- 05 Feb, 2008 40 commits
-
-
Rafael J. Wysocki authored
Modify the b43 driver to avoid deadlocking suspend and resume, which happens as a result of attempting to unregister device objects locked by the PM core during suspend/resume cycles. Also, make it use a suspend-safe method of unregistering device object in the resume error path. Signed-off-by:
Rafael J. Wysocki <rjw@sisk.pl> Acked-by:
Michael Buesch <mb@bu3sch.de> Cc: Pavel Machek <pavel@ucw.cz> Cc: "John W. Linville" <linville@tuxdriver.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Len Brown <lenb@kernel.org> Cc: Greg KH <greg@kroah.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Richard Purdie <rpurdie@rpsys.net> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
-
Rafael J. Wysocki authored
Make it possible to unregister a led classdev object in a safe way during a suspend/resume cycle. Signed-off-by:
-
Rafael J. Wysocki authored
Make it possible to unregister a Hardware Random Number Generator device object in a safe way during a suspend/resume cycle. Signed-off-by:
-
Rafael J. Wysocki authored
Make it possible to unregister a misc device object in a safe way during a suspend/resume cycle. Signed-off-by:
-
Mark Gross authored
Replace latency.c use with pm_qos_params use. Signed-off-by:
mark gross <mgross@linux.intel.com> Cc: "John W. Linville" <linville@tuxdriver.com> Cc: Len Brown <lenb@kernel.org> Cc: Jaroslav Kysela <perex@suse.cz> Cc: Takashi Iwai <tiwai@suse.de> Cc: Arjan van de Ven <arjan@infradead.org> Signed-off-by:
-
Mark Gross authored
The following patch is a generalization of the latency.c implementation done by Arjan last year. It provides infrastructure for more than one parameter, and exposes a user mode interface for processes to register pm_qos expectations of processes. This interface provides a kernel and user mode interface for registering performance expectations by drivers, subsystems and user space applications on one of the parameters. Currently we have {cpu_dma_latency, network_latency, network_throughput} as the initial set of pm_qos parameters. The infrastructure exposes multiple misc device nodes one per implemented parameter. The set of parameters implement is defined by pm_qos_power_init() and pm_qos_params.h. This is done because having the available parameters being runtime configurable or changeable from a driver was seen as too easy to abuse. For each parameter a list of performance requirements is maintained along with an aggregated target value. The aggregated target value is updated with changes to the requirement list or elements of the list. Typically the aggregated target value is simply the max or min of the requirement values held in the parameter list elements. >From kernel mode the use of this interface is simple: pm_qos_add_requirement(param_id, name, target_value): Will insert a named element in the list for that identified PM_QOS parameter with the target value. Upon change to this list the new target is recomputed and any registered notifiers are called only if the target value is now different. pm_qos_update_requirement(param_id, name, new_target_value): Will search the list identified by the param_id for the named list element and then update its target value, calling the notification tree if the aggregated target is changed. with that name is already registered. pm_qos_remove_requirement(param_id, name): Will search the identified list for the named element and remove it, after removal it will update the aggregate target and call the notification tree if the target was changed as a result of removing the named requirement. >From user mode: Only processes can register a pm_qos requirement. To provide for automatic cleanup for process the interface requires the process to register its parameter requirements in the following way: To register the default pm_qos target for the specific parameter, the process must open one of /dev/[cpu_dma_latency, network_latency, network_throughput] As long as the device node is held open that process has a registered requirement on the parameter. The name of the requirement is "process_<PID>" derived from the current->pid from within the open system call. To change the requested target value the process needs to write a s32 value to the open device node. This translates to a pm_qos_update_requirement call. To remove the user mode request for a target value simply close the device node. [akpm@linux-foundation.org: fix warnings] [akpm@linux-foundation.org: fix build] [akpm@linux-foundation.org: fix build again] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: -
Adrian Bunk authored
