* Re: [PATCH v2 04/10] DMA, CMA: support alignment constraint on cma region
From: Joonsoo Kim @ 2014-06-12 6:07 UTC (permalink / raw)
To: Minchan Kim
Cc: kvm-ppc, Russell King - ARM Linux, kvm, Gleb Natapov,
Greg Kroah-Hartman, Alexander Graf, Michal Nazarewicz,
linux-kernel, linux-mm, Paul Mackerras, Aneesh Kumar K.V,
Paolo Bonzini, Andrew Morton, linuxppc-dev, linux-arm-kernel,
Marek Szyprowski
In-Reply-To: <20140612055219.GG12415@bbox>
On Thu, Jun 12, 2014 at 02:52:20PM +0900, Minchan Kim wrote:
> On Thu, Jun 12, 2014 at 12:21:41PM +0900, Joonsoo Kim wrote:
> > ppc kvm's cma area management needs alignment constraint on
> > cma region. So support it to prepare generalization of cma area
> > management functionality.
> >
> > Additionally, add some comments which tell us why alignment
> > constraint is needed on cma region.
> >
> > Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> >
> > diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
> > index 8a44c82..bc4c171 100644
> > --- a/drivers/base/dma-contiguous.c
> > +++ b/drivers/base/dma-contiguous.c
> > @@ -32,6 +32,7 @@
> > #include <linux/swap.h>
> > #include <linux/mm_types.h>
> > #include <linux/dma-contiguous.h>
> > +#include <linux/log2.h>
> >
> > struct cma {
> > unsigned long base_pfn;
> > @@ -219,6 +220,7 @@ core_initcall(cma_init_reserved_areas);
> > * @size: Size of the reserved area (in bytes),
> > * @base: Base address of the reserved area optional, use 0 for any
> > * @limit: End address of the reserved memory (optional, 0 for any).
> > + * @alignment: Alignment for the contiguous memory area, should be power of 2
> > * @res_cma: Pointer to store the created cma region.
> > * @fixed: hint about where to place the reserved area
> > *
>
> Pz, move the all description to new API function rather than internal one.
Reason I leave all description as is is that I will remove it in
following patch. I think that moving these makes patch bigger and hard
to review.
But, if it is necessary, I will do it. :)
>
> > @@ -233,15 +235,15 @@ core_initcall(cma_init_reserved_areas);
> > */
> > static int __init __dma_contiguous_reserve_area(phys_addr_t size,
> > phys_addr_t base, phys_addr_t limit,
> > + phys_addr_t alignment,
> > struct cma **res_cma, bool fixed)
> > {
> > struct cma *cma = &cma_areas[cma_area_count];
> > - phys_addr_t alignment;
> > int ret = 0;
> >
> > - pr_debug("%s(size %lx, base %08lx, limit %08lx)\n", __func__,
> > - (unsigned long)size, (unsigned long)base,
> > - (unsigned long)limit);
> > + pr_debug("%s(size %lx, base %08lx, limit %08lx align_order %08lx)\n",
>
> Why is it called by "align_order"?
Oops... mistake.
I will fix it.
Thanks.
^ permalink raw reply
* Re: [PATCH v2 05/10] DMA, CMA: support arbitrary bitmap granularity
From: Minchan Kim @ 2014-06-12 6:06 UTC (permalink / raw)
To: Joonsoo Kim
Cc: kvm-ppc, Russell King - ARM Linux, kvm, Gleb Natapov,
Greg Kroah-Hartman, Alexander Graf, Michal Nazarewicz,
linux-kernel, linux-mm, Paul Mackerras, Aneesh Kumar K.V,
Paolo Bonzini, Andrew Morton, linuxppc-dev, linux-arm-kernel,
Marek Szyprowski
In-Reply-To: <1402543307-29800-6-git-send-email-iamjoonsoo.kim@lge.com>
On Thu, Jun 12, 2014 at 12:21:42PM +0900, Joonsoo Kim wrote:
> ppc kvm's cma region management requires arbitrary bitmap granularity,
> since they want to reserve very large memory and manage this region
> with bitmap that one bit for several pages to reduce management overheads.
> So support arbitrary bitmap granularity for following generalization.
>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
>
> diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
> index bc4c171..9bc9340 100644
> --- a/drivers/base/dma-contiguous.c
> +++ b/drivers/base/dma-contiguous.c
> @@ -38,6 +38,7 @@ struct cma {
> unsigned long base_pfn;
> unsigned long count;
> unsigned long *bitmap;
> + int order_per_bit; /* Order of pages represented by one bit */
Hmm, I'm not sure it's good as *general* interface even though it covers
existing usecases.
It forces a cma area should be handled by same size unit. Right?
It's really important point for this patchset's motivation so I will stop
review and wait other opinions.
> struct mutex lock;
> };
>
> @@ -157,9 +158,38 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
>
> static DEFINE_MUTEX(cma_mutex);
>
> +static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
> +{
> + return (1 << (align_order >> cma->order_per_bit)) - 1;
> +}
> +
> +static unsigned long cma_bitmap_maxno(struct cma *cma)
> +{
> + return cma->count >> cma->order_per_bit;
> +}
> +
> +static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
> + unsigned long pages)
> +{
> + return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
> +}
> +
> +static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
> +{
> + unsigned long bitmapno, nr_bits;
> +
> + bitmapno = (pfn - cma->base_pfn) >> cma->order_per_bit;
> + nr_bits = cma_bitmap_pages_to_bits(cma, count);
> +
> + mutex_lock(&cma->lock);
> + bitmap_clear(cma->bitmap, bitmapno, nr_bits);
> + mutex_unlock(&cma->lock);
> +}
> +
> static int __init cma_activate_area(struct cma *cma)
> {
> - int bitmap_size = BITS_TO_LONGS(cma->count) * sizeof(long);
> + int bitmap_maxno = cma_bitmap_maxno(cma);
> + int bitmap_size = BITS_TO_LONGS(bitmap_maxno) * sizeof(long);
> unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
> unsigned i = cma->count >> pageblock_order;
> struct zone *zone;
> @@ -221,6 +251,7 @@ core_initcall(cma_init_reserved_areas);
> * @base: Base address of the reserved area optional, use 0 for any
> * @limit: End address of the reserved memory (optional, 0 for any).
> * @alignment: Alignment for the contiguous memory area, should be power of 2
> + * @order_per_bit: Order of pages represented by one bit on bitmap.
> * @res_cma: Pointer to store the created cma region.
> * @fixed: hint about where to place the reserved area
> *
> @@ -235,7 +266,7 @@ core_initcall(cma_init_reserved_areas);
> */
> static int __init __dma_contiguous_reserve_area(phys_addr_t size,
> phys_addr_t base, phys_addr_t limit,
> - phys_addr_t alignment,
> + phys_addr_t alignment, int order_per_bit,
> struct cma **res_cma, bool fixed)
> {
> struct cma *cma = &cma_areas[cma_area_count];
> @@ -269,6 +300,8 @@ static int __init __dma_contiguous_reserve_area(phys_addr_t size,
> base = ALIGN(base, alignment);
> size = ALIGN(size, alignment);
> limit &= ~(alignment - 1);
> + /* size should be aligned with order_per_bit */
> + BUG_ON(!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit));
>
> /* Reserve memory */
> if (base && fixed) {
> @@ -294,6 +327,7 @@ static int __init __dma_contiguous_reserve_area(phys_addr_t size,
> */
> cma->base_pfn = PFN_DOWN(base);
> cma->count = size >> PAGE_SHIFT;
> + cma->order_per_bit = order_per_bit;
> *res_cma = cma;
> cma_area_count++;
>
> @@ -313,7 +347,7 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
> {
> int ret;
>
> - ret = __dma_contiguous_reserve_area(size, base, limit, 0,
> + ret = __dma_contiguous_reserve_area(size, base, limit, 0, 0,
> res_cma, fixed);
> if (ret)
> return ret;
> @@ -324,13 +358,6 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
> return 0;
> }
>
> -static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
> -{
> - mutex_lock(&cma->lock);
> - bitmap_clear(cma->bitmap, pfn - cma->base_pfn, count);
> - mutex_unlock(&cma->lock);
> -}
> -
> /**
> * dma_alloc_from_contiguous() - allocate pages from contiguous area
> * @dev: Pointer to device for which the allocation is performed.
> @@ -345,7 +372,8 @@ static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
> static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
> unsigned int align)
> {
> - unsigned long mask, pfn, pageno, start = 0;
> + unsigned long mask, pfn, start = 0;
> + unsigned long bitmap_maxno, bitmapno, nr_bits;
> struct page *page = NULL;
> int ret;
>
> @@ -358,18 +386,19 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
> if (!count)
> return NULL;
>
> - mask = (1 << align) - 1;
> -
> + mask = cma_bitmap_aligned_mask(cma, align);
> + bitmap_maxno = cma_bitmap_maxno(cma);
> + nr_bits = cma_bitmap_pages_to_bits(cma, count);
>
> for (;;) {
> mutex_lock(&cma->lock);
> - pageno = bitmap_find_next_zero_area(cma->bitmap, cma->count,
> - start, count, mask);
> - if (pageno >= cma->count) {
> + bitmapno = bitmap_find_next_zero_area(cma->bitmap,
> + bitmap_maxno, start, nr_bits, mask);
> + if (bitmapno >= bitmap_maxno) {
> mutex_unlock(&cma->lock);
> break;
> }
> - bitmap_set(cma->bitmap, pageno, count);
> + bitmap_set(cma->bitmap, bitmapno, nr_bits);
> /*
> * It's safe to drop the lock here. We've marked this region for
> * our exclusive use. If the migration fails we will take the
> @@ -377,7 +406,7 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
> */
> mutex_unlock(&cma->lock);
>
> - pfn = cma->base_pfn + pageno;
> + pfn = cma->base_pfn + (bitmapno << cma->order_per_bit);
> mutex_lock(&cma_mutex);
> ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
> mutex_unlock(&cma_mutex);
> @@ -392,7 +421,7 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
> pr_debug("%s(): memory range at %p is busy, retrying\n",
> __func__, pfn_to_page(pfn));
> /* try again with a bit different memory target */
> - start = pageno + mask + 1;
> + start = bitmapno + mask + 1;
> }
>
> pr_debug("%s(): returned %p\n", __func__, page);
> --
> 1.7.9.5
--
Kind regards,
Minchan Kim
^ permalink raw reply
* Re: [PATCH v2 05/10] DMA, CMA: support arbitrary bitmap granularity
From: Joonsoo Kim @ 2014-06-12 6:43 UTC (permalink / raw)
To: Minchan Kim
Cc: kvm-ppc, Russell King - ARM Linux, kvm, Gleb Natapov,
Greg Kroah-Hartman, Alexander Graf, Michal Nazarewicz,
linux-kernel, linux-mm, Paul Mackerras, Aneesh Kumar K.V,
Paolo Bonzini, Andrew Morton, linuxppc-dev, linux-arm-kernel,
Marek Szyprowski
In-Reply-To: <20140612060610.GH12415@bbox>
On Thu, Jun 12, 2014 at 03:06:10PM +0900, Minchan Kim wrote:
> On Thu, Jun 12, 2014 at 12:21:42PM +0900, Joonsoo Kim wrote:
> > ppc kvm's cma region management requires arbitrary bitmap granularity,
> > since they want to reserve very large memory and manage this region
> > with bitmap that one bit for several pages to reduce management overheads.
> > So support arbitrary bitmap granularity for following generalization.
> >
> > Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> >
> > diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
> > index bc4c171..9bc9340 100644
> > --- a/drivers/base/dma-contiguous.c
> > +++ b/drivers/base/dma-contiguous.c
> > @@ -38,6 +38,7 @@ struct cma {
> > unsigned long base_pfn;
> > unsigned long count;
> > unsigned long *bitmap;
> > + int order_per_bit; /* Order of pages represented by one bit */
>
> Hmm, I'm not sure it's good as *general* interface even though it covers
> existing usecases.
>
> It forces a cma area should be handled by same size unit. Right?
> It's really important point for this patchset's motivation so I will stop
> review and wait other opinions.
If you pass 0 to order_per_bit, you can manage cma area in every
size(page unit) you want. If you pass certain number to order_per_bit,
you can allocate and release cma area in multiple of such page order.
I think that this is more general implementation than previous versions.
Thanks.
^ permalink raw reply
* Re: [PATCH] powerpc, kexec: Fix "Processor X is stuck" issue during kexec from ST mode
From: Joel Stanley @ 2014-06-12 6:39 UTC (permalink / raw)
To: Srivatsa S. Bhat
Cc: ego, matt, Mahesh Salgaonkar, kexec, linux-kernel, suzuki,
ebiederm, Paul Mackerras, linuxppc-dev, Vivek Goyal
In-Reply-To: <53922FB8.6070408@linux.vnet.ibm.com>
Hi Srivatsa,
On Sat, Jun 7, 2014 at 7:16 AM, Srivatsa S. Bhat
<srivatsa.bhat@linux.vnet.ibm.com> wrote:
> And with the following hunk added (which I had forgotten earlier), it worked just
> fine on powernv :-)
How are the patches coming along?
