From: Richard Henderson <richard.henderson@linaro.org>
To: Warner Losh <imp@bsdimp.com>, Karim Taha <kariem.taha2.7@gmail.com>
Cc: qemu-devel@nongnu.org, Stacey Son <sson@freebsd.org>
Subject: Re: [PATCH 15/22] Implement mlock(2), munlock(2), mlockall(2), munlockall(2), madvise(2), minherit(2)
Date: Sun, 20 Aug 2023 07:42:00 -0700 [thread overview]
Message-ID: <fb8dc083-96e1-1a18-fc89-63c305b56640@linaro.org> (raw)
In-Reply-To: <CANCZdfoTq3oYL007soQTn-4XhtxchqBkWecUk6QiEOcTNMvoFA@mail.gmail.com>
On 8/19/23 21:37, Warner Losh wrote:
> +/* madvise(2) */
> +static inline abi_long do_bsd_madvise(abi_long arg1, abi_long arg2,
> + abi_long arg3)
> +{
> + /*
> + * A straight passthrough may not be safe because qemu sometimes
> + * turns private file-backed mapping into anonymous mappings. This
> + * will break MADV_DONTNEED. This is a hint, so ignoring and returing
> + * success is ok.
> + */
> + return get_errno(0);
>
>
> This looks like it was copied from an early linux-user implementation, and
> that seems to have been fixed to no longer cause problems. Can someone
> that knows about the linux-user history here comment?
We now track pages that are "passthrough" and ok for DONTNEED etc.
case MADV_DONTNEED:
if (page_check_range(start, len, PAGE_PASSTHROUGH)) {
ret = get_errno(madvise(g2h_untagged(start), len, advice));
if ((advice == MADV_DONTNEED) && (ret == 0)) {
page_reset_target_data(start, start + len - 1);
}
}
It's still not ideal, but it's something.
r~
next prev parent reply other threads:[~2023-08-20 14:42 UTC|newest]
Thread overview: 79+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-19 9:47 [PATCH 00/22] Implement the mmap system call for FreeBSD Karim Taha
2023-08-19 9:47 ` [PATCH 01/22] Implement struct target_ipc_perm Karim Taha
2023-08-19 14:37 ` Richard Henderson
2023-08-20 4:07 ` Warner Losh
2023-08-19 9:47 ` [PATCH 02/22] Implement struct target_shmid_ds Karim Taha
2023-08-19 14:38 ` Richard Henderson
2023-08-20 4:08 ` Warner Losh
2023-08-19 9:47 ` [PATCH 03/22] Declarations for ipc_perm and shmid_ds conversion functions Karim Taha
2023-08-19 14:40 ` Richard Henderson
2023-08-20 4:08 ` Warner Losh
2023-08-19 9:47 ` [PATCH 04/22] Introduce freebsd/os-misc.h to the source tree Karim Taha
2023-08-19 14:40 ` Richard Henderson
2023-08-20 4:09 ` Warner Losh
2023-08-19 9:47 ` [PATCH 05/22] Implement shm_open2(2) system call Karim Taha
2023-08-19 15:10 ` Richard Henderson
2023-08-20 4:16 ` Warner Losh
2023-08-19 9:47 ` [PATCH 06/22] Implement shm_rename(2) " Karim Taha
2023-08-20 4:18 ` Warner Losh
2023-08-20 14:05 ` Richard Henderson
2023-08-19 9:47 ` [PATCH 07/22] Add bsd-mem.c to meson.build Karim Taha
2023-08-20 4:19 ` Warner Losh
2023-08-20 14:06 ` Richard Henderson
2023-08-19 9:47 ` [PATCH 08/22] Implement target_set_brk function in bsd-mem.c instead of os-syscall.c Karim Taha
2023-08-20 4:22 ` Warner Losh
2023-08-20 14:12 ` Richard Henderson
2023-08-19 9:47 ` [PATCH 09/22] Implement ipc_perm conversion between host and target Karim Taha
2023-08-20 4:23 ` Warner Losh
2023-08-20 14:16 ` Richard Henderson
2023-08-19 9:47 ` [PATCH 10/22] Implement shmid_ds " Karim Taha
2023-08-20 4:25 ` Warner Losh
2023-08-20 14:20 ` Richard Henderson
2023-09-03 8:45 ` Kariiem Taha
2023-09-05 1:43 ` Richard Henderson
2023-08-19 9:47 ` [PATCH 11/22] Introduce bsd-mem.h to the source tree Karim Taha
2023-08-20 4:26 ` Warner Losh
2023-08-20 14:21 ` Richard Henderson
2023-08-19 9:47 ` [PATCH 12/22] Implement mmap(2) and munmap(2) Karim Taha
2023-08-20 4:27 ` Warner Losh
2023-08-20 14:25 ` Richard Henderson
2023-08-19 9:47 ` [PATCH 13/22] Implement mprotect(2) Karim Taha
2023-08-20 4:28 ` Warner Losh
2023-08-20 14:25 ` Richard Henderson
2023-08-19 9:47 ` [PATCH 14/22] Implement msync(2) Karim Taha
2023-08-20 4:34 ` Warner Losh
2023-08-20 14:37 ` Richard Henderson
2023-08-19 9:47 ` [PATCH 15/22] Implement mlock(2), munlock(2), mlockall(2), munlockall(2), madvise(2), minherit(2) Karim Taha
2023-08-20 4:37 ` Warner Losh
2023-08-20 14:42 ` Richard Henderson [this message]
2023-08-20 14:43 ` Richard Henderson
2023-08-19 9:48 ` [PATCH 16/22] Implement mincore(2) Karim Taha
2023-08-20 4:37 ` Warner Losh
2023-08-20 14:55 ` Richard Henderson
2023-08-19 9:48 ` [PATCH 17/22] Implement do_obreak function Karim Taha
2023-08-20 4:40 ` Warner Losh
2023-08-20 15:03 ` Richard Henderson
2023-08-19 9:48 ` [PATCH 18/22] Implement shm_open(2) Karim Taha
2023-08-20 4:42 ` Warner Losh
2023-08-20 15:04 ` Richard Henderson
2023-08-20 15:10 ` Richard Henderson
2023-08-19 9:48 ` [PATCH 19/22] Implement shm_unlink(2) and shmget(2) Karim Taha
2023-08-20 4:42 ` Warner Losh
2023-08-20 15:05 ` Richard Henderson
2023-08-20 15:07 ` Richard Henderson
2023-08-19 9:48 ` [PATCH 20/22] Implement shmctl(2) Karim Taha
2023-08-20 4:43 ` Warner Losh
2023-08-20 15:13 ` Richard Henderson
2023-09-09 1:59 ` Karim Taha
2023-09-09 17:51 ` Richard Henderson
2023-08-19 9:48 ` [PATCH 21/22] Implement shmat(2) and shmdt(2) Karim Taha
2023-08-20 4:44 ` Warner Losh
2023-08-20 15:30 ` Richard Henderson
2023-08-22 18:03 ` Warner Losh
2023-08-22 18:11 ` Richard Henderson
2023-08-22 19:54 ` Warner Losh
2023-08-22 21:00 ` Richard Henderson
2023-08-19 9:48 ` [PATCH 22/22] Add stubs for vadvise(), sbrk() and sstk() Karim Taha
2023-08-20 4:45 ` Warner Losh
2023-08-20 15:35 ` Richard Henderson
2023-08-20 20:42 ` Warner Losh
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