), &(src), MAX_NUMNODES)
+ __nodes_complement(&(dst), &(src), small_nodemask_bits)
static inline void __nodes_complement(nodemask_t *dstp,
const nodemask_t *srcp, unsigned int nbits)
{
@@ -200,7 +242,7 @@ static inline void __nodes_complement(no
}
#define nodes_equal(src1, src2) \
- __nodes_equal(&(src1), &(src2), MAX_NUMNODES)
+ __nodes_equal(&(src1), &(src2), small_nodemask_bits)
static inline bool __nodes_equal(const nodemask_t *src1p,
const nodemask_t *src2p, unsigned int nbits)
{
@@ -208,7 +250,7 @@ static inline bool __nodes_equal(const n
}
#define nodes_intersects(src1, src2) \
- __nodes_intersects(&(src1), &(src2), MAX_NUMNODES)
+ __nodes_intersects(&(src1), &(src2), small_nodemask_bits)
static inline bool __nodes_intersects(const nodemask_t *src1p,
const nodemask_t *src2p, unsigned int nbits)
{
@@ -216,33 +258,33 @@ static inline bool __nodes_intersects(co
}
#define nodes_subset(src1, src2) \
- __nodes_subset(&(src1), &(src2), MAX_NUMNODES)
+ __nodes_subset(&(src1), &(src2), small_nodemask_bits)
static inline bool __nodes_subset(const nodemask_t *src1p,
const nodemask_t *src2p, unsigned int nbits)
{
return bitmap_subset(src1p->bits, src2p->bits, nbits);
}
-#define nodes_empty(src) __nodes_empty(&(src), MAX_NUMNODES)
+#define nodes_empty(src) __nodes_empty(&(src), small_nodemask_bits)
static inline bool __nodes_empty(const nodemask_t *srcp, unsigned int nbits)
{
return bitmap_empty(srcp->bits, nbits);
}
-#define nodes_full(nodemask) __nodes_full(&(nodemask), MAX_NUMNODES)
+#define nodes_full(nodemask) __nodes_full(&(nodemask), small_nodemask_bits)
static inline bool __nodes_full(const nodemask_t *srcp, unsigned int nbits)
{
return bitmap_full(srcp->bits, nbits);
}
-#define nodes_weight(nodemask) __nodes_weight(&(nodemask), MAX_NUMNODES)
+#define nodes_weight(nodemask) __nodes_weight(&(nodemask), small_nodemask_bits)
static inline int __nodes_weight(const nodemask_t *srcp, unsigned int nbits)
{
return bitmap_weight(srcp->bits, nbits);
}
#define nodes_shift_right(dst, src, n) \
- __nodes_shift_right(&(dst), &(src), (n), MAX_NUMNODES)
+ __nodes_shift_right(&(dst), &(src), (n), small_nodemask_bits)
static inline void __nodes_shift_right(nodemask_t *dstp,
const nodemask_t *srcp, int n, int nbits)
{
@@ -250,26 +292,38 @@ static inline void __nodes_shift_right(n
}
#define nodes_shift_left(dst, src, n) \
- __nodes_shift_left(&(dst), &(src), (n), MAX_NUMNODES)
+ __nodes_shift_left(&(dst), &(src), (n), small_nodemask_bits)
static inline void __nodes_shift_left(nodemask_t *dstp,
const nodemask_t *srcp, int n, int nbits)
{
bitmap_shift_left(dstp->bits, srcp->bits, n, nbits);
}
-/* FIXME: better would be to fix all architectures to never return
- > MAX_NUMNODES, then the silly min_ts could be dropped. */
+/*
+ * FIXME: audit tree to move end-of-nodemask to >= nr_nodemask_bits;
+ * for now, map it to >= MAX_NUMNODES.