I just hung a machine here while attempting to kexec. It appears to
have onlined all of the secondary threads, and then hung here:
kexec: Waking offline cpu 1.
kvm: enabling virtualization on CPU1
kexec: Waking offline cpu 2.
kvm: enabling virtualization on CPU2
kexec: Waking offline cpu 3.
kvm: enabling virtualization on CPU3
kexec: Waking offline cpu 5.
kvm: enabling virtualization on CPU5
[...]
kvm: enabling virtualization on CPU63
kexec: waiting for cpu 1 (physical 1) to enter OPAL
kexec: waiting for cpu 2 (physical 2) to enter OPAL
kexec: waiting for cpu 3 (physical 3) to enter OPAL
I'm running benh's next branch as of thismorning, and SMT was off.
Could you please post your latest patches a series? I will test them here.
Cheers,
Joel
^ permalink raw reply
* Re: [PATCH v2 05/10] DMA, CMA: support arbitrary bitmap granularity
From: Minchan Kim @ 2014-06-12 6:42 UTC (permalink / raw)
To: Joonsoo Kim
Cc: kvm-ppc, Russell King - ARM Linux, kvm, Gleb Natapov,
Greg Kroah-Hartman, Alexander Graf, Michal Nazarewicz,
linux-kernel, linux-mm, Paul Mackerras, Aneesh Kumar K.V,
Paolo Bonzini, Andrew Morton, linuxppc-dev, linux-arm-kernel,
Marek Szyprowski
In-Reply-To: <20140612064355.GC19918@js1304-P5Q-DELUXE>
On Thu, Jun 12, 2014 at 03:43:55PM +0900, Joonsoo Kim wrote:
> On Thu, Jun 12, 2014 at 03:06:10PM +0900, Minchan Kim wrote:
> > On Thu, Jun 12, 2014 at 12:21:42PM +0900, Joonsoo Kim wrote:
> > > ppc kvm's cma region management requires arbitrary bitmap granularity,
> > > since they want to reserve very large memory and manage this region
> > > with bitmap that one bit for several pages to reduce management overheads.
> > > So support arbitrary bitmap granularity for following generalization.
> > >
> > > Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> > >
> > > diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
> > > index bc4c171..9bc9340 100644
> > > --- a/drivers/base/dma-contiguous.c
> > > +++ b/drivers/base/dma-contiguous.c
> > > @@ -38,6 +38,7 @@ struct cma {
> > > unsigned long base_pfn;
> > > unsigned long count;
> > > unsigned long *bitmap;
> > > + int order_per_bit; /* Order of pages represented by one bit */
> >
> > Hmm, I'm not sure it's good as *general* interface even though it covers
> > existing usecases.
> >
> > It forces a cma area should be handled by same size unit. Right?
> > It's really important point for this patchset's motivation so I will stop
> > review and wait other opinions.
>
> If you pass 0 to order_per_bit, you can manage cma area in every
> size(page unit) you want. If you pass certain number to order_per_bit,
> you can allocate and release cma area in multiple of such page order.
>
> I think that this is more general implementation than previous versions.
Fair enough.
--
Kind regards,
Minchan Kim
^ permalink raw reply
* [PATCH] powerpc: Reduce scariness of interrupt frames in stack traces
From: Paul Mackerras @ 2014-06-12 6:53 UTC (permalink / raw)
To: linuxppc-dev
Some people see things like "Exception: 501" in stack traces in dmesg
and assume that means that something has gone badly wrong, when in
fact "Exception: 501" just means a device interrupt was taken.
This changes "Exception" to "interrupt" to make it clearer that we
are just recording the fact of a change in control flow rather than
some error condition.
Signed-off-by: Paul Mackerras <paulus@samba.org>
---
arch/powerpc/kernel/process.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 31d0215..aa103dc 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1577,7 +1577,7 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
struct pt_regs *regs = (struct pt_regs *)
(sp + STACK_FRAME_OVERHEAD);
lr = regs->link;
- printk("--- Exception: %lx at %pS\n LR = %pS\n",
+ printk("--- interrupt: %lx at %pS\n LR = %pS\n",
regs->trap, (void *)regs->nip, (void *)lr);
firstframe = 1;
}
--
2.0.0.rc4
^ permalink raw reply related
* [PATCH v1] fs2dt: Refine kdump device_tree sort
From: Wei.Yang @ 2014-06-12 5:16 UTC (permalink / raw)
To: horms; +Cc: linuxppc-dev, linux-kernel, linux-arm-kernel, wei.yang
From: Yang Wei <Wei.Yang@windriver.com>
The commit b02d735bf was to rearrange the device-tree entries, and
assumed that these entries are sorted in the ascending order. but
acctually when I was validating kexec and kdump, the order of
serial node still is changed. We should not only compare the length
of directory name, but also compare the directory name, it would
ensure that the order of device node is really in ascending order.
Signed-off-by: Yang Wei <Wei.Yang@windriver.com>
---
kexec/fs2dt.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
It is validated on Freescale t4240qds.
diff --git a/kexec/fs2dt.c b/kexec/fs2dt.c
index 1e5f074..0bffaf5 100644
--- a/kexec/fs2dt.c
+++ b/kexec/fs2dt.c
@@ -479,6 +479,9 @@ static int comparefunc(const struct dirent **dentry1,
{
char *str1 = (*(struct dirent **)dentry1)->d_name;
char *str2 = (*(struct dirent **)dentry2)->d_name;
+ char* ptr1 = strchr(str1, '@');
+ char* ptr2 = strchr(str2, '@');
+ int len1, len2;
/*
* strcmp scans from left to right and fails to idetify for some
@@ -486,9 +489,13 @@ static int comparefunc(const struct dirent **dentry1,
* Therefore, we get the wrong sorted order like memory@10000000 and
* memory@f000000.
*/
- if (strchr(str1, '@') && strchr(str2, '@') &&
- (strlen(str1) > strlen(str2)))
- return 1;
+ if (ptr1 && ptr2) {
+ len1 = ptr1 - str1;
+ len2 = ptr2 - str2;
+ if (!strncmp(str1, str2, len1 >len2 ? len1: len2) &&
+ (strlen(str1) > strlen(str2)))
+ return 1;
+ }
return strcmp(str1, str2);
}
--
1.7.9.5
^ permalink raw reply related
* Re: [PATCH v2 05/10] DMA, CMA: support arbitrary bitmap granularity
From: Minchan Kim @ 2014-06-12 7:08 UTC (permalink / raw)
To: Joonsoo Kim
Cc: kvm-ppc, Russell King - ARM Linux, kvm, Gleb Natapov,
Greg Kroah-Hartman, Alexander Graf, Michal Nazarewicz,
linux-kernel, linux-mm, Paul Mackerras, Aneesh Kumar K.V,
Paolo Bonzini, Andrew Morton, linuxppc-dev, linux-arm-kernel,
Marek Szyprowski
In-Reply-To: <1402543307-29800-6-git-send-email-iamjoonsoo.kim@lge.com>
On Thu, Jun 12, 2014 at 12:21:42PM +0900, Joonsoo Kim wrote:
> ppc kvm's cma region management requires arbitrary bitmap granularity,
> since they want to reserve very large memory and manage this region
> with bitmap that one bit for several pages to reduce management overheads.
> So support arbitrary bitmap granularity for following generalization.
>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Just a nit below.
>
> diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
> index bc4c171..9bc9340 100644
> --- a/drivers/base/dma-contiguous.c
> +++ b/drivers/base/dma-contiguous.c
> @@ -38,6 +38,7 @@ struct cma {
> unsigned long base_pfn;
> unsigned long count;
> unsigned long *bitmap;
> + int order_per_bit; /* Order of pages represented by one bit */
> struct mutex lock;
> };
>
> @@ -157,9 +158,38 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
>
> static DEFINE_MUTEX(cma_mutex);
>
> +static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
> +{
> + return (1 << (align_order >> cma->order_per_bit)) - 1;
> +}
> +
> +static unsigned long cma_bitmap_maxno(struct cma *cma)
> +{
> + return cma->count >> cma->order_per_bit;
> +}
> +
> +static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
> + unsigned long pages)
> +{
> + return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
> +}
> +
> +static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
> +{
> + unsigned long bitmapno, nr_bits;
> +
> + bitmapno = (pfn - cma->base_pfn) >> cma->order_per_bit;
> + nr_bits = cma_bitmap_pages_to_bits(cma, count);
> +
> + mutex_lock(&cma->lock);
> + bitmap_clear(cma->bitmap, bitmapno, nr_bits);
> + mutex_unlock(&cma->lock);
> +}
> +
> static int __init cma_activate_area(struct cma *cma)
> {
> - int bitmap_size = BITS_TO_LONGS(cma->count) * sizeof(long);
> + int bitmap_maxno = cma_bitmap_maxno(cma);
> + int bitmap_size = BITS_TO_LONGS(bitmap_maxno) * sizeof(long);
> unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
> unsigned i = cma->count >> pageblock_order;
> struct zone *zone;
> @@ -221,6 +251,7 @@ core_initcall(cma_init_reserved_areas);
> * @base: Base address of the reserved area optional, use 0 for any
> * @limit: End address of the reserved memory (optional, 0 for any).
> * @alignment: Alignment for the contiguous memory area, should be power of 2
> + * @order_per_bit: Order of pages represented by one bit on bitmap.
> * @res_cma: Pointer to store the created cma region.
> * @fixed: hint about where to place the reserved area
> *
> @@ -235,7 +266,7 @@ core_initcall(cma_init_reserved_areas);
> */
> static int __init __dma_contiguous_reserve_area(phys_addr_t size,
> phys_addr_t base, phys_addr_t limit,
> - phys_addr_t alignment,
> + phys_addr_t alignment, int order_per_bit,
> struct cma **res_cma, bool fixed)
> {
> struct cma *cma = &cma_areas[cma_area_count];
> @@ -269,6 +300,8 @@ static int __init __dma_contiguous_reserve_area(phys_addr_t size,
> base = ALIGN(base, alignment);
> size = ALIGN(size, alignment);
> limit &= ~(alignment - 1);
> + /* size should be aligned with order_per_bit */
> + BUG_ON(!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit));
>
> /* Reserve memory */
> if (base && fixed) {
> @@ -294,6 +327,7 @@ static int __init __dma_contiguous_reserve_area(phys_addr_t size,
> */
> cma->base_pfn = PFN_DOWN(base);
> cma->count = size >> PAGE_SHIFT;
> + cma->order_per_bit = order_per_bit;
> *res_cma = cma;
> cma_area_count++;
>
> @@ -313,7 +347,7 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
> {
> int ret;
>
> - ret = __dma_contiguous_reserve_area(size, base, limit, 0,
> + ret = __dma_contiguous_reserve_area(size, base, limit, 0, 0,
> res_cma, fixed);
> if (ret)
> return ret;
> @@ -324,13 +358,6 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
> return 0;
> }
>
> -static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
> -{
> - mutex_lock(&cma->lock);
> - bitmap_clear(cma->bitmap, pfn - cma->base_pfn, count);
> - mutex_unlock(&cma->lock);
> -}
> -
> /**
> * dma_alloc_from_contiguous() - allocate pages from contiguous area
> * @dev: Pointer to device for which the allocation is performed.
> @@ -345,7 +372,8 @@ static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
> static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
> unsigned int align)
> {
> - unsigned long mask, pfn, pageno, start = 0;
> + unsigned long mask, pfn, start = 0;
> + unsigned long bitmap_maxno, bitmapno, nr_bits;
Just Nit: bitmap_maxno, bitmap_no or something consistent.
I know you love consistent when I read description in first patch
in this patchset. ;-)
> struct page *page = NULL;
> int ret;
>
> @@ -358,18 +386,19 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
> if (!count)
> return NULL;
>
> - mask = (1 << align) - 1;
> -
> + mask = cma_bitmap_aligned_mask(cma, align);
> + bitmap_maxno = cma_bitmap_maxno(cma);
> + nr_bits = cma_bitmap_pages_to_bits(cma, count);
>
> for (;;) {
> mutex_lock(&cma->lock);
> - pageno = bitmap_find_next_zero_area(cma->bitmap, cma->count,
> - start, count, mask);
> - if (pageno >= cma->count) {
> + bitmapno = bitmap_find_next_zero_area(cma->bitmap,
> + bitmap_maxno, start, nr_bits, mask);
> + if (bitmapno >= bitmap_maxno) {
> mutex_unlock(&cma->lock);
> break;
> }
> - bitmap_set(cma->bitmap, pageno, count);
> + bitmap_set(cma->bitmap, bitmapno, nr_bits);
> /*
> * It's safe to drop the lock here. We've marked this region for
> * our exclusive use. If the migration fails we will take the
> @@ -377,7 +406,7 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
> */
> mutex_unlock(&cma->lock);
>
> - pfn = cma->base_pfn + pageno;
> + pfn = cma->base_pfn + (bitmapno << cma->order_per_bit);
> mutex_lock(&cma_mutex);
> ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
> mutex_unlock(&cma_mutex);
> @@ -392,7 +421,7 @@ static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
> pr_debug("%s(): memory range at %p is busy, retrying\n",
> __func__, pfn_to_page(pfn));
> /* try again with a bit different memory target */
> - start = pageno + mask + 1;
> + start = bitmapno + mask + 1;
> }
>
> pr_debug("%s(): returned %p\n", __func__, page);
> --
> 1.7.9.5
--
Kind regards,
Minchan Kim
^ permalink raw reply
* Re: [PATCH v2 06/10] CMA: generalize CMA reserved area management functionality
From: Minchan Kim @ 2014-06-12 7:13 UTC (permalink / raw)
To: Joonsoo Kim
Cc: kvm-ppc, Russell King - ARM Linux, kvm, Gleb Natapov,
Greg Kroah-Hartman, Alexander Graf, Michal Nazarewicz,
linux-kernel, linux-mm, Paul Mackerras, Aneesh Kumar K.V,
Paolo Bonzini, Andrew Morton, linuxppc-dev, linux-arm-kernel,
Marek Szyprowski
In-Reply-To: <1402543307-29800-7-git-send-email-iamjoonsoo.kim@lge.com>
On Thu, Jun 12, 2014 at 12:21:43PM +0900, Joonsoo Kim wrote:
> Currently, there are two users on CMA functionality, one is the DMA
> subsystem and the other is the kvm on powerpc. They have their own code
> to manage CMA reserved area even if they looks really similar.
