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[34.85.221.182]) by smtp.gmail.com with ESMTPSA id 00721157ae682-78a798a5518sm57284357b3.14.2025.11.25.08.59.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 25 Nov 2025 08:59:16 -0800 (PST) From: Pasha Tatashin To: pratyush@kernel.org, jasonmiu@google.com, graf@amazon.com, pasha.tatashin@soleen.com, rppt@kernel.org, dmatlack@google.com, rientjes@google.com, corbet@lwn.net, rdunlap@infradead.org, ilpo.jarvinen@linux.intel.com, kanie@linux.alibaba.com, ojeda@kernel.org, aliceryhl@google.com, masahiroy@kernel.org, akpm@linux-foundation.org, tj@kernel.org, yoann.congal@smile.fr, mmaurer@google.com, roman.gushchin@linux.dev, chenridong@huawei.com, axboe@kernel.dk, mark.rutland@arm.com, jannh@google.com, vincent.guittot@linaro.org, hannes@cmpxchg.org, dan.j.williams@intel.com, david@redhat.com, joel.granados@kernel.org, rostedt@goodmis.org, anna.schumaker@oracle.com, song@kernel.org, linux@weissschuh.net, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, gregkh@linuxfoundation.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, rafael@kernel.org, dakr@kernel.org, bartosz.golaszewski@linaro.org, cw00.choi@samsung.com, myungjoo.ham@samsung.com, yesanishhere@gmail.com, Jonathan.Cameron@huawei.com, quic_zijuhu@quicinc.com, aleksander.lobakin@intel.com, ira.weiny@intel.com, andriy.shevchenko@linux.intel.com, leon@kernel.org, lukas@wunner.de, bhelgaas@google.com, wagi@kernel.org, djeffery@redhat.com, stuart.w.hayes@gmail.com, ptyadav@amazon.de, lennart@poettering.net, brauner@kernel.org, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, saeedm@nvidia.com, ajayachandra@nvidia.com, jgg@nvidia.com, parav@nvidia.com, leonro@nvidia.com, witu@nvidia.com, hughd@google.com, skhawaja@google.com, chrisl@kernel.org Subject: [PATCH v8 10/18] mm: shmem: use SHMEM_F_* flags instead of VM_* flags Date: Tue, 25 Nov 2025 11:58:40 -0500 Message-ID: <20251125165850.3389713-11-pasha.tatashin@soleen.com> X-Mailer: git-send-email 2.52.0.460.gd25c4c69ec-goog In-Reply-To: <20251125165850.3389713-1-pasha.tatashin@soleen.com> References: <20251125165850.3389713-1-pasha.tatashin@soleen.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Pratyush Yadav shmem_inode_info::flags can have the VM flags VM_NORESERVE and VM_LOCKED. These are used to suppress pre-accounting or to lock the pages in the inode respectively. Using the VM flags directly makes it difficult to add shmem-specific flags that are unrelated to VM behavior since one would need to find a VM flag not used by shmem and re-purpose it. Introduce SHMEM_F_NORESERVE and SHMEM_F_LOCKED which represent the same information, but their bits are independent of the VM flags. Callers can still pass VM_NORESERVE to shmem_get_inode(), but it gets transformed to the shmem-specific flag internally. No functional changes intended. Signed-off-by: Pratyush Yadav Signed-off-by: Pasha Tatashin Reviewed-by: Mike Rapoport (Microsoft) --- include/linux/shmem_fs.h | 6 ++++++ mm/shmem.c | 28 +++++++++++++++------------- 2 files changed, 21 insertions(+), 13 deletions(-) diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h index 0e47465ef0fd..650874b400b5 100644 --- a/include/linux/shmem_fs.h +++ b/include/linux/shmem_fs.h @@ -10,6 +10,7 @@ #include #include #include +#include =20 struct swap_iocb; =20 @@ -19,6 +20,11 @@ struct swap_iocb; #define SHMEM_MAXQUOTAS 2 #endif =20 +/* Suppress pre-accounting of the entire object size. */ +#define SHMEM_F_NORESERVE BIT(0) +/* Disallow swapping. */ +#define SHMEM_F_LOCKED BIT(1) + struct shmem_inode_info { spinlock_t lock; unsigned int seals; /* shmem seals */ diff --git a/mm/shmem.c b/mm/shmem.c index 58701d14dd96..1d5036dec08a 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -175,20 +175,20 @@ static inline struct shmem_sb_info *SHMEM_SB(struct s= uper_block *sb) */ static inline int shmem_acct_size(unsigned long flags, loff_t size) { - return (flags & VM_NORESERVE) ? + return (flags & SHMEM_F_NORESERVE) ? 