On Mon, Jan 06, 2025 at 10:48:47AM -0700, Jens Axboe wrote: > Using RWF_DONTCACHE tells the kernel that any page cache instantiated > by this operation should get pruned once the operation completes. If > data is in cache prior to the operation it will remain there. > > Add ops for testing both the read and write side of this. At startup, > kernel support for this feature is probed. If support isn't available, > uncached/dontcache IO is performed as regular buffered IO. If -Z is > used to turn on O_DIRECT, then uncached/dontcache IO isn't performed. > Defaults to on if available, and adds a -T parameter to turn it off. > > See the kernel posting adding support: > > https://lore.kernel.org/linux-fsdevel/20241220154831.1086649-1-axboe@xxxxxxxxx/ > > Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> > --- > ltp/fsx.c | 115 ++++++++++++++++++++++++++++++++++++------------------ > 1 file changed, 77 insertions(+), 38 deletions(-) > > diff --git a/ltp/fsx.c b/ltp/fsx.c > index 41933354328a..7c996026157d 100644 > --- a/ltp/fsx.c > +++ b/ltp/fsx.c > @@ -43,6 +43,10 @@ > # define MAP_FILE 0 > #endif > > +#ifndef RWF_DONTCACHE > +#define RWF_DONTCACHE 0x80 > +#endif > + > #define NUMPRINTCOLUMNS 32 /* # columns of data to print on each line */ > > /* Operation flags (bitmask) */ > @@ -101,7 +105,9 @@ int logcount = 0; /* total ops */ > enum { > /* common operations */ > OP_READ = 0, > + OP_READ_DONTCACHE, > OP_WRITE, > + OP_WRITE_DONTCACHE, > OP_MAPREAD, > OP_MAPWRITE, > OP_MAX_LITE, > @@ -190,15 +196,16 @@ int o_direct; /* -Z */ > int aio = 0; > int uring = 0; > int mark_nr = 0; > +int dontcache_io = 1; > > int page_size; > int page_mask; > int mmap_mask; > -int fsx_rw(int rw, int fd, char *buf, unsigned len, unsigned offset); > +int fsx_rw(int rw, int fd, char *buf, unsigned len, unsigned offset, int flags); > #define READ 0 > #define WRITE 1 > -#define fsxread(a,b,c,d) fsx_rw(READ, a,b,c,d) > -#define fsxwrite(a,b,c,d) fsx_rw(WRITE, a,b,c,d) > +#define fsxread(a,b,c,d,f) fsx_rw(READ, a,b,c,d,f) > +#define fsxwrite(a,b,c,d,f) fsx_rw(WRITE, a,b,c,d,f) > > struct timespec deadline; > > @@ -266,7 +273,9 @@ prterr(const char *prefix) > > static const char *op_names[] = { > [OP_READ] = "read", > + [OP_READ_DONTCACHE] = "read_dontcache", > [OP_WRITE] = "write", > + [OP_WRITE_DONTCACHE] = "write_dontcache", > [OP_MAPREAD] = "mapread", > [OP_MAPWRITE] = "mapwrite", > [OP_TRUNCATE] = "truncate", > @@ -393,12 +402,14 @@ logdump(void) > prt("\t******WWWW"); > break; > case OP_READ: > + case OP_READ_DONTCACHE: > prt("READ 0x%x thru 0x%x\t(0x%x bytes)", > lp->args[0], lp->args[0] + lp->args[1] - 1, > lp->args[1]); > if (overlap) > prt("\t***RRRR***"); > break; > + case OP_WRITE_DONTCACHE: > case OP_WRITE: > prt("WRITE 0x%x thru 0x%x\t(0x%x bytes)", > lp->args[0], lp->args[0] + lp->args[1] - 1, > @@ -784,9 +795,8 @@ doflush(unsigned offset, unsigned size) > } > > void > -doread(unsigned offset, unsigned size) > +doread(unsigned offset, unsigned size, int flags) > { > - off_t ret; > unsigned iret; > > offset -= offset % readbdy; > @@ -818,12 +828,7 @@ doread(unsigned offset, unsigned size) > (monitorend == -1 || offset <= monitorend)))))) > prt("%lld read\t0x%x thru\t0x%x\t(0x%x