From b9da6f70e07200798b08b620896da4ebdfe10c98 Mon Sep 17 00:00:00 2001 From: Kuan-Wei Chiu Date: Sat, 30 Nov 2024 02:12:22 +0800 Subject: Documentation/core-api: min_heap: add author information As with other documentation files, author information is added to min_heap.rst, providing contact details for any questions regarding the Min Heap API or the document itself. Link: https://lkml.kernel.org/r/20241129181222.646855-5-visitorckw@gmail.com Signed-off-by: Kuan-Wei Chiu Cc: Ching-Chun (Jim) Huang Cc: Geert Uytterhoeven Cc: Jonathan Corbet Signed-off-by: Andrew Morton --- Documentation/core-api/min_heap.rst | 2 ++ 1 file changed, 2 insertions(+) (limited to 'Documentation') diff --git a/Documentation/core-api/min_heap.rst b/Documentation/core-api/min_heap.rst index 0c636c8b7aa5..683bc6d09f00 100644 --- a/Documentation/core-api/min_heap.rst +++ b/Documentation/core-api/min_heap.rst @@ -4,6 +4,8 @@ Min Heap API ============ +:Author: Kuan-Wei Chiu + Introduction ============ -- cgit From 658eb5ab916ddc92f294dbce8e3d449470be9f86 Mon Sep 17 00:00:00 2001 From: Wang Yaxin Date: Tue, 3 Dec 2024 16:48:48 +0800 Subject: delayacct: add delay max to record delay peak Introduce the use cases of delay max, which can help quickly detect potential abnormal delays in the system and record the types and specific details of delay spikes. Problem ======== Delay accounting can track the average delay of processes to show system workload. However, when a process experiences a significant delay, maybe a delay spike, which adversely affects performance, getdelays can only display the average system delay over a period of time. Yet, average delay is unhelpful for diagnosing delay peak. It is not even possible to determine which type of delay has spiked, as this information might be masked by the average delay. Solution ========= the 'delay max' can display delay peak since the system's startup, which can record potential abnormal delays over time, including the type of delay and the maximum delay. This is helpful for quickly identifying crash caused by delay. Use case ========= bash# ./getdelays -d -p 244 print delayacct stats ON PID 244 CPU count real total virtual total delay total delay average delay max 68 192000000 213676651 705643 0.010ms 0.306381ms IO count delay total delay average delay max 0 0 0.000ms 0.000000ms SWAP count delay total delay average delay max 0 0 0.000ms 0.000000ms RECLAIM count delay total delay average delay max 0 0 0.000ms 0.000000ms THRASHING count delay total delay average delay max 0 0 0.000ms 0.000000ms COMPACT count delay total delay average delay max 0 0 0.000ms 0.000000ms WPCOPY count delay total delay average delay max 235 15648284 0.067ms 0.263842ms IRQ count delay total delay average delay max 0 0 0.000ms 0.000000ms [wang.yaxin@zte.com.cn: update docs and fix some spelling errors] Link: https://lkml.kernel.org/r/20241213192700771XKZ8H30OtHSeziGqRVMs0@zte.com.cn Link: https://lkml.kernel.org/r/20241203164848805CS62CQPQWG9GLdQj2_BxS@zte.com.cn Co-developed-by: Wang Yong Signed-off-by: Wang Yong Co-developed-by: xu xin Signed-off-by: xu xin Co-developed-by: Wang Yaxin Signed-off-by: Wang Yaxin Signed-off-by: Kun Jiang Cc: Balbir Singh Cc: David Hildenbrand Cc: Fan Yu Cc: Peilin He Cc: tuqiang Cc: Yang Yang Cc: ye xingchen Cc: Yunkai Zhang Signed-off-by: Andrew Morton --- Documentation/accounting/delay-accounting.rst | 42 +++++++++++++-------------- 1 file changed, 21 insertions(+), 21 deletions(-) (limited to 'Documentation') diff --git a/Documentation/accounting/delay-accounting.rst b/Documentation/accounting/delay-accounting.rst index f61c01fc376e..8a0277428ccf 100644 --- a/Documentation/accounting/delay-accounting.rst +++ b/Documentation/accounting/delay-accounting.rst @@ -100,29 +100,29 @@ Get delays, since system boot, for pid 10:: # ./getdelays -d -p 10 (output similar to next case) -Get sum of