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Mmap engine fixes #2017

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Merged
merged 3 commits into from
Nov 24, 2025
Merged

Mmap engine fixes #2017

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240c070
engines/mmap: support fadvise_hint
geertj Nov 22, 2025
4857911
engines/mmap: fix logic when "offset" > 0
geertj Nov 22, 2025
1a3e01f
engines/mmap: fix full/limited prep logic
geertj Nov 22, 2025
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41 changes: 21 additions & 20 deletions engines/mmap.c
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Original file line number Diff line number Diff line change
Expand Up @@ -15,7 +15,7 @@
#include "../verify.h"

/*
* Limits us to 1GiB of mapped files in total
* Limits us to 1GiB of mapped files in total on 32-bit architectures
*/
#define MMAP_TOTAL_SZ (1 * 1024 * 1024 * 1024UL)

Expand Down Expand Up @@ -53,6 +53,7 @@ static bool fio_madvise_file(struct thread_data *td, struct fio_file *f,
size_t length)

{
int flags;
struct fio_mmap_data *fmd = FILE_ENG_DATA(f);
#ifdef CONFIG_HAVE_THP
struct mmap_options *o = td->eo;
Expand All @@ -65,16 +66,20 @@ static bool fio_madvise_file(struct thread_data *td, struct fio_file *f,
if (!td->o.fadvise_hint)
return true;

if (!td_random(td)) {
if (posix_madvise(fmd->mmap_ptr, length, POSIX_MADV_SEQUENTIAL) < 0) {
td_verror(td, errno, "madvise");
return false;
}
} else {
if (posix_madvise(fmd->mmap_ptr, length, POSIX_MADV_RANDOM) < 0) {
td_verror(td, errno, "madvise");
return false;
}
if (td->o.fadvise_hint == F_ADV_TYPE)
flags = td_random(td) ? POSIX_MADV_RANDOM : POSIX_MADV_SEQUENTIAL;
else if (td->o.fadvise_hint == F_ADV_RANDOM)
flags = POSIX_MADV_RANDOM;
else if (td->o.fadvise_hint == F_ADV_SEQUENTIAL)
flags = POSIX_MADV_SEQUENTIAL;
else {
log_err("fio: unknown madvise type %d\n", td->o.fadvise_hint);
return false;
}

if (posix_madvise(fmd->mmap_ptr, length, flags) < 0) {
td_verror(td, errno, "madvise");
return false;
}

return true;
Expand Down Expand Up @@ -152,11 +157,8 @@ static int fio_mmapio_prep_limited(struct thread_data *td, struct io_u *io_u)
return EIO;
}

fmd->mmap_sz = mmap_map_size;
if (fmd->mmap_sz > f->io_size)
fmd->mmap_sz = f->io_size;

fmd->mmap_off = io_u->offset;
fmd->mmap_sz = io_u->buflen;

return fio_mmap_file(td, f, fmd->mmap_sz, fmd->mmap_off);
}
Expand All @@ -172,14 +174,14 @@ static int fio_mmapio_prep_full(struct thread_data *td, struct io_u *io_u)

if (fio_file_partial_mmap(f))
return EINVAL;
if (io_u->offset != (size_t) io_u->offset ||
f->io_size != (size_t) f->io_size) {

if (sizeof(size_t) < 8 && f->io_size > mmap_map_size) {
fio_file_set_partial_mmap(f);
return EINVAL;
}

fmd->mmap_sz = f->io_size;
fmd->mmap_off = 0;
fmd->mmap_off = f->file_offset;

ret = fio_mmap_file(td, f, fmd->mmap_sz, fmd->mmap_off);
if (ret)
Expand Down Expand Up @@ -218,8 +220,7 @@ static int fio_mmapio_prep(struct thread_data *td, struct io_u *io_u)
}

done:
io_u->mmap_data = fmd->mmap_ptr + io_u->offset - fmd->mmap_off -
f->file_offset;
io_u->mmap_data = fmd->mmap_ptr + io_u->offset - fmd->mmap_off;
return 0;
}

Expand Down
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