bytes)\n", testcalls, > offset, offset + size - 1, size); > - ret = lseek(fd, (off_t)offset, SEEK_SET); > - if (ret == (off_t)-1) { > - prterr("doread: lseek"); > - report_failure(140); > - } > - iret = fsxread(fd, temp_buf, size, offset); > + iret = fsxread(fd, temp_buf, size, offset, flags); > if (iret != size) { > if (iret == -1) > prterr("doread: read"); > @@ -870,7 +875,6 @@ check_contents(void) > unsigned map_offset; > unsigned map_size; > char *p; > - off_t ret; > unsigned iret; > > if (!check_buf) { > @@ -885,13 +889,7 @@ check_contents(void) > if (size == 0) > return; > > - ret = lseek(fd, (off_t)offset, SEEK_SET); > - if (ret == (off_t)-1) { > - prterr("doread: lseek"); > - report_failure(140); > - } > - > - iret = fsxread(fd, check_buf, size, offset); > + iret = fsxread(fd, check_buf, size, offset, 0); > if (iret != size) { > if (iret == -1) > prterr("check_contents: read"); > @@ -1064,9 +1062,8 @@ update_file_size(unsigned offset, unsigned size) > } > > void > -dowrite(unsigned offset, unsigned size) > +dowrite(unsigned offset, unsigned size, int flags) > { > - off_t ret; > unsigned iret; > > offset -= offset % writebdy; > @@ -1099,14 +1096,9 @@ dowrite(unsigned offset, unsigned size) > (monitorstart == -1 || > (offset + size > monitorstart && > (monitorend == -1 || offset <= monitorend)))))) > - prt("%lld write\t0x%x thru\t0x%x\t(0x%x bytes)\n", testcalls, > - offset, offset + size - 1, size); > - ret = lseek(fd, (off_t)offset, SEEK_SET); > - if (ret == (off_t)-1) { > - prterr("dowrite: lseek"); > - report_failure(150); > - } > - iret = fsxwrite(fd, good_buf + offset, size, offset); > + prt("%lld write\t0x%x thru\t0x%x\t(0x%x bytes)\tdontcache=%d\n", testcalls, > + offset, offset + size - 1, size, (flags & RWF_DONTCACHE) != 0); > + iret = fsxwrite(fd, good_buf + offset, size, offset, flags); > if (iret != size) { > if (iret == -1) > prterr("dowrite: write"); > @@ -1954,6 +1946,26 @@ do_preallocate(unsigned offset, unsigned length, int keep_size, int unshare) > } > #endif > > +int > +test_dontcache_io(void) > +{ > + char buf[4096]; > + struct iovec iov = { .iov_base = buf, .iov_len = sizeof(buf) }; > + int ret, e; > + > + ret = preadv2(fd, &iov, 1, 0, RWF_DONTCACHE); > + e = ret < 0 ? errno : 0; > + if (e == EOPNOTSUPP) { > + if (!quiet) > + fprintf(stderr, > + "main: filesystem does not support " > + "dontcache IO, disabling!\n"); > + return 0; > + } > + > + return 1; > +} > + > void > writefileimage() > { > @@ -2337,12 +2349,28 @@ have_op: > switch (op) { > case OP_READ: > TRIM_OFF_LEN(offset, size, file_size); > - doread(offset, size); > + doread(offset, size, 0); > + break; > + > + case OP_READ_DONTCACHE: > + TRIM_OFF_LEN(offset, size, file_size); > + if (dontcache_io) > + doread(offset, size, RWF_DONTCACHE); > + else > + doread(offset, size, 0); > break; > > case OP_WRITE: > TRIM_OFF_LEN(offset, size, maxfilelen); > - dowrite(offset, size); > + dowrite(offset, size, 0); > + break; > + > + case OP_WRITE_DONTCACHE: > + TRIM_OFF_LEN(offset, size, maxfilelen); > + if (dontcache_io) > + dowrite(offset, size, RWF_DONTCACHE); > + else > + dowrite(offset, size, 0); > break; > > case OP_MAPREAD: > @@ -2538,6 +2566,7 @@ usage(void) > " -0: Do not use