git: d689fda0703b - stable/13 - shmfd: account for the actually allocated pages
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Date: Fri, 20 Jan 2023 03:23:35 UTC
The branch stable/13 has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=d689fda0703bd7bf7320fe6e34f2abf260650f8e commit d689fda0703bd7bf7320fe6e34f2abf260650f8e Author: Konstantin Belousov <kib@FreeBSD.org> AuthorDate: 2022-11-23 21:26:38 +0000 Commit: Konstantin Belousov <kib@FreeBSD.org> CommitDate: 2023-01-20 03:20:02 +0000 shmfd: account for the actually allocated pages Tested by: pho (cherry picked from commit 0919f29d91031cf42eca99266bffe7b0faef8f1b) --- sys/kern/uipc_shm.c | 83 +++++++++++++++++++++++++++++++++++++++++++++++++---- sys/sys/mman.h | 1 + 2 files changed, 79 insertions(+), 5 deletions(-) diff --git a/sys/kern/uipc_shm.c b/sys/kern/uipc_shm.c index a1f26b40f343..f1dc0f828b23 100644 --- a/sys/kern/uipc_shm.c +++ b/sys/kern/uipc_shm.c @@ -343,6 +343,61 @@ shm_largepage(struct shmfd *shmfd) return (shmfd->shm_object->type == OBJT_PHYS); } +static void +shm_pager_freespace(vm_object_t obj, vm_pindex_t start, vm_size_t size) +{ + struct shmfd *shm; + vm_size_t c; + + swap_pager_freespace(obj, start, size, &c); + if (c == 0) + return; + + shm = obj->un_pager.swp.swp_priv; + if (shm == NULL) + return; + KASSERT(shm->shm_pages >= c, + ("shm %p pages %jd free %jd", shm, + (uintmax_t)shm->shm_pages, (uintmax_t)c)); + shm->shm_pages -= c; +} + +static void +shm_page_inserted(vm_object_t obj, vm_page_t m) +{ + struct shmfd *shm; + + shm = obj->un_pager.swp.swp_priv; + if (shm == NULL) + return; + if (!vm_pager_has_page(obj, m->pindex, NULL, NULL)) + shm->shm_pages += 1; +} + +static void +shm_page_removed(vm_object_t obj, vm_page_t m) +{ + struct shmfd *shm; + + shm = obj->un_pager.swp.swp_priv; + if (shm == NULL) + return; + if (!vm_pager_has_page(obj, m->pindex, NULL, NULL)) { + KASSERT(shm->shm_pages >= 1, + ("shm %p pages %jd free 1", shm, + (uintmax_t)shm->shm_pages)); + shm->shm_pages -= 1; + } +} + +static struct pagerops shm_swap_pager_ops = { + .pgo_kvme_type = KVME_TYPE_SWAP, + .pgo_freespace = shm_pager_freespace, + .pgo_page_inserted = shm_page_inserted, + .pgo_page_removed = shm_page_removed, +}; +static int shmfd_pager_type = -1; + static int shm_seek(struct file *fp, off_t offset, int whence, struct thread *td) { @@ -560,7 +615,6 @@ shm_stat(struct file *fp, struct stat *sb, struct ucred *active_cred, bzero(sb, sizeof(*sb)); sb->st_blksize = PAGE_SIZE; sb->st_size = shmfd->shm_size; - sb->st_blocks = howmany(sb->st_size, sb->st_blksize); mtx_lock(&shm_timestamp_lock); sb->st_atim = shmfd->shm_atime; sb->st_ctim = shmfd->shm_ctime; @@ -573,8 +627,12 @@ shm_stat(struct file *fp, struct stat *sb, struct ucred *active_cred, sb->st_dev = shm_dev_ino; sb->st_ino = shmfd->shm_ino; sb->st_nlink = shmfd->shm_object->ref_count; - sb->st_blocks = shmfd->shm_object->size / - (pagesizes[shmfd->shm_lp_psind] >> PAGE_SHIFT); + if (shm_largepage(shmfd)) { + sb->st_blocks = shmfd->shm_object->size / + (pagesizes[shmfd->shm_lp_psind] >> PAGE_SHIFT); + } else { + sb->st_blocks = shmfd->shm_pages; + } return (0); } @@ -858,6 +916,7 @@ struct shmfd * shm_alloc(struct ucred *ucred, mode_t mode, bool largepage) { struct shmfd *shmfd; + vm_object_t obj; shmfd = malloc(sizeof(*shmfd), M_SHMFD, M_WAITOK | M_ZERO); shmfd->shm_size = 0; @@ -870,8 +929,12 @@ shm_alloc(struct ucred *ucred, mode_t mode, bool largepage) VM_PROT_DEFAULT, 0, ucred); shmfd->shm_lp_alloc_policy = SHM_LARGEPAGE_ALLOC_DEFAULT; } else { - shmfd->shm_object = vm_pager_allocate(OBJT_SWAP, NULL, + obj = vm_pager_allocate(shmfd_pager_type, NULL, shmfd->shm_size, VM_PROT_DEFAULT, 0, ucred); + VM_OBJECT_WLOCK(obj); + obj->un_pager.swp.swp_priv = shmfd; + VM_OBJECT_WUNLOCK(obj); + shmfd->shm_object = obj; } KASSERT(shmfd->shm_object != NULL, ("shm_create: vm_pager_allocate")); vfs_timestamp(&shmfd->shm_birthtime); @@ -900,6 +963,7 @@ shm_hold(struct shmfd *shmfd) void shm_drop(struct shmfd *shmfd) { + vm_object_t obj; if (refcount_release(&shmfd->shm_refs)) { #ifdef MAC @@ -907,7 +971,13 @@ shm_drop(struct shmfd *shmfd) #endif rangelock_destroy(&shmfd->shm_rl); mtx_destroy(&shmfd->shm_mtx); - vm_object_deallocate(shmfd->shm_object); + obj = shmfd->shm_object; + if (!shm_largepage(shmfd)) { + VM_OBJECT_WLOCK(obj); + obj->un_pager.swp.swp_priv = NULL; + VM_OBJECT_WUNLOCK(obj); + } + vm_object_deallocate(obj); free(shmfd, M_SHMFD); } } @@ -946,6 +1016,9 @@ shm_init(void *arg) new_unrhdr64(&shm_ino_unr, 1); shm_dev_ino = devfs_alloc_cdp_inode(); KASSERT(shm_dev_ino > 0, ("shm dev inode not initialized")); + shmfd_pager_type = vm_pager_alloc_dyn_type(&shm_swap_pager_ops, + OBJT_SWAP); + MPASS(shmfd_pager_type != -1); for (i = 1; i < MAXPAGESIZES; i++) { if (pagesizes[i] == 0) diff --git a/sys/sys/mman.h b/sys/sys/mman.h index 71172bfd49a3..0413249dee2c 100644 --- a/sys/sys/mman.h +++ b/sys/sys/mman.h @@ -268,6 +268,7 @@ struct file; struct shmfd { vm_ooffset_t shm_size; vm_object_t shm_object; + vm_pindex_t shm_pages; /* allocated pages */ int shm_refs; uid_t shm_uid; gid_t shm_gid;