+ */
#define first_node(src) __first_node(&(src))
static inline unsigned int __first_node(const nodemask_t *srcp)
{
- return min_t(unsigned int, MAX_NUMNODES, find_first_bit(srcp->bits, MAX_NUMNODES));
+ unsigned int bit = find_first_bit(srcp->bits, small_nodemask_bits);
+
+ if (bit >= nr_nodemask_bits)
+ bit = MAX_NUMNODES;
+
+ return bit;
}
#define next_node(n, src) __next_node((n), &(src))
static inline unsigned int __next_node(int n, const nodemask_t *srcp)
{
- return min_t(unsigned int, MAX_NUMNODES, find_next_bit(srcp->bits, MAX_NUMNODES, n+1));
+ unsigned int bit = find_next_bit(srcp->bits, small_nodemask_bits, n+1);
+
+ if (bit >= nr_nodemask_bits)
+ bit = MAX_NUMNODES;
+
+ return bit;
}
/*
@@ -283,6 +337,7 @@ static inline unsigned int __next_node_i
if (ret == MAX_NUMNODES)
ret = __first_node(srcp);
+
return ret;
}
@@ -306,8 +361,12 @@ static inline void init_nodemask_of_node
#define first_unset_node(mask) __first_unset_node(&(mask))
static inline unsigned int __first_unset_node(const nodemask_t *maskp)
{
- return min_t(unsigned int, MAX_NUMNODES,
- find_first_zero_bit(maskp->bits, MAX_NUMNODES));
+ unsigned int bit = find_first_zero_bit(maskp->bits, small_nodemask_bits);
+
+ if (bit >= nr_nodemask_bits)
+ bit = MAX_NUMNODES;
+
+ return bit;
}
#define NODE_MASK_LAST_WORD BITMAP_LAST_WORD_MASK(MAX_NUMNODES)
@@ -337,21 +396,21 @@ static inline unsigned int __first_unset
#define nodes_addr(src) ((src).bits)
#define nodemask_parse_user(ubuf, ulen, dst) \
- __nodemask_parse_user((ubuf), (ulen), &(dst), MAX_NUMNODES)
+ __nodemask_parse_user((ubuf), (ulen), &(dst), nr_nodemask_bits)
static inline int __nodemask_parse_user(const char __user *buf, int len,
nodemask_t *dstp, int nbits)
{
return bitmap_parse_user(buf, len, dstp->bits, nbits);
}
-#define nodelist_parse(buf, dst) __nodelist_parse((buf), &(dst), MAX_NUMNODES)
+#define nodelist_parse(buf, dst) __nodelist_parse((buf), &(dst), nr_nodemask_bits)
static inline int __nodelist_parse(const char *buf, nodemask_t *dstp, int nbits)
{
return bitmap_parselist(buf, dstp->bits, nbits);
}
#define node_remap(oldbit, old, new) \
- __node_remap((oldbit), &(old), &(new), MAX_NUMNODES)
+ __node_remap((oldbit), &(old), &(new), nr_nodemask_bits)
static inline int __node_remap(int oldbit,
const nodemask_t *oldp, const nodemask_t *newp, int nbits)
{
@@ -359,7 +418,7 @@ static inline int __node_remap(int oldbi
}
#define nodes_remap(dst, src, old, new) \
- __nodes_remap(&(dst), &(src), &(old), &(new), MAX_NUMNODES)
+ __nodes_remap(&(dst), &(src), &(old), &(new), nr_nodemask_bits)
static inline void __nodes_remap(nodemask_t *dstp, const nodemask_t *srcp,
const nodemask_t *oldp, const nodemask_t *newp, int nbits)
{
@@ -367,7 +426,7 @@ static inline void __nodes_remap(nodemas
}
#define nodes_onto(dst, orig, relmap) \
- __nodes_onto(&(dst), &(orig), &(relmap), MAX_NUMNODES)
+ __nodes_onto(&(dst), &(orig), &(relmap), nr_nodemask_bits)
static inline void __nodes_onto(nodemask_t *dstp, const nodemask_t *origp,
const nodemask_t *relmapp, int nbits)
{
@@ -375,7 +434,7 @@ static inline void __nodes_onto(nodemask
}
#define nodes_fold(dst, orig, sz) \
- __nodes_fold(&(dst), &(orig), sz, MAX_NUMNODES)
+ __nodes_fold(&(dst), &(orig), sz, nr_nodemask_bits)
static inline void __nodes_fold(nodemask_t *dstp, const nodemask_t *origp,
int sz, int nbits)
{
@@ -385,7 +444,7 @@ static inline void __nodes_fold(nodemask
#if MAX_NUMNODES > 1
#define for_each_node_mask(node, mask) \
for ((node) = first_node(mask); \
- (node) < MAX_NUMNODES; \
+ (node) < nr_nodemask_bits; \
(node) = next_node((node), (mask)))
#else /* MAX_NUMNODES == 1 */
#define for_each_node_mask(node, mask) \
@@ -452,7 +511,6 @@ static inline unsigned int next_memory_n
return next_node(nid, node_states[N_MEMORY]);
}
-extern unsigned int nr_node_ids;
extern unsigned int nr_online_nodes;
static inline void node_set_online(int nid)
@@ -494,7 +552,6 @@ static inline int num_node_state(enum no
#define first_memory_node 0
#define next_online_node(nid) (MAX_NUMNODES)
#define next_memory_node(nid) (MAX_NUMNODES)
-#define nr_node_ids 1U
#define nr_online_nodes 1U
#define node_set_online(node) node_set_state((node), N_ONLINE)
@@ -516,7 +573,7 @@ static inline int node_random(const node
bit = first_node(*maskp);
break;
default:
- bit = find_nth_bit(maskp->bits, MAX_NUMNODES, get_random_u32_below(w));
+ bit = find_nth_bit(maskp->bits, nr_node_ids, get_random_u32_below(w));
break;
}
return bit;
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