Merge branch 'linus' into perf/urgent

Merge reason: Fix upstream breakage introduced by:

 de5d9bf: Move list types from <linux/list.h> to <linux/types.h>.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 275 insertions, 0 deletions

diff --git a/arch/tile/lib/memset_32.c b/arch/tile/lib/memset_32.c
new file mode 100644
index 00000000000..bfde5d864df
--- /dev/null
+++ b/arch/tile/lib/memset_32.c
@@ -0,0 +1,275 @@
+/*
+ * Copyright 2010 Tilera Corporation. All Rights Reserved.
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU General Public License
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful, but
+ *   WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ *   NON INFRINGEMENT.  See the GNU General Public License for
+ *   more details.
+ */
+
+#include <arch/chip.h>
+
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/module.h>
+
+
+void *memset(void *s, int c, size_t n)
+{
+	uint32_t *out32;
+	int n32;
+	uint32_t v16, v32;
+	uint8_t *out8 = s;
+#if !CHIP_HAS_WH64()
+	int ahead32;
+#else
+	int to_align32;
+#endif
+
+	/* Experimentation shows that a trivial tight loop is a win up until
+	 * around a size of 20, where writing a word at a time starts to win.
+	 */
+#define BYTE_CUTOFF 20
+
+#if BYTE_CUTOFF < 3
+	/* This must be at least at least this big, or some code later
+	 * on doesn't work.
+	 */
+#error "BYTE_CUTOFF is too small"
+#endif
+
+	if (n < BYTE_CUTOFF) {
+		/* Strangely, this turns out to be the tightest way to
+		 * write this loop.
+		 */
+		if (n != 0) {
+			do {
+				/* Strangely, combining these into one line
+				 * performs worse.
+				 */
+				*out8 = c;
+				out8++;
+			} while (--n != 0);
+		}
+
+		return s;
+	}
+
+#if !CHIP_HAS_WH64()
+	/* Use a spare issue slot to start prefetching the first cache
+	 * line early. This instruction is free as the store can be buried
+	 * in otherwise idle issue slots doing ALU ops.
+	 */
+	__insn_prefetch(out8);
+
+	/* We prefetch the end so that a short memset that spans two cache
+	 * lines gets some prefetching benefit. Again we believe this is free
+	 * to issue.
+	 */
+	__insn_prefetch(&out8[n - 1]);
+#endif /* !CHIP_HAS_WH64() */
+
+
+	/* Align 'out8'. We know n >= 3 so this won't write past the end. */
+	while (((uintptr_t) out8 & 3) != 0) {
+		*out8++ = c;
+		--n;
+	}
+
+	/* Align 'n'. */
+	while (n & 3)
+		out8[--n] = c;
+
+	out32 = (uint32_t *) out8;
+	n32 = n >> 2;
+
+	/* Tile input byte out to 32 bits. */
+	v16 = __insn_intlb(c, c);
+	v32 = __insn_intlh(v16, v16);
+
+	/* This must be at least 8 or the following loop doesn't work. */
+#define CACHE_LINE_SIZE_IN_WORDS (CHIP_L2_LINE_SIZE() / 4)
+
+#if !CHIP_HAS_WH64()
+
+	ahead32 = CACHE_LINE_SIZE_IN_WORDS;
+
+	/* We already prefetched the first and last cache lines, so
+	 * we only need to do more prefetching if we are storing
+	 * to more than two cache lines.
+	 */
+	if (n32 > CACHE_LINE_SIZE_IN_WORDS * 2) {
+		int i;
+
+		/* Prefetch the next several cache lines.
+		 * This is the setup code for the software-pipelined
+		 * loop below.
+		 */
+#define MAX_PREFETCH 5
+		ahead32 = n32 & -CACHE_LINE_SIZE_IN_WORDS;
+		if (ahead32 > MAX_PREFETCH * CACHE_LINE_SIZE_IN_WORDS)
+			ahead32 = MAX_PREFETCH * CACHE_LINE_SIZE_IN_WORDS;
+
+		for (i = CACHE_LINE_SIZE_IN_WORDS;
+		     i < ahead32; i += CACHE_LINE_SIZE_IN_WORDS)
+			__insn_prefetch(&out32[i]);
+	}
+
+	if (n32 > ahead32) {
+		while (1) {
+			int j;
+
+			/* Prefetch by reading one word several cache lines
+			 * ahead.  Since loads are non-blocking this will
+			 * cause the full cache line to be read while we are
+			 * finishing earlier cache lines.  Using a store
+			 * here causes microarchitectural performance