exchange range calls\n" > #endif > " -K: Do not use keep size\n\ > + -T: Do not use dontcache IO\n\ > -L: fsxLite - no file creations & no file size changes\n\ > -N numops: total # operations to do (default infinity)\n\ > -O: use oplen (see -o flag) for every op (default random)\n\ > @@ -2546,7 +2575,7 @@ usage(void) > -S seed: for random # generator (default 1) 0 gets timestamp\n\ > -W: mapped write operations DISabled\n\ > -X: Read file and compare to good buffer after every operation\n\ > - -Z: O_DIRECT (use -R, -W, -r and -w too)\n\ > + -Z: O_DIRECT (use -R, -W, -r and -w too, excludes dontcache IO)\n\ > --replay-ops=opsfile: replay ops from recorded .fsxops file\n\ > --record-ops[=opsfile]: dump ops file also on success. optionally specify ops file name\n\ > --duration=seconds: ignore any -N setting and run for this many seconds\n\ > @@ -2702,7 +2731,7 @@ uring_setup() > } > > int > -uring_rw(int rw, int fd, char *buf, unsigned len, unsigned offset) > +uring_rw(int rw, int fd, char *buf, unsigned len, unsigned offset, int flags) > { > struct io_uring_sqe *sqe; > struct io_uring_cqe *cqe; > @@ -2733,6 +2762,7 @@ uring_rw(int rw, int fd, char *buf, unsigned len, unsigned offset) > } else { > io_uring_prep_writev(sqe, fd, &iovec, 1, o); > } > + sqe->rw_flags = flags; > > ret = io_uring_submit_and_wait(&ring, 1); > if (ret != 1) { > @@ -2781,7 +2811,7 @@ uring_rw(int rw, int fd, char *buf, unsigned len, unsigned offset) > } > #else > int > -uring_rw(int rw, int fd, char *buf, unsigned len, unsigned offset) > +uring_rw(int rw, int fd, char *buf, unsigned len, unsigned offset, int flags) > { > fprintf(stderr, "io_rw: need IO_URING support!\n"); > exit(111); > @@ -2789,19 +2819,21 @@ uring_rw(int rw, int fd, char *buf, unsigned len, unsigned offset) > #endif > > int > -fsx_rw(int rw, int fd, char *buf, unsigned len, unsigned offset) > +fsx_rw(int rw, int fd, char *buf, unsigned len, unsigned offset, int flags) > { > int ret; > > if (aio) { > ret = aio_rw(rw, fd, buf, len, offset); > } else if (uring) { > - ret = uring_rw(rw, fd, buf, len, offset); > + ret = uring_rw(rw, fd, buf, len, offset, flags); > } else { > + struct iovec iov = { .iov_base = buf, .iov_len = len }; > + > if (rw == READ) > - ret = read(fd, buf, len); > + ret = preadv2(fd, &iov, 1, offset, flags); > else > - ret = write(fd, buf, len); > + ret = pwritev2(fd, &iov, 1, offset, flags); > } > return ret; > } > @@ -3065,6 +3097,9 @@ main(int argc, char **argv) > if (seed < 0) > usage(); > break; > + case 'T': > + dontcache_io = 0; > + break; > case 'W': > mapped_writes = 0; > if (!quiet) > @@ -3076,6 +3111,7 @@ main(int argc, char **argv) > case 'Z': > o_direct = O_DIRECT; > o_flags |= O_DIRECT; > + dontcache_io = 0; > break; > case 254: /* --duration */ > if (!optarg) { > @@ -3293,6 +3329,9 @@ main(int argc, char **argv) > copy_range_calls = test_copy_range(); > if (exchange_range_calls) > exchange_range_calls = test_exchange_range(); > + if (dontcache_io) > + dontcache_io = test_dontcache_io(); > + printf("Dontcache_io=%d\n", dontcache_io); Is this a debug printf that got left in by mistake? (Everything else in here looks fine to me...) --D > > while (keep_running()) > if (!test()) > -- > 2.47.1 > >