> >From my guess, it is caused by some needs on bitmap management. Kvm side
> wants to maintain bitmap not for 1 page, but for more size. Eventually it
> use bitmap where one bit represents 64 pages.
>
> When I implement CMA related patches, I should change those two places
> to apply my change and it seem to be painful to me. I want to change
> this situation and reduce future code management overhead through
> this patch.
>
> This change could also help developer who want to use CMA in their
> new feature development, since they can use CMA easily without
> copying & pasting this reserved area management code.
>
> In previous patches, we have prepared some features to generalize
> CMA reserved area management and now it's time to do it. This patch
> moves core functions to mm/cma.c and change DMA APIs to use
> these functions.
>
> There is no functional change in DMA APIs.
>
> v2: There is no big change from v1 in mm/cma.c. Mostly renaming.
>
> Acked-by: Michal Nazarewicz <mina86@mina86.com>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acutally, I want to remove bool return of cma_release but it's not
a out of scope in this patchset.
Acked-by: Minchan Kim <minchan@kernel.org>
>
> diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
> index 00e13ce..4eac559 100644
> --- a/drivers/base/Kconfig
> +++ b/drivers/base/Kconfig
> @@ -283,16 +283,6 @@ config CMA_ALIGNMENT
>
> If unsure, leave the default value "8".
>
> -config CMA_AREAS
> - int "Maximum count of the CMA device-private areas"
> - default 7
> - help
> - CMA allows to create CMA areas for particular devices. This parameter
> - sets the maximum number of such device private CMA areas in the
> - system.
> -
> - If unsure, leave the default value "7".
> -
> endif
>
> endmenu
> diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
> index 9bc9340..f177f73 100644
> --- a/drivers/base/dma-contiguous.c
> +++ b/drivers/base/dma-contiguous.c
> @@ -24,25 +24,10 @@
>
> #include <linux/memblock.h>
> #include <linux/err.h>
> -#include <linux/mm.h>
> -#include <linux/mutex.h>
> -#include <linux/page-isolation.h>
> #include <linux/sizes.h>
> -#include <linux/slab.h>
> -#include <linux/swap.h>
> -#include <linux/mm_types.h>
> #include <linux/dma-contiguous.h>
> #include <linux/log2.h>
Should we remain log2.h in here?
> -
> -struct cma {
> - unsigned long base_pfn;
> - unsigned long count;
> - unsigned long *bitmap;
> - int order_per_bit; /* Order of pages represented by one bit */
> - struct mutex lock;
> -};
> -
> -struct cma *dma_contiguous_default_area;
> +#include <linux/cma.h>
>
> #ifdef CONFIG_CMA_SIZE_MBYTES
> #define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
> @@ -50,6 +35,8 @@ struct cma *dma_contiguous_default_area;
> #define CMA_SIZE_MBYTES 0
> #endif
>
> +struct cma *dma_contiguous_default_area;
> +
> /*
> * Default global CMA area size can be defined in kernel's .config.
> * This is useful mainly for distro maintainers to create a kernel
> @@ -156,199 +143,13 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
> }
> }
>
> -static DEFINE_MUTEX(cma_mutex);
> -
> -static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
> -{
> - return (1 << (align_order >> cma->order_per_bit)) - 1;
> -}
> -
> -static unsigned long cma_bitmap_maxno(struct cma *cma)
> -{
> - return cma->count >> cma->order_per_bit;
> -}
> -
> -static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
> - unsigned long pages)
> -{
> - return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
> -}
> -
> -static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
> -{
> - unsigned long bitmapno, nr_bits;
> -
> - bitmapno = (pfn - cma->base_pfn) >> cma->order_per_bit;
> - nr_bits = cma_bitmap_pages_to_bits(cma, count);
> -
> - mutex_lock(&cma->lock);
> - bitmap_clear(cma->bitmap, bitmapno, nr_bits);
> - mutex_unlock(&cma->lock);
> -}
> -
> -static int __init cma_activate_area(struct cma *cma)
> -{
> - int bitmap_maxno = cma_bitmap_maxno(cma);
> - int bitmap_size = BITS_TO_LONGS(bitmap_maxno) * sizeof(long);
> - unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
> - unsigned i = cma->count >> pageblock_order;
> - struct zone *zone;
> -
> - pr_debug("%s()\n", __func__);
> -
> - cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> - if (!cma->bitmap)
> - return -ENOMEM;
> -
> - WARN_ON_ONCE(!pfn_valid(pfn));
> - zone = page_zone(pfn_to_page(pfn));
> -
> - do {
> - unsigned j;
> - base_pfn = pfn;
> - for (j = pageblock_nr_pages; j; --j, pfn++) {
> - WARN_ON_ONCE(!pfn_valid(pfn));
> - /*
> - * alloc_contig_range requires the pfn range
> - * specified to be in the same zone. Make this
> - * simple by forcing the entire CMA resv range
> - * to be in the same zone.
> - */
> - if (page_zone(pfn_to_page(pfn)) != zone)
> - goto err;
> - }
> - init_cma_reserved_pageblock(pfn_to_page(base_pfn));
> - } while (--i);
> -
> - mutex_init(&cma->lock);
> - return 0;
> -
> -err:
> - kfree(cma->bitmap);
> - return -EINVAL;
> -}
> -
> -static struct cma cma_areas[MAX_CMA_AREAS];
> -static unsigned cma_area_count;
> -
> -static int __init cma_init_reserved_areas(void)
> -{
> - int i;
> -
> - for (i = 0; i < cma_area_count; i++) {
> - int ret = cma_activate_area(&cma_areas[i]);
> - if (ret)
> - return ret;
> - }
> -
> - return 0;
> -}
> -core_initcall(cma_init_reserved_areas);
> -
> -/**
> - * dma_contiguous_reserve_area() - reserve custom contiguous area
> - * @size: Size of the reserved area (in bytes),
> - * @base: Base address of the reserved area optional, use 0 for any
> - * @limit: End address of the reserved memory (optional, 0 for any).
> - * @alignment: Alignment for the contiguous memory area, should be power of 2
> - * @order_per_bit: Order of pages represented by one bit on bitmap.
> - * @res_cma: Pointer to store the created cma region.
> - * @fixed: hint about where to place the reserved area
> - *
> - * This function reserves memory from early allocator. It should be
> - * called by arch specific code once the early allocator (memblock or bootmem)
> - * has been activated and all other subsystems have already allocated/reserved
> - * memory. This function allows to create custom reserved areas for specific
> - * devices.
> - *
> - * If @fixed is true, reserve contiguous area at exactly @base. If false,
> - * reserve in range from @base to @limit.
> - */
> -static int __init __dma_contiguous_reserve_area(phys_addr_t size,
> - phys_addr_t base, phys_addr_t limit,
> - phys_addr_t alignment, int order_per_bit,
> - struct cma **res_cma, bool fixed)
> -{
> - struct cma *cma = &cma_areas[cma_area_count];
> - int ret = 0;
> -
> - pr_debug("%s(size %lx, base %08lx, limit %08lx align_order %08lx)\n",
> - __func__, (unsigned long)size, (unsigned long)base,
> - (unsigned long)limit, (unsigned long)alignment);
> -
> - /* Sanity checks */
> - if (cma_area_count == ARRAY_SIZE(cma_areas)) {
> - pr_err("%s(): Not enough slots for CMA reserved regions!\n",
> - __func__);
> - return -ENOSPC;
> - }
> -
> - if (!size)
> - return -EINVAL;
> -
> - if (alignment && !is_power_of_2(alignment))
> - return -EINVAL;
> -
> - /*
> - * Sanitise input arguments.
> - * CMA area should be at least MAX_ORDER - 1 aligned. Otherwise,
> - * CMA area could be merged into other MIGRATE_TYPE by buddy mechanism
> - * and CMA property will be broken.
> - */
> - alignment = max(alignment,
> - (phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
> - base = ALIGN(base, alignment);
> - size = ALIGN(size, alignment);
> - limit &= ~(alignment - 1);
> - /* size should be aligned with order_per_bit */
> - BUG_ON(!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit));
> -
> - /* Reserve memory */
> - if (base && fixed) {
> - if (memblock_is_region_reserved(base, size) ||
> - memblock_reserve(base, size) < 0) {
> - ret = -EBUSY;
> - goto err;
> - }
> - } else {
> - phys_addr_t addr = memblock_alloc_range(size, alignment, base,
> - limit);
> - if (!addr) {
> - ret = -ENOMEM;
> - goto err;
> - } else {
> - base = addr;
> - }
> - }
> -
> - /*
> - * Each reserved area must be initialised later, when more kernel
> - * subsystems (like slab allocator) are available.
> - */
> - cma->base_pfn = PFN_DOWN(base);
> - cma->count = size >> PAGE_SHIFT;
> - cma->order_per_bit = order_per_bit;
> - *res_cma = cma;
> - cma_area_count++;
> -
> - pr_info("%s(): reserved %ld MiB at %08lx\n",
> - __func__, (unsigned long)size / SZ_1M, (unsigned long)base);
> - return 0;
> -
> -err:
> - pr_err("%s(): failed to reserve %ld MiB\n",
> - __func__, (unsigned long)size / SZ_1M);
> - return ret;
> -}
> -
> int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
> phys_addr_t limit, struct cma **res_cma,
> bool fixed)
> {
> int ret;
>
> - ret = __dma_contiguous_reserve_area(size, base, limit, 0, 0,
> - res_cma, fixed);
> + ret = cma_declare_contiguous(size, base, limit, 0, 0, res_cma, fixed);
> if (ret)
> return ret;
>
> @@ -358,124 +159,17 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
> return 0;
> }
>
> -/**
> - * dma_alloc_from_contiguous() - allocate pages from contiguous area
> - * @dev: Pointer to device for which the allocation is performed.
> - * @count: Requested number of pages.
> - * @align: Requested alignment of pages (in PAGE_SIZE order).
> - *
> - * This function allocates memory buffer for specified device. It uses
> - * device specific contiguous memory area if available or the default
> - * global one. Requires architecture specific dev_get_cma_area() helper
> - * function.
> - */
> -static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
> - unsigned int align)
> -{
> - unsigned long mask, pfn, start = 0;
> - unsigned long bitmap_maxno, bitmapno, nr_bits;
> - struct page *page = NULL;
> - int ret;
> -
> - if (!cma || !cma->count)
> - return NULL;
> -
> - pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
> - count, align);
> -
> - if (!count)
> - return NULL;
> -
> - mask = cma_bitmap_aligned_mask(cma, align);
> - bitmap_maxno = cma_bitmap_maxno(cma);
> - nr_bits = cma_bitmap_pages_to_bits(cma, count);
> -
> - for (;;) {
> - mutex_lock(&cma->lock);
> - bitmapno = bitmap_find_next_zero_area(cma->bitmap,
> - bitmap_maxno, start, nr_bits, mask);
> - if (bitmapno >= bitmap_maxno) {
> - mutex_unlock(&cma->lock);
> - break;
> - }
> - bitmap_set(cma->bitmap, bitmapno, nr_bits);
> - /*
> - * It's safe to drop the lock here. We've marked this region for
> - * our exclusive use. If the migration fails we will take the
> - * lock again and unmark it.
> - */
> - mutex_unlock(&cma->lock);
> -
> - pfn = cma->base_pfn + (bitmapno << cma->order_per_bit);
> - mutex_lock(&cma_mutex);
> - ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
> - mutex_unlock(&cma_mutex);
> - if (ret == 0) {
> - page = pfn_to_page(pfn);
> - break;
> - } else if (ret != -EBUSY) {
> - clear_cma_bitmap(cma, pfn, count);
> - break;
> - }
> - clear_cma_bitmap(cma, pfn, count);
> - pr_debug("%s(): memory range at %p is busy, retrying\n",
> - __func__, pfn_to_page(pfn));
> - /* try again with a bit different memory target */
> - start = bitmapno + mask + 1;
> - }
> -
> - pr_debug("%s(): returned %p\n", __func__, page);
> - return page;
> -}
> -
> struct page *dma_alloc_from_contiguous(struct device *dev, int count,
> unsigned int align)
> {
> - struct cma *cma = dev_get_cma_area(dev);
> -
> if (align > CONFIG_CMA_ALIGNMENT)
> align = CONFIG_CMA_ALIGNMENT;
>
> - return __dma_alloc_from_contiguous(cma, count, align);
> -}
> -
> -/**
> - * dma_release_from_contiguous() - release allocated pages
> - * @dev: Pointer to device for which the pages were allocated.
