The patch titled Subject: mm/vmalloc: prevent flushing dirty space over and over has been added to the -mm mm-unstable branch. Its filename is mm-vmalloc-prevent-flushing-dirty-space-over-and-over.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-vmalloc-prevent-flushing-dirty-space-over-and-over.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Subject: mm/vmalloc: prevent flushing dirty space over and over Date: Thu, 25 May 2023 14:57:05 +0200 (CEST) vmap blocks which have active mappings cannot be purged. Allocations which have been freed are accounted for in vmap_block::dirty_min/max, so that they can be detected in _vm_unmap_aliases() as potentially stale TLBs. If there are several invocations of _vm_unmap_aliases() then each of them will flush the dirty range. That's pointless and just increases the probability of full TLB flushes. Avoid that by resetting the flush range after accounting for it. That's safe versus other invocations of _vm_unmap_aliases() because this is all serialized with vmap_purge_lock. Link: https://lkml.kernel.org/r/20230525124504.692056496@xxxxxxxxxxxxx Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Reviewed-by: Baoquan He <bhe@xxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxx> Cc: Lorenzo Stoakes <lstoakes@xxxxxxxxx> Cc: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/vmalloc.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/mm/vmalloc.c~mm-vmalloc-prevent-flushing-dirty-space-over-and-over +++ a/mm/vmalloc.c @@ -2226,7 +2226,7 @@ static void vb_free(unsigned long addr, spin_lock(&vb->lock); - /* Expand dirty range */ + /* Expand the not yet TLB flushed dirty range */ vb->dirty_min = min(vb->dirty_min, offset); vb->dirty_max = max(vb->dirty_max, offset + (1UL << order)); @@ -2264,7 +2264,7 @@ static void _vm_unmap_aliases(unsigned l * space to be flushed. */ if (!purge_fragmented_block(vb, vbq, &purge_list) && - vb->dirty && vb->dirty != VMAP_BBMAP_BITS) { + vb->dirty_max && vb->dirty != VMAP_BBMAP_BITS) { unsigned long va_start = vb->va->va_start; unsigned long s, e; @@ -2274,6 +2274,10 @@ static void _vm_unmap_aliases(unsigned l start = min(s, start); end = max(e, end); + /* Prevent that this is flushed again */ + vb->dirty_min = VMAP_BBMAP_BITS; + vb->dirty_max = 0; + flush = 1; } spin_unlock(&vb->lock); _ Patches currently in -mm which might be from tglx@xxxxxxxxxxxxx are mm-vmalloc-prevent-stale-tlbs-in-fully-utilized-blocks.patch mm-vmalloc-avoid-iterating-over-per-cpu-vmap-blocks-twice.patch mm-vmalloc-prevent-flushing-dirty-space-over-and-over.patch mm-vmalloc-check-free-space-in-vmap_block-lockless.patch mm-vmalloc-add-missing-read-write_once-annotations.patch mm-vmalloc-dont-purge-usable-blocks-unnecessarily.patch