+			 * problems where a victimizing store miss goes to
+			 * the head of the retry FIFO and locks the pipe for
+			 * a few cycles.  So a few subsequent stores in this
+			 * loop go into the retry FIFO, and then later
+			 * stores see other stores to the same cache line
+			 * are already in the retry FIFO and themselves go
+			 * into the retry FIFO, filling it up and grinding
+			 * to a halt waiting for the original miss to be
+			 * satisfied.
+			 */
+			__insn_prefetch(&out32[ahead32]);
+
+#if 1
+#if CACHE_LINE_SIZE_IN_WORDS % 4 != 0
+#error "Unhandled CACHE_LINE_SIZE_IN_WORDS"
+#endif
+
+			n32 -= CACHE_LINE_SIZE_IN_WORDS;
+
+			/* Save icache space by only partially unrolling
+			 * this loop.
+			 */
+			for (j = CACHE_LINE_SIZE_IN_WORDS / 4; j > 0; j--) {
+				*out32++ = v32;
+				*out32++ = v32;
+				*out32++ = v32;
+				*out32++ = v32;
+			}
+#else
+			/* Unfortunately, due to a code generator flaw this
+			 * allocates a separate register for each of these
+			 * stores, which requires a large number of spills,
+			 * which makes this procedure enormously bigger
+			 * (something like 70%)
+			 */
+			*out32++ = v32;
+			*out32++ = v32;
+			*out32++ = v32;
+			*out32++ = v32;
+			*out32++ = v32;
+			*out32++ = v32;
+			*out32++ = v32;
+			*out32++ = v32;
+			*out32++ = v32;
+			*out32++ = v32;
+			*out32++ = v32;
+			*out32++ = v32;
+			*out32++ = v32;
+			*out32++ = v32;
+			*out32++ = v32;
+			n32 -= 16;
+#endif
+
+			/* To save compiled code size, reuse this loop even
+			 * when we run out of prefetching to do by dropping
+			 * ahead32 down.
+			 */
+			if (n32 <= ahead32) {
+				/* Not even a full cache line left,
+				 * so stop now.
+				 */
+				if (n32 < CACHE_LINE_SIZE_IN_WORDS)
+					break;
+
+				/* Choose a small enough value that we don't
+				 * prefetch past the end.  There's no sense
+				 * in touching cache lines we don't have to.
+				 */
+				ahead32 = CACHE_LINE_SIZE_IN_WORDS - 1;
+			}
+		}
+	}
+
+#else /* CHIP_HAS_WH64() */
+
+	/* Determine how many words we need to emit before the 'out32'
+	 * pointer becomes aligned modulo the cache line size.
+	 */
+	to_align32 =
+		(-((uintptr_t)out32 >> 2)) & (CACHE_LINE_SIZE_IN_WORDS - 1);
+
+	/* Only bother aligning and using wh64 if there is at least
+	 * one full cache line to process.  This check also prevents
+	 * overrunning the end of the buffer with alignment words.
+	 */
+	if (to_align32 <= n32 - CACHE_LINE_SIZE_IN_WORDS) {
+		int lines_left;
+
+		/* Align out32 mod the cache line size so we can use wh64. */
+		n32 -= to_align32;
+		for (; to_align32 != 0; to_align32--) {
+			*out32 = v32;
+			out32++;
+		}
+
+		/* Use unsigned divide to turn this into a right shift. */
+		lines_left = (unsigned)n32 / CACHE_LINE_SIZE_IN_WORDS;
+
+		do {
+			/* Only wh64 a few lines at a time, so we don't
+			 * exceed the maximum number of victim lines.
+			 */
+			int x = ((lines_left < CHIP_MAX_OUTSTANDING_VICTIMS())
+				  ? lines_left
+				  : CHIP_MAX_OUTSTANDING_VICTIMS());
+			uint32_t *wh = out32;
+			int i = x;
+			int j;
+
+			lines_left -= x;
+
+			do {
+				__insn_wh64(wh);
+				wh += CACHE_LINE_SIZE_IN_WORDS;
+			} while (--i);
+
+			for (j = x * (CACHE_LINE_SIZE_IN_WORDS / 4);
+			     j != 0; j--) {
+				*out32++ = v32;
+				*out32++ = v32;
+				*out32++ = v32;
+				*out32++ = v32;
+			}
+		} while (lines_left != 0);
+
+		/* We processed all full lines above, so only this many
+		 * words remain to be processed.
+		 */
+		n32 &= CACHE_LINE_SIZE_IN_WORDS - 1;
+	}
+
+#endif /* CHIP_HAS_WH64() */
+
+	/* Now handle any leftover values. */
+	if (n32 != 0) {
+		do {
+			*out32 = v32;
+			out32++;
+		} while (--n32 != 0);
+	}
+
+	return s;
+}
+EXPORT_SYMBOL(memset);