> - * @pages: Allocated pages.
> - * @count: Number of allocated pages.
> - *
> - * This function releases memory allocated by dma_alloc_from_contiguous().
> - * It returns false when provided pages do not belong to contiguous area and
> - * true otherwise.
> - */
> -static bool __dma_release_from_contiguous(struct cma *cma, struct page *pages,
> - int count)
> -{
> - unsigned long pfn;
> -
> - if (!cma || !pages)
> - return false;
> -
> - pr_debug("%s(page %p)\n", __func__, (void *)pages);
> -
> - pfn = page_to_pfn(pages);
> -
> - if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
> - return false;
> -
> - VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
> -
> - free_contig_range(pfn, count);
> - clear_cma_bitmap(cma, pfn, count);
> -
> - return true;
> + return cma_alloc(dev_get_cma_area(dev), count, align);
> }
>
> bool dma_release_from_contiguous(struct device *dev, struct page *pages,
> int count)
> {
> - struct cma *cma = dev_get_cma_area(dev);
> -
> - return __dma_release_from_contiguous(cma, pages, count);
> + return cma_release(dev_get_cma_area(dev), pages, count);
> }
> diff --git a/include/linux/cma.h b/include/linux/cma.h
> new file mode 100644
> index 0000000..e38efe9
> --- /dev/null
> +++ b/include/linux/cma.h
> @@ -0,0 +1,12 @@
> +#ifndef __CMA_H__
> +#define __CMA_H__
> +
> +struct cma;
> +
> +extern int __init cma_declare_contiguous(phys_addr_t size,
> + phys_addr_t base, phys_addr_t limit,
> + phys_addr_t alignment, int order_per_bit,
> + struct cma **res_cma, bool fixed);
> +extern struct page *cma_alloc(struct cma *cma, int count, unsigned int align);
> +extern bool cma_release(struct cma *cma, struct page *pages, int count);
> +#endif
> diff --git a/include/linux/dma-contiguous.h b/include/linux/dma-contiguous.h
> index 772eab5..a40c1f3 100644
> --- a/include/linux/dma-contiguous.h
> +++ b/include/linux/dma-contiguous.h
> @@ -53,9 +53,10 @@
>
> #ifdef __KERNEL__
>
> +#include <linux/device.h>
> +
> struct cma;
> struct page;
> -struct device;
>
> #ifdef CONFIG_DMA_CMA
>
> diff --git a/mm/Kconfig b/mm/Kconfig
> index 3e9977a..f4899ec 100644
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -508,6 +508,17 @@ config CMA_DEBUG
> processing calls such as dma_alloc_from_contiguous().
> This option does not affect warning and error messages.
>
> +config CMA_AREAS
> + int "Maximum count of the CMA areas"
> + depends on CMA
> + default 7
> + help
> + CMA allows to create CMA areas for particular purpose, mainly,
> + used as device private area. This parameter sets the maximum
> + number of CMA area in the system.
> +
> + If unsure, leave the default value "7".
> +
> config ZBUD
> tristate
> default n
> diff --git a/mm/Makefile b/mm/Makefile
> index 1eaa70b..bc0422b 100644
> --- a/mm/Makefile
> +++ b/mm/Makefile
> @@ -62,3 +62,4 @@ obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o
> obj-$(CONFIG_ZBUD) += zbud.o
> obj-$(CONFIG_ZSMALLOC) += zsmalloc.o
> obj-$(CONFIG_GENERIC_EARLY_IOREMAP) += early_ioremap.o
> +obj-$(CONFIG_CMA) += cma.o
> diff --git a/mm/cma.c b/mm/cma.c
> new file mode 100644
> index 0000000..1e1b017
> --- /dev/null
> +++ b/mm/cma.c
> @@ -0,0 +1,330 @@
> +/*
> + * Contiguous Memory Allocator
> + *
> + * Copyright (c) 2010-2011 by Samsung Electronics.
> + * Copyright IBM Corporation, 2013
> + * Copyright LG Electronics Inc., 2014
> + * Written by:
> + * Marek Szyprowski <m.szyprowski@samsung.com>
> + * Michal Nazarewicz <mina86@mina86.com>
> + * Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> + * Joonsoo Kim <iamjoonsoo.kim@lge.com>
> + *
> + * 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; either version 2 of the
> + * License or (at your optional) any later version of the license.
> + */
> +
> +#define pr_fmt(fmt) "cma: " fmt
> +
> +#ifdef CONFIG_CMA_DEBUG
> +#ifndef DEBUG
> +# define DEBUG
> +#endif
> +#endif
> +
> +#include <linux/memblock.h>
> +#include <linux/err.h>
> +#include <linux/mm.h>
> +#include <linux/mutex.h>
> +#include <linux/sizes.h>
> +#include <linux/slab.h>
> +
> +struct cma {
> + unsigned long base_pfn;
> + unsigned long count;
> + unsigned long *bitmap;
> + int order_per_bit; /* Order of pages represented by one bit */
> + struct mutex lock;
> +};
> +
> +/*
> + * There is always at least global CMA area and a few optional
> + * areas configured in kernel .config.
> + */
> +#define MAX_CMA_AREAS (1 + CONFIG_CMA_AREAS)
> +
> +static struct cma cma_areas[MAX_CMA_AREAS];
> +static unsigned cma_area_count;
> +static DEFINE_MUTEX(cma_mutex);
> +
> +static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
> +{
> + return (1 << (align_order >> cma->order_per_bit)) - 1;
> +}
> +
> +static unsigned long cma_bitmap_maxno(struct cma *cma)
> +{
> + return cma->count >> cma->order_per_bit;
> +}
> +
> +static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
> + unsigned long pages)
> +{
> + return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
> +}
> +
> +static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
> +{
> + unsigned long bitmapno, nr_bits;
> +
> + bitmapno = (pfn - cma->base_pfn) >> cma->order_per_bit;
> + nr_bits = cma_bitmap_pages_to_bits(cma, count);
> +
> + mutex_lock(&cma->lock);
> + bitmap_clear(cma->bitmap, bitmapno, nr_bits);
> + mutex_unlock(&cma->lock);
> +}
> +
> +static int __init cma_activate_area(struct cma *cma)
> +{
> + int bitmap_maxno = cma_bitmap_maxno(cma);
> + int bitmap_size = BITS_TO_LONGS(bitmap_maxno) * sizeof(long);
> + unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
> + unsigned i = cma->count >> pageblock_order;
> + struct zone *zone;
> +
> + pr_debug("%s()\n", __func__);
> +
> + cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> + if (!cma->bitmap)
> + return -ENOMEM;
> +
> + WARN_ON_ONCE(!pfn_valid(pfn));
> + zone = page_zone(pfn_to_page(pfn));
> +
> + do {
> + unsigned j;
> +
> + base_pfn = pfn;
> + for (j = pageblock_nr_pages; j; --j, pfn++) {
> + WARN_ON_ONCE(!pfn_valid(pfn));
> + /*
> + * alloc_contig_range requires the pfn range
> + * specified to be in the same zone. Make this
> + * simple by forcing the entire CMA resv range
> + * to be in the same zone.
> + */
> + if (page_zone(pfn_to_page(pfn)) != zone)
> + goto err;
> + }
> + init_cma_reserved_pageblock(pfn_to_page(base_pfn));
> + } while (--i);
> +
> + mutex_init(&cma->lock);
> + return 0;
> +
> +err:
> + kfree(cma->bitmap);
> + return -EINVAL;
> +}
> +
> +static int __init cma_init_reserved_areas(void)
> +{
> + int i;
> +
> + for (i = 0; i < cma_area_count; i++) {
> + int ret = cma_activate_area(&cma_areas[i]);
> +
> + if (ret)
> + return ret;
> + }
> +
> + return 0;
> +}
> +core_initcall(cma_init_reserved_areas);
> +
> +/**
> + * cma_declare_contiguous() - reserve custom contiguous area
> + * @size: Size of the reserved area (in bytes),
> + * @base: Base address of the reserved area optional, use 0 for any
> + * @limit: End address of the reserved memory (optional, 0 for any).
> + * @alignment: Alignment for the contiguous memory area, should be power of 2
> + * @order_per_bit: Order of pages represented by one bit on bitmap.
> + * @res_cma: Pointer to store the created cma region.
> + * @fixed: hint about where to place the reserved area
> + *
> + * This function reserves memory from early allocator. It should be
> + * called by arch specific code once the early allocator (memblock or bootmem)
> + * has been activated and all other subsystems have already allocated/reserved
> + * memory. This function allows to create custom reserved areas.
> + *
> + * If @fixed is true, reserve contiguous area at exactly @base. If false,
> + * reserve in range from @base to @limit.
> + */
> +int __init cma_declare_contiguous(phys_addr_t size,
> + phys_addr_t base, phys_addr_t limit,
> + phys_addr_t alignment, int order_per_bit,
> + struct cma **res_cma, bool fixed)
> +{
> + struct cma *cma = &cma_areas[cma_area_count];
> + int ret = 0;
> +
> + pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
> + __func__, (unsigned long)size, (unsigned long)base,
> + (unsigned long)limit, (unsigned long)alignment);
> +
> + /* Sanity checks */
> + if (cma_area_count == ARRAY_SIZE(cma_areas)) {
> + pr_err("%s(): Not enough slots for CMA reserved regions!\n",
> + __func__);
> + return -ENOSPC;
> + }
> +
> + if (!size)
> + return -EINVAL;
> +
> + if (alignment && !is_power_of_2(alignment))
> + return -EINVAL;
> +
> + /*
> + * Sanitise input arguments.
> + * CMA area should be at least MAX_ORDER - 1 aligned. Otherwise,
> + * CMA area could be merged into other MIGRATE_TYPE by buddy mechanism
> + * and CMA property will be broken.
> + */
> + alignment = max(alignment,
> + (phys_addr_t)PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order));
> + base = ALIGN(base, alignment);
> + size = ALIGN(size, alignment);
> + limit &= ~(alignment - 1);
> + /* size should be aligned with order_per_bit */
> + BUG_ON(!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit));
> +
> + /* Reserve memory */
> + if (base && fixed) {
> + if (memblock_is_region_reserved(base, size) ||
> + memblock_reserve(base, size) < 0) {
> + ret = -EBUSY;
> + goto err;
> + }
> + } else {
> + phys_addr_t addr = memblock_alloc_range(size, alignment, base,
> + limit);
> + if (!addr) {
> + ret = -ENOMEM;
> + goto err;
> + } else {
> + base = addr;
> + }
> + }
> +
> + /*
> + * Each reserved area must be initialised later, when more kernel
> + * subsystems (like slab allocator) are available.
> + */
> + cma->base_pfn = PFN_DOWN(base);
> + cma->count = size >> PAGE_SHIFT;
> + cma->order_per_bit = order_per_bit;
> + *res_cma = cma;
> + cma_area_count++;
> +
> + pr_info("%s(): reserved %ld MiB at %08lx\n",
> + __func__, (unsigned long)size / SZ_1M, (unsigned long)base);
> + return 0;
> +
> +err:
> + pr_err("%s(): failed to reserve %ld MiB\n",
> + __func__, (unsigned long)size / SZ_1M);
> + return ret;
> +}
> +
> +/**
> + * cma_alloc() - allocate pages from contiguous area
> + * @cma: Contiguous memory region for which the allocation is performed.
> + * @count: Requested number of pages.
> + * @align: Requested alignment of pages (in PAGE_SIZE order).
> + *
> + * This function allocates part of contiguous memory on specific
> + * contiguous memory area.
> + */
> +struct page *cma_alloc(struct cma *cma, int count, unsigned int align)
> +{
> + unsigned long mask, pfn, start = 0;
> + unsigned long bitmap_maxno, bitmapno, nr_bits;
> + struct page *page = NULL;
> + int ret;
> +
> + if (!cma || !cma->count)
> + return NULL;
> +
> + pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
> + count, align);
> +
> + if (!count)
> + return NULL;
> +
> + mask = cma_bitmap_aligned_mask(cma, align);
> + bitmap_maxno = cma_bitmap_maxno(cma);
> + nr_bits = cma_bitmap_pages_to_bits(cma, count);
> +
> + for (;;) {
> + mutex_lock(&cma->lock);
> + bitmapno = bitmap_find_next_zero_area(cma->bitmap,
> + bitmap_maxno, start, nr_bits, mask);
> + if (bitmapno >= bitmap_maxno) {
> + mutex_unlock(&cma->lock);
> + break;
> + }
> + bitmap_set(cma->bitmap, bitmapno, nr_bits);
> + /*
> + * It's safe to drop the lock here. We've marked this region for
> + * our exclusive use. If the migration fails we will take the
> + * lock again and unmark it.
