Message ID | 1389944779-31899-8-git-send-email-qiaonuohan@cn.fujitsu.com |
---|---|
State | New |
Headers | show |
comments below On 01/17/14 08:46, qiaonuohan wrote: > add some members to DumpState that will be used in writing vmcore in > kdump-compressed format. some of them, like page_size, will be initialized > in the patch. > > Signed-off-by: Qiao Nuohan <qiaonuohan@cn.fujitsu.com> > --- > dump.c | 30 ++++++++++++++++++++++++++++++ > include/sysemu/dump.h | 7 +++++++ > 2 files changed, 37 insertions(+), 0 deletions(-) > > diff --git a/dump.c b/dump.c > index 2b940bd..bf7d31d 100644 > --- a/dump.c > +++ b/dump.c > @@ -79,6 +79,16 @@ typedef struct DumpState { > > uint8_t *note_buf; /* buffer for notes */ > size_t note_buf_offset; /* the writing place in note_buf */ > + uint32_t nr_cpus; /* number of guest's cpu */ > + size_t page_size; /* guest's page size */ > + uint32_t page_shift; /* guest's page shift */ > + uint64_t max_mapnr; /* the biggest guest's phys-mem's number */ > + size_t len_dump_bitmap; /* the size of the place used to store > + dump_bitmap in vmcore */ > + off_t offset_dump_bitmap; /* offset of dump_bitmap part in vmcore */ > + off_t offset_page; /* offset of page part in vmcore */ > + size_t num_dumpable; /* number of page that can be dumped */ > + uint32_t flag_compress; /* indicate the compression format */ > } DumpState; v6 06/11 addded these, but we have the following changes here: - flag_flatten is gone, OK, - bunch of comments, good, - page_shift and num_dumpable are now added at once (originally in v6 07/11). > > static int dump_cleanup(DumpState *s) > @@ -796,6 +806,16 @@ static ram_addr_t get_start_block(DumpState *s) > return -1; > } > > +static void get_max_mapnr(DumpState *s) > +{ > + MemoryMapping *memory_mapping; > + > + QTAILQ_FOREACH(memory_mapping, &s->list.head, next) { > + s->max_mapnr = paddr_to_pfn(memory_mapping->phys_addr + > + memory_mapping->length, s->page_shift); > + } > +} > + > static int dump_init(DumpState *s, int fd, bool paging, bool has_filter, > int64_t begin, int64_t length, Error **errp) > { This is from v6 10/11, OK. > @@ -864,6 +884,16 @@ static int dump_init(DumpState *s, int fd, bool paging, bool has_filter, > qemu_get_guest_simple_memory_mapping(&s->list, &s->guest_phys_blocks); > } > > + s->nr_cpus = nr_cpus; > + s->page_size = TARGET_PAGE_SIZE; > + s->page_shift = ffs(s->page_size) - 1; > + > + get_max_mapnr(s); Again from v6 10/11, good. The flag_flatten assignment has been dropped. Initialization seems to happen in a good spot this time too. > + > + uint64_t tmp; > + tmp = DIV_ROUND_UP(DIV_ROUND_UP(s->max_mapnr, CHAR_BIT), s->page_size); > + s->len_dump_bitmap = tmp * s->page_size; > + > if (s->has_filter) { > memory_mapping_filter(&s->list, s->begin, s->length); > } Again from v6 10/11. These assignments now all occur without depending on a user request for a compressed dump (kept this way in v7 12/13 too), but they are not costly. The loop in get_max_mapnr() iterates over less than 10 mappings in the non-paging dump case, and in the paging dump case it also shouldn't be more than a hundred or so (as I recall from earlier testing). This might be worth some regression-testing (perf-wise), but it looks OK to me. > diff --git a/include/sysemu/dump.h b/include/sysemu/dump.h > index b32b390..995bf47 100644 > --- a/include/sysemu/dump.h > +++ b/include/sysemu/dump.h > @@ -20,6 +20,13 @@ > #define VERSION_FLAT_HEADER (1) /* version of flattened format */ > #define END_FLAG_FLAT_HEADER (-1) > > +#define ARCH_PFN_OFFSET (0) > + > +#define paddr_to_pfn(X, page_shift) \ > + (((unsigned long long)(X) >> (page_shift)) - ARCH_PFN_OFFSET) From v6 07/11, needed by get_max_mapnr(). > +#define pfn_to_paddr(X, page_shift) \ > + (((unsigned long long)(X) + ARCH_PFN_OFFSET) << (page_shift)) > + > typedef struct ArchDumpInfo { > int d_machine; /* Architecture */ > int d_endian; /* ELFDATA2LSB or ELFDATA2MSB */ > From v6 09/11. Not strictly needed right now, but it does make sense for consistency. Reviewed-by: Laszlo Ersek <lersek@redhat.com>
