> -----Original Message----- > From: ext Stuart Haslam [mailto:[email protected]] > Sent: Thursday, September 04, 2014 2:19 PM > To: Petri Savolainen > Cc: [email protected] > Subject: Re: [lng-odp] [PATCH 1/2] Shared memory reserve flag > > On Mon, Sep 01, 2014 at 12:53:04PM +0100, Petri Savolainen wrote: > > Add flags parameter to reserve call. > > * SW_ONLY: optimize memory usage when HW accelerators are not > > involved. > > * PROC: for communication with other (non-ODP) processes in the > > system > > The non-ODP part isn't really a limitation as suggested here.
I think it is, since ODP API calls should be the same regardless of the application is running as threads/processes/bare metal. That's supported by default. Here the PROC flag says that external processes should see the memory also. > > > * KERNEL: for communication with a kernel (OS) driver > > > > Signed-off-by: Petri Savolainen <[email protected]> > > --- > > .../linux-generic/include/api/odp_shared_memory.h | 13 ++++++- > > platform/linux-generic/odp_shared_memory.c | 45 > +++++++++++++++++----- > > 2 files changed, 48 insertions(+), 10 deletions(-) > > > > diff --git a/platform/linux-generic/include/api/odp_shared_memory.h > b/platform/linux-generic/include/api/odp_shared_memory.h > > index 8ac8847..814acdc 100644 > > --- a/platform/linux-generic/include/api/odp_shared_memory.h > > +++ b/platform/linux-generic/include/api/odp_shared_memory.h > > @@ -24,6 +24,15 @@ extern "C" { > > /** Maximum shared memory block name lenght in chars */ > > typo - length (I know it wasn't changed in this patch, but if you're > doing a v2 anyway..) > > > #define ODP_SHM_NAME_LEN 32 > > > > +/* > > + * Shared memory flags > > + */ > > + > > +/* Share level */ > > +#define ODP_SHM_SW_ONLY 0x1 /**< Internal to application SW, no HW > access */ > > +#define ODP_SHM_PROC 0x2 /**< Share with external processes */ > > +#define ODP_SHM_KERNEL 0x4 /**< Share with kernel */ > > This seems a bit confused as to whether it's a level or a flag. If you > set only ODP_SHM_PROC the suggestion is that this means it wouldn't be > shared internal to the application.. but ODP_SHM_SW_ONLY|ODP_SHM_PROC > isn't logical either. ODP_SHM_SW_ONLY == HW accelerators will _not_ access this memory define ODP_SHM_PROC == external (user space) processes access this memory For a SW only struct, ODP_SHM_SW_ONLY|ODP_SHM_PROC would be logical choice. > > > + > > > > /** > > * Reserve a block of shared memory > > @@ -31,10 +40,12 @@ extern "C" { > > * @param name Name of the block (maximum ODP_SHM_NAME_LEN - 1 chars) > > * @param size Block size in bytes > > * @param align Block alignment in bytes > > + * @param flags Block parameter flags > > * > > * @return Pointer to the reserved block, or NULL > > */ > > -void *odp_shm_reserve(const char *name, uint64_t size, uint64_t align); > > +void *odp_shm_reserve(const char *name, uint64_t size, uint64_t align, > > + uint32_t flags); > > > > /** > > * Lookup for a block of shared memory > > diff --git a/platform/linux-generic/odp_shared_memory.c > b/platform/linux-generic/odp_shared_memory.c > > index 784f42b..4cb82b5 100644 > > --- a/platform/linux-generic/odp_shared_memory.c > > +++ b/platform/linux-generic/odp_shared_memory.c > > @@ -11,6 +11,7 @@ > > #include <odp_system_info.h> > > #include <odp_debug.h> > > > > +#include <unistd.h> > > #include <sys/mman.h> > > #include <asm/mman.h> > > #include <fcntl.h> > > @@ -44,8 +45,6 @@ typedef struct { > > #define MAP_ANONYMOUS MAP_ANON > > #endif > > > > -#define SHM_FLAGS (MAP_SHARED | MAP_ANONYMOUS) > > - > > > > /* Global shared memory table */ > > static odp_shm_table_t *odp_shm_tbl; > > @@ -60,7 +59,7 @@ int odp_shm_init_global(void) > > #endif > > > > addr = mmap(NULL, sizeof(odp_shm_table_t), > > - PROT_READ | PROT_WRITE, SHM_FLAGS, -1, 0); > > + PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, > 0); > > > > if (addr == MAP_FAILED) > > return -1; > > @@ -95,11 +94,17 @@ static int find_block(const char *name) > > } > > > > > > -void *odp_shm_reserve(const char *name, uint64_t size, uint64_t align) > > +void *odp_shm_reserve(const char *name, uint64_t size, uint64_t align, > > + uint32_t flags) > > { > > int i; > > odp_shm_block_t *block; > > void *addr; > > + int fd = -1; > > + int map_flag = MAP_SHARED; > > + /* O_EXCL: error, O_TRUNC: truncate to zero, if already exists */ > > + int oflag = O_RDWR | O_CREAT | O_TRUNC; > > Not sure why the comment mentions O_EXCL as it isn't being set. I suppose > the expected behaviour is that if the shm already exists it's just opened, > so this is just a comment error. O_EXCL is there to remain, that it should be used after we have proper clean up implemented. I choose to O_TRUNC now so that user do not have to delete the the /dev/shm/foobar file between application runs. -Petri _______________________________________________ lng-odp mailing list [email protected] http://lists.linaro.org/mailman/listinfo/lng-odp
