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linux/arch/arc/include/asm/tlb.h

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ARC: MMU Exception Handling * MMU I-TLB / D-TLB Miss Exceptions - Fast Path TLB Refill Handler - slowpath TLB creation via do_page_fault() -> update_mmu_cache() * Duplicate PD Exception Handler Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2013-01-18 17:42:19 +08:00
/*
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifndef _ASM_ARC_TLB_H
#define _ASM_ARC_TLB_H
ARC: [mm] optimize needless full mm TLB flush on munmap munmap ends up calling tlb_flush() which for ARC was flushing the entire TLB unconditionally (by moving the MMU to a new ASID) do_munmap unmap_region unmap_vmas unmap_single_vma unmap_page_range tlb_start_vma zap_pud_range tlb_end_vma() tlb_finish_mmu tlb_flush() ---> unconditional flush_tlb_mm() So even a single page munmap, a frequent operation when uClibc dynamic linker (ldso) is loading the dependent shared libraries, would move the the ASID multiple times - needlessly invalidating the pre-faulted TLB entries (and increasing the rate of ASID wraparound + full TLB flush). This is now optimised to only be called if tlb->full_mm (which means for exit/execve) cases only. And for those cases, flush_tlb_mm() is already optimised to be a no-op for mm->mm_users == 0. So essentially there are no mmore full mm flushes - except for fork which anyhow needs it for properly COW'ing parent address space. munmap now needs to do TLB range flush, which is implemented with tlb_end_vma() Results ------- 1. ASID now consistenly moves by 4 during a simple ls (as opposed to 5 or 7 before). 2. LMBench microbenchmark also shows improvements Basic system parameters ------------------------------------------------------------------------------ Host OS Description Mhz tlb cache mem scal pages line par load bytes --------- ------------- ----------------------- ---- ----- ----- ------ ---- 3.9-rc5-0 Linux 3.9.0-r 3.9-rc5-0404-gcc-4.4-ba 80 8 64 1.1000 1 3.9-rc5-0 Linux 3.9.0-r 3.9-rc5-0405-avoid-full 80 8 64 1.1200 1 Processor, Processes - times in microseconds - smaller is better ------------------------------------------------------------------------------ Host OS Mhz null null open slct sig sig fork exec sh call I/O stat clos TCP inst hndl proc proc proc --------- ------------- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- 3.9-rc5-0 Linux 3.9.0-r 80 4.81 8.69 68.6 118. 239. 8.53 31.6 4839 13.K 34.K 3.9-rc5-0 Linux 3.9.0-r 80 4.46 8.36 53.8 91.3 223. 8.12 24.2 4725 13.K 33.K File & VM system latencies in microseconds - smaller is better ------------------------------------------------------------------------------- Host OS 0K File 10K File Mmap Prot Page 100fd Create Delete Create Delete Latency Fault Fault selct --------- ------------- ------ ------ ------ ------ ------- ----- ------- ----- 3.9-rc5-0 Linux 3.9.0-r 314.7 223.2 1054.9 390.2 3615.0 1.590 20.1 126.6 3.9-rc5-0 Linux 3.9.0-r 265.8 183.8 1014.2 314.1 3193.0 6.910 18.8 110.4 Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2013-04-05 21:08:31 +08:00
#define tlb_flush(tlb) \
do { \
if (tlb->fullmm) \
flush_tlb_mm((tlb)->mm); \
} while (0)
ARC: TLB flush Handling Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2013-01-18 17:42:20 +08:00
/*
* This pair is called at time of munmap/exit to flush cache and TLB entries
* for mappings being torn down.