0 : security_vm_enough_memory_mm(current->mm, VM_ACCT(size)); } =20 static inline void shmem_unacct_size(unsigned long flags, loff_t size) { - if (!(flags & VM_NORESERVE)) + if (!(flags & SHMEM_F_NORESERVE)) vm_unacct_memory(VM_ACCT(size)); } =20 static inline int shmem_reacct_size(unsigned long flags, loff_t oldsize, loff_t newsize) { - if (!(flags & VM_NORESERVE)) { + if (!(flags & SHMEM_F_NORESERVE)) { if (VM_ACCT(newsize) > VM_ACCT(oldsize)) return security_vm_enough_memory_mm(current->mm, VM_ACCT(newsize) - VM_ACCT(oldsize)); @@ -206,7 +206,7 @@ static inline int shmem_reacct_size(unsigned long flags, */ static inline int shmem_acct_blocks(unsigned long flags, long pages) { - if (!(flags & VM_NORESERVE)) + if (!(flags & SHMEM_F_NORESERVE)) return 0; =20 return security_vm_enough_memory_mm(current->mm, @@ -215,7 +215,7 @@ static inline int shmem_acct_blocks(unsigned long flags= , long pages) =20 static inline void shmem_unacct_blocks(unsigned long flags, long pages) { - if (flags & VM_NORESERVE) + if (flags & SHMEM_F_NORESERVE) vm_unacct_memory(pages * VM_ACCT(PAGE_SIZE)); } =20 @@ -1551,7 +1551,7 @@ int shmem_writeout(struct folio *folio, struct swap_i= ocb **plug, int nr_pages; bool split =3D false; =20 - if ((info->flags & VM_LOCKED) || sbinfo->noswap) + if ((info->flags & SHMEM_F_LOCKED) || sbinfo->noswap) goto redirty; =20 if (!total_swap_pages) @@ -2910,15 +2910,15 @@ int shmem_lock(struct file *file, int lock, struct = ucounts *ucounts) * ipc_lock_object() when called from shmctl_do_lock(), * no serialization needed when called from shm_destroy(). */ - if (lock && !(info->flags & VM_LOCKED)) { + if (lock && !(info->flags & SHMEM_F_LOCKED)) { if (!user_shm_lock(inode->i_size, ucounts)) goto out_nomem; - info->flags |=3D VM_LOCKED; + info->flags |=3D SHMEM_F_LOCKED; mapping_set_unevictable(file->f_mapping); } - if (!lock && (info->flags & VM_LOCKED) && ucounts) { + if (!lock && (info->flags & SHMEM_F_LOCKED) && ucounts) { user_shm_unlock(inode->i_size, ucounts); - info->flags &=3D ~VM_LOCKED; + info->flags &=3D ~SHMEM_F_LOCKED; mapping_clear_unevictable(file->f_mapping); } retval =3D 0; @@ -3062,7 +3062,7 @@ static struct inode *__shmem_get_inode(struct mnt_idm= ap *idmap, spin_lock_init(&info->lock); atomic_set(&info->stop_eviction, 0); info->seals =3D F_SEAL_SEAL; - info->flags =3D flags & VM_NORESERVE; + info->flags =3D (flags & VM_NORESERVE) ? SHMEM_F_NORESERVE : 0; info->i_crtime =3D inode_get_mtime(inode); info->fsflags =3D (dir =3D=3D NULL) ? 0 : SHMEM_I(dir)->fsflags & SHMEM_FL_INHERITED; @@ -5804,8 +5804,10 @@ static inline struct inode *shmem_get_inode(struct m= nt_idmap *idmap, /* common code */ =20 static struct file *__shmem_file_setup(struct vfsmount *mnt, const char *n= ame, - loff_t size, unsigned long flags, unsigned int i_flags) + loff_t size, unsigned long vm_flags, + unsigned int i_flags) { + unsigned long flags =3D (vm_flags & VM_NORESERVE) ? SHMEM_F_NORESERVE : 0; struct inode *inode; struct file *res; =20 @@ -5822,7 +5824,7 @@ static struct file *__shmem_file_setup(struct vfsmoun= t *mnt, const char *name, return ERR_PTR(-ENOMEM); =20 inode =3D shmem_get_inode(&nop_mnt_idmap, mnt->mnt_sb, NULL, - S_IFREG | S_IRWXUGO, 0, flags); + S_IFREG | S_IRWXUGO, 0, vm_flags); if (IS_ERR(inode)) { shmem_unacct_size(flags, size); return ERR_CAST(inode); --=20 2.52.0.460.gd25c4c69ec-goog