> + */
> + mutex_unlock(&cma->lock);
> +
> + pfn = cma->base_pfn + (bitmapno << cma->order_per_bit);
> + mutex_lock(&cma_mutex);
> + ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
> + mutex_unlock(&cma_mutex);
> + if (ret == 0) {
> + page = pfn_to_page(pfn);
> + break;
> + } else if (ret != -EBUSY) {
> + clear_cma_bitmap(cma, pfn, count);
> + break;
> + }
> + clear_cma_bitmap(cma, pfn, count);
> + pr_debug("%s(): memory range at %p is busy, retrying\n",
> + __func__, pfn_to_page(pfn));
> + /* try again with a bit different memory target */
> + start = bitmapno + mask + 1;
> + }
> +
> + pr_debug("%s(): returned %p\n", __func__, page);
> + return page;
> +}
> +
> +/**
> + * cma_release() - release allocated pages
> + * @cma: Contiguous memory region for which the allocation is performed.
> + * @pages: Allocated pages.
> + * @count: Number of allocated pages.
> + *
> + * This function releases memory allocated by alloc_cma().
> + * It returns false when provided pages do not belong to contiguous area and
> + * true otherwise.
> + */
> +bool cma_release(struct cma *cma, struct page *pages, int count)
> +{
> + unsigned long pfn;
> +
> + if (!cma || !pages)
> + return false;
> +
> + pr_debug("%s(page %p)\n", __func__, (void *)pages);
> +
> + pfn = page_to_pfn(pages);
> +
> + if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
> + return false;
> +
> + VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
> +
> + free_contig_range(pfn, count);
> + clear_cma_bitmap(cma, pfn, count);
> +
> + return true;
> +}
> --
> 1.7.9.5
--
Kind regards,
Minchan Kim
^ permalink raw reply
* Re: [PATCH v2 08/10] mm, cma: clean-up cma allocation error path
From: Minchan Kim @ 2014-06-12 7:16 UTC (permalink / raw)
To: Joonsoo Kim
Cc: kvm-ppc, Russell King - ARM Linux, kvm, Gleb Natapov,
Greg Kroah-Hartman, Alexander Graf, Michal Nazarewicz,
linux-kernel, linux-mm, Paul Mackerras, Aneesh Kumar K.V,
Paolo Bonzini, Andrew Morton, linuxppc-dev, linux-arm-kernel,
Marek Szyprowski
In-Reply-To: <1402543307-29800-9-git-send-email-iamjoonsoo.kim@lge.com>
On Thu, Jun 12, 2014 at 12:21:45PM +0900, Joonsoo Kim wrote:
> We can remove one call sites for clear_cma_bitmap() if we first
> call it before checking error number.
>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Minchan Kim <minchan@kernel.org>
--
Kind regards,
Minchan Kim
^ permalink raw reply
* Re: [PATCH v2 09/10] mm, cma: move output param to the end of param list
From: Minchan Kim @ 2014-06-12 7:19 UTC (permalink / raw)
To: Joonsoo Kim
Cc: kvm-ppc, Russell King - ARM Linux, kvm, Gleb Natapov,
Greg Kroah-Hartman, Alexander Graf, Michal Nazarewicz,
linux-kernel, linux-mm, Paul Mackerras, Aneesh Kumar K.V,
Paolo Bonzini, Andrew Morton, linuxppc-dev, linux-arm-kernel,
Marek Szyprowski
In-Reply-To: <1402543307-29800-10-git-send-email-iamjoonsoo.kim@lge.com>
On Thu, Jun 12, 2014 at 12:21:46PM +0900, Joonsoo Kim wrote:
> Conventionally, we put output param to the end of param list.
> cma_declare_contiguous() doesn't look like that, so change it.
If you says "Conventionally", I'd like to suggest one more thing.
Conventionally, we put 'base' ahead 'size' but dma_contiguous_reserve_area
is opposite.
>
> Additionally, move down cma_areas reference code to the position
> where it is really needed.
>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
>
> diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c
> index 28ec226..97613ea 100644
> --- a/arch/powerpc/kvm/book3s_hv_builtin.c
> +++ b/arch/powerpc/kvm/book3s_hv_builtin.c
> @@ -184,7 +184,7 @@ void __init kvm_cma_reserve(void)
>
> align_size = max(kvm_rma_pages << PAGE_SHIFT, align_size);
> cma_declare_contiguous(selected_size, 0, 0, align_size,
> - KVM_CMA_CHUNK_ORDER - PAGE_SHIFT, &kvm_cma, false);
> + KVM_CMA_CHUNK_ORDER - PAGE_SHIFT, false, &kvm_cma);
> }
> }
>
> diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
> index f177f73..bfd4553 100644
> --- a/drivers/base/dma-contiguous.c
> +++ b/drivers/base/dma-contiguous.c
> @@ -149,7 +149,7 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
> {
> int ret;
>
> - ret = cma_declare_contiguous(size, base, limit, 0, 0, res_cma, fixed);
> + ret = cma_declare_contiguous(size, base, limit, 0, 0, fixed, res_cma);
> if (ret)
> return ret;
>
> diff --git a/include/linux/cma.h b/include/linux/cma.h
> index e38efe9..e53eead 100644
> --- a/include/linux/cma.h
> +++ b/include/linux/cma.h
> @@ -6,7 +6,7 @@ struct cma;
> extern int __init cma_declare_contiguous(phys_addr_t size,
> phys_addr_t base, phys_addr_t limit,
> phys_addr_t alignment, int order_per_bit,
> - struct cma **res_cma, bool fixed);
> + bool fixed, struct cma **res_cma);
> extern struct page *cma_alloc(struct cma *cma, int count, unsigned int align);
> extern bool cma_release(struct cma *cma, struct page *pages, int count);
> #endif
> diff --git a/mm/cma.c b/mm/cma.c
> index 01a0713..22a5b23 100644
> --- a/mm/cma.c
> +++ b/mm/cma.c
> @@ -142,8 +142,8 @@ core_initcall(cma_init_reserved_areas);
> * @limit: End address of the reserved memory (optional, 0 for any).
> * @alignment: Alignment for the contiguous memory area, should be power of 2
> * @order_per_bit: Order of pages represented by one bit on bitmap.
> - * @res_cma: Pointer to store the created cma region.
> * @fixed: hint about where to place the reserved area
> + * @res_cma: Pointer to store the created cma region.
> *
> * This function reserves memory from early allocator. It should be
> * called by arch specific code once the early allocator (memblock or bootmem)
> @@ -156,9 +156,9 @@ core_initcall(cma_init_reserved_areas);
> int __init cma_declare_contiguous(phys_addr_t size,
> phys_addr_t base, phys_addr_t limit,
> phys_addr_t alignment, int order_per_bit,
> - struct cma **res_cma, bool fixed)
> + bool fixed, struct cma **res_cma)
> {
> - struct cma *cma = &cma_areas[cma_area_count];
> + struct cma *cma;
> int ret = 0;
>
> pr_debug("%s(size %lx, base %08lx, limit %08lx alignment %08lx)\n",
> @@ -214,6 +214,7 @@ int __init cma_declare_contiguous(phys_addr_t size,
> * Each reserved area must be initialised later, when more kernel
> * subsystems (like slab allocator) are available.
> */
> + cma = &cma_areas[cma_area_count];
> cma->base_pfn = PFN_DOWN(base);
> cma->count = size >> PAGE_SHIFT;
> cma->order_per_bit = order_per_bit;
> --
> 1.7.9.5
--
Kind regards,
Minchan Kim
^ permalink raw reply
* Re: [PATCH v2 05/10] DMA, CMA: support arbitrary bitmap granularity
From: Zhang Yanfei @ 2014-06-12 7:25 UTC (permalink / raw)
To: Minchan Kim
Cc: kvm-ppc, Russell King - ARM Linux, kvm, Gleb Natapov,
Greg Kroah-Hartman, Alexander Graf, Michal Nazarewicz,
linux-kernel, linux-mm, Paul Mackerras, Aneesh Kumar K.V,
Paolo Bonzini, Joonsoo Kim, linuxppc-dev, Andrew Morton,
linux-arm-kernel, Marek Szyprowski
In-Reply-To: <20140612070811.GI12415@bbox>
On 06/12/2014 03:08 PM, Minchan Kim wrote:
> On Thu, Jun 12, 2014 at 12:21:42PM +0900, Joonsoo Kim wrote:
>> ppc kvm's cma region management requires arbitrary bitmap granularity,
>> since they want to reserve very large memory and manage this region
>> with bitmap that one bit for several pages to reduce management overheads.
>> So support arbitrary bitmap granularity for following generalization.
>>
>> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> Acked-by: Minchan Kim <minchan@kernel.org>
>
> Just a nit below.
>
>>
>> diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
>> index bc4c171..9bc9340 100644
>> --- a/drivers/base/dma-contiguous.c
>> +++ b/drivers/base/dma-contiguous.c
>> @@ -38,6 +38,7 @@ struct cma {
>> unsigned long base_pfn;
>> unsigned long count;
>> unsigned long *bitmap;
>> + int order_per_bit; /* Order of pages represented by one bit */
>> struct mutex lock;
>> };
>>
>> @@ -157,9 +158,38 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
>>
>> static DEFINE_MUTEX(cma_mutex);
>>
>> +static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order)
>> +{
>> + return (1 << (align_order >> cma->order_per_bit)) - 1;
>> +}
>> +
>> +static unsigned long cma_bitmap_maxno(struct cma *cma)
>> +{
>> + return cma->count >> cma->order_per_bit;
>> +}
>> +
>> +static unsigned long cma_bitmap_pages_to_bits(struct cma *cma,
>> + unsigned long pages)
>> +{
>> + return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit;
>> +}
>> +
>> +static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
>> +{
>> + unsigned long bitmapno, nr_bits;
>> +
>> + bitmapno = (pfn - cma->base_pfn) >> cma->order_per_bit;
>> + nr_bits = cma_bitmap_pages_to_bits(cma, count);
>> +
>> + mutex_lock(&cma->lock);
>> + bitmap_clear(cma->bitmap, bitmapno, nr_bits);
>> + mutex_unlock(&cma->lock);
>> +}
>> +
>> static int __init cma_activate_area(struct cma *cma)
>> {
>> - int bitmap_size = BITS_TO_LONGS(cma->count) * sizeof(long);
>> + int bitmap_maxno = cma_bitmap_maxno(cma);
>> + int bitmap_size = BITS_TO_LONGS(bitmap_maxno) * sizeof(long);
>> unsigned long base_pfn = cma->base_pfn, pfn = base_pfn;
>> unsigned i = cma->count >> pageblock_order;
>> struct zone *zone;
>> @@ -221,6 +251,7 @@ core_initcall(cma_init_reserved_areas);
>> * @base: Base address of the reserved area optional, use 0 for any
>> * @limit: End address of the reserved memory (optional, 0 for any).
>> * @alignment: Alignment for the contiguous memory area, should be power of 2
>> + * @order_per_bit: Order of pages represented by one bit on bitmap.
>> * @res_cma: Pointer to store the created cma region.
>> * @fixed: hint about where to place the reserved area
>> *
>> @@ -235,7 +266,7 @@ core_initcall(cma_init_reserved_areas);
>> */
>> static int __init __dma_contiguous_reserve_area(phys_addr_t size,
>> phys_addr_t base, phys_addr_t limit,
>> - phys_addr_t alignment,
>> + phys_addr_t alignment, int order_per_bit,
>> struct cma **res_cma, bool fixed)
>> {
>> struct cma *cma = &cma_areas[cma_area_count];
>> @@ -269,6 +300,8 @@ static int __init __dma_contiguous_reserve_area(phys_addr_t size,
>> base = ALIGN(base, alignment);
>> size = ALIGN(size, alignment);
>> limit &= ~(alignment - 1);
>> + /* size should be aligned with order_per_bit */
>> + BUG_ON(!IS_ALIGNED(size >> PAGE_SHIFT, 1 << order_per_bit));
>>
>> /* Reserve memory */
>> if (base && fixed) {
>> @@ -294,6 +327,7 @@ static int __init __dma_contiguous_reserve_area(phys_addr_t size,
>> */
>> cma->base_pfn = PFN_DOWN(base);
>> cma->count = size >> PAGE_SHIFT;
>> + cma->order_per_bit = order_per_bit;
>> *res_cma = cma;
>> cma_area_count++;
>>
>> @@ -313,7 +347,7 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
>> {
>> int ret;
>>
>> - ret = __dma_contiguous_reserve_area(size, base, limit, 0,
>> + ret = __dma_contiguous_reserve_area(size, base, limit, 0, 0,
>> res_cma, fixed);
>> if (ret)
>> return ret;
>> @@ -324,13 +358,6 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
>> return 0;
>> }
>>
>> -static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
>> -{
>> - mutex_lock(&cma->lock);
>> - bitmap_clear(cma->bitmap, pfn - cma->base_pfn, count);
>> - mutex_unlock(&cma->lock);
>> -}
>> -
>> /**
>> * dma_alloc_from_contiguous() - allocate pages from contiguous area
>> * @dev: Pointer to device for which the allocation is performed.
>> @@ -345,7 +372,8 @@ static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
>> static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
>> unsigned int align)
>> {
>> - unsigned long mask, pfn, pageno, start = 0;
>> + unsigned long mask, pfn, start = 0;
>> + unsigned long bitmap_maxno, bitmapno, nr_bits;
>
> Just Nit: bitmap_maxno, bitmap_no or something consistent.
> I know you love consistent when I read description in first patch
> in this patchset. ;-)
>
Yeah, not only in this patchset, I saw Joonsoo trying to unify all
kinds of things in the MM. This is great for newbies, IMO.