On 01/23/2014 01:04 AM, Laszlo Ersek wrote: >> @@ -864,6 +884,16 @@ static int dump_init(DumpState *s, int fd, bool paging, bool has_filter, >> > qemu_get_guest_simple_memory_mapping(&s->list,&s->guest_phys_blocks); >> > } >> > >> > + s->nr_cpus = nr_cpus; >> > + s->page_size = TARGET_PAGE_SIZE; >> > + s->page_shift = ffs(s->page_size) - 1; >> > + >> > + get_max_mapnr(s); > Again from v6 10/11, good. The flag_flatten assignment has been dropped. > Initialization seems to happen in a good spot this time too. > >> > + >> > + uint64_t tmp; >> > + tmp = DIV_ROUND_UP(DIV_ROUND_UP(s->max_mapnr, CHAR_BIT), s->page_size); >> > + s->len_dump_bitmap = tmp * s->page_size; >> > + >> > if (s->has_filter) { >> > memory_mapping_filter(&s->list, s->begin, s->length); >> > } > Again from v6 10/11. > > These assignments now all occur without depending on a user request for > a compressed dump (kept this way in v7 12/13 too), but they are not > costly. The loop in get_max_mapnr() iterates over less than 10 mappings > in the non-paging dump case, and in the paging dump case it also > shouldn't be more than a hundred or so (as I recall from earlier > testing). This might be worth some regression-testing (perf-wise), but > it looks OK to me. > I see, moving them into "if(format...) {...}" block would be better. But, I have no idea of "regression-testing (perf-wise)", would you mind give some hint?
On 01/24/14 02:52, Qiao Nuohan wrote: > On 01/23/2014 01:04 AM, Laszlo Ersek wrote: >>> @@ -864,6 +884,16 @@ static int dump_init(DumpState *s, int fd, bool >>> paging, bool has_filter, >>> > >>> qemu_get_guest_simple_memory_mapping(&s->list,&s->guest_phys_blocks); >>> > } >>> > >>> > + s->nr_cpus = nr_cpus; >>> > + s->page_size = TARGET_PAGE_SIZE; >>> > + s->page_shift = ffs(s->page_size) - 1; >>> > + >>> > + get_max_mapnr(s); >> Again from v6 10/11, good. The flag_flatten assignment has been dropped. >> Initialization seems to happen in a good spot this time too. >> >>> > + >>> > + uint64_t tmp; >>> > + tmp = DIV_ROUND_UP(DIV_ROUND_UP(s->max_mapnr, CHAR_BIT), >>> s->page_size); >>> > + s->len_dump_bitmap = tmp * s->page_size; >>> > + >>> > if (s->has_filter) { >>> > memory_mapping_filter(&s->list, s->begin, s->length); >>> > } >> Again from v6 10/11. >> >> These assignments now all occur without depending on a user request for >> a compressed dump (kept this way in v7 12/13 too), but they are not >> costly. The loop in get_max_mapnr() iterates over less than 10 mappings >> in the non-paging dump case, and in the paging dump case it also >> shouldn't be more than a hundred or so (as I recall from earlier >> testing). This might be worth some regression-testing (perf-wise), but >> it looks OK to me. >> > > I see, moving them into "if(format...) {...