From cf9610f9116d55c5a66ef9f1faecacabd93a9322 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Mon, 24 Aug 2026 08:46:03 -0700 Subject: Merge tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl Pull pin control updates from Linus Walleij: "Core changes: - Use the non-blocking mux_state_try_select() in the generic MUX pin control back-end - Free pin maps on pinctrl_generic_to_map() failure in the core helpers New hardware pin control: - Qualcomm Maili TLMM SoC, PMG1110 PMIC, and Eliza LPASS LPI TLMM SoC (this is for the low power audio, LPASS = Low Power Audio SubSystem portions) - Upboard support on top of the Intel pin controller - Apple T6030 and T6031 support (just compatible strings) - Samsung Exynos 8855 SoC - Mediatek MT6858 SoC - Rockchip RK3308B and RV1106 SoCs - Airoha EN7523 and AN7563 SoCs Improvements: - Qualcomm TLMM GPIOs are unconditionally marked as wakeup capable - Qualcomm improvements on top of the Qualcomm PDC (power domain controller) irqchip improvements from tglx:s tree - Qualcomm IPQ806x and IPQ9650 non-urgent pin grop fixups - The NPCM8xx driver has been put into shape fixing many pin and group definitions - Some non-urgent Tegra 264 pin assignments are fixed up - Some non-urgent fixups to Airoha AN7581 and AN7583 registers and pin assignments, missing features etc" * tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl: (130 commits) dt-bindings: pinctrl: Convert TI DA850 pupd to DT schema pinctrl: meson: sync some modify from A4 pinctrl: meson: a4: Add input enable pin configuration pinctrl: realtek: rtd1625: remove unused group name spdif_sel pinctrl: realtek: rtd1625: fix base_bit for VE4 GPIO 13 dt-bindings: pinctrl: microchip,pic32mzda-pinctrl: Convert to DT schema Revert "Merge branch 'ib-rsk7204' into devel" pinctrl: rockchip: Add RV1106 pinctrl support dt-bindings: pinctrl: rockchip: Add RV1106 compatible pinctrl: rockchip: Decode drive strength in the get function pinctrl: fix PINCTRL_GENERIC_MUX not always being selectable pinctrl: airoha: add support of an7563 SoC dt-bindings: pinctrl: airoha: add support of an7563 pin controller pinctrl: airoha: try to find chip scu node by phandle first pinctrl: airoha: add support of en7523 SoC dt-bindings: pinctrl: airoha: add support of en7523 pin controller pinctrl: airoha: an7583: add support for olt pinmux pinctrl: airoha: an7583: add support for pon_alt pinmux pinctrl: airoha: an7583: add support for npu_uart pinmux dt-bindings: pinctrl: airoha: an7583: add missed features ... --- Documentation/filesystems/ext4/bigalloc.rst | 34 +++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) create mode 100644 Documentation/filesystems/ext4/bigalloc.rst (limited to 'Documentation/filesystems/ext4/bigalloc.rst') diff --git a/Documentation/filesystems/ext4/bigalloc.rst b/Documentation/filesystems/ext4/bigalloc.rst new file mode 100644 index 000000000..976a180b2 --- /dev/null +++ b/Documentation/filesystems/ext4/bigalloc.rst @@ -0,0 +1,34 @@ +.. SPDX-License-Identifier: GPL-2.0 + +Bigalloc +-------- + +At the moment, the default size of a block is 4KiB, which is a commonly +supported page size on most MMU-capable hardware. This is fortunate, as +ext4 code is not prepared to handle the case where the block size +exceeds the page size. However, for a filesystem of mostly huge files, +it is desirable to be able to allocate disk blocks in units of multiple +blocks to reduce both fragmentation and metadata overhead. The +bigalloc feature provides exactly this ability. + +The bigalloc feature (EXT4_FEATURE_RO_COMPAT_BIGALLOC) changes ext4 to +use clustered allocation, so that each bit in the ext4 block allocation +bitmap addresses a power of two number of blocks. For example, if the +file system is mainly going to be storing large files in the 4-32 +megabyte range, it might make sense to set a cluster size of 1 megabyte. +This means that each bit in the block allocation bitmap now addresses +256 4k blocks. This shrinks the total size of the block allocation +bitmaps for a 2T file system from 64 megabytes to 256 kilobytes. It also +means that a block group addresses 32 gigabytes instead of 128 megabytes, +also shrinking the amount of file system overhead for metadata. + +The administrator can set a block cluster size at mkfs time (which is +stored in the s_log_cluster_size field in the superblock); from then +on, the block bitmaps track clusters, not individual blocks. This means +that block groups can be several gigabytes in size (instead of just +128MiB); however, the minimum allocation unit becomes a cluster, not a +block, even for directories. TaoBao had a patchset to extend the “use +units of clusters instead of blocks” to the extent tree, though it is +not clear where those patches went-- they eventually morphed into +“extent tree v2” but that code has not landed as of May 2015. + -- cgit v1.3.1