delays, since system boot, for all pids with tgid 5:: +Get sum and peak of delays, since system boot, for all pids with tgid 242:: - # ./getdelays -d -t 5 + bash-4.4# ./getdelays -d -t 242 print delayacct stats ON - TGID 5 - - - CPU count real total virtual total delay total delay average - 8 7000000 6872122 3382277 0.423ms - IO count delay total delay average - 0 0 0.000ms - SWAP count delay total delay average - 0 0 0.000ms - RECLAIM count delay total delay average - 0 0 0.000ms - THRASHING count delay total delay average - 0 0 0.000ms - COMPACT count delay total delay average - 0 0 0.000ms - WPCOPY count delay total delay average - 0 0 0.000ms - IRQ count delay total delay average - 0 0 0.000ms + TGID 242 + + + CPU count real total virtual total delay total delay average delay max + 239 296000000 307724885 1127792 0.005ms 0.238382ms + IO count delay total delay average delay max + 0 0 0.000ms 0.000000ms + SWAP count delay total delay average delay max + 0 0 0.000ms 0.000000ms + RECLAIM count delay total delay average delay max + 0 0 0.000ms 0.000000ms + THRASHING count delay total delay average delay max + 0 0 0.000ms 0.000000ms + COMPACT count delay total delay average delay max + 0 0 0.000ms 0.000000ms + WPCOPY count delay total delay average delay max + 230 19100476 0.083ms 0.383822ms + IRQ count delay total delay average delay max + 0 0 0.000ms 0.000000ms Get IO accounting for pid 1, it works only with -p:: -- cgit From eb7a18ebd6c72c11494215da603474099b4455af Mon Sep 17 00:00:00 2001 From: Tamir Duberstein Date: Tue, 5 Nov 2024 08:03:42 -0400 Subject: XArray: minor documentation improvements - Replace "they" with "you" where "you" is used in the preceding sentence fragment. - Mention `xa_erase` in discussion of multi-index entries. Split this into a separate sentence. - Add "call" parentheses on "xa_store" for consistency and linkification. - Add caveat that `xa_store` and `xa_erase` are not equivalent in the presence of `XA_FLAGS_ALLOC`. Link: https://lkml.kernel.org/r/20241105-xarray-documentation-v5-1-8e1702321b41@gmail.com Signed-off-by: Tamir Duberstein Acked-by: Randy Dunlap Reviewed-by: Bagas Sanjaya Cc: Jonathan Corbet Cc: Matthew Wilcox Signed-off-by: Andrew Morton --- Documentation/core-api/xarray.rst | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-) (limited to 'Documentation') diff --git a/Documentation/core-api/xarray.rst b/Documentation/core-api/xarray.rst index 77e0ece2b1d6..f6a3eef4fe7f 100644 --- a/Documentation/core-api/xarray.rst +++ b/Documentation/core-api/xarray.rst @@ -42,8 +42,8 @@ call xa_tag_pointer() to create an entry with a tag, xa_untag_pointer() to turn a tagged entry back into an untagged pointer and xa_pointer_tag() to retrieve the tag of an entry. Tagged pointers use the same bits that are used to distinguish value entries from normal pointers, so you must -decide whether they want to store value entries or tagged pointers in -any particular XArray. +decide whether you want to store value entries or tagged pointers in any +particular XArray. The XArray does not support storing IS_ERR() pointers as some conflict with value entries or internal entries. @@ -52,8 +52,9 @@ An unusual feature of the XArray is the ability to create entries which occupy a range of indices. Once stored to, looking up any index in the range will return the same entry as looking up any other index in the range. Storing to any index will store to all of them. Multi-index -entries can be explicitly split into smaller entries, or storing ``NULL`` -into any entry will cause the XArray to forget about the range. +entries can be explicitly split into smaller entries. Unsetting (using +xa_erase() or xa_store() with ``NULL``) any entry will cause the XArray +to forget about the range. Normal API ========== @@ -63,13 +64,14 @@ for statically allocated XArrays or xa_init() for dynamically allocated