On Mon, Jan 06, 2025 at 10:48:46AM -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. If the kernel > being tested doesn't support RWF_DONTCACHE, then operations are performed > with regular read/write buffered IO. > > 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/fsstress.c | 136 +++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 136 insertions(+) > > diff --git a/ltp/fsstress.c b/ltp/fsstress.c > index 3d248ee25791..df9f6ffb86fc 100644 > --- a/ltp/fsstress.c > +++ b/ltp/fsstress.c > @@ -82,6 +82,12 @@ static int renameat2(int dfd1, const char *path1, > #define RENAME_WHITEOUT (1 << 2) /* Whiteout source */ > #endif > > +#ifndef RWF_DONTCACHE > +#define RWF_DONTCACHE 0x80 > +#endif > + > +static int have_rwf_dontcache = 1; > + > #define FILELEN_MAX (32*4096) > > typedef enum { > @@ -117,6 +123,7 @@ typedef enum { > OP_COLLAPSE, > OP_INSERT, > OP_READ, > + OP_READ_DONTCACHE, > OP_READLINK, > OP_READV, > OP_REMOVEFATTR, > @@ -143,6 +150,7 @@ typedef enum { > OP_URING_READ, > OP_URING_WRITE, > OP_WRITE, > + OP_WRITE_DONTCACHE, > OP_WRITEV, > OP_EXCHANGE_RANGE, > OP_LAST > @@ -248,6 +256,7 @@ void zero_f(opnum_t, long); > void collapse_f(opnum_t, long); > void insert_f(opnum_t, long); > void unshare_f(opnum_t, long); > +void read_dontcache_f(opnum_t, long); > void read_f(opnum_t, long); > void readlink_f(opnum_t, long); > void readv_f(opnum_t, long); > @@ -273,6 +282,7 @@ void unlink_f(opnum_t, long); > void unresvsp_f(opnum_t, long); > void uring_read_f(opnum_t, long); > void uring_write_f(opnum_t, long); > +void write_dontcache_f(opnum_t, long); > void write_f(opnum_t, long); > void writev_f(opnum_t, long); > void exchangerange_f(opnum_t, long); > @@ -315,6 +325,7 @@ struct opdesc ops[OP_LAST] = { > [OP_COLLAPSE] = {"collapse", collapse_f, 1, 1 }, > [OP_INSERT] = {"insert", insert_f, 1, 1 }, > [OP_READ] = {"read", read_f, 1, 0 }, > + [OP_READ_DONTCACHE] = {"read_dontcache", read_dontcache_f, 1, 0 }, > [OP_READLINK] = {"readlink", readlink_f, 1, 0 }, > [OP_READV] = {"readv", readv_f, 1, 0 }, > /* remove (delete) extended attribute */ > @@ -346,6 +357,7 @@ struct opdesc ops[OP_LAST] = { > [OP_URING_WRITE] = {"uring_write", uring_write_f, 1, 1 }, > [OP_WRITE] = {"write", write_f, 4, 1 }, > [OP_WRITEV] = {"writev", writev_f, 4, 1 }, > + [OP_WRITE_DONTCACHE]= {"write_dontcache", write_dontcache_f,4, 1 }, > [OP_EXCHANGE_RANGE]= {"exchangerange", exchangerange_f, 2, 1 }, > }, *ops_end; > > @@ -4635,6 +4647,71 @@ readv_f(opnum_t opno, long r) > close(fd); > } > > +void > +read_dontcache_f(opnum_t opno, long r) > +{ > + int e; > + pathname_t f; > + int fd; > + int64_t lr; > + off64_t off; > + struct stat64 stb; > + int v; > + char st[1024]; > + struct iovec iov; > + int flags; > + > + init_pathname(&f); > + if (!get_fname(FT_REGFILE, r, &f, NULL, NULL, &v)) { > + if (v) > + printf("%d/%lld: read - no filename\n", procid, opno); > + free_pathname(&f); > + return; > + } > + fd = open_path(&f, O_RDONLY); > + e = fd < 0 ? errno : 0; > + check_cwd(); > + if (fd < 0) { > + if (v) > + printf("%d/%lld: read - open %s failed %d\n", > + procid, opno, f.path, e); > + free_pathname(&f); > + return; > + } > + if (fstat64(fd, &stb) < 0) { > + if (v) > + printf("%d/%lld: read - fstat64 %s failed %d\n", > + procid, opno, f.path, errno); > + free_pathname(&f); > + close(fd); > + return; > + } > + inode_info(st, sizeof(st), &stb, v); > + if (stb.st_size == 0) { > + if (v) > + printf("%d/%lld: read - %s%s zero size\n", procid, opno, > + f.path, st); > + free_pathname(&f); > + close(fd); > + return; > + } > + lr = ((int64_t)random() << 32) + random(); > + off = (off64_t)(lr % stb.st_size); > + iov.iov_len = (random() % FILELEN_MAX) + 1; > + iov.iov_base = malloc(iov.iov_len); Should there be a check for null iov_base after the allocation? > + flags = have_rwf_dontcache ? RWF_DONTCACHE : 0; > + e = preadv2(fd, &iov, 1, off, flags) < 0 ? errno : 0; > + if (have_rwf_dontcache && e == EOPNOTSUPP) ...and should this set have_rwf_dontcache = 0? (Other than that, thanks for wiring this up...) --D > + e = preadv2(fd, &iov, 1, off, 0) < 0 ? errno : 0; > + free(iov.iov_base); > + if (v) > + printf("%d/%lld: read dontcache %s%s [%lld,%d] %d\n", > + procid, opno, f.path, st, (long long)off, > + (int)iov.iov_len, e); > + free_pathname(&f); > + close(fd); > +} > + > void > removefattr_f(opnum_t opno, long r) > { > @@ -5509,6 +5586,65 @@ writev_f(opnum_t opno, long r) > close(fd); > } > > +void > +write_dontcache_f(opnum_t opno, long r) > +{ > + int e; > + pathname_t f; > + int fd; > + int64_t lr; > + off64_t off; > + struct stat64 stb; > + int v; > + char st[1024]; > + struct iovec iov; > + int flags; > + > + init_pathname(&f); > + if (!get_fname(FT_REGm, r, &f, NULL, NULL, &v)) { > + if (v) > + printf("%d/%lld: write - no filename\n", procid, opno); > + free_pathname(&f); > + return; > + } > + fd = open_path(&f, O_WRONLY); > + e = fd < 0 ? errno : 0; > + check_cwd(); > + if (fd < 0) { > + if (v) > + printf("%d/%lld: write - open %s failed %d\n", > + procid, opno, f.path, e); > + free_pathname(&f); > + return; > + } > + if (fstat64(fd, &stb) < 0) { > + if (v) > + printf("%d/%lld: write - fstat64 %s failed %d\n", > + procid, opno, f.path, errno); > + free_pathname(&f); > + close(fd); > + return; > + } > + inode_info(st, sizeof(st), &stb, v); > + lr = ((int64_t)random() << 32) + random(); > + off = (off64_t)(lr % MIN(stb.st_size + (1024 * 1024), MAXFSIZE)); > + off %= maxfsize; > + iov.iov_len = (random() % FILELEN_MAX) + 1; > + iov.iov_base = malloc(iov.iov_len); > + memset(iov.iov_base, nameseq & 0xff, iov.iov_len); > + flags = have_rwf_dontcache ? RWF_DONTCACHE : 0; > + e = pwritev2(fd, &iov, 1, off, flags) < 0 ? errno : 0; > + if (have_rwf_dontcache && e == EOPNOTSUPP) > + e = pwritev2(fd, &iov, 1, off, 0) < 0 ? errno : 0; > + free(iov.iov_base); > + if (v) > + printf("%d/%lld: write dontcache %s%s [%lld,%d] %d\n", > + procid, opno, f.path, st, (long long)off, > + (int)iov.iov_len, e); > + free_pathname(&f); > + close(fd); > +} > + > char * > xattr_flag_to_string(int flag) > { > -- > 2.47.1 > >