--
Thanks.
Zhang Yanfei
^ permalink raw reply
* Re: [PATCH v2 05/10] DMA, CMA: support arbitrary bitmap granularity
From: Joonsoo Kim @ 2014-06-12 7:41 UTC (permalink / raw)
To: Minchan Kim
Cc: kvm-ppc, Russell King - ARM Linux, kvm, Gleb Natapov,
Greg Kroah-Hartman, Alexander Graf, Michal Nazarewicz,
linux-kernel, linux-mm, Paul Mackerras, Aneesh Kumar K.V,
Paolo Bonzini, Andrew Morton, linuxppc-dev, linux-arm-kernel,
Marek Szyprowski
In-Reply-To: <20140612070811.GI12415@bbox>
On Thu, Jun 12, 2014 at 04:08:11PM +0900, Minchan Kim wrote:
> On Thu, Jun 12, 2014 at 12:21:42PM +0900, Joonsoo Kim wrote:
> > ppc kvm's cma region management requires arbitrary bitmap granularity,
> > since they want to reserve very large memory and manage this region
> > with bitmap that one bit for several pages to reduce management overheads.
> > So support arbitrary bitmap granularity for following generalization.
> >
> > Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
> Acked-by: Minchan Kim <minchan@kernel.org>
>
Thanks.
[snip...]
> > /**
> > * dma_alloc_from_contiguous() - allocate pages from contiguous area
> > * @dev: Pointer to device for which the allocation is performed.
> > @@ -345,7 +372,8 @@ static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
> > static struct page *__dma_alloc_from_contiguous(struct cma *cma, int count,
> > unsigned int align)
> > {
> > - unsigned long mask, pfn, pageno, start = 0;
> > + unsigned long mask, pfn, start = 0;
> > + unsigned long bitmap_maxno, bitmapno, nr_bits;
>
> Just Nit: bitmap_maxno, bitmap_no or something consistent.
> I know you love consistent when I read description in first patch
> in this patchset. ;-)
Yeah, I will fix it. :)
Thanks.
^ permalink raw reply
* Re: [PATCH v2 06/10] CMA: generalize CMA reserved area management functionality
From: Joonsoo Kim @ 2014-06-12 7:42 UTC (permalink / raw)
To: Minchan Kim
Cc: kvm-ppc, Russell King - ARM Linux, kvm, Gleb Natapov,
Greg Kroah-Hartman, Alexander Graf, Michal Nazarewicz,
linux-kernel, linux-mm, Paul Mackerras, Aneesh Kumar K.V,
Paolo Bonzini, Andrew Morton, linuxppc-dev, linux-arm-kernel,
Marek Szyprowski
In-Reply-To: <20140612071311.GJ12415@bbox>
On Thu, Jun 12, 2014 at 04:13:11PM +0900, Minchan Kim wrote:
> On Thu, Jun 12, 2014 at 12:21:43PM +0900, Joonsoo Kim wrote:
> > Currently, there are two users on CMA functionality, one is the DMA
> > subsystem and the other is the kvm on powerpc. They have their own code
> > to manage CMA reserved area even if they looks really similar.
> > >From my guess, it is caused by some needs on bitmap management. Kvm side
> > wants to maintain bitmap not for 1 page, but for more size. Eventually it
> > use bitmap where one bit represents 64 pages.
> >
> > When I implement CMA related patches, I should change those two places
> > to apply my change and it seem to be painful to me. I want to change
> > this situation and reduce future code management overhead through
> > this patch.
> >
> > This change could also help developer who want to use CMA in their
> > new feature development, since they can use CMA easily without
> > copying & pasting this reserved area management code.
> >
> > In previous patches, we have prepared some features to generalize
> > CMA reserved area management and now it's time to do it. This patch
> > moves core functions to mm/cma.c and change DMA APIs to use
> > these functions.
> >
> > There is no functional change in DMA APIs.
> >
> > v2: There is no big change from v1 in mm/cma.c. Mostly renaming.
> >
> > Acked-by: Michal Nazarewicz <mina86@mina86.com>
> > Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
>
> Acutally, I want to remove bool return of cma_release but it's not
> a out of scope in this patchset.
>
> Acked-by: Minchan Kim <minchan@kernel.org>
>
> >
> > diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
> > index 00e13ce..4eac559 100644
> > --- a/drivers/base/Kconfig
> > +++ b/drivers/base/Kconfig
> > @@ -283,16 +283,6 @@ config CMA_ALIGNMENT
> >
> > If unsure, leave the default value "8".
> >
> > -config CMA_AREAS
> > - int "Maximum count of the CMA device-private areas"
> > - default 7
> > - help
> > - CMA allows to create CMA areas for particular devices. This parameter
> > - sets the maximum number of such device private CMA areas in the
> > - system.
> > -
> > - If unsure, leave the default value "7".
> > -
> > endif
> >
> > endmenu
> > diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
> > index 9bc9340..f177f73 100644
> > --- a/drivers/base/dma-contiguous.c
> > +++ b/drivers/base/dma-contiguous.c
> > @@ -24,25 +24,10 @@
> >
> > #include <linux/memblock.h>
> > #include <linux/err.h>
> > -#include <linux/mm.h>
> > -#include <linux/mutex.h>
> > -#include <linux/page-isolation.h>
> > #include <linux/sizes.h>
> > -#include <linux/slab.h>
> > -#include <linux/swap.h>
> > -#include <linux/mm_types.h>
> > #include <linux/dma-contiguous.h>
> > #include <linux/log2.h>
>
> Should we remain log2.h in here?
>
We should remove it. I will fix it.
Thanks.
^ permalink raw reply
* Re: [PATCH v2 09/10] mm, cma: move output param to the end of param list
From: Joonsoo Kim @ 2014-06-12 7:43 UTC (permalink / raw)
To: Minchan Kim
Cc: kvm-ppc, Russell King - ARM Linux, kvm, Gleb Natapov,
Greg Kroah-Hartman, Alexander Graf, Michal Nazarewicz,
linux-kernel, linux-mm, Paul Mackerras, Aneesh Kumar K.V,
Paolo Bonzini, Andrew Morton, linuxppc-dev, linux-arm-kernel,
Marek Szyprowski
In-Reply-To: <20140612071930.GL12415@bbox>
On Thu, Jun 12, 2014 at 04:19:31PM +0900, Minchan Kim wrote:
> On Thu, Jun 12, 2014 at 12:21:46PM +0900, Joonsoo Kim wrote:
> > Conventionally, we put output param to the end of param list.
> > cma_declare_contiguous() doesn't look like that, so change it.
>
> If you says "Conventionally", I'd like to suggest one more thing.
> Conventionally, we put 'base' ahead 'size' but dma_contiguous_reserve_area
> is opposite.
Okay. I will do it. :)
Thanks.
^ permalink raw reply
* Re: [PATCH v2 10/10] mm, cma: use spinlock instead of mutex
From: Minchan Kim @ 2014-06-12 7:40 UTC (permalink / raw)
To: Joonsoo Kim
Cc: kvm-ppc, Russell King - ARM Linux, kvm, Gleb Natapov,
Greg Kroah-Hartman, Alexander Graf, Michal Nazarewicz,
linux-kernel, linux-mm, Paul Mackerras, Aneesh Kumar K.V,
Paolo Bonzini, Andrew Morton, linuxppc-dev, linux-arm-kernel,
Marek Szyprowski
In-Reply-To: <1402543307-29800-11-git-send-email-iamjoonsoo.kim@lge.com>
On Thu, Jun 12, 2014 at 12:21:47PM +0900, Joonsoo Kim wrote:
> Currently, we should take the mutex for manipulating bitmap.
> This job may be really simple and short so we don't need to sleep
> if contended. So I change it to spinlock.
I'm not sure it would be good always.
Maybe you remember we discussed about similar stuff about bitmap
searching in vmap friend internally, which was really painful
when it was fragmented. So, at least we need number if you really want
and I hope the number from ARM machine most popular platform for CMA
at the moment.
>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
>
> diff --git a/mm/cma.c b/mm/cma.c
> index 22a5b23..3085e8c 100644
> --- a/mm/cma.c
> +++ b/mm/cma.c
> @@ -27,6 +27,7 @@
> #include <linux/memblock.h>
> #include <linux/err.h>
> #include <linux/mm.h>
> +#include <linux/spinlock.h>
> #include <linux/mutex.h>
> #include <linux/sizes.h>
> #include <linux/slab.h>
> @@ -36,7 +37,7 @@ struct cma {
> unsigned long count;
> unsigned long *bitmap;
> int order_per_bit; /* Order of pages represented by one bit */
> - struct mutex lock;
> + spinlock_t lock;
> };
>
> /*
> @@ -72,9 +73,9 @@ static void clear_cma_bitmap(struct cma *cma, unsigned long pfn, int count)
> bitmapno = (pfn - cma->base_pfn) >> cma->order_per_bit;
> nr_bits = cma_bitmap_pages_to_bits(cma, count);
>
> - mutex_lock(&cma->lock);
> + spin_lock(&cma->lock);
> bitmap_clear(cma->bitmap, bitmapno, nr_bits);
> - mutex_unlock(&cma->lock);
> + spin_unlock(&cma->lock);
> }
>
> static int __init cma_activate_area(struct cma *cma)
> @@ -112,7 +113,7 @@ static int __init cma_activate_area(struct cma *cma)
> init_cma_reserved_pageblock(pfn_to_page(base_pfn));
> } while (--i);
>
> - mutex_init(&cma->lock);
> + spin_lock_init(&cma->lock);
> return 0;
>
> err:
> @@ -261,11 +262,11 @@ struct page *cma_alloc(struct cma *cma, int count, unsigned int align)
> nr_bits = cma_bitmap_pages_to_bits(cma, count);
>
> for (;;) {
> - mutex_lock(&cma->lock);
> + spin_lock(&cma->lock);
> bitmapno = bitmap_find_next_zero_area(cma->bitmap,
> bitmap_maxno, start, nr_bits, mask);
> if (bitmapno >= bitmap_maxno) {
> - mutex_unlock(&cma->lock);
> + spin_unlock(&cma->lock);
> break;
> }
> bitmap_set(cma->bitmap, bitmapno, nr_bits);
> @@ -274,7 +275,7 @@ struct page *cma_alloc(struct cma *cma, int count, unsigned int align)
> * our exclusive use. If the migration fails we will take the
> * lock again and unmark it.
> */
> - mutex_unlock(&cma->lock);
> + spin_unlock(&cma->lock);
>
> pfn = cma->base_pfn + (bitmapno << cma->order_per_bit);
> mutex_lock(&cma_mutex);
> --
> 1.7.9.5
>
> --
> 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: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
--
Kind regards,
Minchan Kim
^ permalink raw reply
* Re: [PATCH v2 10/10] mm, cma: use spinlock instead of mutex
From: Joonsoo Kim @ 2014-06-12 7:56 UTC (permalink / raw)
To: Minchan Kim
Cc: kvm-ppc, Russell King - ARM Linux, kvm, Gleb Natapov,
Greg Kroah-Hartman, Alexander Graf, Michal Nazarewicz,
linux-kernel, linux-mm, Paul Mackerras, Aneesh Kumar K.V,
Paolo Bonzini, Andrew Morton, linuxppc-dev, linux-arm-kernel,
Marek Szyprowski
In-Reply-To: <20140612074029.GB12663@bbox>
On Thu, Jun 12, 2014 at 04:40:29PM +0900, Minchan Kim wrote:
> On Thu, Jun 12, 2014 at 12:21:47PM +0900, Joonsoo Kim wrote:
> > Currently, we should take the mutex for manipulating bitmap.
> > This job may be really simple and short so we don't need to sleep
> > if contended. So I change it to spinlock.
>
> I'm not sure it would be good always.
> Maybe you remember we discussed about similar stuff about bitmap
> searching in vmap friend internally, which was really painful
> when it was fragmented. So, at least we need number if you really want
> and I hope the number from ARM machine most popular platform for CMA
> at the moment.
Good Point!! Agreed. I will drop this one in next spin and re-submit
in separate patchset after some testing.
Thanks.
^ permalink raw reply
* Re: [PATCH v2] powerpc: Avoid circular dependency with zImage.%
From: Michal Marek @ 2014-06-12 8:09 UTC (permalink / raw)
To: Mike Qiu; +Cc: Sam Ravnborg, linuxppc-dev, linux-kernel, linux-kbuild
In-Reply-To: <53990B48.8010902@linux.vnet.ibm.com>
Dne 12.6.2014 04:07, Mike Qiu napsal(a):
> This v2 patch is good,
>
> Tested-by: Mike Qiu <qiudayu@linux.vnet.ibm.com>
Thanks. In kbuild.git it goes.
Michal
^ permalink raw reply
* [PATCH 1/4] KVM: PPC: Book3S PR: Fix ABIv2 issues
From: Anton Blanchard @ 2014-06-12 8:14 UTC (permalink / raw)
To: benh, paulus, agraf, clg; +Cc: linuxppc-dev, kvm, kvm-ppc
binutils knows that a branch to a function descriptor is actually
a branch to the function text. By removing the explicit branch to
dot symbols, we maintain both ABIv1 and ABIv2 compatibility.