ones. A freshly-initialised XArray contains a ``NULL`` pointer at every index. -You can then set entries using xa_store() and get entries -using xa_load(). xa_store will overwrite any entry with the -new entry and return the previous entry stored at that index. You can -use xa_erase() instead of calling xa_store() with a -``NULL`` entry. There is no difference between an entry that has never -been stored to, one that has been erased and one that has most recently -had ``NULL`` stored to it. +You can then set entries using xa_store() and get entries using +xa_load(). xa_store() will overwrite any entry with the new entry and +return the previous entry stored at that index. You can unset entries +using xa_erase() or by setting the entry to ``NULL`` using xa_store(). +There is no difference between an entry that has never been stored to +and one that has been erased with xa_erase(); an entry that has most +recently had ``NULL`` stored to it is also equivalent except if the +XArray was initialized with ``XA_FLAGS_ALLOC``. You can conditionally replace an entry at an index by using xa_cmpxchg(). Like cmpxchg(), it will only succeed if -- cgit From f65c64f311ee2f1ddc1eb395ed8b20e6b9d14e85 Mon Sep 17 00:00:00 2001 From: Wang Yaxin Date: Fri, 20 Dec 2024 17:31:05 +0800 Subject: delayacct: add delay min to record delay peak Delay accounting can now calculate the average delay of processes, detect the overall system load, and also record the 'delay max' to identify potential abnormal delays. However, 'delay min' can help us identify another useful delay peak. By comparing the difference between 'delay max' and 'delay min', we can understand the optimization space for latency, providing a reference for the optimization of latency performance. Use case ========= bash-4.4# ./getdelays -d -t 242 print delayacct stats ON TGID 242 CPU count real total virtual total delay total delay average delay max delay min 39 156000000 156576579 2111069 0.054ms 0.212296ms 0.031307ms IO count delay total delay average delay max delay min 0 0 0.000ms 0.000000ms 0.000000ms SWAP count delay total delay average delay max delay min 0 0 0.000ms 0.000000ms 0.000000ms RECLAIM count delay total delay average delay max delay min 0 0 0.000ms 0.000000ms 0.000000ms THRASHING count delay total delay average delay max delay min 0 0 0.000ms 0.000000ms 0.000000ms COMPACT count delay total delay average delay max delay min 0 0 0.000ms 0.000000ms 0.000000ms WPCOPY count delay total delay average delay max delay min 156 11215873 0.072ms 0.207403ms 0.033913ms IRQ count delay total delay average delay max delay min 0 0 0.000ms 0.000000ms 0.000000ms Link: https://lkml.kernel.org/r/20241220173105906EOdsPhzjMLYNJJBqgz1ga@zte.com.cn Co-developed-by: Wang Yong Signed-off-by: Wang Yong Co-developed-by: xu xin Signed-off-by: xu xin Signed-off-by: Wang Yaxin Co-developed-by: Kun Jiang Signed-off-by: Kun Jiang Cc: Balbir Singh Cc: David Hildenbrand Cc: Fan Yu Cc: Peilin He Cc: tuqiang Cc: ye xingchen Cc: Yunkai Zhang Signed-off-by: Andrew Morton --- Documentation/accounting/delay-accounting.rst | 32 +++++++++++++-------------- 1 file changed, 16 insertions(+), 16 deletions(-) (limited to 'Documentation') diff --git a/Documentation/accounting/delay-accounting.rst b/Documentation/accounting/delay-accounting.rst index 8a0277428ccf..210c194d4a7b 100644 --- a/Documentation/accounting/delay-accounting.rst +++ b/Documentation/accounting/delay-accounting.rst @@ -107,22 +107,22 @@ Get sum and peak of delays, since system boot, for all pids with tgid 242:: TGID 242 - CPU count real total virtual total delay total delay average delay max - 239 296000000 307724885 1127792 0.005ms 0.238382ms - IO count delay total delay average delay max - 0 0 0.000ms 0.000000ms - SWAP count delay total delay average delay max - 0 0 0.000ms 0.000000ms - RECLAIM count delay total delay average delay max - 0 