}" block would be better. But, I > have no idea of "regression-testing (perf-wise)", would you mind give > some hint? I meant comparing how long it would take to dump in paging mode before this patchset, vs. after this patchset. In order to see the difference that is introduced by get_max_mapnr() when paging is enabled. However, please ignore this point. First, the loop is most probably negligible even for a paging dump. Second, you could make it conditional on compressed dumps (which force non-paging + non-filtering), where the number of mappings is very low. And third, as I wrote in later, the loop should be replaced anyway with an O(1) QTAILQ_LAST() access. So please just ignore this "performance" remark. Ultimately, what I suggest for get_max_mapnr() is: - rebase it to guest_phys_blocks, just like the other two places (which are now calling get_next_page()), - use QTAILQ_LAST() in it, - don't bother making it conditional (ie. its current call site is fine), because: - It'll be fast with QTAILQ_LAST(), - guest_phys_blocks is available in any case, so you can access it always Thanks Laszlo
diff --git a/dump.c b/dump.c index 2b940bd..bf7d31d 100644 --- a/dump.c +++ b/dump.c @@ -79,6 +79,16 @@ typedef struct DumpState { uint8_t *note_buf; /* buffer for notes */ size_t note_buf_offset; /* the writing place in note_buf */ + uint32_t nr_cpus; /* number of guest's cpu */ + size_t page_size; /* guest's page size */ + uint32_t page_shift; /* guest's page shift */ + uint64_t max_mapnr; /* the biggest guest's phys-mem's number */ + size_t len_dump_bitmap; /* the size of the place used to store + dump_bitmap in vmcore */ + off_t offset_dump_bitmap; /* offset of dump_bitmap part in vmcore */ + off_t offset_page; /* offset of page part in vmcore */ + size_t num_dumpable; /* number of page that can be dumped */ + uint32_t flag_compress; /* indicate the compression format */ } DumpState; static int dump_cleanup(DumpState *s) @@ -796,6 +806,16 @@ static ram_addr_t get_start_block(DumpState *s) return -1; } +static void get_max_mapnr(DumpState *s) +{ + MemoryMapping *memory_mapping; + + QTAILQ_FOREACH(memory_mapping, &s->list.head, next) { + s->max_mapnr = paddr_to_pfn(memory_mapping->phys_addr + + memory_mapping->length, s->page_shift); + } +} + static int dump_init(DumpState *s, int fd, bool paging, bool has_filter, int64_t begin, int64_t length, Error **errp) { @@ -864,6 +884,16 @@ static int dump_init(DumpState *s, int fd, bool paging, bool has_filter, qemu_get_guest_simple_memory_mapping(&s->list, &s->guest_phys_blocks); } + s->nr_cpus = nr_cpus; + s->page_size = TARGET_PAGE_SIZE; + s->page_shift = ffs(s->page_size) - 1; + + get_max_mapnr(s); + + uint64_t tmp; + tmp = DIV_ROUND_UP(DIV_ROUND_UP(s->max_mapnr, CHAR_BIT), s->page_size); + s->len_dump_bitmap = tmp * s->page_size; + if (s->has_filter) { memory_mapping_filter(&s->list, s->begin, s->length); } diff --git a/include/sysemu/dump.h b/include/sysemu/dump.h index b32b390..995bf47 100644 --- a/include/sysemu/dump.h +++ b/include/sysemu/dump.h @@ -20,6 +20,13 @@ #define VERSION_FLAT_HEADER (1) /* version of flattened format */ #define END_FLAG_FLAT_HEADER (-1) +#define ARCH_PFN_OFFSET (0) + +#define paddr_to_pfn(X, page_shift) \ + (((unsigned long long)(X) >> (page_shift)) - ARCH_PFN_OFFSET) +#define pfn_to_paddr(X, page_shift) \ + (((unsigned long long)(X) + ARCH_PFN_OFFSET) << (page_shift)) + typedef struct ArchDumpInfo { int d_machine; /* Architecture */ int d_endian; /* ELFDATA2LSB or ELFDATA2MSB */
add some members to DumpState that will be used in writing vmcore in kdump-compressed format. some of them, like page_size, will be initialized in the patch. Signed-off-by: Qiao Nuohan <qiaonuohan@cn.fujitsu.com> --- dump.c | 30 ++++++++++++++++++++++++++++++ include/sysemu/dump.h | 7 +++++++ 2 files changed, 37 insertions(+), 0 deletions(-)