Signed-off-by: Anton Blanchard <anton@samba.org>
---
Index: b/arch/powerpc/kvm/book3s_interrupts.S
===================================================================
--- a/arch/powerpc/kvm/book3s_interrupts.S
+++ b/arch/powerpc/kvm/book3s_interrupts.S
@@ -25,11 +25,9 @@
#include <asm/exception-64s.h>
#if defined(CONFIG_PPC_BOOK3S_64)
-#define FUNC(name) GLUE(.,name)
#define GET_SHADOW_VCPU(reg) addi reg, r13, PACA_SVCPU
#elif defined(CONFIG_PPC_BOOK3S_32)
-#define FUNC(name) name
#define GET_SHADOW_VCPU(reg) lwz reg, (THREAD + THREAD_KVM_SVCPU)(r2)
#endif /* CONFIG_PPC_BOOK3S_XX */
@@ -93,7 +91,7 @@ kvm_start_entry:
kvm_start_lightweight:
/* Copy registers into shadow vcpu so we can access them in real mode */
GET_SHADOW_VCPU(r3)
- bl FUNC(kvmppc_copy_to_svcpu)
+ bl kvmppc_copy_to_svcpu
nop
REST_GPR(4, r1)
@@ -131,7 +129,7 @@ after_sprg3_load:
PPC_LL r4, VCPU_SHADOW_MSR(r4) /* get shadow_msr */
/* Jump to segment patching handler and into our guest */
- bl FUNC(kvmppc_entry_trampoline)
+ bl kvmppc_entry_trampoline
nop
/*
@@ -164,7 +162,7 @@ after_sprg3_load:
/* On 64-bit, interrupts are still off at this point */
GET_SHADOW_VCPU(r4)
- bl FUNC(kvmppc_copy_from_svcpu)
+ bl kvmppc_copy_from_svcpu
nop
#ifdef CONFIG_PPC_BOOK3S_64
@@ -203,7 +201,7 @@ after_sprg3_load:
/* Restore r3 (kvm_run) and r4 (vcpu) */
REST_2GPRS(3, r1)
- bl FUNC(kvmppc_handle_exit_pr)
+ bl kvmppc_handle_exit_pr
/* If RESUME_GUEST, get back in the loop */
cmpwi r3, RESUME_GUEST
Index: b/arch/powerpc/kvm/book3s_rmhandlers.S
===================================================================
--- a/arch/powerpc/kvm/book3s_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_rmhandlers.S
@@ -34,13 +34,7 @@
* *
****************************************************************************/
-#if defined(CONFIG_PPC_BOOK3S_64)
-
-#define FUNC(name) GLUE(.,name)
-
-#elif defined(CONFIG_PPC_BOOK3S_32)
-
-#define FUNC(name) name
+#ifdef CONFIG_PPC_BOOK3S_32
.macro INTERRUPT_TRAMPOLINE intno
^ permalink raw reply
* Re: [PATCH v2 01/10] DMA, CMA: clean-up log message
From: Zhang Yanfei @ 2014-06-12 8:15 UTC (permalink / raw)
To: Joonsoo Kim
Cc: kvm-ppc, Russell King - ARM Linux, kvm, linux-mm, Gleb Natapov,
Greg Kroah-Hartman, Alexander Graf, Michal Nazarewicz,
linux-kernel, Minchan Kim, Paul Mackerras, Aneesh Kumar K.V,
Paolo Bonzini, Andrew Morton, linuxppc-dev, linux-arm-kernel,
Marek Szyprowski
In-Reply-To: <1402543307-29800-2-git-send-email-iamjoonsoo.kim@lge.com>
On 06/12/2014 11:21 AM, Joonsoo Kim wrote:
> We don't need explicit 'CMA:' prefix, since we already define prefix
> 'cma:' in pr_fmt. So remove it.
>
> And, some logs print function name and others doesn't. This looks
> bad to me, so I unify log format to print function name consistently.
>
> Lastly, I add one more debug log on cma_activate_area().
>
> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
>
> diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
> index 83969f8..bd0bb81 100644
> --- a/drivers/base/dma-contiguous.c
> +++ b/drivers/base/dma-contiguous.c
> @@ -144,7 +144,7 @@ void __init dma_contiguous_reserve(phys_addr_t limit)
> }
>
> if (selected_size && !dma_contiguous_default_area) {
> - pr_debug("%s: reserving %ld MiB for global area\n", __func__,
> + pr_debug("%s(): reserving %ld MiB for global area\n", __func__,
> (unsigned long)selected_size / SZ_1M);
>
> dma_contiguous_reserve_area(selected_size, selected_base,
> @@ -163,8 +163,9 @@ static int __init cma_activate_area(struct cma *cma)
> unsigned i = cma->count >> pageblock_order;
> struct zone *zone;
>
> - cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> + pr_debug("%s()\n", __func__);
>
> + cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> if (!cma->bitmap)
> return -ENOMEM;
>
> @@ -234,7 +235,8 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
>
> /* Sanity checks */
> if (cma_area_count == ARRAY_SIZE(cma_areas)) {
> - pr_err("Not enough slots for CMA reserved regions!\n");
> + pr_err("%s(): Not enough slots for CMA reserved regions!\n",
> + __func__);
> return -ENOSPC;
> }
>
> @@ -274,14 +276,15 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
> *res_cma = cma;
> cma_area_count++;
>
> - pr_info("CMA: reserved %ld MiB at %08lx\n", (unsigned long)size / SZ_1M,
> - (unsigned long)base);
> + pr_info("%s(): reserved %ld MiB at %08lx\n",
> + __func__, (unsigned long)size / SZ_1M, (unsigned long)base);
>
> /* Architecture specific contiguous memory fixup. */
> dma_contiguous_early_fixup(base, size);
> return 0;
> err:
> - pr_err("CMA: failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
> + pr_err("%s(): failed to reserve %ld MiB\n",
> + __func__, (unsigned long)size / SZ_1M);
> return ret;
> }
>
>
--
Thanks.
Zhang Yanfei
^ permalink raw reply
* [PATCH 2/4] KVM: PPC: Book3S HV: Fix ABIv2 issues
From: Anton Blanchard @ 2014-06-12 8:15 UTC (permalink / raw)
To: benh, paulus, agraf, clg; +Cc: linuxppc-dev, kvm, kvm-ppc
In-Reply-To: <20140612181420.65b05675@kryten>
binutils knows that a branch to a function descriptor is actually
a branch to the function text. By removing the explicit branch to
dot symbols, we maintain both ABIv1 and ABIv2 compatibility.
Signed-off-by: Anton Blanchard <anton@samba.org>
---
Index: b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
===================================================================
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -675,9 +675,9 @@ END_FTR_SECTION_IFCLR(CPU_FTR_TM)
mr r31, r4
addi r3, r31, VCPU_FPRS_TM
- bl .load_fp_state
+ bl load_fp_state
addi r3, r31, VCPU_VRS_TM
- bl .load_vr_state
+ bl load_vr_state
mr r4, r31
lwz r7, VCPU_VRSAVE_TM(r4)
mtspr SPRN_VRSAVE, r7
@@ -1421,9 +1421,9 @@ END_FTR_SECTION_IFCLR(CPU_FTR_TM)
/* Save FP/VSX. */
addi r3, r9, VCPU_FPRS_TM
- bl .store_fp_state
+ bl store_fp_state
addi r3, r9, VCPU_VRS_TM
- bl .store_vr_state
+ bl store_vr_state
mfspr r6, SPRN_VRSAVE
stw r6, VCPU_VRSAVE_TM(r9)
1:
@@ -2421,11 +2421,11 @@ END_FTR_SECTION_IFSET(CPU_FTR_VSX)
mtmsrd r8
isync
addi r3,r3,VCPU_FPRS
- bl .store_fp_state
+ bl store_fp_state
#ifdef CONFIG_ALTIVEC
BEGIN_FTR_SECTION
addi r3,r31,VCPU_VRS
- bl .store_vr_state
+ bl store_vr_state
END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
#endif
mfspr r6,SPRN_VRSAVE
@@ -2457,11 +2457,11 @@ END_FTR_SECTION_IFSET(CPU_FTR_VSX)
mtmsrd r8
isync
addi r3,r4,VCPU_FPRS
- bl .load_fp_state
+ bl load_fp_state
#ifdef CONFIG_ALTIVEC
BEGIN_FTR_SECTION
addi r3,r31,VCPU_VRS
- bl .load_vr_state
+ bl load_vr_state
END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
#endif
lwz r7,VCPU_VRSAVE(r31)
^ permalink raw reply
* [PATCH 3/4] KVM: PPC: Book3S HV: Fix ABIv2 indirect branch issue
From: Anton Blanchard @ 2014-06-12 8:16 UTC (permalink / raw)
To: benh, paulus, agraf, clg; +Cc: linuxppc-dev, kvm, kvm-ppc
In-Reply-To: <20140612181420.65b05675@kryten>
To establish addressability quickly, ABIv2 requires the target
address of the function being called to be in r12.
Signed-off-by: Anton Blanchard <anton@samba.org>
---
Index: b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
===================================================================
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -1920,8 +1920,8 @@ hcall_try_real_mode:
lwax r3,r3,r4
cmpwi r3,0
beq guest_exit_cont
- add r3,r3,r4
- mtctr r3
+ add r12,r3,r4
+ mtctr r12
mr r3,r9 /* get vcpu pointer */
ld r4,VCPU_GPR(R4)(r9)
bctrl
^ permalink raw reply
* [PATCH 4/4] KVM: PPC: Assembly functions exported to modules need _GLOBAL_TOC()
From: Anton Blanchard @ 2014-06-12 8:16 UTC (permalink / raw)
To: benh, paulus, agraf, clg; +Cc: linuxppc-dev, kvm, kvm-ppc
In-Reply-To: <20140612181420.65b05675@kryten>
Both kvmppc_hv_entry_trampoline and kvmppc_entry_trampoline are
assembly functions that are exported to modules and also require
a valid r2.
As such we need to use _GLOBAL_TOC so we provide a global entry
point that establishes the TOC (r2).
Signed-off-by: Anton Blanchard <anton@samba.org>
---
Index: b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
===================================================================
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -51,7 +51,7 @@
*
* LR = return address to continue at after eventually re-enabling MMU
*/
-_GLOBAL(kvmppc_hv_entry_trampoline)
+_GLOBAL_TOC(kvmppc_hv_entry_trampoline)
mflr r0
std r0, PPC_LR_STKOFF(r1)
stdu r1, -112(r1)
Index: b/arch/powerpc/kvm/book3s_rmhandlers.S
===================================================================
--- a/arch/powerpc/kvm/book3s_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_rmhandlers.S
@@ -140,7 +140,7 @@ kvmppc_handler_skip_ins:
* On entry, r4 contains the guest shadow MSR
* MSR.EE has to be 0 when calling this function
*/
-_GLOBAL(kvmppc_entry_trampoline)
+_GLOBAL_TOC(kvmppc_entry_trampoline)
mfmsr r5
LOAD_REG_ADDR(r7, kvmppc_handler_trampoline_enter)
toreal(r7)
^ permalink raw reply
* Re: [PATCH] powerpc, kexec: Fix "Processor X is stuck" issue during kexec from ST mode
From: Srivatsa S. Bhat @ 2014-06-12 8:17 UTC (permalink / raw)
To: Joel Stanley
Cc: ego, matt, Mahesh Salgaonkar, kexec, linux-kernel, suzuki,
ebiederm, Paul Mackerras, linuxppc-dev, Vivek Goyal
In-Reply-To: <CACPK8Xea+7rPHSCp51fVkX=GTmEwbV0T=JHDZ-XYt6RU96uyyg@mail.gmail.com>
Hi Joel,
On 06/12/2014 12:09 PM, Joel Stanley wrote:
> Hi Srivatsa,
>
> On Sat, Jun 7, 2014 at 7:16 AM, Srivatsa S. Bhat
> <srivatsa.bhat@linux.vnet.ibm.com> wrote:
>> And with the following hunk added (which I had forgotten earlier), it worked just
>> fine on powernv :-)
>
> How are the patches coming along?
>
I'm still waiting to test this patch series on a PowerVM box, and unfortunately
there are some machine issues to debug first :-( So that's why this is taking
time... :-(
> I just hung a machine here while attempting to kexec. It appears to
> have onlined all of the secondary threads, and then hung here:
>
> kexec: Waking offline cpu 1.
> kvm: enabling virtualization on CPU1
> kexec: Waking offline cpu 2.
> kvm: enabling virtualization on CPU2
> kexec: Waking offline cpu 3.
> kvm: enabling virtualization on CPU3
> kexec: Waking offline cpu 5.
> kvm: enabling virtualization on CPU5
> [...]
> kvm: enabling virtualization on CPU63
> kexec: waiting for cpu 1 (physical 1) to enter OPAL
> kexec: waiting for cpu 2 (physical 2) to enter OPAL
> kexec: waiting for cpu 3 (physical 3) to enter OPAL
>
> I'm running benh's next branch as of thismorning, and SMT was off.
>
Oh! This looks like a different hang than the one I tried to fix. My patch
("powerpc, kexec: Fix "Processor X is stuck" issue during kexec from ST mode")
which is already in benh's next branch was aimed at fixing the "CPU is stuck"
issue which was observed during the second kernel boot. If the first kernel
itself is hanging in the down-path, then it looks like a different problem
altogether.
