From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f178.google.com (mail-pd0-f178.google.com [209.85.192.178]) by kanga.kvack.org (Postfix) with ESMTP id 2C28F6B0100 for ; Mon, 11 Nov 2013 18:37:13 -0500 (EST) Received: by mail-pd0-f178.google.com with SMTP id p10so1304488pdj.9 for ; Mon, 11 Nov 2013 15:37:12 -0800 (PST) Received: from psmtp.com ([74.125.245.138]) by mx.google.com with SMTP id qj1si17217889pbc.354.2013.11.11.15.37.10 for ; Mon, 11 Nov 2013 15:37:11 -0800 (PST) Received: by mail-ob0-f182.google.com with SMTP id wp18so5189906obc.27 for ; Mon, 11 Nov 2013 15:37:09 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <1384212412-21236-4-git-send-email-lauraa@codeaurora.org> References: <1384212412-21236-1-git-send-email-lauraa@codeaurora.org> <1384212412-21236-4-git-send-email-lauraa@codeaurora.org> Date: Tue, 12 Nov 2013 08:37:09 +0900 Message-ID: Subject: Re: [RFC PATCH 3/4] mm/vmalloc.c: Allow lowmem to be tracked in vmalloc From: Kyungmin Park Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Laura Abbott Cc: linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, Neeti Desai Hi Laura, On Tue, Nov 12, 2013 at 8:26 AM, Laura Abbott wrote: > vmalloc is currently assumed to be a completely separate address space > from the lowmem region. While this may be true in the general case, > there are some instances where lowmem and virtual space intermixing > provides gains. One example is needing to steal a large chunk of physical > lowmem for another purpose outside the systems usage. Rather than > waste the precious lowmem space on a 32-bit system, we can allow the > virtual holes created by the physical holes to be used by vmalloc > for virtual addressing. Track lowmem allocations in vmalloc to > allow mixing of lowmem and vmalloc. > > Signed-off-by: Laura Abbott > Signed-off-by: Neeti Desai > --- > include/linux/mm.h | 6 ++++++ > include/linux/vmalloc.h | 1 + > mm/Kconfig | 11 +++++++++++ > mm/vmalloc.c | 26 ++++++++++++++++++++++++++ > 4 files changed, 44 insertions(+), 0 deletions(-) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index f022460..76df50d 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -308,6 +308,10 @@ unsigned long vmalloc_to_pfn(const void *addr); > * On nommu, vmalloc/vfree wrap through kmalloc/kfree directly, so there > * is no special casing required. > */ > + > +#ifdef CONFIG_VMALLOC_SAVING mismatch below Kconfig. CONFIG_ENABLE_VMALLOC_SAVING? > +extern int is_vmalloc_addr(const void *x) > +#else > static inline int is_vmalloc_addr(const void *x) > { > #ifdef CONFIG_MMU > @@ -318,6 +322,8 @@ static inline int is_vmalloc_addr(const void *x) > return 0; > #endif > } > +#endif > + > #ifdef CONFIG_MMU > extern int is_vmalloc_or_module_addr(const void *x); > #else > diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h > index 4b8a891..e0c8c49 100644 > --- a/include/linux/vmalloc.h > +++ b/include/linux/vmalloc.h > @@ -16,6 +16,7 @@ struct vm_area_struct; /* vma defining user mapping in mm_types.h */ > #define VM_USERMAP 0x00000008 /* suitable for remap_vmalloc_range */ > #define VM_VPAGES 0x00000010 /* buffer for pages was vmalloc'ed */ > #define VM_UNINITIALIZED 0x00000020 /* vm_struct is not fully initialized */ > +#define VM_LOWMEM 0x00000040 /* Tracking of direct mapped lowmem */ > /* bits [20..32] reserved for arch specific ioremap internals */ > > /* > diff --git a/mm/Kconfig b/mm/Kconfig > index 8028dcc..b3c459d 100644 > --- a/mm/Kconfig > +++ b/mm/Kconfig > @@ -519,3 +519,14 @@ config MEM_SOFT_DIRTY > it can be cleared by hands. > > See Documentation/vm/soft-dirty.txt for more details. > + > +config ENABLE_VMALLOC_SAVING > + bool "Intermix lowmem and vmalloc virtual space" > + depends on ARCH_TRACKS_VMALLOC > + help > + Some memory layouts on embedded systems steal large amounts > + of lowmem physical memory for purposes outside of the kernel. > + Rather than waste the physical and virtual space, allow the > + kernel to use the virtual space as vmalloc space. > + > + If unsure, say N. > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 13a5495..c7b138b 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -204,6 +204,29 @@ static int vmap_page_range(unsigned long start, unsigned long end, > return ret; > } > > +#ifdef ENABLE_VMALLOC_SAVING missing "CONFIG_" Thank you, Kyungimn Park > +int is_vmalloc_addr(const void *x) > +{ > + struct rb_node *n; > + struct vmap_area *va; > + int ret = 0; > + > + spin_lock(&vmap_area_lock); > + > + for (n = rb_first(vmap_area_root); n; rb_next(n)) { > + va = rb_entry(n, struct vmap_area, rb_node); > + if (x >= va->va_start && x < va->va_end) { > + ret = 1; > + break; > + } > + } > + > + spin_unlock(&vmap_area_lock); > + return ret; > +} > +EXPORT_SYMBOL(is_vmalloc_addr); > +#endif > + > int is_vmalloc_or_module_addr(const void *x) > { > /* > @@ -2628,6 +2651,9 @@ static int s_show(struct seq_file *m, void *p) > if (v->flags & VM_VPAGES) > seq_printf(m, " vpages"); > > + if (v->flags & VM_LOWMEM) > + seq_printf(m, " lowmem"); > + > show_numa_info(m, v); > seq_putc(m, '\n'); > return 0; > -- > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, > hosted by The Linux Foundation > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: email@kvack.org -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org