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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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4804e382c1
The I/O bitmap is duplicated on fork. That's wasting memory and slows down fork. There is no point to do so. As long as the bitmap is not modified it can be shared between threads and processes. Add a refcount and just share it on fork. If a task modifies the bitmap then it has to do the duplication if and only if it is shared. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Andy Lutomirski <luto@kernel.org>
24 lines
479 B
C
24 lines
479 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_X86_IOBITMAP_H
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#define _ASM_X86_IOBITMAP_H
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#include <linux/refcount.h>
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#include <asm/processor.h>
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struct io_bitmap {
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u64 sequence;
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refcount_t refcnt;
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/* The maximum number of bytes to copy so all zero bits are covered */
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unsigned int max;
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unsigned long bitmap[IO_BITMAP_LONGS];
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};
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struct task_struct;
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void io_bitmap_share(struct task_struct *tsk);
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void io_bitmap_exit(void);
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void tss_update_io_bitmap(void);
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#endif
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