> Could you please post your latest patches a series? I will test them here.
>
The 4 patches that I proposed in this thread are aimed at making the above
solution more elegant, by not having to actually online the secondary threads
while doing kexec. I don't think it will solve the hang that you are seeing.
In any case, I'll provide the consolidated patch below if you want to give it
a try.
By the way, I have a few questions regarding the hang you observed: is it
always reproducible with SMT=off? And if SMT was 8 (i.e, all CPUs in the system
were online) and then you did a kexec, do you still see the hang?
Regards,
Srivatsa S. Bhat
---------------------------------------------------------------------------
diff --git a/arch/powerpc/include/asm/kexec.h b/arch/powerpc/include/asm/kexec.h
index 16d7e33..2a31b52 100644
--- a/arch/powerpc/include/asm/kexec.h
+++ b/arch/powerpc/include/asm/kexec.h
@@ -68,6 +68,7 @@ static inline void crash_setup_regs(struct pt_regs *newregs,
ppc_save_regs(newregs);
}
+extern bool kexec_cpu_wake(void);
extern void kexec_smp_wait(void); /* get and clear naca physid, wait for
master to copy new code to 0 */
extern int crashing_cpu;
diff --git a/arch/powerpc/include/asm/machdep.h b/arch/powerpc/include/asm/machdep.h
index f92b0b5..39f721d 100644
--- a/arch/powerpc/include/asm/machdep.h
+++ b/arch/powerpc/include/asm/machdep.h
@@ -255,6 +255,16 @@ struct machdep_calls {
void (*machine_shutdown)(void);
#ifdef CONFIG_KEXEC
+#if (defined CONFIG_PPC64) && (defined CONFIG_PPC_BOOK3S)
+
+ /*
+ * The pseries and powernv book3s platforms have a special requirement
+ * that soft-offline CPUs have to be woken up before kexec, to avoid
+ * CPUs getting stuck. This callback prepares the system for the
+ * impending wakeup of the offline CPUs.
+ */
+ void (*kexec_wake_prepare)(void);
+#endif
void (*kexec_cpu_down)(int crash_shutdown, int secondary);
/* Called to do what every setup is needed on image and the
diff --git a/arch/powerpc/kernel/machine_kexec_64.c b/arch/powerpc/kernel/machine_kexec_64.c
index 879b3aa..84e91293 100644
--- a/arch/powerpc/kernel/machine_kexec_64.c
+++ b/arch/powerpc/kernel/machine_kexec_64.c
@@ -182,6 +182,14 @@ static void kexec_smp_down(void *arg)
/* NOTREACHED */
}
+bool kexec_cpu_wake(void)
+{
+ kexec_smp_down(NULL);
+
+ /* NOTREACHED */
+ return true;
+}
+
static void kexec_prepare_cpus_wait(int wait_state)
{
int my_cpu, i, notified=-1;
@@ -202,7 +210,7 @@ static void kexec_prepare_cpus_wait(int wait_state)
* these possible-but-not-online-but-should-be CPUs and chaperone them
* into kexec_smp_wait().
*/
- for_each_online_cpu(i) {
+ for_each_present_cpu(i) {
if (i == my_cpu)
continue;
@@ -228,16 +236,22 @@ static void kexec_prepare_cpus_wait(int wait_state)
* threads as offline -- and again, these CPUs will be stuck.
*
* So, we online all CPUs that should be running, including secondary threads.
+ *
+ * TODO: Update this comment
*/
static void wake_offline_cpus(void)
{
int cpu = 0;
+ if (ppc_md.kexec_wake_prepare)
+ ppc_md.kexec_wake_prepare();
+
for_each_present_cpu(cpu) {
if (!cpu_online(cpu)) {
printk(KERN_INFO "kexec: Waking offline cpu %d.\n",
cpu);
- WARN_ON(cpu_up(cpu));
+ /* This should work even though the cpu is offline */
+ smp_send_reschedule(cpu);
}
}
}
diff --git a/arch/powerpc/platforms/powernv/powernv.h b/arch/powerpc/platforms/powernv/powernv.h
index 75501bf..910081c 100644
--- a/arch/powerpc/platforms/powernv/powernv.h
+++ b/arch/powerpc/platforms/powernv/powernv.h
@@ -27,4 +27,8 @@ extern void pnv_lpc_init(void);
bool cpu_core_split_required(void);
+#ifdef CONFIG_KEXEC
+extern void pnv_kexec_wake_prepare(void);
+#endif
+
#endif /* _POWERNV_H */
diff --git a/arch/powerpc/platforms/powernv/setup.c b/arch/powerpc/platforms/powernv/setup.c
index 8c16a5f..8dbccb7 100644
--- a/arch/powerpc/platforms/powernv/setup.c
+++ b/arch/powerpc/platforms/powernv/setup.c
@@ -331,6 +331,7 @@ define_machine(powernv) {
.calibrate_decr = generic_calibrate_decr,
.dma_set_mask = pnv_dma_set_mask,
#ifdef CONFIG_KEXEC
+ .kexec_wake_prepare = pnv_kexec_wake_prepare,
.kexec_cpu_down = pnv_kexec_cpu_down,
#endif
#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
diff --git a/arch/powerpc/platforms/powernv/smp.c b/arch/powerpc/platforms/powernv/smp.c
index 0062a43..0b017b0 100644
--- a/arch/powerpc/platforms/powernv/smp.c
+++ b/arch/powerpc/platforms/powernv/smp.c
@@ -32,6 +32,7 @@
#include <asm/opal.h>
#include <asm/runlatch.h>
#include <asm/code-patching.h>
+#include <asm/kexec.h>
#include "powernv.h"
@@ -140,6 +141,15 @@ static int pnv_smp_cpu_disable(void)
return 0;
}
+#ifdef CONFIG_KEXEC
+static bool kexec_wake_offline_cpus;
+
+void pnv_kexec_wake_prepare(void)
+{
+ kexec_wake_offline_cpus = true;
+}
+#endif
+
static void pnv_smp_cpu_kill_self(void)
{
unsigned int cpu;
@@ -170,6 +180,11 @@ static void pnv_smp_cpu_kill_self(void)
if (cpu_core_split_required())
continue;
+#ifdef CONFIG_KEXEC
+ if (kexec_wake_offline_cpus)
+ kexec_cpu_wake(); /* This function won't return! */
+#endif
+
if (!generic_check_cpu_restart(cpu))
DBG("CPU%d Unexpected exit while offline !\n", cpu);
}
diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
index 20d6297..d026028 100644
--- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -31,6 +31,7 @@
#include <asm/vdso_datapage.h>
#include <asm/xics.h>
#include <asm/plpar_wrappers.h>
+#include <asm/kexec.h>
#include "offline_states.h"
@@ -143,6 +144,13 @@ static void pseries_mach_cpu_die(void)
get_lppaca()->donate_dedicated_cpu = 0;
get_lppaca()->idle = 0;
+#if CONFIG_KEXEC
+ if (get_preferred_offline_state(cpu) == CPU_STATE_KEXEC_WAKE) {
+ /* This function won't return! */
+ kexec_cpu_wake();
+ }
+#endif
+
if (get_preferred_offline_state(cpu) == CPU_STATE_ONLINE) {
unregister_slb_shadow(hwcpu);
diff --git a/arch/powerpc/platforms/pseries/kexec.c b/arch/powerpc/platforms/pseries/kexec.c
index 13fa95b3..fc135e6 100644
--- a/arch/powerpc/platforms/pseries/kexec.c
+++ b/arch/powerpc/platforms/pseries/kexec.c
@@ -20,6 +20,17 @@
#include <asm/plpar_wrappers.h>
#include "pseries.h"
+#include "offline_states.h"
+
+void pseries_kexec_wake_prepare(void)
+{
+ unsigned int cpu;
+
+ for_each_present_cpu(cpu) {
+ if (!cpu_online(cpu))
+ set_preferred_offline_state(cpu, CPU_STATE_KEXEC_WAKE);
+ }
+}
static void pseries_kexec_cpu_down(int crash_shutdown, int secondary)
{
diff --git a/arch/powerpc/platforms/pseries/offline_states.h b/arch/powerpc/platforms/pseries/offline_states.h
index 08672d9..32fe5e8 100644
--- a/arch/powerpc/platforms/pseries/offline_states.h
+++ b/arch/powerpc/platforms/pseries/offline_states.h
@@ -5,6 +5,9 @@
enum cpu_state_vals {
CPU_STATE_OFFLINE,
CPU_STATE_INACTIVE,
+#ifdef CONFIG_KEXEC
+ CPU_STATE_KEXEC_WAKE,
+#endif
CPU_STATE_ONLINE,
CPU_MAX_OFFLINE_STATES
};
diff --git a/arch/powerpc/platforms/pseries/pseries.h b/arch/powerpc/platforms/pseries/pseries.h
index 361add6..35ecb99 100644
--- a/arch/powerpc/platforms/pseries/pseries.h
+++ b/arch/powerpc/platforms/pseries/pseries.h
@@ -38,6 +38,8 @@ static inline void smp_init_pseries_xics(void) { };
#endif
#ifdef CONFIG_KEXEC
+extern void pseries_kexec_wake_prepare(void);
+
extern void setup_kexec_cpu_down_xics(void);
extern void setup_kexec_cpu_down_mpic(void);
#else
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index adc21a0..c1a0722 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -808,6 +808,7 @@ define_machine(pseries) {
.system_reset_exception = pSeries_system_reset_exception,
.machine_check_exception = pSeries_machine_check_exception,
#ifdef CONFIG_KEXEC
+ .kexec_wake_prepare = pseries_kexec_wake_prepare,
.machine_kexec = pSeries_machine_kexec,
#endif
#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
diff --git a/kernel/kexec.c b/kernel/kexec.c
index 28c5706..55a6350 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -1684,13 +1684,6 @@ int kernel_kexec(void)
kernel_restart_prepare(NULL);
migrate_to_reboot_cpu();
- /*
- * migrate_to_reboot_cpu() disables CPU hotplug assuming that
- * no further code needs to use CPU hotplug (which is true in
- * the reboot case). However, the kexec path depends on using
- * CPU hotplug again; so re-enable it here.
- */
- cpu_hotplug_enable();
printk(KERN_EMERG "Starting new kernel\n");
machine_shutdown();
}
^ permalink raw reply related
* Re: [PATCH v2 02/10] DMA, CMA: fix possible memory leak
From: Zhang Yanfei @ 2014-06-12 8:19 UTC (permalink / raw)
To: Joonsoo Kim
Cc: kvm-ppc, Russell King - ARM Linux, kvm, linux-mm, Gleb Natapov,
Greg Kroah-Hartman, Alexander Graf, Michal Nazarewicz,
linux-kernel, Minchan Kim, Paul Mackerras, Aneesh Kumar K.V,
Paolo Bonzini, Andrew Morton, linuxppc-dev, linux-arm-kernel,
Marek Szyprowski
In-Reply-To: <20140612060211.GC30128@js1304-P5Q-DELUXE>
On 06/12/2014 02:02 PM, Joonsoo Kim wrote:
> On Thu, Jun 12, 2014 at 02:25:43PM +0900, Minchan Kim wrote:
>> On Thu, Jun 12, 2014 at 12:21:39PM +0900, Joonsoo Kim wrote:
>>> We should free memory for bitmap when we find zone mis-match,
>>> otherwise this memory will leak.
>>
>> Then, -stable stuff?
>
> I don't think so. This is just possible leak candidate, so we don't
> need to push this to stable tree.
>
>>
>>>
>>> Additionally, I copy code comment from ppc kvm's cma code to notify
>>> why we need to check zone mis-match.
>>>
>>> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
>>>
>>> diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
>>> index bd0bb81..fb0cdce 100644
>>> --- a/drivers/base/dma-contiguous.c
>>> +++ b/drivers/base/dma-contiguous.c
>>> @@ -177,14 +177,24 @@ static int __init cma_activate_area(struct cma *cma)
>>> base_pfn = pfn;
>>> for (j = pageblock_nr_pages; j; --j, pfn++) {
>>> WARN_ON_ONCE(!pfn_valid(pfn));
>>> + /*
>>> + * alloc_contig_range requires the pfn range
>>> + * specified to be in the same zone. Make this
>>> + * simple by forcing the entire CMA resv range
>>> + * to be in the same zone.
>>> + */
>>> if (page_zone(pfn_to_page(pfn)) != zone)
>>> - return -EINVAL;
>>> + goto err;
>>
>> At a first glance, I thought it would be better to handle such error
>> before activating.
>> So when I see the registration code(ie, dma_contiguous_revere_area),
>> I realized it is impossible because we didn't set up zone yet. :(
>>
>> If so, when we detect to fail here, it would be better to report more
>> meaningful error message like what was successful zone and what is
>> new zone and failed pfn number?
>
> What I want to do in early phase of this patchset is to make cma code
> on DMA APIs similar to ppc kvm's cma code. ppc kvm's cma code already
> has this error handling logic, so I make this patch.
>
> If we think that we need more things, we can do that on general cma code
> after merging this patchset.
>
Yeah, I also like the idea. After all, this patchset aims to a general CMA
management, we could improve more after this patchset. So
Acked-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
--
Thanks.
Zhang Yanfei
^ permalink raw reply
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