one comment below On 01/17/14 08:46, qiaonuohan wrote: > DataCache is used to store data temporarily, then the data will be written to > vmcore. These functions will be called later when writing data of page to > vmcore. > > Signed-off-by: Qiao Nuohan <qiaonuo...@cn.fujitsu.com> > Reviewed-by: Laszlo Ersek <ler...@redhat.com> > --- > dump.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ > include/sysemu/dump.h | 9 +++++++++ > 2 files changed, 56 insertions(+), 0 deletions(-) > > diff --git a/dump.c b/dump.c > index 26a1756..fa183cb 100644 > --- a/dump.c > +++ b/dump.c > @@ -1173,6 +1173,53 @@ out: > return ret; > } > > +static void prepare_data_cache(DataCache *data_cache, DumpState *s, > + off_t offset) > +{ > + data_cache->fd = s->fd; > + data_cache->data_size = 0; > + data_cache->buf_size = BUFSIZE_DATA_CACHE; > + data_cache->buf = g_malloc0(BUFSIZE_DATA_CACHE); > + data_cache->offset = offset; > +} > + > +static int write_cache(DataCache *dc, const void *buf, size_t size, > + bool flag_sync) > +{ > + /* > + * dc->buf_size should not be less than size, otherwise dc will never be > + * enough > + */ > + assert(size <= dc->buf_size); > + > + /* > + * if flag_sync is set, synchronize data in dc->buf into vmcore. > + * otherwise check if the space is enough for caching data in buf, if > not, > + * write the data in dc->buf to dc->fd and reset dc->buf > + */ > + if ((!flag_sync && dc->data_size + size > dc->buf_size) || > + (flag_sync && dc->data_size > 0)) { > + if (write_buffer(dc->fd, dc->offset, dc->buf, dc->data_size) < 0) { > + return -1; > + } > + > + dc->offset += dc->data_size; > + dc->data_size = 0; > + } > + > + if (!flag_sync) { > + memcpy(dc->buf + dc->data_size, buf, size); > + dc->data_size += size; > + }
You don't need to make this block conditional on !flag_sync. By removing that restriction, the function would become more general. But I assume you don't need that -- I believe you feed all data to this function with flag_sync==false, then call it one last time with (flag_sync==false && size==0). Thanks for adding the assert() and for the type change on "buf". My R-b stands. Laszlo > + > + return 0; > +} > + > +static void free_data_cache(DataCache *data_cache) > +{ > + g_free(data_cache->buf); > +} > + > static ram_addr_t get_start_block(DumpState *s) > { > GuestPhysBlock *block; > diff --git a/include/sysemu/dump.h b/include/sysemu/dump.h > index 6d4d0bc..92a95e4 100644 > --- a/include/sysemu/dump.h > +++ b/include/sysemu/dump.h > @@ -41,6 +41,7 @@ > #define DISKDUMP_HEADER_BLOCKS (1) > #define BUFSIZE_BITMAP (TARGET_PAGE_SIZE) > #define PFN_BUFBITMAP (CHAR_BIT * BUFSIZE_BITMAP) > +#define BUFSIZE_DATA_CACHE (TARGET_PAGE_SIZE * 4) > > typedef struct ArchDumpInfo { > int d_machine; /* Architecture */ > @@ -142,6 +143,14 @@ typedef struct QEMU_PACKED KdumpSubHeader64 { > uint64_t max_mapnr_64; /* header_version 6 and later */ > } KdumpSubHeader64; > > +typedef struct DataCache { > + int fd; /* fd of the file where to write the cached data */ > + uint8_t *buf; /* buffer for cached data */ > + size_t buf_size; /* size of the buf */ > + size_t data_size; /* size of cached data in buf */ > + off_t offset; /* offset of the file */ > +} DataCache; > + > struct GuestPhysBlockList; /* memory_mapping.h */ > int cpu_get_dump_info(ArchDumpInfo *info, > const struct GuestPhysBlockList *guest_phys_blocks); >