kernel_shutdown_prepare() can now become static. Signed-off-by:
Adrian Bunk <bunk@kernel.org> Acked-by:
Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by:
-
Adrian Bunk authored
resume_file[] and create_image() can become static. Signed-off-by:
-
Andrew Morton authored
mm/vmalloc.c: In function 'unmap_kernel_range': mm/vmalloc.c:75: warning: unused variable 'start' Macros are so horrid. Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Signed-off-by:
-
Nick Piggin authored
Convert AGP alpha driver from nopage to fault. NULL is NOPAGE_SIGBUS, so we aren't changing behaviour there. Signed-off-by:
Nick Piggin <npiggin@suse.de> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Signed-off-by:
-
Samuel Thibault authored
Alpha doesn't use socketcall and doesn't provide __NR_socketcall. Signed-off-by:
Samuel Thibault <samuel.thibault@citrix.com> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Signed-off-by:
-
FUJITA Tomonori authored
pci-noop.c doesn't use DMA mappings. Signed-off-by:
FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Signed-off-by:
-
Andrew Morton authored
Prevents stuff like drivers/crypto/hifn_795x.c:2443: warning: format '%d' expects type 'int', but argument 4 has type 'long int' drivers/crypto/hifn_795x.c:2443: warning: format '%d' expects type 'int', but argument 4 has type 'long int' (at least). Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Signed-off-by:
-
Lucas Woods authored
Signed-off-by:
Lucas Woods <woodzy@gmail.com> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Signed-off-by:
-
Adrian Bunk authored
One EXPORT_SYMBOL should be enough for everyone. Signed-off-by:
Greg Ungerer <gerg@uclinux.org> Signed-off-by:
-
Paul Mundt authored
This builds on top of the earlier vmalloc_32_user() work introduced by b5073173, as we now have places in the nommu allmodconfig that hit up against these missing APIs. As vmalloc_32_user() is already implemented, this is moved over to vmalloc_user() and simply made a wrapper. As all current nommu platforms are 32-bit addressable, there's no special casing we have to do for ZONE_DMA and things of that nature as per GFP_VMALLOC32. remap_vmalloc_range() needs to check VM_USERMAP in order to figure out whether we permit the remap or not, which means that we also have to rework the vmalloc_user() code to grovel for the VMA and set the flag. Signed-off-by:
Paul Mundt <lethal@linux-sh.org> Acked-by:
David McCullough <david_mccullough@securecomputing.com> Acked-by:
David Howells <dhowells@redhat.com> Acked-by:
Greg Ungerer <gerg@snapgear.com> Signed-off-by:
-
Jiri Olsa authored
Removing config variable DUMPTOFLASH, since it is not used Signed-off-by:
Jiri Olsa <olsajiri@gmail.com> Acked-by:
-
Jiri Olsa authored
remove dead config symbols from m68knommu code Signed-off-by:
-
Greg Ungerer authored
Use ARRAY_SIZE macroto get maximum ports in ColdFire serial driver. Signed-off-by:
-
Pavel Emelyanov authored
The function is question gets the pid from sysctl table, so this one is a virtual pid, i.e. the pid of a task as it is seen from inside a namespace. So the find_task_by_vpid() must be used here. Signed-off-by:
Pavel Emelyanov <xemul@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: David Howells <dhowells@redhat.com> Signed-off-by:
-
Jiri Olsa authored
Remove dead config symbol from FRV code. Signed-off-by:
-
Robert P. J. Day authored
To be consistent with other architectures, these two DMA macros should be defined in scatterlist.h as opposed to dma-mapping.h Signed-off-by:
Robert P. J. Day <rpjday@crashcourse.ca> Acked-by:
-
David Howells authored
Permit the memory to be located somewhere other than address 0xC0000000 in NOMMU mode. The configuration options are already present, it just requires wiring up in the linker script. Note that only a limited set of locations of runtime addresses are available because of the way the CPU protection registers work. Signed-off-by:
-
Casey Schaufler authored