ARC: [mm] Aliasing VIPT dcache support 2/4 This is the meat of the series which prevents any dcache alias creation by always keeping the U and K mapping of a page congruent. If a mapping already exists, and other tries to access the page, prev one is flushed to physical page (wback+inv) Essentially flush_dcache_page()/copy_user_highpage() create K-mapping of a page, but try to defer flushing, unless U-mapping exist. When page is actually mapped to userspace, update_mmu_cache() flushes the K-mapping (in certain cases this can be optimised out) Additonally flush_cache_mm(), flush_cache_range(), flush_cache_page() handle the puring of stale userspace mappings on exit/munmap... flush_anon_page() handles the existing U-mapping for anon page before kernel reads it via the GUP path. Note that while not complete, this is enough to boot a simple dynamically linked Busybox based rootfs Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2013-05-10 00:24:51 +08:00
* 1) cache-flush part -implemented via tlb_start_vma( ) for VIPT aliasing D$
ARC: [mm] optimize needless full mm TLB flush on munmap munmap ends up calling tlb_flush() which for ARC was flushing the entire TLB unconditionally (by moving the MMU to a new ASID) do_munmap unmap_region unmap_vmas unmap_single_vma unmap_page_range tlb_start_vma zap_pud_range tlb_end_vma() tlb_finish_mmu tlb_flush() ---> unconditional flush_tlb_mm() So even a single page munmap, a frequent operation when uClibc dynamic linker (ldso) is loading the dependent shared libraries, would move the the ASID multiple times - needlessly invalidating the pre-faulted TLB entries (and increasing the rate of ASID wraparound + full TLB flush). This is now optimised to only be called if tlb->full_mm (which means for exit/execve) cases only. And for those cases, flush_tlb_mm() is already optimised to be a no-op for mm->mm_users == 0. So essentially there are no mmore full mm flushes - except for fork which anyhow needs it for properly COW'ing parent address space. munmap now needs to do TLB range flush, which is implemented with tlb_end_vma() Results ------- 1. ASID now consistenly moves by 4 during a simple ls (as opposed to 5 or 7 before). 2. LMBench microbenchmark also shows improvements Basic system parameters ------------------------------------------------------------------------------ Host OS Description Mhz tlb cache mem scal pages line par load bytes --------- ------------- ----------------------- ---- ----- ----- ------ ---- 3.9-rc5-0 Linux 3.9.0-r 3.9-rc5-0404-gcc-4.4-ba 80 8 64 1.1000 1 3.9-rc5-0 Linux 3.9.0-r 3.9-rc5-0405-avoid-full 80 8 64 1.1200 1 Processor, Processes - times in microseconds - smaller is better ------------------------------------------------------------------------------ Host OS Mhz null null open slct sig sig fork exec sh call I/O stat clos TCP inst hndl proc proc proc --------- ------------- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- 3.9-rc5-0 Linux 3.9.0-r 80 4.81 8.69 68.6 118. 239. 8.53 31.6 4839 13.K 34.K 3.9-rc5-0 Linux 3.9.0-r 80 4.46 8.36 53.8 91.3 223. 8.12 24.2 4725 13.K 33.K File & VM system latencies in microseconds - smaller is better ------------------------------------------------------------------------------- Host OS 0K File 10K File Mmap Prot Page 100fd Create Delete Create Delete Latency Fault Fault selct --------- ------------- ------ ------ ------ ------ ------- ----- ------- ----- 3.9-rc5-0 Linux 3.9.0-r 314.7 223.2 1054.9 390.2 3615.0 1.590 20.1 126.6 3.9-rc5-0 Linux 3.9.0-r 265.8 183.8 1014.2 314.1 3193.0 6.910 18.8 110.4 Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2013-04-05 21:08:31 +08:00
* 2) tlb-flush part - implemted via tlb_end_vma( ) flushes the TLB range
ARC: TLB flush Handling Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2013-01-18 17:42:20 +08:00
*
* Note, read http://lkml.org/lkml/2004/1/15/6
*/
ARC: [mm] Aliasing VIPT dcache support 2/4 This is the meat of the series which prevents any dcache alias creation by always keeping the U and K mapping of a page congruent. If a mapping already exists, and other tries to access the page, prev one is flushed to physical page (wback+inv) Essentially flush_dcache_page()/copy_user_highpage() create K-mapping of a page, but try to defer flushing, unless U-mapping exist. When page is actually mapped to userspace, update_mmu_cache() flushes the K-mapping (in certain cases this can be optimised out) Additonally flush_cache_mm(), flush_cache_range(), flush_cache_page() handle the puring of stale userspace mappings on exit/munmap... flush_anon_page() handles the existing U-mapping for anon page before kernel reads it via the GUP path. Note that while not complete, this is enough to boot a simple dynamically linked Busybox based rootfs Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2013-05-10 00:24:51 +08:00
