# HG changeset patch
# User Olaf Hering <olaf@xxxxxxxxx>
# Date 1305037539 -7200
# Node ID 1a45e40add8b407532374c34f20bad51707808cf
# Parent 575bf78214ef193e44806aa9766e084d721783b5
xentrace: update __insert_record() to copy the trace record to individual mfns
Update __insert_record() to copy the trace record to individual mfns.
This is a prereq before changing the per-cpu allocation from contiguous
to non-contiguous allocation.
v2:
update offset calculation to use shift and mask
update type of mfn_offset to match type of data source
Signed-off-by: Olaf Hering <olaf@xxxxxxxxx>
diff -r 575bf78214ef -r 1a45e40add8b xen/common/trace.c
--- a/xen/common/trace.c Tue May 10 16:23:01 2011 +0200
+++ b/xen/common/trace.c Tue May 10 16:25:39 2011 +0200
@@ -52,7 +52,6 @@ static struct t_info *t_info;
static unsigned int t_info_pages;
static DEFINE_PER_CPU_READ_MOSTLY(struct t_buf *, t_bufs);
-static DEFINE_PER_CPU_READ_MOSTLY(unsigned char *, t_data);
static DEFINE_PER_CPU_READ_MOSTLY(spinlock_t, t_lock);
static u32 data_size __read_mostly;
@@ -208,7 +207,6 @@ static int alloc_trace_bufs(unsigned int
per_cpu(t_bufs, cpu) = buf = rawbuf;
buf->cons = buf->prod = 0;
- per_cpu(t_data, cpu) = (unsigned char *)(buf + 1);
}
offset = t_info_first_offset;
@@ -472,10 +470,16 @@ static inline u32 calc_bytes_avail(const
return data_size - calc_unconsumed_bytes(buf);
}
-static inline struct t_rec *next_record(const struct t_buf *buf,
- uint32_t *next)
+static unsigned char *next_record(const struct t_buf *buf, uint32_t *next,
+ unsigned char **next_page,
+ uint32_t *offset_in_page)
{
u32 x = buf->prod, cons = buf->cons;
+ uint16_t per_cpu_mfn_offset;
+ uint32_t per_cpu_mfn_nr;
+ uint32_t *mfn_list;
+ uint32_t mfn;
+ unsigned char *this_page;
barrier(); /* must read buf->prod and buf->cons only once */
*next = x;
@@ -487,7 +491,27 @@ static inline struct t_rec *next_record(
ASSERT(x < data_size);
- return (struct t_rec *)&this_cpu(t_data)[x];
+ /* add leading header to get total offset of next record */
+ x += sizeof(struct t_buf);
+ *offset_in_page = x & ~PAGE_MASK;
+
+ /* offset into array of mfns */
+ per_cpu_mfn_nr = x >> PAGE_SHIFT;
+ per_cpu_mfn_offset = t_info->mfn_offset[smp_processor_id()];
+ mfn_list = (uint32_t *)t_info;
+ mfn = mfn_list[per_cpu_mfn_offset + per_cpu_mfn_nr];
+ this_page = mfn_to_virt(mfn);
+ if (per_cpu_mfn_nr + 1 >= opt_tbuf_size)
+ {
+ /* reached end of buffer? */
+ *next_page = NULL;
+ }
+ else
+ {
+ mfn = mfn_list[per_cpu_mfn_offset + per_cpu_mfn_nr + 1];
+ *next_page = mfn_to_virt(mfn);
+ }
+ return this_page;
}
static inline void __insert_record(struct t_buf *buf,
@@ -497,28 +521,37 @@ static inline void __insert_record(struc
unsigned int rec_size,
const void *extra_data)
{
- struct t_rec *rec;
+ struct t_rec split_rec, *rec;
uint32_t *dst;
+ unsigned char *this_page, *next_page;
unsigned int extra_word = extra / sizeof(u32);
unsigned int local_rec_size = calc_rec_size(cycles, extra);
uint32_t next;
+ uint32_t offset;
+ uint32_t remaining;
BUG_ON(local_rec_size != rec_size);
BUG_ON(extra & 3);
- rec = next_record(buf, &next);
- if ( !rec )
+ this_page = next_record(buf, &next, &next_page, &offset);
+ if ( !this_page )
return;
- /* Double-check once more that we have enough space.
- * Don't bugcheck here, in case the userland tool is doing
- * something stupid. */
- if ( (unsigned char *)rec + rec_size > this_cpu(t_data) + data_size )
+
+ remaining = PAGE_SIZE - offset;
+
+ if ( unlikely(rec_size > remaining) )
{
- if ( printk_ratelimit() )
+ if ( next_page == NULL )
+ {
+ /* access beyond end of buffer */
printk(XENLOG_WARNING
- "%s: size=%08x prod=%08x cons=%08x rec=%u\n",
- __func__, data_size, next, buf->cons, rec_size);
- return;
+ "%s: size=%08x prod=%08x cons=%08x rec=%u remaining=%u\n",
+ __func__, data_size, next, buf->cons, rec_size, remaining);
+ return;
+ }
+ rec = &split_rec;
+ } else {
+ rec = (struct t_rec*)(this_page + offset);
}
rec->event = event;
@@ -535,6 +568,12 @@ static inline void __insert_record(struc
if ( extra_data && extra )
memcpy(dst, extra_data, extra);
+ if ( unlikely(rec_size > remaining) )
+ {
+ memcpy(this_page + offset, rec, remaining);
+ memcpy(next_page, (char *)rec + remaining, rec_size - remaining);
+ }
+
wmb();
next += rec_size;
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