Smack is the Simplified Mandatory Access Control Kernel. Smack implements mandatory access control (MAC) using labels attached to tasks and data containers, including files, SVIPC, and other tasks. Smack is a kernel based scheme that requires an absolute minimum of application support and a very small amount of configuration data. Smack uses extended attributes and provides a set of general mount options, borrowing technics used elsewhere. Smack uses netlabel for CIPSO labeling. Smack provides a pseudo-filesystem smackfs that is used for manipulation of system Smack attributes. The patch, patches for ls and sshd, a README, a startup script, and x86 binaries for ls and sshd are also available on http://www.schaufler-ca.com Development has been done using Fedora Core 7 in a virtual machine environment and on an old Sony laptop. Smack provides mandatory access controls based on the label attached to a task and the label attached to the object it is attempting to access. Smack labels are deliberately short (1-23 characters) text strings. Single character labels using special characters are reserved for system use. The only operation applied to Smack labels is equality comparison. No wildcards or expressions, regular or otherwise, are used. Smack labels are composed of printable characters and may not include "/". A file always gets the Smack label of the task that created it. Smack defines and uses these labels: "*" - pronounced "star" "_" - pronounced "floor" "^" - pronounced "hat" "?" - pronounced "huh" The access rules enforced by Smack are, in order: 1. Any access requested by a task labeled "*" is denied. 2. A read or execute access requested by a task labeled "^" is permitted. 3. A read or execute access requested on an object labeled "_" is permitted. 4. Any access requested on an object labeled "*" is permitted. 5. Any access requested by a task on an object with the same label is permitted. 6. Any access requested that is explicitly defined in the loaded rule set is permitted. 7. Any other access is denied. Rules may be explicitly defined by writing subject,object,access triples to /smack/load. Smack rule sets can be easily defined that describe Bell&LaPadula sensitivity, Biba integrity, and a variety of interesting configurations. Smack rule sets can be modified on the fly to accommodate changes in the operating environment or even the time of day. Some practical use cases: Hierarchical levels. The less common of the two usual uses for MLS systems is to define hierarchical levels, often unclassified, confidential, secret, and so on. To set up smack to support this, these rules could be defined: C Unclass rx S C rx S Unclass rx TS S rx TS C rx TS Unclass rx A TS process can read S, C, and Unclass data, but cannot write it. An S process can read C and Unclass. Note that specifying that TS can read S and S can read C does not imply TS can read C, it has to be explicitly stated. Non-hierarchical categories. This is the more common of the usual uses for an MLS system. Since the default rule is that a subject cannot access an object with a different label no access rules are required to implement compartmentalization. A case that the Bell & LaPadula policy does not allow is demonstrated with this Smack access rule: A case that Bell&LaPadula does not allow that Smack does: ESPN ABC r ABC ESPN r On my portable video device I have two applications, one that shows ABC programming and the other ESPN programming. ESPN wants to show me sport stories that show up as news, and ABC will only provide minimal information about a sports story if ESPN is covering it. Each side can look at the other's info, neither can change the other. Neither can see what FOX is up to, which is just as well all things considered. Another case that I especially like: SatData Guard w Guard Publish w A program running with the Guard label opens a UDP socket and accepts messages sent by a program running with a SatData label. The Guard program inspects the message to ensure it is wholesome and if it is sends it to a program running with the Publish label. This program then puts the information passed in an appropriate place. Note that the Guard program cannot write to a Publish file system object because file system semanitic require read as well as write. The four cases (categories, levels, mutual read, guardbox) here are all quite real, and problems I've been asked to solve over the years. The first two are easy to do with traditonal MLS systems while the last two you can't without invoking privilege, at least for a while. Signed-off-by:Casey Schaufler <casey@schaufler-ca.com> Cc: Joshua Brindle <method@manicmethod.com> Cc: Paul Moore <paul.moore@hp.com> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: Chris Wright <chrisw@sous-sol.org> Cc: James Morris <jmorris@namei.org> Cc: "Ahmed S. Darwish" <darwish.07@gmail.com> Cc: Andrew G. Morgan <morgan@kernel.org> Signed-off-by:
-
Paul Moore authored
Add a new set of configuration functions to the NetLabel/LSM API so that LSMs can perform their own configuration of the NetLabel subsystem without relying on assistance from userspace. Signed-off-by:
Paul Moore <paul.moore@hp.com> Signed-off-by:
James Morris <jmorris@namei.org> Cc: Chris Wright <chrisw@sous-sol.org> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by:
-
Serge E. Hallyn authored
Root processes are considered more important when out of memory and killing proceses. The check for CAP_SYS_ADMIN was augmented with a check for uid==0 or euid==0. There are several possible ways to look at this: 1. uid comparisons are unnecessary, trust CAP_SYS_ADMIN alone. However CAP_SYS_RESOURCE is the one that really means "give me extra resources" so allow for that as well. 2. Any privileged code should be protected, but uid is not an indication of privilege. So we should check whether any capabilities are raised. 3. uid==0 makes processes on the host as well as in containers more important, so we should keep the existing checks. 4. uid==0 makes processes only on the host more important, even without any capabilities. So we should be keeping the (uid==0||euid==0) check but only when userns==&init_user_ns. I'm following number 1 here. Signed-off-by:
Serge Hallyn <serue@us.ibm.com> Cc: Andrew Morgan <morgan@kernel.org> Signed-off-by:
-
Serge E. Hallyn authored
The capability bounding set is a set beyond which capabilities cannot grow. Currently cap_bset is per-system. It can be manipulated through sysctl, but only init can add capabilities. Root can remove capabilities. By default it includes all caps except CAP_SETPCAP. This patch makes the bounding set per-process when file capabilities are enabled. It is inherited at fork from parent. Noone can add elements, CAP_SETPCAP is required to remove them. One example use of this is to start a safer container. For instance, until device namespaces or per-container device whitelists are introduced, it is best to take CAP_MKNOD away from a container. The bounding set will not affect pP and pE immediately. It will only affect pP' and pE' after subsequent exec()s. It also does not affect pI, and exec() does not constrain pI'. So to really start a shell with no way of regain CAP_MKNOD, you would do prctl(PR_CAPBSET_DROP, CAP_MKNOD); cap_t cap = cap_get_proc(); cap_value_t caparray[1]; caparray[0] = CAP_MKNOD; cap_set_flag(cap, CAP_INHERITABLE, 1, caparray, CAP_DROP); cap_set_proc(cap); cap_free(cap); The following test program will get and set the bounding set (but not pI). For instance ./bset get (lists capabilities in bset) ./bset drop cap_net_raw (starts shell with new bset) (use capset, setuid binary, or binary with file capabilities to try to increase caps) ************************************************************ cap_bound.c ************************************************************ #include <sys/prctl.h> #include <linux/capability.h> #include <sys/types.h> #include <unistd.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #ifndef PR_CAPBSET_READ #define PR_CAPBSET_READ 23 #endif #ifndef PR_CAPBSET_DROP #define PR_CAPBSET_DROP 24 #endif int usage(char *me) { printf("Usage: %s get\n", me); printf(" %s drop <capability>\n", me); return 1; } #define numcaps 32 char *captable[numcaps] = { "cap_chown", "cap_dac_override", "cap_dac_read_search", "cap_fowner", "cap_fsetid", "cap_kill", "cap_setgid", "cap_setuid", "cap_setpcap", "cap_linux_immutable", "cap_net_bind_service", "cap_net_broadcast", "cap_net_admin", "cap_net_raw", "cap_ipc_lock", "cap_ipc_owner", "cap_sys_module", "cap_sys_rawio", "cap_sys_chroot", "cap_sys_ptrace", "cap_sys_pacct", "cap_sys_admin", "cap_sys_boot", "cap_sys_nice", "cap_sys_resource", "cap_sys_time", "cap_sys_tty_config", "cap_mknod", "cap_lease", "cap_audit_write", "cap_audit_control", "cap_setfcap" }; int getbcap(void) { int comma=0; unsigned long i; int ret; printf("i know of %d capabilities\n", numcaps); printf("capability bounding set:"); for (i=0; i<numcaps; i++) { ret = prctl(PR_CAPBSET_READ, i); if (ret < 0) perror("prctl"); else if (ret==1) printf("%s%s", (comma++) ? ", " : " ", captable[i]); } printf("\n"); return 0; } int capdrop(char *str) { unsigned long i; int found=0; for (i=0; i<numcaps; i++) { if (strcmp(captable[i], str) == 0) { found=1; break; } } if (!found) return 1; if (prctl(PR_CAPBSET_DROP, i)) { perror("prctl"); return 1; } return 0; } int main(int argc, char *argv[]) { if (argc<2) return usage(argv[0]); if (strcmp(argv[1], "get")==0) return getbcap(); if (strcmp(argv[1], "drop")!=0 || argc<3) return usage(argv[0]); if (capdrop(argv[2])) { printf("unknown capability\n"); return 1; } return execl("/bin/bash", "/bin/bash", NULL); } ************************************************************ [serue@us.ibm.com: fix typo] Signed-off-by:Andrew G. Morgan <morgan@kernel.org> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: James Morris <jmorris@namei.org> Cc: Chris Wright <chrisw@sous-sol.org> Cc: Casey Schaufler <casey@schaufler-ca.com>a Signed-off-by:
Jiri Slaby <jirislaby@gmail.com> Signed-off-by:
-
Andrew Morgan authored
KaiGai Kohei observed that this line in the linux header is not needed. Signed-off-by:
-
Andrew Morgan authored
The patch supports legacy (32-bit) capability userspace, and where possible translates 32-bit capabilities to/from userspace and the VFS to 64-bit kernel space capabilities. If a capability set cannot be compressed into 32-bits for consumption by user space, the system call fails, with -ERANGE. FWIW libcap-2.00 supports this change (and earlier capability formats) http://www.kernel.org/pub/linux/libs/security/linux-privs/kernel-2.6/ [akpm@linux-foundation.org: coding-syle fixes] [akpm@linux-foundation.org: use get_task_comm()] [ezk@cs.sunysb.edu: build fix] [akpm@linux-foundation.org: do not initialise statics to 0 or NULL] [akpm@linux-foundation.org: unused var] [serue@us.ibm.com: export __cap_ symbols] Signed-off-by:
Erez Zadok <ezk@cs.sunysb.edu> Signed-off-by:
-
Andrew Morton authored
Revert b68680e4 to make way for the next patch: "Add 64-bit capability support to the kernel". We want to keep the vfs_cap_data.data[] structure, using two 'data's for 64-bit caps (and later three for 96-bit caps), whereas b68680e4 had gotten rid of the 'data' struct made its members inline. The 64-bit caps patch keeps the stack abuse fix at get_file_caps(), which was the more important part of that patch. [akpm@linux-foundation.org: coding-style fixes] Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: Serge Hallyn <serue@us.ibm.com> Cc: Chris Wright <chrisw@sous-sol.org> Cc: James Morris <jmorris@namei.org> Cc: Casey Schaufler <casey@schaufler-ca.com> Cc: Andrew Morgan <morgan@kernel.org> Signed-off-by:
-
David P. Quigley authored
Originally vfs_getxattr would pull the security xattr variable using the inode getxattr handle and then proceed to clobber it with a subsequent call to the LSM. This patch reorders the two operations such that when the xattr requested is in the security namespace it first attempts to grab the value from the LSM directly. If it fails to obtain the value because there is no module present or the module does not support the operation it will fall back to using the inode getxattr operation. In the event that both are inaccessible it returns EOPNOTSUPP. Signed-off-by:
David P. Quigley <dpquigl@tycho.nsa.gov> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: Chris Wright <chrisw@sous-sol.org> Acked-by:
-
David P. Quigley authored
This patch modifies the interface to inode_getsecurity to have the function return a buffer containing the security blob and its length via parameters instead of relying on the calling function to give it an appropriately sized buffer. Security blobs obtained with this function should be freed using the release_secctx LSM hook. This alleviates the problem of the caller having to guess a length and preallocate a buffer for this function allowing it to be used elsewhere for Labeled NFS. The patch also removed the unused err parameter. The conversion is similar to the one performed by Al Viro for the security_getprocattr hook. Signed-off-by:
-
Matt Mackall authored
Signed-off-by:
Matt Mackall <mpm@selenic.com> Signed-off-by:
-
Matt Mackall authored
By putting smaller objects on their own list, we greatly reduce overall external fragmentation and increase repeatability. This reduces total SLOB overhead from > 50% to ~6% on a simple boot test. Signed-off-by:
-
Matt Mackall authored
We weren't merging freed blocks at the beginning of the free list. Fixing this showed a 2.5% efficiency improvement in a userspace test harness. Signed-off-by:
-
Fengguang Wu authored
After making dirty a 100M file, the normal behavior is to start the writeback for all data after 30s delays. But sometimes the following happens instead: - after 30s: ~4M - after 5s: ~4M - after 5s: all remaining 92M Some analyze shows that the internal io dispatch queues goes like this: s_io s_more_io ------------------------- 1) 100M,1K 0 2) 1K 96M 3) 0 96M 1) initial state with a 100M file and a 1K file 2) 4M written, nr_to_write <= 0, so write more 3) 1K written, nr_to_write > 0, no more writes(BUG) nr_to_write > 0 in (3) fools the upper layer to think that data have all been written out. The big dirty file is actually still sitting in s_more_io. We cannot simply splice s_more_io back to s_io as soon as s_io becomes empty, and let the loop in generic_sync_sb_inodes() continue: this may starve newly expired inodes in s_dirty. It is also not an option to draw inodes from both s_more_io and s_dirty, an let the