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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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32d6bd9059
This is the third version of the patchset previously sent [1]. I have basically only rebased it on top of 4.7-rc1 tree and dropped "dm: get rid of superfluous gfp flags" which went through dm tree. I am sending it now because it is tree wide and chances for conflicts are reduced considerably when we want to target rc2. I plan to send the next step and rename the flag and move to a better semantic later during this release cycle so we will have a new semantic ready for 4.8 merge window hopefully. Motivation: While working on something unrelated I've checked the current usage of __GFP_REPEAT in the tree. It seems that a majority of the usage is and always has been bogus because __GFP_REPEAT has always been about costly high order allocations while we are using it for order-0 or very small orders very often. It seems that a big pile of them is just a copy&paste when a code has been adopted from one arch to another. I think it makes some sense to get rid of them because they are just making the semantic more unclear. Please note that GFP_REPEAT is documented as * __GFP_REPEAT: Try hard to allocate the memory, but the allocation attempt * _might_ fail. This depends upon the particular VM implementation. while !costly requests have basically nofail semantic. So one could reasonably expect that order-0 request with __GFP_REPEAT will not loop for ever. This is not implemented right now though. I would like to move on with __GFP_REPEAT and define a better semantic for it. $ git grep __GFP_REPEAT origin/master | wc -l 111 $ git grep __GFP_REPEAT | wc -l 36 So we are down to the third after this patch series. The remaining places really seem to be relying on __GFP_REPEAT due to large allocation requests. This still needs some double checking which I will do later after all the simple ones are sorted out. I am touching a lot of arch specific code here and I hope I got it right but as a matter of fact I even didn't compile test for some archs as I do not have cross compiler for them. Patches should be quite trivial to review for stupid compile mistakes though. The tricky parts are usually hidden by macro definitions and thats where I would appreciate help from arch maintainers. [1] http://lkml.kernel.org/r/1461849846-27209-1-git-send-email-mhocko@kernel.org This patch (of 19): __GFP_REPEAT has a rather weak semantic but since it has been introduced around 2.6.12 it has been ignored for low order allocations. Yet we have the full kernel tree with its usage for apparently order-0 allocations. This is really confusing because __GFP_REPEAT is explicitly documented to allow allocation failures which is a weaker semantic than the current order-0 has (basically nofail). Let's simply drop __GFP_REPEAT from those places. This would allow to identify place which really need allocator to retry harder and formulate a more specific semantic for what the flag is supposed to do actually. Link: http://lkml.kernel.org/r/1464599699-30131-2-git-send-email-mhocko@kernel.org Signed-off-by: Michal Hocko <mhocko@suse.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andy Lutomirski <luto@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chen Liqin <liqin.linux@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> [for tile] Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: John Crispin <blogic@openwrt.org> Cc: Lennox Wu <lennox.wu@gmail.com> Cc: Ley Foon Tan <lftan@altera.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
138 lines
3.8 KiB
C
138 lines
3.8 KiB
C
/*
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* OpenRISC ioremap.c
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*
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* Linux architectural port borrowing liberally from similar works of
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* others. All original copyrights apply as per the original source
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* declaration.
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*
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* Modifications for the OpenRISC architecture:
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* Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
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* Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/vmalloc.h>
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#include <linux/io.h>
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#include <asm/pgalloc.h>
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#include <asm/kmap_types.h>
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#include <asm/fixmap.h>
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#include <asm/bug.h>
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#include <asm/pgtable.h>
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#include <linux/sched.h>
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#include <asm/tlbflush.h>
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extern int mem_init_done;
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static unsigned int fixmaps_used __initdata;
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/*
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* Remap an arbitrary physical address space into the kernel virtual
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* address space. Needed when the kernel wants to access high addresses
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* directly.
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*
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* NOTE! We need to allow non-page-aligned mappings too: we will obviously
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* have to convert them into an offset in a page-aligned mapping, but the
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* caller shouldn't need to know that small detail.
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*/
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void __iomem *__init_refok
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__ioremap(phys_addr_t addr, unsigned long size, pgprot_t prot)
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{
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phys_addr_t p;
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unsigned long v;
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unsigned long offset, last_addr;
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struct vm_struct *area = NULL;
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/* Don't allow wraparound or zero size */
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last_addr = addr + size - 1;
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if (!size || last_addr < addr)
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return NULL;
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/*
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* Mappings have to be page-aligned
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*/
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offset = addr & ~PAGE_MASK;
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p = addr & PAGE_MASK;
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size = PAGE_ALIGN(last_addr + 1) - p;
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if (likely(mem_init_done)) {
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area = get_vm_area(size, VM_IOREMAP);
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if (!area)
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return NULL;
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v = (unsigned long)area->addr;
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} else {
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if ((fixmaps_used + (size >> PAGE_SHIFT)) > FIX_N_IOREMAPS)
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return NULL;
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v = fix_to_virt(FIX_IOREMAP_BEGIN + fixmaps_used);
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fixmaps_used += (size >> PAGE_SHIFT);
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}
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if (ioremap_page_range(v, v + size, p, prot)) {
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if (likely(mem_init_done))
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vfree(area->addr);
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else
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fixmaps_used -= (size >> PAGE_SHIFT);
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return NULL;
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}
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return (void __iomem *)(offset + (char *)v);
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}
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void iounmap(void *addr)
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{
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/* If the page is from the fixmap pool then we just clear out
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* the fixmap mapping.
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*/
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if (unlikely((unsigned long)addr > FIXADDR_START)) {
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/* This is a bit broken... we don't really know
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* how big the area is so it's difficult to know
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* how many fixed pages to invalidate...
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* just flush tlb and hope for the best...
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* consider this a FIXME
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*
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* Really we should be clearing out one or more page
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* table entries for these virtual addresses so that
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* future references cause a page fault... for now, we
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* rely on two things:
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* i) this code never gets called on known boards
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* ii) invalid accesses to the freed areas aren't made
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*/
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flush_tlb_all();
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return;
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}
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return vfree((void *)(PAGE_MASK & (unsigned long)addr));
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}
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/**
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* OK, this one's a bit tricky... ioremap can get called before memory is
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* initialized (early serial console does this) and will want to alloc a page
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* for its mapping. No userspace pages will ever get allocated before memory
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* is initialized so this applies only to kernel pages. In the event that
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* this is called before memory is initialized we allocate the page using
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* the memblock infrastructure.
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*/
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pte_t __init_refok *pte_alloc_one_kernel(struct mm_struct *mm,
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unsigned long address)
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{
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pte_t *pte;
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if (likely(mem_init_done)) {
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pte = (pte_t *) __get_free_page(GFP_KERNEL);
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} else {
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pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
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#if 0
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/* FIXME: use memblock... */
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pte = (pte_t *) __va(memblock_alloc(PAGE_SIZE, PAGE_SIZE));
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#endif
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}
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if (pte)
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clear_page(pte);
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return pte;
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}
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