0 0.000ms 0.000000ms - THRASHING count delay total delay average delay max - 0 0 0.000ms 0.000000ms - COMPACT count delay total delay average delay max - 0 0 0.000ms 0.000000ms - WPCOPY count delay total delay average delay max - 230 19100476 0.083ms 0.383822ms - IRQ count delay total delay average delay max - 0 0 0.000ms 0.000000ms + CPU count real total virtual total delay total delay average delay max delay min + 39 156000000 156576579 2111069 0.054ms 0.212296ms 0.031307ms + IO count delay total delay average delay max delay min + 0 0 0.000ms 0.000000ms 0.000000ms + SWAP count delay total delay average delay max delay min + 0 0 0.000ms 0.000000ms 0.000000ms + RECLAIM count delay total delay average delay max delay min + 0 0 0.000ms 0.000000ms 0.000000ms + THRASHING count delay total delay average delay max delay min + 0 0 0.000ms 0.000000ms 0.000000ms + COMPACT count delay total delay average delay max delay min + 0 0 0.000ms 0.000000ms 0.000000ms + WPCOPY count delay total delay average delay max delay min + 156 11215873 0.072ms 0.207403ms 0.033913ms + IRQ count delay total delay average delay max delay min + 0 0 0.000ms 0.000000ms 0.000000ms Get IO accounting for pid 1, it works only with -p:: -- cgit From f2cad9850ede417d81aaf30644f50767993bbc0e Mon Sep 17 00:00:00 2001 From: Phillip Lougher Date: Sun, 29 Dec 2024 23:37:51 +0000 Subject: Documentation: update the Squashfs filesystem documentation This patch updates the following which are out of date. - Zstd has been added to the compression algorithms supported. - The filesystem mailing list (for the kernel code) is changed to linux-fsdevel rather than the now very little used Sourceforge mailing list. - The Squashfs website has been changed to the Squashfs-tools github repository. - The fact that Squashfs-tools is likely packaged by the linux distribution is mentioned. Link: https://lkml.kernel.org/r/20241229233752.54481-4-phillip@squashfs.org.uk Signed-off-by: Phillip Lougher Signed-off-by: Andrew Morton --- Documentation/filesystems/squashfs.rst | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) (limited to 'Documentation') diff --git a/Documentation/filesystems/squashfs.rst b/Documentation/filesystems/squashfs.rst index 4af8d6207509..45653b3228f9 100644 --- a/Documentation/filesystems/squashfs.rst +++ b/Documentation/filesystems/squashfs.rst @@ -6,7 +6,7 @@ Squashfs 4.0 Filesystem Squashfs is a compressed read-only filesystem for Linux. -It uses zlib, lz4, lzo, or xz compression to compress files, inodes and +It uses zlib, lz4, lzo, xz or zstd compression to compress files, inodes and directories. Inodes in the system are very small and all blocks are packed to minimise data overhead. Block sizes greater than 4K are supported up to a maximum of 1Mbytes (default block size 128K). @@ -16,8 +16,8 @@ use (i.e. in cases where a .tar.gz file may be used), and in constrained block device/memory systems (e.g. embedded systems) where low overhead is needed. -Mailing list: squashfs-devel@lists.sourceforge.net -Web site: www.squashfs.org +Mailing list (kernel code): linux-fsdevel@vger.kernel.org +Web site: github.com/plougher/squashfs-tools 1. Filesystem Features ---------------------- @@ -58,11 +58,9 @@ inodes have different sizes). As squashfs is a read-only filesystem, the mksquashfs program must be used to create populated squashfs filesystems. This and other squashfs utilities -can be obtained from http://www.squashfs.org. Usage instructions can be -obtained from this site also. - -The squashfs-tools development tree is now located on kernel.org - git://git.kernel.org/pub/scm/fs/squashfs/squashfs-tools.git +are very likely packaged by your linux distribution (called squashfs-tools). +The source code can be obtained from github.com/plougher/squashfs-tools. +Usage instructions can also be obtained from this site. 2.1 Mount options ----------------- -- cgit