loop go on: this might lead to live locks, and might also starve other superblocks in sync time(well kupdate may still starve some superblocks, that's another bug). We have to return when a full scan of s_io completes. So nr_to_write > 0 does not necessarily mean that "all data are written". This patch introduces a flag writeback_control.more_io to indicate that more io should be done. With it the big dirty file no longer has to wait for the next kupdate invokation 5s later. In sync_sb_inodes() we only set more_io on super_blocks we actually visited. This avoids the interaction between two pdflush deamons. Also in __sync_single_inode() we don't blindly keep requeuing the io if the filesystem cannot progress. Failing to do so may lead to 100% iowait. Tested-by:
Mike Snitzer <snitzer@gmail.com> Signed-off-by:
Fengguang Wu <wfg@mail.ustc.edu.cn> Cc: Michael Rubin <mrubin@google.com> Signed-off-by:
-
Sam Ravnborg authored
Fix following warning: WARNING: mm/built-in.o(.text+0x22069): Section mismatch in reference from the function sparse_early_usemap_alloc() to the function .init.text:__alloc_bootmem_node() static sparse_early_usemap_alloc() were used only by sparse_init() and with sparse_init() annotated _init it is safe to annotate sparse_early_usemap_alloc with __init too. Signed-off-by:
Sam Ravnborg <sam@ravnborg.org> Cc: Andy Whitcroft <apw@shadowen.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by:
-
Nick Piggin authored
After running SetPageUptodate, preceeding stores to the page contents to actually bring it uptodate may not be ordered with the store to set the page uptodate. Therefore, another CPU which checks PageUptodate is true, then reads the page contents can get stale data. Fix this by having an smp_wmb before SetPageUptodate, and smp_rmb after PageUptodate. Many places that test PageUptodate, do so with the page locked, and this would be enough to ensure memory ordering in those places if SetPageUptodate were only called while the page is locked. Unfortunately that is not always the case for some filesystems, but it could be an idea for the future. Also bring the handling of anonymous page uptodateness in line with that of file backed page management, by marking anon pages as uptodate when they _are_ uptodate, rather than when our implementation requires that they be marked as such. Doing allows us to get rid of the smp_wmb's in the page copying functions, which were especially added for anonymous pages for an analogous memory ordering problem. Both file and anonymous pages are handled with the same barriers. FAQ: Q. Why not do this in flush_dcache_page? A. Firstly, flush_dcache_page handles only one side (the smb side) of the ordering protocol; we'd still need smp_rmb somewhere. Secondly, hiding away memory barriers in a completely unrelated function is nasty; at least in the PageUptodate macros, they are located together with (half) the operations involved in the ordering. Thirdly, the smp_wmb is only required when first bringing the page uptodate, wheras flush_dcache_page should be called each time it is written to through the kernel mapping. It is logically the wrong place to put it. Q. Why does this increase my text size / reduce my performance / etc. A. Because it is adding the necessary instructions to eliminate the data-race. Q. Can it be improved? A. Yes, eg. if you were to create a rule that all SetPageUptodate operations run under the page lock, we could avoid the smp_rmb places where PageUptodate is queried under the page lock. Requires audit of all filesystems and at least some would need reworking. That's great you're interested, I'm eagerly awaiting your patches. Signed-off-by:
-
Shaohua Li authored
Orphaned page might have fs-private metadata, the page is truncated. As the page hasn't mapping, page migration refuse to migrate the page. It appears the page is only freed in page reclaim and if zone watermark is low, the page is never freed, as a result migration always fail. I thought we could free the metadata so such page can be freed in migration and make migration more reliable. [akpm@linux-foundation.org: go direct to try_to_free_buffers()] Signed-off-by:
Shaohua Li <shaohua.li@intel.com> Acked-by:
Christoph Lameter <clameter@sgi.com> Signed-off-by:
-
Yasunori Goto authored
Though the lower_zone_protection was changed to lowmem_reserve_ratio, the document has been not changed. The lowmem_reserve_ratio seems quite hard to estimate, but there is no guidance. This patch is to change document for it. Signed-off-by:
Yasunori Goto <y-goto@jp.fujitsu.com> Cc: Andrea Arcangeli <andrea@cpushare.com> Signed-off-by:
-