#ifndef CONFIG_ARC_CACHE_VIPT_ALIASING
ARC: TLB flush Handling Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2013-01-18 17:42:20 +08:00
#define tlb_start_vma(tlb, vma)
ARC: [mm] Aliasing VIPT dcache support 2/4 This is the meat of the series which prevents any dcache alias creation by always keeping the U and K mapping of a page congruent. If a mapping already exists, and other tries to access the page, prev one is flushed to physical page (wback+inv) Essentially flush_dcache_page()/copy_user_highpage() create K-mapping of a page, but try to defer flushing, unless U-mapping exist. When page is actually mapped to userspace, update_mmu_cache() flushes the K-mapping (in certain cases this can be optimised out) Additonally flush_cache_mm(), flush_cache_range(), flush_cache_page() handle the puring of stale userspace mappings on exit/munmap... flush_anon_page() handles the existing U-mapping for anon page before kernel reads it via the GUP path. Note that while not complete, this is enough to boot a simple dynamically linked Busybox based rootfs Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2013-05-10 00:24:51 +08:00
#else
#define tlb_start_vma(tlb, vma) \
do { \
if (!tlb->fullmm) \
flush_cache_range(vma, vma->vm_start, vma->vm_end); \
} while(0)
#endif
ARC: [mm] optimize needless full mm TLB flush on munmap munmap ends up calling tlb_flush() which for ARC was flushing the entire TLB unconditionally (by moving the MMU to a new ASID) do_munmap unmap_region unmap_vmas unmap_single_vma unmap_page_range tlb_start_vma zap_pud_range tlb_end_vma() tlb_finish_mmu tlb_flush() ---> unconditional flush_tlb_mm() So even a single page munmap, a frequent operation when uClibc dynamic linker (ldso) is loading the dependent shared libraries, would move the the ASID multiple times - needlessly invalidating the pre-faulted TLB entries (and increasing the rate of ASID wraparound + full TLB flush). This is now optimised to only be called if tlb->full_mm (which means for exit/execve) cases only. And for those cases, flush_tlb_mm() is already optimised to be a no-op for mm->mm_users == 0. So essentially there are no mmore full mm flushes - except for fork which anyhow needs it for properly COW'ing parent address space. munmap now needs to do TLB range flush, which is implemented with tlb_end_vma() Results ------- 1. ASID now consistenly moves by 4 during a simple ls (as opposed to 5 or 7 before). 2. LMBench microbenchmark also shows improvements Basic system parameters ------------------------------------------------------------------------------ Host OS Description Mhz tlb cache mem scal pages line par load bytes --------- ------------- ----------------------- ---- ----- ----- ------ ---- 3.9-rc5-0 Linux 3.9.0-r 3.9-rc5-0404-gcc-4.4-ba 80 8 64 1.1000 1 3.9-rc5-0 Linux 3.9.0-r 3.9-rc5-0405-avoid-full 80 8 64 1.1200 1 Processor, Processes - times in microseconds - smaller is better ------------------------------------------------------------------------------ Host OS Mhz null null open slct sig sig fork exec sh call I/O stat clos TCP inst hndl proc proc proc --------- ------------- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- ---- 3.9-rc5-0 Linux 3.9.0-r 80 4.81 8.69 68.6 118. 239. 8.53 31.6 4839 13.K 34.K 3.9-rc5-0 Linux 3.9.0-r 80 4.46 8.36 53.8 91.3 223. 8.12 24.2 4725 13.K 33.K File & VM system latencies in microseconds - smaller is better ------------------------------------------------------------------------------- Host OS 0K File 10K File Mmap Prot Page 100fd Create Delete Create Delete Latency Fault Fault selct --------- ------------- ------ ------ ------ ------ ------- ----- ------- ----- 3.9-rc5-0 Linux 3.9.0-r 314.7 223.2 1054.9 390.2 3615.0 1.590 20.1 126.6 3.9-rc5-0 Linux 3.9.0-r 265.8 183.8 1014.2 314.1 3193.0 6.910 18.8 110.4 Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2013-04-05 21:08:31 +08:00
#define tlb_end_vma(tlb, vma) \
do { \
if (!tlb->fullmm) \
flush_tlb_range(vma, vma->vm_start, vma->vm_end); \
} while (0)
ARC: TLB flush Handling Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2013-01-18 17:42:20 +08:00
#define __tlb_remove_tlb_entry(tlb, ptep, address)
ARC: MMU Exception Handling * MMU I-TLB / D-TLB Miss Exceptions - Fast Path TLB Refill Handler - slowpath TLB creation via do_page_fault() -> update_mmu_cache() * Duplicate PD Exception Handler Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2013-01-18 17:42:19 +08:00
#include <linux/pagemap.h>
#include <asm-generic/tlb.h>
#endif /* _ASM_ARC_TLB_H */